Article I Welding General RequirementsGeneral Requirements Overview
Overview
Since this article covers the requirements in general terms it is often given just cursory attention or skipped altogether. This is a mistake for anyone wishing to be competent in applying this section of the ASME Code.
It is mandatory to read every article of Section IX in order to apply the code rules and since many questions on an exam could come from this article alone, it should not be overlooked. As an example, the purpose of a welding procedure is given in paragraph QW-100.1. In the very given next paragraph, welders' performance qualification tests are addressed. In QW- 100.3 it is stated that a Welding Procedure Specification written and qualified in accordance with the rules of Section IX may be used in any construction built to the requirements of the ASME Boiler and Pressure Vessel Code or the ASME B-31 Code for Pressure Piping. In the next paragraph you are cautioned that other Sections of the Code state the conditions under which Section IX requirements are mandatory, in whole or in part.
Also in QW-120, QW-130 and QW-132 of this article, test positions are listed with written definitions and references to Article IV where illustrations of these positions are to be found. Types and purposes of tests are addressed in the paragraphs of QW-141.1 through QW-141.5, and all the subsequent paragraphs contain explanations of the tests and examinations required. Acceptance criteria is listed for each type of test described.
Beginning with QW-190, other types of tests and examinations are listed, most notable being radiographic and liquid penetrant examinations. Here you are referred to Section V, and then told the acceptance standards of QW-191.2 and QW-195.2 respectively shall be met.
API 510 Module SECTION IX PART QW Article I
Article II. I. Welding PrWelding Procedure ocedure QualificationsQualifications Overview
Overview
In the QW-200.1 paragraphs you are given the definition of a Welding Procedure Specification (WPS); what its contents must consist of, as well as what changes may be made with out requalifying the WPS. Also, here you are directed that the format may be of any form desired as long as every essential, nonessential and supplementary essential variable (when required) is included or referenced as outlined in QW-250 through QW-265.
In the paragraphs of QW-200.2 the same type of information for the Procedure Qualification Record (PQR) is listed as was given for a WPS in the previous paragraph, starting with the definition. As in the WPS, you are given the required contents for a PQR. We are told that changes in a PQR are not permitted except for editorial changes such as the recording of a P- Number incorrectly when filling out the srcinal PQR. Addendum is permitted if it meets the
definitions as given in this paragraph. Examples of permitted addendum are given to clarify its meaning. Finally, we are instructed that it is possible to have multiple WPS's with one PQR and also to have multiple PQR's with one WPS.
QW-200.3 gives the purpose and an explanation of the use of P-Numbers. It is stated here that P-Numbers are assigned to base metals dependent on characteristics such as composition, weldabilty, and mechanical properties where it can logically be done. Group Numbers are introduced here, stating that Group Numbers are assigned among P-Numbers to classify the metals for procedure qualification where notch toughness requirements are specified. You are also cautioned here that these assignments do not imply that base metals within a P- Number may be indiscriminately substituted.
The combination of welding procedures is permitted as given in paragraph QW-200.4. That is to say, more than one WPS can be used in a production joint, and they may include one or a combination of processes. QW-451 is referenced to make sure the reader is aware that limitations are placed on the base metal thickness and the deposited filler metal thickness of each procedure.
The type of tests required to qualify a procedure are given in paragraphs QW-202.1 through QW-202.5. Referenced therein are mechanical tests, groove and fillet welds, weld repair, dissimilar base metal thickness and stud welding. In each of the paragraphs, other QW paragraphs are referenced for details and exceptions that might exist.
QW-203 states that unless required otherwise by welding variables of QW-250, a qualification in any position qualifies the procedure for all positions. So, most PQR’s can be performed on plate since the goal is to prove that the metal or metals can be successfully joined as opposed to proving the skills of a welder or welding operator.
QW-265. These paragraphs are in tabular form and cover some fourteen (14) different welding processes. Within these tables for each process are lists of variables, and whether or not they are essential, nonessential or supplementary essential. These paragraphs in tabular form also reference where in the other code paragraphs specific requirements and definitions can be found.
API 510 Module SECTION IX PART QW
Article I
Article III. II. Welding PeWelding Performance rformance QualificationsQualifications Overview
Overview
This article lists the welding processes separately, with the essential variables which apply to welder and welding operator performance qualifications.
In QW-300.2, the responsibility for the qualification of welders and welding operators is placed on the manufacturer and/or contractor. One important fact given is that if twocompanies of different names are actually part of one organization, then one company may control the welder and welding operator qualifications. That is so long as this condition is included in the quality control system of the companies and all other requirements of Section IX are met.
Starting with QW-301, tests required for welders and operators are addressed. This includes the intent of such tests, the extent of testing, identification of individual welders along with the records required for such tests.
QW-302 calls out the type of tests. They are mechanical or radiographic, and in QW-302.3, the location and removal of pipe test coupons for mechanical tests are described.
Next in this series is QW-303 where limits of qualified positions and diameters are located. You are immediately directed to QW-461 which has the graphics defining positions.
QW-303.1 through QW-303.4 give details of groove and fillet weld positions and the limits of qualifications for each.
