Senior Welding Inspector Guide Book

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(3) SENIOR WELDING INSPECTION (WIS 10) ~... 'I. ) ,/. Y. TWI. VOl. WORLD CENfRE FOR MATERIALS JOINING TECHNOLOGY. Copyright o 2002, TWI Limited. Training & Examination Services. Granta Park, Great Abington. Cambridge, CB 1 6AL, UK.

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(5) SENIOR WELDING INSPECTION (WlS 10). ) j. ,,. Section. Title. 1). Terms & Definitions. 2). Duties & Responsibilities. 2a). Duties of a Senior 'Welding Inspector. 2b). QA/QC. 3). Welding Imperfections. 4). Mechanical Testing. 5). Welding Procedures/Welder approval. 6). Materials Inspection. 7). Codes and Standards. 8). Welding Symbols on Drawings. 9). Introduction to 'Welding Processes. 0). Manual Metal Arc Welding. 11). Tungsten Inert Gas Welding. 12). Metal Inert/Active Gas Welding. 13). Submerged Arc Welding. 14). Welding Consumables. 15). Non Destructive Testing. 16). Weld Repairs. 17). Residual Stress & Distortion. 18). Heat Treatment of Steels. 19). Oxy-Fuel Gas Welding & Cutting. 20). Arc Cutting Processes. 21). Welding Safety. 22). Weldability of steels. 23). Fracture Assessments.

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(7) TWI. VOl.. THE WELDING INSTITUTE. Senior welding Inspection General Theory (situations) Paper SWI·Q~S1 1. You are an SWI who has taken over from an SWI who has been on site for a few months. It becomes obvious that there is a complete lack of moral amongst your inspectors but they do not approach you to discuss any grievance. What would be your approach to the situation?. 2. You are an SWI responsible for a team of welding inspectors who have been on~site for two months. A welding inspector who has been on site for only one week informs you that the contractor has approached him with an offer of money in return for ). "turning a blind eye" when certain welding work is being performed. Discuss your . course of action.. 3. You are the SWI on a pipeline project. The radiographic interpreter informs you that he believes that the same weld has been radiographed with different weld numbers on a number of occasions and the radiographs have been submitted. 'J\/hat action do you take?. 4. You are the SWI working on behalf of a client on a project to build an offshore platform. You discover that one of the welding inspectors, supplied from a different agency, who has been on site for one week, does not hold a valid welding inspector approval. State the actions that you would take.. C'. You visit a fabrication company as an SWI on behalf of a client and you discover in a welders electrode quiver a number of incorrect electrodes among the correct ones which are very different to' those specified for the item being welded. The welder states that he only uses the correct electrodes. State your course of action. 6. Question number 6 is a compulsory question for the SWI examination. You are required to visit a site on which your welding inspectors have been involved.. The work concerns the inspection of a welded structure to a specified application. standard and is now completed and ready for final approval.. What questions do you ask, what documents do you review and what inspections do. you require before submitting your inspection report to the authorities concerned?. WIS LO MSR/SWI-Q-S l issue 2 Date: 28/05/03. lof4.

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(10) TWI. 1ll01.. _. THE WELDING INSTITUTE. Terms and Definitions:. A Weld:. A Joint:. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.1. Rev 09-09-02.

(11) TWI. 1ll01.. _. THE WELDING II\JSTITUTE. Types of common welds:. Welds.. -,. Welds.. ,;,a~tJI~'t~'~ .'?~". ~. -. -~,,-,.~, - .... :.,.:. Welds.. Welds.. Welds.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.2. Rev 09-09-02.

(12) TWI. 1ll01._ _- -. _. THE WELDII'JG INSTITUTE. Welded Closed Corner Joints:. ••. (. .1. A. Welded Closed Corner Joint.. A. Welded Closed Corner Joint.. A. Welded Closed Corner Joint.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.10. Rev 09-09-02.

(13) TWI. V!lOI._----. _. THE WELDII\JG INSTITUTE. Welded Open Corner Joints:. ( ) A. Welded OQen Corner Joint.. A. Welded O.l!en Corner Joint.. A. Welded OQen Corner Joint.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.11. (. Rev 09-09-02.

(14) TWI VIJI.. _. THE WELDING INSTITUTE. Terms of a Butt Welded Butt Joint:. Weld zone. = Weld Metal + HAZ. (~). \. Root. .,. A, B, C & 0. Welding Inspection - Duties of a Welding Inspector Copyright © 2002 TWI Ltd. =Weld Toes. 1.12 .. Rev 09-09-02.

(15) TWI VOI.. _. THE WELDING INSTITUTE. Terms of a Fillet Welded T Joint:. \ In visual inspection it is usually the leg length that is used to size fillet welded joints. It. is possible to find the design throat thickness easily by multiplying the leg length by 0.7. The excess weld metal can be measured by taking the measurable throat reading, then by. deducting the design throat thickness calculated above.. Example:. If the leg length of a convex fillet weld is measured at 10 mm, then the design throat. thickness. >. 10 x 0.7 which is 7mm.. If the actual throat thickness is 8.5 mm then the excess weld metal is calculated as:. 8.5 -7mm = 1.5mm excess weld metal.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.13. Rev 09-09-02. .'.

(16) TWI. V[JI.. _. THE WELDING INSTITUTE. 'Nominal' and 'Effective' Design Throat Thickness:. Same leg length. --.I. I I I I. ~ I I. --.I. I. I. I I I I I. I I I. I I I. (. ). ~ I I I. "s" = 'Effective' design throat thickness. "a" = 'Nominal' design throat thickness. (deep penetration fillets). When using deep penetrating processes with high current density it is possible to create deeper throat dimensions. This may be used in design calculations to carry stresses and is a big advantage by reducing overall weight of welds in a large welded structure. Deep throat fillet welds are possible when using high penetration (High current density) processes, such as FCA \V & SAW. This throat notation "a" or "s" is used in BSEn 22553 for weld symbols on drawings throughout Europe.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.14. Rev 09-09-02.

(17) TWI V[J[JI.. _. THE WELDING INSTITUTE. Fillet Weld Profiles:. (. /. (. In joints that are to be dynamically loaded with cyclic stresses, concave fillet weld are preferred to minimise any stress concentrations or sites for fatigue crack initiation. In critical applications it may be a requirement of the welding procedure that the toes are lightly ground, or even flushed i~ with a TIG run, to remove any notches that are present.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TW[ Ltd. 1.15. Rev 09-09-02. ).

(18) TWI. I[JOI.. _. THE WELDING II\JSTITUTE. Effect of a Poor Toe Blend:. A very poor weld toe blend angle 6mm. ! _. <~~1~~~~~1~t~~~t'~~lj. An improved weld toe blend angle 3mm ,~~~~atr~%~~~;r1.~t~:tl~~~:!i.;·~. Generally speaking, most specifications tend to quote that "The weld toes shall blend smoothly" This statement can cause problems as it is not a quantitative statement, and therefore very much open to individual interpretation. To help in your assessment of the acceptance of the toe blend it should be remembered that the higher the angle at the toe then the higher is the concentration of stresses, which between 20 0 - 30 0 is almost at a ratio of2:1 A poor toe blend will be present when the excess weld metal height is excessive, however it may be possible that the height is within the given limits, yet the toe blend is not smooth, and is therefore a defect, and unacceptable.. It should be remembered, that effect.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. a poor toe blend in the. l.t6. root of the weld has the same. Rev 09-09-02.

(19) TWI V!l!ll.. _. THE WELDING INSTITUTE. Summary of "Veld and Joint Terms and Definitions:. A Weld:. A Union of materials, produced by heat ancIJor pressure.. A Joint:. A Configuration of members.. A weld preparation:. Preparing a joint to allow access & fusion through the joint. faces.. Types of weld:. Butt. Fillet. Spot. Seam. Edge.. Types of joint:. Butt. T. Lap. Open Comer. Closed Comer.. Types of preparation:. Bevel's. V's. J's. U's. (Single & Double).. Preparation terms:. Bevel angle. Included angle. Root face. Root gap.. Weldment terms:. Weld face. Weld root. Fusion Zone. Fusion boundary.. HAZ. Weld toes. Weld width.. Weld sizing (Butts):. Design throat thickness. Actual throat thickness. Excess. weld metal. Excess root penetration.. Weld sizing (Fillets):. Design throat thickness. Actual throat thickness. Excess weld metal. Leg length.. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.17. Rev 09-09-02. (.

(20) TWI. 1ll01.. _. THE WELDING INSTITUTE. Welding positions in accordance with BS EN 287. -. ~. ~. ~ ~. #. {«(((((. «c«: «« (l«. ~. PA. PC. Flat. Horizontal vertical. .v -:. ~,. ...;;,.". ..-.. ,..... ~ ,-.. 0"". ,:,". ........ ~). ". -=. ---. --~l. -. -. -. ---. ,<::-". .•~~..<\\. §j ........ -- -. ......... PE Overhead. -...J. .......... --. .......". ......... ..-. ......... PF Vertical upwards. PG Vertical downwards. a) Butt welds. :'1""\"\. \,"\ ),\\\. x PA. \. Flat. ..:::,.;.(.:,. PB. Horizontal vertical. •.:.<';\.~\ . .. .'. ........ ~. ~. ,... ~t PO Horizontal overhead. ~. ~. PF Vertical upwards. PG Vertical downwards. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. '-' ...., ..... 1.18. Rev 09-09-02.

(21) TWI. V!l!ll.. _. THE WELDII\JG II\JSTITUTE. Welding positions in accordance with BS EN 287 continued. PA. Pipe: rotating Axis: horizontal Weld: flat. PG. Pipe: fixed Axis: horizontal Weld: vertical downwards. ). 45° Pipe: fixed PFAxis: horizontal Weld: vertical upwards. PC. Pipe; fixed Axis: vertical Weld: horizontal vertical. H·L045. Pipe: fixed Axis: inclined Weld: upward. al Butt welds. PB. Pipe: rotating Axis: horizontal Weld: horizontal vertical. PF. PB. PG. Pipe: fixed Axis: horizontal Weld: vertical downwards. PD. Pipe: fixed Axis: vertical Weld: horizontal overhead. Pipe: fixed Axis: horizontal Weld: vertical upwards. Pipe: fixed Axis: vertical Weld: horizontal vertical . b) Fillet welds. Senior Welding Inspection - Terms & Definitions Copyright © 2002 TWI Ltd. 1.19. Rev. 09-09-02.

(22) TWI. VOl.. THE WELDING INSTITUTE. Senior Welding Inspection, Steels - WIS 10 Question Paper (MSR-S-SWI-1) Nam e:. . Answer all questions. 1. In accordance with BS 499 what is the weld junction?. a. The area containing HAZ and weld metal. b. The weld metal and parent metal. c. The boundary between the fusion zone and HAZ. d. The part of the weld, which undergoes metallurgical, changes due to heat from welding. 2.. Which of the following are essential factors for lamellar tearing? a. High residual stresses, poor through thickness ductility, existing plate laminations. b. Poor through thickness ductility, fusion face parallel with rolled direction of parent plate, most commonly occurs in butt welds. c. Stress, poor through thickness ductility, fusion face parallel with rolled direction of parent material. d. Tensile stress, deoxidised parent plate, poor through thickness ductility.. ). 3.. The strength of a fillet weld is primary controlled by the: a. Leg length. b. Weld face. c. Throat thickness. d. All of the above.. 4.. Which of the following is not a fusion welding process? a. Thermit welding. b. Electro slag welding. c. Laser welding. d. Friction welding. WIS 10 Qu paper MSR-A-SWI-l issue 3 Date 28/05/03. 1 of 17.

(23) TWI. VOl.. THE WELDING INSTITUTE. Name the fourth weld process crack which has a totally different formation mechanism to HICC, solidification cracking and lamellar tearing: a. Liquiation cracking. b. Re heat cracking. c. Crater cracking. d. Hot tearing. Which of the following will vary the most when varying the arc length using the m.m.a. process? a. Voltage. b. Amperage. c. Polarity. d. Both a and b.. What is another term for suckback? a. Concave root. b. Elongated porosity in the rot area of a weld. c. Lack of root penetration. d. None of the above. Which of the following materials has the poorest weldability? a. Austenitic stainless steel. b. Martensitic stainless steel. c. Carbon manganese steel. d. HSLA steel.. In a fusion weld, which usually has the highest tensile strength? a. Weld metal. b. Parent material. c. Heat affected zone. d. Fusion zone.. WIS LO Qu paper MSR-A-SWI-L issue 3 Date 28/05/03. 2 of 17.

(24) TWI. VOL. THE WELDING INSTITUTE. 10. An undesirable property of aluminium oxide residue is that it: a. Creates problems when welding in position (vertical, horizontal, overhead). b. Requires more heat to melt it when compared with aluminium. c. Creates problems when welding in position (vertical, horizontal, overhead). d. Decreases weld pool fluidity. e. Both a and b.. 11. Which of the following statements is true regarding hydrogen cracking? a. It is a type of hot crack. I. j. b. It most frequently occurs in ductile materials. c. It only occurs in the h.a.z of fusion welds. d. It is the most common type of crack encountered in steel weldments.. 12. Which material is the most susceptible to re heat cracking? a. High carbon steels. b. Killed steels. c. Creep resistant steels. d. Austenitic steels.. ~. I. 13. Three essential factors for producing a fusion weld are; Melting, the removal of surface oxide from the joint surfaces and elimination of atmosphere from the region of the arc. Name the fourth? a. The weld must be free from stress. b. The filler material must match that of the weld. c. The completed joint must at least match the mechanical properties required by the specification. d. An arc for a heat source.. WIS 10 Qu paper MSR-A-SWI-l issue J Date 28/05/03. 3 of 17.

(25) TWI. VOL. THE WELDING INSTITUTE. 14. Which arc welding process/technique is likely to be used to repair localised porosity in a weld? a. MMA, PG position. b. Mechanised arc welding. c. Sub Arc. d. All of the above. e. None of the above.. 15. A welder qualified in the PG position would normally be qualified for welding: a. All diameters of pipe.. ••. b. Welding positions PA, PC, PG, and PF. c. In position PG only. d. All pipe wall thickness. 16. Which ofthe following are considered to be heat affected zone cracks? a. Solidification cracks, lamellar tearing and reheat cracks. b. Reheat cracks, Iiquation cracks and solidification cracks. c. Hydrogen cracks, solidification cracks and liquation cracks. d. Re heat cracks, liquation cracks and hydrogen cracks.. c.. 17. The h.a.z associated with a fusion zone: a. Cannot be avoided. b. Usually has the highest u.t.s value of the weld joint. c. Is desirable to maintain ductility. d. Both a and b. e. All of the above.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 4 of 17.

(26) TWI. VOL. THE WELDING INSTITUTE. 18. What four criteria are necessary to produce h.i.e.e? a. Hydrogen. moisture, martensite and heat. b. Hydrogen, poor weld profiles, a temperature above 200°C and slow cooling. c. A grain structure susceptible to cracking, stress, hydrogen, and a temperature below 200°C. d. Weld defects, pearlite, hydrogen and a temperature above the material being welded. 19. A carbon equivalent of 0.48%: a. Is high for carbon steel and may require a preheat temperature over 100°C. b. Is insignificant for carbon steel and preheat will not be required. c. Is calculated from the heat-input formula. d. Is not a consideration for determining preheating temperatures? 20. A semi-automatic welding process is best described as: a. The welder is responsible for the arc gap and travel speed. b. The welder is responsible for the travel speed only. c. The welding plant controls both travel speed and arc gap but under constant supervision. d. The welding plant controls both travel speed and arc gap, no supervision required. . .. ~1. Which of the following statements is true?. (. \.. a. The core wire of an MMA electrode has a higher melting point than the flux. b. Basic electrodes are preferred when welding is carried out in situations where porosity free welds are specified c. Rutile electrodes always contain a large proportion of iron powder. d. Cellulose electrodes may deposit in excess of 40 ml of hydrogen per 100g of weld metal. 22. Preheat prior to welding: a. Must always be carried put on steels. b. Need not be carried put if post weld heat is to follow? c. Is always carried out using gas flames. d. None of the above. WIS 10 Qu paper MSR-A-SWr-l issue 3 Date 28/05/03. 5 of 17.

(27) TWI. VOL. THE WELDING INSTITUTE. 23. Root concavity may be caused by which of the following: a. Insufficient back purge gas. b. Entrapped gas. c. Slow travel speed. d. Excessive back purge pressure. 24. High phosphorous contents in carbon steels may cause: a. Cold shortness. b. Hot shortness. c. An increase in ductility.. ) j. d. An increase in malleability.. 25. If arc strikes are found on carbon steel (carbon equivalent of 0.5%), what undesirable grain structure may be present? a. Perlite. b. Martensite. c. Bainite. d. All of the above are undesirable grain structures in constructional steels. 26. When considering the heat treatment process of tempering: a. This is achieved by slowly heating the material to a temperature between. 200DC-650 DC and slow cooling in air.. b. This is achieved by heating the material to around 200 DC and soaking for. approximately 10-12 hours and cooling down in air.. c. Very fast cooling from the austenite region. d. All of the above could give a temper. 27. Which element in steel has the greatest effect on hardness? a. Manganese. b. Chromium. c. Carbon. d. Nickel.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 6 of 17.

(28) TWI". VOL. THE WELDING INSTITUTE. 28. Which of the following units is used to express the energy absorbed by a charpy specimen? a. Joules. b. Newton's. c. Mega Pascal's. d. P.s.i.. 29. Which mechanical test(s) can be used to make an assessment of surface breaking defects? \. (. "J. a. Bend test. b. Nick-break test. c. Micro test. d. All of the above.. 30. Which of the following is the odd one out? a. Neon. b. Xenon. c. Argon. d. Nitrogen.. ( .. 11. What does the 70 represent on an E7010 AWS A5.1 classified electrode? a. 70 N/mm2 minimum u.t.s. b. 70 N/mm2 minimum impact strength. c. 70,000 p.s.i. minimum u.t.s. d. 70 p.s.i. minimum yield strength.. 32. If a material has a CE of 0.46: a. Post heat treatment would always be necessary. b. It will probably require preheat prior to welding c. The h.a.z. will be very tough. d. All of the above.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 7 of 17.

(29) TWI. IDOL. THE WELDING INSTITUTE. 33. Assuming no post-heat treatment has been carried out which of the following is normally the hardest part of a multi-pass butt weld made on low alloy steel? a. The cap. b. The root. c. The HAZ of the cap. d. The HAZ of the root.. 34. Which of the following is the correct heat input if the amps are 350, volts 32 and travel speed 310 mm/minute. a. 2.16 kJ/mm. ). b. 0.036 kJ/mm.. _/. c. 2.61 kJ/mm. d. 0.36 kJ/mm.. 35. Assuming that the specification makes no reference to arc strikes, what would you do if you found arc strikes on a fabrication constructed out of high tensile strength material? a. Have the welders re-approved. b. Reject all the areas where the arc strikes occur. c. Have the areas checked for cracking. d. If the specification makes no reference to arc strikes ignore them.. 36. Which of the following may be used for the TIG welding of Nickel and its alloys? a. Lanthanum electrode, DC. -ve. b. Cerium electrode, DC -ve. c. Zirconium electrode AC d. Thorium electrode, DC +ve.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 8 of 17.

(30) TWI. roOI.. THE WELDING INSTITUTE. 37. Which of the following welding processes uses resistive heating to achieve weld metal deposition? a. Flux-core m.a.g. b. Sub-arc. c. Resistive spot welding. d. Electro slag.. 38. What are the possible results of having a lower heat input from the approved. procedure?. a. An increase in hardness, lower yield strength and lack of fusion. b. A reduction in toughness, hydrogen entrapment and an increase in hardness. c. Entrapped hydrogen, an increase in hardness and lack of fusion. d. Entrapped hydrogen, a reduction in carbon content and lack of fusion.. 39. A multi-run MMA butt weld made on low alloy steel consists of 5 passes using a 6 mm diameter electrode, a 12 pass weld made on the same joint using a 4 mm diameter electrode on the same material will: a. Have a lower heat input and a higher degree of grain refinement. b. Have a lower heat input and a coarse grain structure. c. Have a lower heat amount of distortion and a higher degree of grain refinement. d. Have a higher amount of distortion and a lower degree of grain refinement.. (. \. 40. Which of the following heat treatments may be applied to a material to give maximum toughness values: a. Normalising. b. Tempering. c. Annealing. d. Both a and b. e. All of the above.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 9 of 17.

(31) TWI. VOL. THE WELDING INSTITUTE. 41. The main reason for using a back purge when welding 18-8 stainless steel with the TIG welding process is to: a. Control the root penetration. b. Prevent the formation of a dense oxide layer on the root bead. c. Control porosity in the root bead. d. Improve positional welding.. 42. Which of the following would you expect of a martensitic grain structure? a. An increase in toughness and a reduction in hardness. b. An increase in hardness and a reduction in ductility. (. c. An increase in ductility and a reduction in toughness.. ). d. An increase in malleability and an increase in hardness.. 43. Which of the following reduce the chances of arc blow? a. A change from AC current to DC current. b. A change from DC current to AC current. c. A change from DC electrode +ve to DC electrode -ve. d. A change from DC electrode -ve to DC electrode +ve.. 44. When considering the advantages of site radiography over conventional ultrasonic inspection which of the following applies? a. A permanent record produced, good for the detection of defects that do not have significant depth in relation to the x-ray beam and defect identification. b. A permanent record produced, defect identification and not so reliant upon operator skill for the detection of any possible defects present. c. A permanent record produced, good for the detection of all surface and sub surface defects and assessing the through thickness depths of most defects. d. No controlled areas required on site, a permanent record produced and good for assessing the extent of pipe wall thickness reductions due to internal corrosion.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 10 of 17. (. ).

(32) TWI. VOl.. THE WELDING INSTITUTE. 49. What paper work is required prior to witnessing of mechanical testing? a. Calibration certificates for each test piece. b. Calibration certificates for the test equipment being used. c. Test operator's qualifications. d. Test procedure qualification certificates e. All of the above.. 50. When using basic coated electrodes, to keep the weld metals hydrogen content down to scale C:. j. a. The electrodes must be used indoors, can only be used in a down hand position and the use of pre-heat. b. The electrodes must be used in a dry condition but never baked, the use of pre heat and used with a short arc gap. c. The electrodes must be used with a short arc gap, the use of a minimum weave and used in a baked condition. d. The electrodes must be pre-baked, used on DC electrode +ve and with a. minimum arc gap.. 51. The primary function of the addition of silicon to an MMA welding electrode covering would be to act as: a. A deoxidiser. . b. An arc stabiliser.. (.. c. A slag-forming agent.. -,. d. A shielding gas forming agent.. 52. Which of the following is most likely to be an essential variable for a welder's. qualification?. a. A change from an electrode to BS EN E46 3 B to an electrode to AWS A5.1 E7018. b. A change of pipe wall thickness by at least 25 mm. c. A change in pre-heat from 50° to 100°C. d. All of the above.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05103. 12 of 17.

(33) TWI. VOL. THE WELDING INSTITUTE. 53. Which of the following are applicable to DC electrode -ve when using the rn.rn.a. welding process? a. A broad heat affected zone, a reduction in hardness and a narrow deep fast freezing weld pool. b. A narrow heat affected zone, fast freezing weld pool and good penetration properties. c. Mechanically and metallurgical no difference to DC electrode -ve. d. Wide shallow weld pools, flat weld profiles and lower hardness values. 54. When welding rimming steel with autogenous TI8 process which of the following problems may occur?. (-). a. Porosity. b. Lack of fusion. c. Tungsten inclusions. d. Excessive root penetration.. 55. In MMA welding process, which of the following flux types gives the deepest penetration? a. Rutile b. Acidic. c. Cellulosic. d. Basic (low hydrogen). (. 56. Basic coated electrodes have which of the following properties? a. High mechanical properties may be used to produce welds of high deposition rates and are designed to produce welds of low hydrogen content. b. Friable slag, high mechanical properties and are designed to produce welds of low hydrogen content. c. Ease of use, good stop/starting properties and high mechanical properties. d. High mechanical strength, friable slag and may produce welds of low hydrogen content.. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/05/03. 13 of 17. ).

(34) TWI. VOl.. THE WELDING INSTITUTE. 57. Which of the following is the most likely appearance of lack of root fusion on a. radiograph taken of a single-vee butt weld in C/C Mn steel?. a. A dark straight line with a light root. b. A dark straight line with a darker root. c. A dark root with straight edges. d. A dark uneven line with a light root.. 58. Which of the following methods would be the best suited for the detection of lamellar tearing in a fabrication? a. Radiography.. CJ. b. Ultrasonic testing c. Dye penetrant testing d. Magnetic particle testing. 59. Which of the following are applicable to fatigue cracking? a. A rough randomly torn fracture surface, an initiation point and beach mark(s). b. A smooth fracture surface, an initiation point and beach mark(s). c. Beach mark(s), step like appearance and a secondary mode of failure. d. All of the above.. (. 60. Which of the following weld symbols in accordance with BS EN 22553 represents a fillet weld made on the other side?. a.. ~ ___LJ _. b.. c.. d.. :?= ~. WIS 10 Qu paper MSR-A-SWI-l issue 3 Date 28/05/03. 14 of 17.

(35) TWI. VOl.. THE WELDII\JG INSTITUTE. 61. A back step welding technique is most often used to? a. Reduce welding time. b. Increases weld toughness. c. Reduce the chances of undercut. d. Reduce distortion.. 62. E6013 electrode would most probably-be used for the welding of? a. Low-pressure pipe work. b. High pressure pipe work. c. Vertical down welding on pressure vessels.. (). d. Where welds of low hydrogen content are specified.. 63. The need for pre heat for steel will be increased by? a. Lower carbon contents. b. A reduction in material thickness. c. Faster welding speeds. d. The use of a larger dlarneter-weldlng electrode.. 64. From the following ·electrode coding E50 4 B 160 20 H5, the compulsory part is:. 65. When considering radiography using x-ray, which of the following techniques is most likely to be used for a pipe-to-pipe weld (circumferential), 610 mm diameter pipe with no internal access? a. SWSI. b. DWSI. c. DWDI. d. SWSI (panoramic).. WIS 10 Qu paper MSR-A-SWI-1 issue 3 Date 28/U5103. 15 of 17.

(36) TWI. VOl.. THE WELDING INSTITUTE. 66. What happens to the mechanical properties of carbon steel if its carbon content is Increased from 0.12% to 0.5%? a. The material becomes softer. b. Malleability increases. c. The tensile strength increases. d. Ductility increases. e. None of the above.. 67. One purpose of microscopic examination of a welded joint is to establish? ( _). a. The strength of the weld. b. The number of alloying elements presents. c. The grain size. d. The overall weld toughness. e. All of the above.. 68. Which of the following tests would you not expect to be carried out on a welder qualification test? a. Radiography. b. Tensile test. c. Marco.. \. d. Bend test.. 69. Which of the following can be welded by DC output when using the TIG welding process? a. Copper. b. Commercial pure aluminium. c. Siltcon-alurniniurn. d. Magnesium alloys. e. None of the above.. WIS 10 Qu paper MSR-A-SWI~1 issue 3 Date 28/05/03. 16 of 17.

(37) TWI. VOl.. THE WELDING INSTITUTE. 70. Which of the following defects is most likely to be missed by visual inspection. a. Cap undercut. b. Centreline crack. c. Lack of interun fusion. d. Lack of root fusion.. (. .... \.. WIS 10 Qu paper MSR-A-SWI-l issue 3 Date 28/05/03. 17 of 17.

(38) TWI. VOI._ _- - - - - . THE WELDING INSTITUTE. Questions. Terms and Definitions. au 1.. Sketch a single-U butt joint and indicate the following: b: root face. a: root gap. c: included angle. d: root radius. ~~. au 2.. Sketch a tee joint, fillet welded and indicate the following a: leg length. b: throat thickness. d: weld toes. c: root. au 3.. Sketch five joint types in addition to a butt weld.. aU4.. Identify the following butt weld features.. ~. A: B:. F E. ~I. I~. c:. .C. D:. E:. s-r. \. \:. :/~. ". . '\.. Senior Welding Inspection - QU Terms & Definitions Sec 1 Copyright © 2003 TWI Ltd. I. F:.

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(41) TWI VflIJI.. _. THE WELDING INSTITUTE. Duties of a Welding Inspector: It is the duty of a welding inspector and Senior welding inspector to ensure that all operations concerning welding are carried out in strict accordance with written, or agreed practices, or specifications. This will include monitoring or checking a number of operations including:. Before welding: Safety: Ensure that all operations are carried out in complete compliance with local, company, or National safety legislation (i.e. permits to work are in place). Documentation: Specification. (Year and revision) Drawings. (Correct revisions) Welding procedure specifications and welder approvals. Calibration certification. (Welding equipment/ancillaries and all inspection instruments) Material and consumable certification Welding Process and ancillaries: Welding equipment and all related ancillaries. (Cables, regulators, ovens, quivers etc.) Incoming Consumables: All pipe/plate and welding consumables for Size, Type and Condition. Marking out preparation & set up: Correct method of cutting weld preparations. (Pre-Heat for thermal cutting if applicable) Correct preparation. (Relevant bevel angles, root face, root gap, root radius, land, etc.) Correct pre-welding distortion control. (Tacking, bridging, jigs, line up clamps, etc.). Senior Welding Inspection - Duties ofa Welding Inspector 2.1 Copyright © 2002 TWI Ltd. Rev 09-09-02. ).

(42) TWI V!7I.. _. THE WELDING INSTITUTE. Correct pre heat applied prior to tack welding.. All tack welding to be monitored and inspected. During welding: Pre-heat values. (Heating method, location and control). In-process distortion control. (Sequence or balanced welding). Consumable control. (Specification, size, condition, and any special treatments). Process type and all related variable parameters. (Voltage, amperage, travel speed). (. ). <:>. Purging gases. (Type, pressure/flow and control method). Welding conditions for root run/hot pass and all subsequent run, and inter-run cleaning.. Minimum, or maximum inter-pass temperature. (Temperature and controlling method). Compliance with all other variables stated on the approved welding procedure.. After welding: Visual inspection of the welded joint. (Including dimensional aspects). NDT requirements. (Method and qualification of operator, and execution). Identify repairs from assessment of visual or NDT reports. (Refer to repairs below). (. Post weld heat treatment (PWHT) (Heating method and temperature recording system). Re-inspect with visuallNDT after PWHT. (If applicable). Hydrostatic test procedures. (For pipelines or pressure vessels). Repairs: Excavation procedure. (Approval and execution). Approval of the NDT procedures (For assessment of complete defect removal). Repair procedure. (Approval of're-welding procedures and welder approval). Execution of approved re-welding procedure. (Compliance with repair procedure). Senior Welding Inspection - Duties ora Welding Inspector 2.2 Copyright © 2002 TW [ Ltd. Rev 09-09-02.

(43) TWI. 11001.. _. THE WELDING INSTITUTE. Re-inspect the repair area with visual inspection and approved NDT method. Submission of inspection reports, and all related documents to the Q/C department.. Responsibilities of a Welding Inspector:. '----_1-+ To Observe. ). To observe all relevant actions related to weld quality throughout production. This will include a final visual inspection of the weld area.. To Record ( To record, or log all production inspection points relevant to quality, including a final map and report sheet showing all identified welding imperfections.. To Compare. 1-+. ' - - - - - - - . To compare all reported inforrriation with the acceptance levels/criteria and clauses within the applied application standard. Senior Welding Inspection - Duties of a Welding Inspector 2.3 Copyright © 2002 TWI Ltd. Rev 09-09-02.

(44) TWI. roOI.. _. THE WELDING INSTITUTE. Submit a final inspection report of your findings to the QA/QC department for analysis and any remedial actions.. '>'. \, ~. I. Senior Welding Inspection - Duties of a Welding Inspector 2.4 Copyright © 2002 TWI Ltd. Rev 09-09-02.

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(46) TWI V!JOI.. _. THE WELDING INSTITUTE. The duties and responsibilities of a senior welding inspector The fabrication industry has come to accept the need for a detailed inspection of welding for a combination of two reasons:. 1. The quality of a manually made weld id critically dependent on the skill of the welder. 2. Much fabrication is made under sub-contracting conditions.. There has developed, therefore, a system which is quite general, but is more obvious in the fabrication field, of client appointed inspectors who may work independently or alongside the fabricators own inspectors with or sometimes without the full co-operation of the welding supervisors and welders (. \. ",-j. Welding inspection in general sense is the monitoring of the formation of the weld. I.e. materials, equipment, consumables, approvals of staff and procedures, examination of the compilation, i.e. size, excess metal, undercut, surface defects, spatter etc., and the compilation of documents into the fabrication file. Many quality welds are required to be examined by non-destructive testing techniques and operatives with required skills are called in as a required and the senior welding inspector obtains the NDT reports for the fabrication file. The senior welding inspector grade is able to assess and control welding inspection with a wide perspective because of his/her wider qualifications and experience. In addition he/she must have the knowledge of the practice of supervision and to have the necessary personal quality of leadership.. (. It is not possible to be a senior welding inspector without technical knowledge but the quality of leadership is an essential addition. \. It is sometimes said that leadership cannot be taught and there is a lot of truth in this but the ability to lead can be improved by teaching.. Tasks and responsibilities The following list shows the tasks and responsibilities of welding co-ordination personnel, not all the tasks given will necessarily be carried out by the senior welding inspector, the tasks and responsibilities allocated will depend on the contract/project being carried out. Each single activity in the following list may be associated with a number of tasks and responsibilities such as: - specification or preparation; -co-ordination; - control; - inspection, check or witnessing. Where welding co-ordination is carried out by a number of persons, the client will generally nominate the tasks and responsibilities for the appropriate persons. Welding co-ordination is considered to be the responsibility of the manufacturing organisation. For some work activities the co-ordination tasks and responsibilities may be carried out by subcontractors.. Senior Welding Inspection -- Duties SWf Copyright © 2002 TWI Ltd.. 2a.l. Rev 09-09-0~.

(47) TWI VlJOI.. _. THE WELDII\JG INSTITUTE. Welding related activities to be considered 1.. Contract review • Meetings. • Welding capability and associated activities of the manufacturing organisation.. 2.. Design review • Relevant welding standards. • Joint location with relation to the design requirements. • Access for welding, inspection and testing • Weld joint details. • Quality and acceptance requirements for welds.. 3.. Parent material • Weldability of parent material. • Parent material certificates. • Identification of parent material. • Handling and storage of parent materials. • Tractability.. 4.. Consumables • Compatibility • Delivery' conditions. • Identification of consumables. • Storage and handling of consumables.. 5.. (. Subcontractors· • Suitability of any subcontractors.. 6.. Production planning • Suitability of welding procedure specifications (WPS) and welding procedure approval records (WP AR). • Work instructions. • Welding jigs and fixtures. • Suitability and validity ofwelder approvals. • Welding and assembly sequences for the component • Production weld test requirements.. Senior Welding Inspection -Duties SWI Copyright © 2002 TWI Ltd.. 2a.2. Rev 09-09-02. ..

(48) TWI. I[JOI. 7.. 8.. 9.. _. THE WELDING INSTITUTE. Equipment. •. Suitability of welding and associated equipment.. • •. Equipment supplies, identification and handling. Calibration of equipment.. Safety. •. Health and safety requirements.. • •. Suitability of working area. Ventilation, extraction etc.. Welding operations ;.~. (. •. Issue of work permits,. • •. Issue of work instructions,. •. Preparation of production tests.. • •. Assignment and instruction 0 f welders.. • • • • •. Application of tack welding.. ,. -~(. Joint fit up and cleaning.. Welding consumables and auxiliaries.. Application of welding process parameters. Application of any intermediate testing. Application and method of preheating. Application and method of post weld heat treatment. Welding sequences.. 10.. Visual inspection .. • • • • 11.. Weld dimensions. Shape, dimensions and tolerances of the welded components. Joint appearance.. Destructive testing. • 12.. Completeness of welding.. Application and records of destructive testing.. Non-destructive testing. •. Application and records of non-destructive testing.. Senior Welding Inspection - Duties Copyright © 2002 Twl Ltd.. swr. 2a.3. Rev 09-09-02.

(49) TWI VOI. D.. 14.. _. THE WELDING INSTITUTE. \-Veld acceptance. •. Assessment of inspection and test results.. •. Weld repairs.. •. Reassessment of repaired welds.. •. Corrective actions. Documentation •. Preparation and maintenance of the necessary records.. The technical skills required by a Senior Welding Inspector are:. 1. Knowledge of technology. 2. Knowledge of codes of practice / Normative documents (. 3. Knowledge of planning. 4. Knowledge of organisation.. 5. Knowledge of auditing. The responsibilities of a Senior Welding Inspector:. 1. Supervision 2. Planning. 3. Organisation. 4. Auditing.. Supervision A supervisor is any person who id given authority and responsibility for planning and controlling the work of others with whom they are in close touch. Supervisor and operatives The difference between a supervisor and an operator is that an operator performs his/her own work but the supervisor gets work done through his operators. Supervisors and managers Supervisors are part of the management structure. The term supervision, however generally implies overseeing and controlling a working group on the spot dealing with situations and details as they arise. The term management implies planning ahead and controlling work more remotely using administrative procedures and reporting systems. The supervisor is in a key position between operatives and management able to encourage smooth. working or cause disruption both wilfully and unintentionally. He/she is also subject to pressure. from both sides that each expects the supervisor to support their views. He/she must seek to earn. the respect and support of managers and operators, carry out sometimes-unpopular orders and. duties at the same time as looking after the group he/she leads.. Senior Welding Inspection - Duties SWI Copyright © 2002 TW[ Ltd.. 2aA. Rev 09-09-02. (. ).

(50) TWI VOOI.. _. THE WELDING INSTITUTE. Working with others The job of the supervisor is enhanced and becomes more satisfying if he she makes LbC of the assistance of specialist advisors on personnel, work scheduling, work study, finance, etc, thereby allowing him to spend more time on organising and dealing with his/her staff.. Responsibilities of a supervisor A supervisor is responsible for his/her subordinates, the activities and the work place, which he is given formal authority to control, this usually includes: 1. Staff - moral, consultation, discipline, welfare, safety, employment induction, training.. 2. Work - maximum economy. 3. Cost - maximum economy. \. (, _/1. .~:.. 4. Machines and equipment - maintenance, loading, operation. 5. Materials - supplies, suitability, economic use. 6. Workplace - layout, tidiness, good housekeeping. Qualities of a good supervisor Particular circumstances will give different emphasis to the following essential basic qualities required in the good supervisor. I. Technical skill and knowledge - ability to explain why and how jobs are to be performed to eliminate faults, dangerous practices, wastage, to keep up to date. 2. Intelligence - judgment, sound common sense, ability to determine priorities. 3. Drive - vitality, energy, enthusiasm and general good health. Vigour is as infectious as fatigue is demoralising.. (. 4. Leadership - maintenance of high personal standards, goal setting, trustworthiness, reliability, consistency, fairness, stability, persistence and a sense of humour. Motivation and the supervisor It is very important for a supervisor to take an interest in his/her operators, to try to understand their attitudes and reactions, to treat them in a responsible manner and give respect to their views, efforts and skills. Responsible treatment includes correcting or reprimanding those who fail to respond responsibly. Good operatives expect the supervisor to act justly when dealing with those who do not conform to working requirements.. Staff assessment Linking motivation with responsibility of a supervisor to achieve targets of performance is the. assessment of staff and the development needs of the supervisor's section.. Whatever policy an organisation applies to staff assessment, a supervisor inevitably forms. judgments on varying capabilities and. attributes of his/her operatives. Assessment procedures. only differ in the degree to which they are formalized... If no other agreed system applies, a supervisor should first decide the factors that are important in. constituting a good worker. These usually include such factors as quality of output, quantity of. Senior Welding Inspection - Duties SW[ Copyright © 2002 TW[ Ltd.. la.5. Rev 09-09-02. ., ,<,. iI.

(51) TWI Illfll.. _. THE WELDING INSTITUTE. Output, versatility (range of capabilities) co-operation, timekeeping, conduct, relationships with others etc. On the basis of factual records where possible, each operative can be assessed against each factor using for instance a grading scale. Below is an example of a grading scale:. POOR. BELOW AVERAGE. AVERAGE. ABOVE AVERAGE. A simpler three-grade scale may be:. BELOW. AVERAGE. ABOVE. Operatives should be made aware of those factors, which are satisfactory and by discussion methods should be agreed for improving those aspects, which are not satisfactory.. Planning The planning function may be taken to mean the consideration of the necessary arrangements, which must be made from the general notification of the job requirement through to the final advice of completion. It is usual to find that this falls into three stages.. 1.. Preparation and dispatch of staff. 2.. The inspection and documentation.. 3.. • • • • • • • •. Equipment.. •. Welding operations.. Personnel approvals. Procedure approvals. Materials. Consumables. (. Edge preparations. Tacking. Preheats.. Collection of data and certificates.. There are various methods of dealing with the planning function and the three most common are:. 1.. Allocate staff on a block basis i.e. send an inspector on to the site and allow and expect. himlher to make a useful return on his/her time.. 2.. The use of charts in which each job function is estimated for time. In certain cases this. situation enables a considerable saving of staff and time to be made. But by the. implication the inspector works harder and tends to travel more.. 3.. The use of a critical path analysis in which a detailed assessment is made or obtained of. the overall production plan and the inspection function is meshed into this.. Senior Welding Inspection - Duties SW[ Copyright © 2002 TW[ Ltd.. 2a.6. Rev 09-09-02.

(52) TWI. V!l!ll.. _. THE WELDING INSTITUTE. Which of these approaches is used will depend on the nature of the workflow and the number of calibre of the available inspectors and back-up staff. Also critical is the degree of competition. which may be the driving force for economic use of staff hence low tendering. Planning aspects. Planning can be taken to mean to make the general arrangements. There are many ways of increasing productivity. Amongst them, production projects planning id high on the list. Apart from improving the utilisation of resources it also forms the basis for effective production or project control, and thereby reduces the risk of over spending budgets and for failing to achieve delivery targets. Some advantages of planning. C_). 1.. Jobs are planned and issued in correct sequences thereby reducing unnecessary work-in progress and minimising the need for overtime or subcontractors.. 2.. Men and machines are supplied with the correct materials and tools at the right time.. 3.. The correct quality standards are achieved for minimum cost.. 4.. Completed goods are dispatched to customers as promised.. 5.. Adequate stock levels of materials and components are maintained.. 6.. Greater job satisfaction.. 7.. Greater job security.. A sound system of planning should clearly show the stages of manufacture and inspection. It should draw attention to bottlenecks and areas of unused resources, and show what, and Where, additional resources are needed.. (. Senior Welding Inspection - Duties SWI Copyright © 2002 TW[ Ltd.. 2a.7. Rev 09-09-02.

(53) TWI. IllIJI.. _. THE WELDING INSTITUTE. Organisation The organisation function may be taken to mean the fitting of staff to the plan, which must be supervised to completion. In these terms the organisation function means the ability to assess the detailed requirements of the plan and to gauge the ability of individual staff to be technically competent, available and temperamentally able to perform the tasks involved. As a preliminary checklist organisation involves: 1.. How much inspection is required. 2.. Total man hours. 3.. Number of personnel required. 4.. Estimation of job times. 5.. Analysis ofjob sequences. 6.. Preparation requirements and time. 7.. Travel and down time (mobilisation/demobilisation). 8.. Leave time for personnel. 9.. Ability of staff. (). Auditing The term audit has been taken from accounting practice and means: I. An overall check of inspection. 2. A detailed check of a very limited area of inspection In the overall check the general content of the fabrication file examined for completeness and. presentation and generally impression is formed as to the visual quality of the product.. For the detailed check the requirements of a very limited zone is examined with great care and (as. appropriate) the code requirements are checked against the documents in the fabrication file.. Definitions • Audit Program: set of one or more audits planned. • Audit Criteria: set of policies, procedures or requirements used as a reference. • Audit evidence: records, statements of fact, which relate to audit criteria. • Audit findings: results of the evidence of the collected audit evidence against audit criteria • Audit conclusion: outcome of an audit provided by the audit team, after considerations of the audit findings.. Senior Welding Inspection - Duties SWI Copyright © 2002 TWI Ltd.. 2a.8. Rev 09-09-02.

(54) TWI. V!J!JI.. _. THE WELDING INSTITUTE. Assessments of:. • Staff • Equipment • QA / QC and inspection • Documents • Safety Internal Audits First-party audits are conducted by or on behalf of, the organisation itself for intemal purposes and can form the basis for an organisation's self-declaration of conformity.. (j. External Audits Second-party audits are conducted by customers of the organisation or by other persons on behalf of the customer. Third-party audits are conducted by extemal independent organisations. Such organisations, usually accredited, provide certification or registration of conformity against documented requirements There are three types of audits currently used in the fabrication industry. I. Pre - production. This is usually undertaken to assess ability in terms of staff and facilities to perform a task. 2. In - production. (. This is to confirm that the welding and related activities are being carried out accordance with the requirements of the applicable procedures and specifications.. 111. 3. Post - production The objective in this instance is to ensure that the welding and welding inspection are satisfactory. Audits are used to determine the extent to which the quality system requirements are fulfilled. Audit findings are used to assess the effectiveness of the quality system and to identify opportunities for improvement for improvement.. Senior Welding lnspection Duties SW[ Copyright © 2002 TW [ Ltd. >. 2a.9. Rev 09-09-02.

(55) TWI. V!l!ll.. _. THE WELDII\JG II\JSTITUTE. Concepts relating to an audit. Audit client Organization or person requesting an audit. Audit program Set of one or more audits planned for a specific time frame and directed towards a specific purpose. Auditee Organization being. audited. (-) Audit <Ill Systematic, independent and documented process for obtaining audit evidence and evaluating it objectively to determine the extent to which audit criteria ate fulfilled. Audit criteria / Set of policy procedures or requirements used as a reference. !. Audit team One or more auditors conducting an audit. Technical expert Person who provides specific knowledge of or expertise on the subject to be audited. Senior Welding Inspection - Duties SW[ Copyright © 2002 T\\'I Ltd.. Auditor A person with competence to conduct on audit. 2a.lO. ~ Audit findings. Results of the evaluation of the collected audit evidence against audit criteria. I. Audit evidence Records, statements of fact or other information, which are relevant to the audit criteria and verifiable. I. Audit conclusion Outcome of an audit provided by the audit team after consideration of the audit objectives and all audit findings. Rev 09-09-02. \,.

(56) TWI. 1ll01.. _. THE WELDING INSTITUTE. Knowledge of technology The scope and level of the technical aspects of welding with which the senior welding inspector needs to be familiar are similar to those of the welding inspector with slightly more depth but in addition a good appreciation of NDT is required together with a proven ability in radiographic interpretation. The reason for this is a senior welding inspector on certain projects may also be employed to view radiographs as well as checking the NDT reports and supervising and giving advice to NDT operatives. For all tasks assigned, a senior welding shall be able to demonstrate adequate technical knowledge to enable such tasks to be performed satisfactorily. The following factors should be considered: (. \. ~~. •. General technical knowledge;. • Specialised technical knowledge relevant to the assigned tasks. This may be attained by a combination of theoretical knowledge, training and/or experience.. Knowledge of codes of practice Neither welding inspectors or senior welding inspectors would be expected to have a detailed recall of the requirements of a code of practice or be expected to write welding procedures. What is expected is at a senior level an appreciation of the commonly used codes and a capacity to give. advise on the application of these documents. The senior welding inspector must be aware of the quality levels required for a particular product and be able to implement the quality requirements of the applicable codes and standards. Such documents include:. \'1. 1. Standards for consumables. • BS EN 499 covered electrodes. • BSEN 440 gas shielded filler wires. • AWS A5.1/A5.5 covered electrodes. • AWS A5.8 shielded filler wires. 2. Standards for welding procedure approval • BS EN 287 approval of welding procedures. • ASME IX approval of welding procedures. 3. Standards for welder approval • BS EN 287 the approval of we~ders. • ASME IX. Senior Welding Inspection - Duties Copyright © 2002 TWI Ltd.. swr. 2a.11. Rev 09-09-02.

(57) TWI. V!lOI. '-1-.. Standards for quality of fabrications.. •. BS 5500.. •. ASME VIII. _. THE WELDING INSTITUTE. 5. Standards for pipeline construction. •. BS 4515.. •. API 1104. •. B'Gas P2.. It must be noted that standards are merely convenient collections of good practice data, but as a stand-alone document it is not mandatory. If the client who is commissioning the manufacture may incorporate a standard into the specification and therefore the legal contract, but the client may add requirements for the particular component being constructed. Codes and standards plus client requirements control many major fabrications and projects.. (. Senior Welding Inspection - Duties SWI Copyright © 2002 TWI Ltd.. 2a.12. Rev 09-09-02.

(58) TWI. rtlOI.. _. THE WELDING INSTITUTE. Questions. Terms and Definitions. QU 1.. Sketch a single-U butt joint and indicate the following: a: root gap. lJ. QU 2.. b: root face. c: included angle. Sketch a tee joint, fillet welded and indicate the following a: leg length. b: throat thickness. c: root. d: weld toes. QU 3.. Sketch five joint types in addition to a butt weld.. QU4.. Identify the following butt weld features.. ~. ). A: B:. F. c:. C. D:. E:. S-r-. d: root radius. ,. v: : /~ " -,. Senior Welding Inspection - QU Terms & Definitions Sec I Copyright © 2003 TWI Ltd. I. F:.

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(61) TWI VOI.. _. THE WELDING INSTITUTE. Quality Quality is a subjective thing, what is quality to one person might not be quality to another person. Quality its self is very difficult to define but the concepts of quality or shown below. r -----. Requirement . . . . Need or expectation that is stated, generally implied or obligatory. --IIIo... ~ Grade Category or rank given to the different quality requirements for products, processes or systems having the same function use. Quality Degree to which a set of inherent characteristics fulfils requirements. Capability Ability of an organisation, system or process to realise a product that will fulfil the requirements for that product.. ( ., Customer satisfaction Customer's perception of the degree to which the customer's requirements have been fulfilled. It must be said that these terms although they are all widely used and definitions of their meanings defined in many documents, are not sufficiently precise for really general application. It is not uncommon to find that these functions overlap or that in particular instances QA isplanned and organized as a department, which in practice covers inspection and quality control. Again many manufacturing plants are organized with a Project Office dealing with the aims of quality and an Inspection Office dealing with the attainment of quality.. Senior Welding Inspection - QA/ QC Copyright © 2002 TWI Ltd. 2b. I. Rev 09-09-02.

(62) TWI V!lOI.. _. THE WELDING INSTITUTE. Note: quality can be used with objectives such as poor, good or excellent.. Note: inherent, as opposed to assigned, means existing in something, especially as a permanent. characteristic. Note: requirements can be generated by different interested parties. Note: a specified requirement is one which is stated, for example a document Note: when establishing a quality requirement, the grade is generally specified. Note: customer complaints are a common indicator of low customer satisfaction but their absence does not necessarily imply high customer satisfaction. Note: Even when customer requirements have been agreed with the customer and fulfilled, this does not necessarily ensure high customer satisfaction. QAVSQC (,,~. QA applies to all areas, which have an affect on quality and asks the question "has the work been performed correctly?" QC deals with the actual measurement of quality performance, this performance is compared against what is required, and action is taken on the difference and asks the question "is the work been performed correctly?". QA VS Inspection QA is not inspection. It deals mainly with documentation and must see the entire picture. Inspection is mainly about physical reality, monitoring and measuring basically inspection is a QC tool.. Definitions Relating to Quality Quality Assurance: all those planned and systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality or that quality requirements will be fulfilled. (. Quality Control: The operational techniques and activities that are used to fulfil the requirements for quality Inspection: activities such as measuring, examining, testing, gauging one or more characteristics of a product or service and comparing these with specified requirements to determine conformity. Inspection is a tool used for quality control.. Aim of quality assurance The aim of quality assurance is to improve quality whilst keeping costs to an acceptable level. The objectives of a system used to implement quality assurance, i.e. a quality system is to determine and rectify the root cause(s) of any problems, thereby reducing faults and wastage. This will in tum improve quality and reduce costs. The emphasis is on fault prevention rather that detection and cure i.e. it is a lot more cost effective to prevent welding defects from occurring rather than repairing defective welds after- detection.. Senior Welding Inspection - QA / QC Copyright © 2002 TWI Ltd. 2b. 2. Rev 09-09-02.

(63) TWI V!lIJI.. _. THE WELDING INSTITUTE. Benefits of adopting quality assurance. A properly implemented and managed quality system should:. I. Help to ensure that the company focuses on the market needs and requirements.. 2. Make the company more competitive in the market place due to an increased customer confidence in the company's output, i.e. a product or service that a customer wants 3. Lead to a reduction of costs due to a reduction in defective items and wastage 4. Give a measure of performance, which will enable any areas for improvement to be identified. 5. Introduce a more organized way of thinking. 6. Provide motivation, motivate employees provide a better working environment in addition to the product or service output benefits. Quality assurance provides the objective evidence needed to give maximum confidence for quality. Quality assurance should be considered as a management tool when used within an organization. A supplier who implements and maintains a system for assuring quality, is providing maximum confidence to a purchaser, or potential purchaser, that the supplied product or service attains, or is going to attain, its fitness for purpose.. (-). Concepts relating to quality assurance for measurement process. Metrological confirmation Set of operations required to ensure that measuring equipment conforms to the requirements for its intended use. Measurement process Set of operations to. determine the value of. quality. ~ Measurement control system Set of interrelated or interacting elements necessary to achieve metrological confirmation and continual control of measurement process. ~. Measurement function Function with organisational responsibility for defining and implementing the measurement control system. •. Measuring equipment Measuring instrument, software, measurement .......... Metrological characteristic Distinguishing features which standard, reference material can influence the results of or auxiliary apparatus or measurement combination thereof necessary to realise a measurement process Senior Welding Inspection - QA / QC Copyright © 2002 TWI Ltd. 2b.3. Rev 09-09-02. ~.

(64) TWI VOI.. _. THE WELDING INSTITUTE. Questions Responsibilities and duties of a welding inspector. QU1.. Give the three main responsibilities of a welding inspector:. QU2.. Give three main attributes. which all welding inspectors must possess.. QU3.. The welding inspector should refer to what documents and records.. QU4.. Give six main duties of a welding inspector before welding.. QU5.. Give six main duties of a welding inspector during welding.. QU6.. Give six main duties of a welding inspector after welding. J. Senior Welding Inspection - QU Duties ofa Welding Inspector Sec 2 Copyright © 2003 TWI Ltd.

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(67) TWI. V!lOI.. _. THE WELDII\JG INSTITUTE. Welding Imperfections: What are welding imperfections? Welding imperfections are material discontinuities caused by, or during, the process of welding. All things contain imperfections, but it is only when they fall outside of a "level of acceptance" that they should be termed defects, as they may render the product defective, or unfit for its purpose. As welds can be considered as castings they may contain all kinds of imperfections associated with the casting of metals, plus any other particular imperfections associated with the specific welding process being used.. :). We can classify welding imperfections into the following groups: 1). 3) 5) 7). 1). Cracks Solid inclusions Surface and profile Misalignment. 2) 4) 6). Gas pores and porosity Lack of fusion Mechanical damage. Cracks:. Cracks sometimes oceur in welded materials, and may be caused by a great number of factors. Generally, we can say that for any crack like imperfection to occur in a material, there are 3 criteria that must be present: a) A force. b). Restraint. c) A weakened structure ( .. Typical types of cracks that will be discussed later in the course are: 1). Hz Cracks. 2). Solidification Cracks. 3) Lamellar Tears. A Material's likelihood to crack during welding can be evaluated under the term Weldability. This may be defined as: "The ease with which materials may be welded by the common welding processes" All cracks have sharp edges, which produce high stress concentrations. This generally results in rapid progression, however this also depends on the properties of the metal. Cracks are classed as planar imperfections as they generally have only 2 visible, or . measurable dimensions i.e. length and depth. Most fall into the defects category, though some standards allow crater cracks.. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.1. Rev 09-09-02.

(68) TWI V!l!ll. 2). _. THE WELDING INSTITUTE. Gas pores, porosity and cavities:. Gas pores: Gas pores are defined as intemal gas filled cavities smaller than 1.6mm diameter, which are created during solidification by the expulsion of gases from solution in the solidifying weld metal.. (~). Porosity: These are gas pores < 1.6mm diameter which are generally grouped together, and may be classified by their number, size and grouping. (i.e. Fine, or coarse cluster porosity) A singular gas filled cavity = or > 1.6mm diameter is termed a "blow hole" Porosity is mainly produced when welding improperly cleaned plate, or when using damp welding consumables. Gases may also be formed by the breakdown of paints, oil based products, corrosion or anti corrosion products that have been left on the plates to be welded.. (' Shrinkage cavity. Hollow root bead. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWl Ltd. . An isolated internal pore. 3.2. Rev 09-09-02. ""o.l.

(69) TWI. V!lOI.. _. 4). THE WELDING INSTITUTE. Solid inclusions:. Solid inclusions include metallic and non-metallic inclusions that may be trapped in the weld during the process of welding. The type of solid inclusion that may be expected is really dependant on the welding process being used. In welding processes that use fluxes to form all the required functions of shielding and chemical cleaning, such as MMA and Submerged Arc welding, slag inclusions may occur. Other welding processes such as MIG and TIG use silicon, aluminium and other elements to de-oxidise the weld. These may form silica, or alumina inclusions. Any of these non-metallic compounds may be trapped inside a weld during welding. This often happens after slag traps, such as undercut have been formed. Slag traps are mostly caused by incorrect welding technique. Metallic inclusions include tungsten inclusions that may be produced during TIG welding by a poor welding technique, an incorrect tungsten vertex angle, or too high amperage for the diameter of tungsten being used. Copper inclusions may be caused during MIGIMAG welding by a lack of welding skill, or incorrect settings in mechanised, or automated MIG welding. (Mainly welding Aluminium alloys). ( ). Other welding phenomena such "arc blow" or the deviation of the electric arc by magnetic forces, can cause solid inclusions to be trapped in welds. The locations of these inclusions may be within the centre of a deposited weld, or between welds where the result causes "Lack of inter-run fusion", or at the sidewall of the weld preparation causing "Lack of side wall fusion" Generally solid internal inclusions may be caused by:. 1) 2) 3) 4) 5) 6). Lack of welder skill. (Incorrect welding technique). Poor manipulation of the welding process, or electrode.. Incorrect parameter settings, i.e. voltage, amperage, speed of travel.. Magnetic arc blow.. Incorrect positional use of the process, or consumable.. Incorrect inter-run cleaning.. Surface breaking solid inclusion Internal solid inclusion causing. a lack of sidewall fusion. Internal solid inclusion causing a lack of inter-run fusion. Solid inclusions caused by undercut in the previous weld run. Internal solid inclusion. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.3. Rev 09-09-02. (.

(70) TWI. VIJI. 3). _. THE WELDII\JG INSTITUTE. Lack of fusion:. Lack of fusion imperfections, are defined as a lack of union between two adjacent areas of material. This may be accompanied, or caused by other imperfections as explained in the last section. Lack of fusion can be considered a serious imperfection, as like cracks, they produce areas of high stress concentration. Lack of fusion, or overlap (a form of lack of fusion) may occur in the weld face area during positional welding caused by the action of gravity and incorrect use of the process.. l). Arc blow is a prime cause of lack of fusion imperfections, particularly when using high current processes, such as Sub Arc using high direct electric currents. (DC+ or DC -) Lack of fusion may also be formed in the root area of the weld where it may be found on one, or both plate edges. It may also be accompanied by incomplete root penetration. Lack of fusion is also a common imperfection in "Dip transfer MIG welding" of metals over 3mm thickness, especially when welding vertically down. This is caused by the inherent coldness of this form of metal transfer, and the action of gravity. Like solid inclusions, lack of fusion imperfections may be caused by:. 1) 2) 3) 4) 5) 6). Lack of welder skill. (Incorrect welding technique). Poor manipulation of the welding process, or electrode.. Incorrect parameter settings, i.e. voltage, amperage, speed of travel.. Magnetic arc blow.. Incorrect positional use of the process, or consumable.. Incorrect inter-run cleaning.. Lack of sidewall fusion (Incompletely filled groove in some standards). (J. Lack of inter-run fusion. I.. \. Lack of sidewall fusion. Lack of root fusion. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.4. Rev 09-09-02.

(71) TWI. lllOI.. _. 4). THE WELDING INSTITUTE. Surface and profile:. Surface and profile imperfections are generally caused by poor welding techniques. This includes the use of incorrect welding parameters, electrodelblowpipe sizes and/or manipulation and joint set up. This category may be split into two further groups of weld face and weld root. Surface and profile imperfections are shown pictorially in A & B below:. A: Spatter is not a major factor in lowering the weldment strength, though it may mask other imperfections, and should therefore be cleaned off before inspection. Spatter may also hinder NDT and be detrimental to coatings It can also cause micro cracking or hard spots in some materials due to the localised heating/quenching effect. An incompletely filled groove may bring the weld below its DTT. It is a major stress concentration when accompanied by lack of sidewall fusion. Lack of root fusion causes a serious stress concentration to occur in the root. It may also render the root area more susceptible to corrosion in service. Spatter (.. A. Lack of root fusion. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.5. Rev 09-09-02.

(72) TWI VOOI.. _. THE WELDIf\IG INSTITUTE. B: A bulbous contour is an imperfection as it causes sharp stress concentrations at the toes of individual passes and may also contribute to overall poor toe blend Arc strikes, Stray-arcing, or Stray flash may cause many problems including several types of cracks to occur. They can also cause depressions in the plate bringing it below its DTT. Arc strikes would normally be NDT inspected and then repaired. Incomplete root penetration may be caused by too small a root gap, insufficient amperage, or poor welding technique. It also causes high stress concentrations to occur. It also generally produces a weld with less throat thickness than the DTT of the joint. An irregular bead width is a surface imperfection, which is often referenced application standards as. "The weld bead should be regular along its linear length" /. in. Bulbous, or irregular contour. Arc Strikes. <, ~. G)r-~. Poor toe blend. B. Incomplete ro'ot penetration /. (. Undercut: Undercut can be defined as a depression at the toe of a weld in a previous deposited weld, or base metal, caused by welding. Undercut is generally caused by incorrect welding technique, including the use of too high a current for the electrode being used, and the welding position. It is often caused in the top toe of fillet welds when attempting to produce a large leg length fillet weld in one run. Undercut can also be considered a serious imperfection particularly if it is sharp, as again it causes high stress concentrations. It is gauged in severity by its length, depth and sharpness. Fillet welded structures intended for fatigue loaded applications often require the toes' to be lightly ground, or flushed in with a TIG run to remove any toe undercut. Shrinkage grooves: Shrinkage grooves may occurin the root area and are caused by contractional forces pulling on the hot plastic base metal in the root area. It is often mistaken as root undercut.. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.6. Rev 09-09-02.

(73) TWI V!lOI.. _. Root Run or "Hot pass" undercut. THE WELDII\JG II\JSTITUTE. Parent metal, "top,,:e" nn?t. s.> "!i"!iq;:R~~.'.'~. Parent metal, surface undercut. ,~. ~.. _. ._Q~~'~i{'=,.. y. Weld metal, surface undercut. ). Weld metal, surface undercut. t. ~"" ".jfj: Shrinkage grooves. (. Root concavity: (suck back) This may be caused when using too high a gas backing pressure in purging. It may also be produced when welding with too large a root gap and depositing too thin a root bead, when the hot pass may pull back the root bead through contractional strains,. . Root concavity Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.7. Rev 09-09-02.

(74) TWI. VlJOI.. _. THE WELDING INSTITUTE. Excess penetration:. Often caused by using too high a welding current, and/or, slow travel speed, coupled. with a large root gap, and/or a small root face for the current or process being used. It is. often accompanied by bum through, which can be defined as a local collapse of the weld. puddle causing a hole, or depression in the final weld root bead.. Root oxidation:. Root oxidation may take place when welding re-active metals such as stainless steels. with contaminated, or inadequate purging gas flow.. Crater pipes:. Often occurs during TIG welding, at the end of the weld run, on final solidification. It is. caused by insufficient filler material to meet the solidification process. It can be. eliminated by careful application of the filler metal, or using a slope out control.. I. \. <:. Crater pipe. Excess penetration, and bnrn tbrougb. /'1',",. Root oxidation in Stainless Steel. To summarize, we can list surface or profile welding imperfections as follows:. (. 1). Incompletely filled grove.. 2). Spatter.. 3). Arc strikes. (Stray arcs). 4). Incomplete root penetration.. S). Bulbous or irregular contour.. 6). Poor toe blend.. 7). Irregular bead width.. 8). Undercut.. 9). Root concavity.. 10). Excess penetration/Burn through.. 11). Root oxidation.. Senior Welding Inspection - Welding Imperfections Copyright © 2002 TWI Ltd. 3.8. Rev 09-09-02.

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