Welder qualifications to weld to various WPS's and limitations on qualification by radiography are to be found in QW-304. Specifics of examination for welders begins in QW- 304.1. It says that welds made in test coupons may be radiographed or have bend tests performed. Alternatively, a six inch length of the first production weld made by the welder being examined may be qualified by radiography.
In QW-304.2, failure to meet radiographic standards is discussed. If a production welder's test is flunked, the entire production weld made by the welder being tested must be radiographed and repaired by a welder who is qualified.
QW-305 through QW-305.2 is a description of how welding operators are examined and qualified. It's essentially the same as QW-304, with the length of the production radiograph being 3 feet instead of 6 inches.
In QW-320 retests and renewal of qualifications are divided into two categories. Immediate retest by mechanical or radiography means, and retest after further practice.
QW-321.1 outlines the mechanical tests and basically says the welder will make two consecutive test coupons for every position he failed, all of which must pass the test requirements. Retest by radiography is laid out in QW-321.2. How to handle situations dealing with further training is found in QW-321.3.
Renewal of a welder's qualification for a process is mandatory when he has not used the process for the time limits as given in QW-322.1 (a) and (b).
The QW-350 paragraphs have all of the variables for welders and here you will find what changes to his essential variables will require a welder to requalify.
QW-352 to QW-357 are in tabular form in order to easily determine the essential welders variables for each process.
API 510 Module SECTION IX PART QW
Article
Article IV. IV. Welding Welding DataData Overview
Overview
This article contains within it all of data for the variables that pertain to Welding Procedure Specifications and Welder Performance. These include joints, base metals, filler metals, preheat, postweld heat treatment and electrical characteristics.
By using the tabular paragraphs and reading the written paragraphs they reference, requirements for a welding procedure or a welder's performance test can be interpreted. Since metals are given P-Numbers and their P-Numbers greatly affect their applications, they are listed by P-Number; for qualification in the tabular forms of paragraph QW-422 which is 52 pages long.
In QW-423.1, it is given that base material for welder's qualification to a WPS may be substituted with a different base material, and lists the permissible substitutions.
QW-430 starts the F-numbers for electrodes and welding rods, these paragraphs are also in tabular form.
QW-440 addresses weld metal chemical composition. As can be seen there are 12 A- Numbers. As the A-Number must be listed on the WPS, one should become acquainted with
these A-Numbers.
The remaining paragraphs of Article IV deal with thickness 1imits for tension and bend tests, diameter limits, fillet welds, test specimens and their order of removal. Also given are the configurations of test jigs. In short, Article IV is where you will be constantly sent for the "how to's of welding in accordance with the ASME Code.
Remember that it is possible to write a perfectly good welding procedure using Section IX that will not meet one of the construction codes. An important paragraph for understanding Section IX is QW-492 "Definitions". If in doubt go here first for clarification. Lastly, non- mandatory appendix A has sample forms that list the necessary information for the WPS, PQR and WPQ.
API 510 Module SECTION IX PART QW
Welding Procedure Specification Welding Procedure Specification Overview
Overview
In all welding procedures there are three (3) types of variables. The first is being the essential variable, which is a variable that if changed will cause a change in the mechanical properties of the weldment. Any time an essential variable is changed outside of the range given in the WPS, the procedure must be requalified by mechanical testing on the weld using the new values.
The second type is the nonessential variable. Changes in these can be made without requalification of the WPS. HOWEVER, THE WPS MUST BE REVISED TO REFLECT THESE CHANGES.
Lastly, the supplementary essential variables need only be given if the weld must have specific impact properties for low temperature service. If supplement essential variables are required they automatically become essential variables and must be handled the same as any other essential variable. That is to say all required testing (including impact testing) must be done to qualify the WPS.
The purpose of this portion of instruction is not to teach every welding process recognized by the ASME Code. It is to concentrate on the Shielded Metal Arc Welding process, which will serve as an example for all of the procedures that could be on the API 510 exam.
The way to understand how WPS’s are created is to turn to Article 11. In our case specifically to paragraph QW-253 (SMAW). Here the essential, supplementary essential and nonessential variables are given. As can be seen, there are several variables to be dealt with. When a WPS is written every variable listed must be included whether or not it is essential, supplementary essential (when required) or nonessential.
Joints Joints
There are no essential or supplementary essential variables given for the joint category. However, we do have four (4) nonessential variables. As stated above, all variables (when required) must be included in the WPS. Our first variable, which pertains to joints, is groove design.
Groove Design Groove Design
Looking in the box labeled joints, we see that information on grooves may be found in paragraph QW-402.1. A change in groove from double vee to single vee can be made with
only a revision in the WPS.
Here, why not enter All Joints in the WPS? Then you can legally use any you need now or later. If you specify "U" groove on the WPS, you must use only U grooves in production or revise the WPS to reflect the new groove. Also, you must use a U groove when performing the PQR. Although the PQR need not list any of the nonessential variables, the signature of the manufacturer's representative is testament to using one of the grooves listed on the WPS. Backing:
Backing: The deletion of backing is a nonessential variable specified in QW-402.4. If we do not want to place unnecessary restrictions on ourselves we can state this variable as being "With Or Without Backing"; or simply place X's in both blocks..
Root Spacing:
Root Spacing: Here again this is a nonessential variable. Give the widest range possible. Do not leave this blank e.g. 1/32nd to 1/16th inches.
Retainers:
Retainers: "With or Without" is appropriate. Don't leave it blank. If you are not going to use retainers you should so indicate. "No retainers used".
Base Metals Base Metals
In this category there are no nonessential variables. There are only essential and supplementary essential variables. Supplementary essential variables apply only when impact properties are required. They put restrictions on the base metal material that can be qualified with any one PQR. It also puts restrictions on the base metal thickness range that can be qualified when running a PQR.
Group Number:
Group Number: A change in a group number becomes an essential variable when impact properties are required of the base material.
T Limits Impact:
T Limits Impact: In QW-403.6 the minimum thickness ranges qualified by impact testing is called out.
T/t Limits > 8 in.:
T/t Limits > 8 in.: This is the first essential variable in the base metal category. It becomes effective when trying to qualify welds greater than 8 inches in thickness.
Change in T Qualified:
Change in T Qualified: Essentially it stipulates that the welding procedure depending on the thickness of the coupon used in the PQR is qualified for a range of base metal thickness. If base metal thickness goes beyond that qualified, a new PQR will be required.
t Pass > 1/2 in.:
Filler Metals Filler Metals
In the filler metal category, all three types of variables apply. The first two have to do with chemistry and the types of electrodes used in the welding process. The F number is a grouping of electrodes that have similar characteristics in the way that they produce mechanical properties. Deposition is also similar among F Numbers. A-Numbers are chemical limitations and all electrodes that fall under the same A-Number have similar chemical properties. A-Numbers apply only to ferrous materials.
Change in F-number:
Change in F-number: Requires requalification of the procedure.
Change in A-Number:
Change in A-Number: Requires requalification of the procedure, except as given in QW- 404.5, which says that A-No. 1 and A-No. 2 can be exchanged.
Change in Diameter:
Change in Diameter: Since this is a nonessential variable changing it does not demand requalification of the procedure. However, you should revise the WPS to reflect the change. Change in Diameter > 1/4 in.:
Change in Diameter > 1/4 in.: This is used as a supplementary essential variable. It says that if impact properties are necessary and an electrode of greater than 1/4 inch is used, that size electrode must be qualified for impact properties in the weld.
Change in AWS Class:
Change in AWS Class: Requires requalification as a supplementary variable if impact properties are required. This is an SFA number given in Section II of the ASME Code.
Change in t:
Change in t: A change in the thickness of deposited weld metal beyond the range qualified. Change in AWS Class:
Change in AWS Class: This is a nonessential variable where impact properties are not required. It must be addressed on the WPS however.
Position Position
There are three (3) variables listed for position. Notice that unless impact properties are required position is a nonessential variable. Again when specifying position as a nonessential variable, don't box yourself in, Just say "all".
Addition of a Position:
Addition of a Position: Nonessential but the WPS must be revised if one position is given then another is used in production.
Change in Position:
Preheat Maintenance:
Preheat Maintenance: This is the continuance of preheat temperature after the completion of welding. Will preheat be maintained for a given time or will the weld be allowed to cool in air and not monitored?
Increase > 100 degrees:(interpass temp.):
Increase > 100 degrees:(interpass temp.): If the weld requires impact values using the Shielded Metal Arc process, the interpass temperature must be maintained below some maximum temperature. If the interpass temperature is increased by more than 100 degrees over what was qualified, the procedure must be requalified.
Post Weld Heat Treatment Post Weld Heat Treatment
The first variable given is a change in postweld heat treatment. This is an essential variable. While it is not always necessary to postweld heat treat a material, a change in postweld heat treatment or the lack of is an essential variable and must be reflected on the WPS and the PQR.
Change in PWHT:
Change in PWHT: If PWHT will not be performed, this should be indicated on the WPS by entering the words: “No Postweld Heat Treatment" or simply “None". If PWHT is required and then changed from that specified on the WPS, the WPS must be requalified since it is an essential variable.
PWHT (Time and Temperature Range):
PWHT (Time and Temperature Range): Again when impact properties are required of a weldment, a change in the time span of PWHT or the temperature range will require requalification of the procedure.
Thickness Limits:
Thickness Limits: As indicated, this is an essential variable. It deals with exceeding the upper transformation temperature of alloys. It says that if the test coupon being heat treated exceeds the upper transformation temperature of the alloy the maximum thickness qualified is 1.1 times the thickness of the test coupon as opposed to two times the coupon thickness allowed if the upper transformation has not been exceeded. See QW-451 for T limits.
Electrical Characteristics Electrical Characteristics
Change in Current or > Heat input: This is a supplementary essential variable that deals with impact properties. Here if the heat input due to welding is changed or the type of current is changed resulting in an increased deposition of weld metal the procedure must be requalified for impact values.
Change in the Type of Current or a Change in the Current or Voltage Range: