Microstructure of cold drawn steel

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Recrystallization Kinetics and Microstructure Evolution of Annealed Cold Drawn Low Carbon Steel

Recrystallization Kinetics and Microstructure Evolution of Annealed Cold Drawn Low Carbon Steel

The recrystallization behavior of cold-drawn 0.12 wt% C steel during annealing at temperatures 600˚C and 650˚C was investigated. Hardness tests were used to characterize the recrystallization kinetics. The micrographs of the steel were obtained using optical microscopy (OM) to characterize the grain microstructure of the non-treated and the annealed steel samples. Annihilation of dislocation defects occur within the soaking time of 5 - 10 minutes for all the deformed steel after annealing at 650˚C. Specifically at 5 minutes soaking time the grains elongation is still observed indicating that reformation of grains is not taking place but recovery of the deformed grains. At the 10 minutes annealing time, new grains are observed to begin and full recrystallization is achieved at 15 minutes annealing time. At annealing time between 20 - 25 minutes, grains coarsening are observed indicating the onset of grain growth. The hardness of the ma- terial reduces with increasing annealing temperature for all the degree of cold drawn deformation. On the basis of the experimentally obtained hardness values, recrystallization increases with increasing degree of cold drawn deformation for the annealed steel. Recovery process was found to prolong in the 20% cold drawn steel as compared to the 55% cold drawn steel. The prolong recovery process is due to reduction in the driving force. Full recrystallization of the annealed steel is achieved at different soaking time depending on the degree of the cold drawn steel.
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Microstructure and Mechanical Properties in Progressively Drawn Pearlitic Steel

Microstructure and Mechanical Properties in Progressively Drawn Pearlitic Steel

a finer microstructural scale, the lamellar pearlitic structure itself made up of ferrite and cementite is the following level of analysis (second microstructural unit), the key parameter being the pearlite interlamellar spacing. Cold drawing also produces changes in the lamellae in the form of increase of packing closeness associated with decrease of interlamellar spacing 6) and orientation parallel to the main axis or cold drawing direction. 7) During the earliest stages of drawing (small cumulative plastic strain) the orientation effect predominates while during the final stages of drawing (large cumulative plastic strain) both the slenderising of pearlitic colonies and the decrease of pearlite interlamellar spacing (with increase of packing closeness) predominate, cf. 4­7)
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Effect of Soaking Time on the Mechanical Properties of Annealed Cold Drawn Low Carbon Steel

Effect of Soaking Time on the Mechanical Properties of Annealed Cold Drawn Low Carbon Steel

Results of an investigation of annealing time and tem- perature on strain inhomogeneity of copper wires after drawing through dies with various die-angles and reduc- tion of areas are presented in [13]. As an important industrial tool for the evaluation of strain, the distributions of the microhardness over the transverse cross-sections were measured. Inhomogeneity factors (I.F.), as a func- tion of above parameters were determined. The results indicate that due to different grain growth kinetics of the coarse and fine microstructure both surface and center grains grow but with different rates in applied dies, and hence strain inhomogeneity decreases as time and tem- perature increase. Due to different recrystalization kine- tics vs. time and temperature inhomogeneity is more sen- sitive to temperature rather than to time.
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Microstructure and mechanical properties during annealing of cold-drawn pearlitic steel wire

Microstructure and mechanical properties during annealing of cold-drawn pearlitic steel wire

To further observe this microstructure, Figure no 6 shows the micrograph of the annealed material at 600 ° C for 30 min at a magnification of 5000x. Note that, the ferrite, as it is the most ductile constituent, presents a greater depth in the image due to the metallographic preparation. The cementite, harder and more resistant, appears prominent in the images obtained with secondary electron. In this way, it is observed that the elevated regions are composed of small spheres which are represented in the image by the white color, while the ferritic matrix has a flat topography and gray color. In the treatment at 700ºC the material presented a microstructure constituted by the spheroidized cementite in all the annealing ranges performed. It was also observed that the increase in the annealing time caused a gradual increase in the size of the globular cementite.
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Experimental and analytical investigation torsional behavior of sigma profile

Experimental and analytical investigation torsional behavior of sigma profile

The major function of most of the cold-formed thin-walled steel members is to carry or transfer the load in order to maintain the global stability of the structure. Thus, structural strength and stiffness of the members are normally being the main consideration during constructing the design. Since the member steel facing various types of joints in order to hook up the connection of the structure, design of the structure tends to be critical part of study for overall safety of the structure.

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Atmospheric Corrosion Studies of Ductile Iron and Austenitic Stainless Steel in an Extreme Marine Environment

Atmospheric Corrosion Studies of Ductile Iron and Austenitic Stainless Steel in an Extreme Marine Environment

Ductile Iron (DI) consists of graphite in the form of nodules or spheroids in a matrixof either ferrite or pear- lite [10,11]. DI is not a single material but part of a group of materials which can be produced to have a wide range of properties through control of the microstructure. The common defining characteristic of this group of materials is the morphological dominance of the graphite structure. In DIs, the graphite is in the form of spherical nodules rather than flakes (as in grey iron), thus inhibiting the creation of cracks and providing the enhanced ductility that gives the alloy its name. The formation of nodules is achieved by addition of nodularizing elements into the melt especially magnesium and less often, cerium [12]. Yttrium has also been studied as a possible nodularizer
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Notch aspects of RSP steel microstructure

Notch aspects of RSP steel microstructure

notches. Thus, stress concentration caused by notch eff ect on edges of grains does not occur. According to most commonly accepted fracture mechanics models, very fi ne grains do not provide condition for possible nucleation of microcracks in martensite packets (see Figure 8). An exception to this concept might be high-speed-loading model. This speed is connected with strain mechanism caused by twin band development. Quoting complete and exact material property information (by manufacturer!) is vital. This includes grain size, size and distribution of carbides, surface energy,  (this value signifi cantly aff ects critical fracture stress value), yield stress, and fracture toughness. With this data available, it could be possible to defi ne size of critical crack using shape function of the body produced of the RSP steel and loading type. Size of such crack could be then compared with the observed structure geometry. The verifi cation would defi nitely confi rm data obtained using material analysis.
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An Experimentalstudy On Concrete Filled Tubular Columns Using Varying Steel Materials

An Experimentalstudy On Concrete Filled Tubular Columns Using Varying Steel Materials

Abstract: This paper presentsan experimental studyon concrete filled tubular columns using varying steel materials under axial loading. A total of 12 specimens were casted and subjected to testing.Out of 12 specimens, 4 No’s is of specimens for stainless steel, 4 No’s is of Mild steel and 4 No’s is of cold formed steel were tested under axial loading. The main parameters used in the test are as follows:(a) Varying steel materials are Stainless steel , Mild steel and Cold formed steel , (b) Tube thickness of 2mm and 3mm,.(c)Diameter/thickness (D/t) ratio of 50 and 75,(d)Length/diameter (L/D) ratio of 4 ,(e) Concrete cube strength of 30MPa .The experimental investigations have been carried out for casting and testing the cube ,cylinders and Concrete filled tubular specimens. Duringtesting, the common modes of failures that have been observed in the columns are slight localbulking and weld failure.The presence of concrete infill provided additional stability of the tube walls against the influence of local buckling mechanisms.From the cost analysis, it is found that the rate of Stainless steel concrete filled tubular columns is costlier than Mild steel and Cold formed steel. Though economically the initial cost of mild steel and cold formed steel is lesser than that of stainless steel, strength of stainless steel column is far better than the other two. So it is preferable to use stainless steel columns in case of high performance requirement.
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Effect of High Magnetic Field Annealing on Microstructure and Texture at the Initial Stage of Recrystallization in a Cold Rolled Interstitial Free Steel

Effect of High Magnetic Field Annealing on Microstructure and Texture at the Initial Stage of Recrystallization in a Cold Rolled Interstitial Free Steel

Obviously, the free energy of the grains with h100i orientation parallel to the magnetic field is the lowest, and they have the largest driving force for recrystallization, then the h110i oriented grains, and the h111i oriented grains. While for the IF steel sheet investigated in this study, no measurable orientation intensity at {hkl}h100i was deter- mined before and after annealing, which suggests that nucleation of grains with h110i orientation become the most preferred during magnetic field annealing. Therefore, when the magnetic field direction parallel to the specimens’ rolling direction, at the initial stage of recrystallization, the h110i
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Precipitation in an Al 300 ppm Fe Alloy

Precipitation in an Al 300 ppm Fe Alloy

higher aging temperatures as described in 4-1. Starting times of the second stage decrease of in the 65% cold-drawn specimens are plotted with disregard to precipitate phases, which leads to solid curves in Fig. 12, that is the TTP diagram composed of two C-curves. The boundary between the curves is about 750 K. Obvious third stage decrease in 673 K aging (Fig. 4(c)) shifted to earlier in 698 K aging, and agings at higher temperatures than 723 K lead to two-stage decrease as shown in Fig. 5. The boundary temperature, 750 K, seems to be a temperature above which three-stage decrease does not occur. The C curve of the cold-drawn specimen at higher temperatures roughly coincides with that of the undeformed specimens (broken curve).
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Evaluation of applicability of thick E500 TMCP and F500W QT steel plates for Arctic service

Evaluation of applicability of thick E500 TMCP and F500W QT steel plates for Arctic service

Results: F500W QT obtains better results in special tests like NDT ( − 100 °C is better than − 65 °C) and CTOD (CTOD − 40 °C average 1.18 mm > 0.41 mm). Using quenching followed by high tempering enables possible operational temperatures down to − 70 °C. However, the NDT test is required only in Russian standards. E500 steel base metal tests showed applicability based on criteria of the Charpy test at temperatures as low as − 85 °C; based on criteria of NDT at − 65 °C; based on Tkb criteria only at − 40 °C; and CTOD test showed E500 applicability to as low as − 55 °C. E500 welding tests showed, that Charpy impact toughness values are limiting the use of MMA welds to − 20 °C, and FCAW and SAW welds can be utilized with some limitations at − 40 °C. CTOD of the welded joint showed that E500
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The Corrosion Behavior Studies of Cold Rolled Austenitic Stainless Steel

The Corrosion Behavior Studies of Cold Rolled Austenitic Stainless Steel

for 30 hours showed higher values but lower repassivation potentials than the non sensitized samples as shown in Table 6 ,Table 10, Table 11 and Table 12.The change observed in pitting behavior in sensitized samples could be due to chromium carbide precipitate at the grain boundaries causing chromium impoverishment of the adjacent matrix. It is therefore expected that sensitized steel will be more susceptible to pitting corrosion. As the sensitized time and temperature were increased, leveling of chromium distribution occurred and rate of pitting decreased.

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Note to: Ms Melinda Bills, SPP Washington; Subject: South African sanctions, 17 September 1986

Note to: Ms Melinda Bills, SPP Washington; Subject: South African sanctions, 17 September 1986

Angles, shapes and sections, of iron or steel, hot-rolled, forged, extruded, cold-formed or cold-finished; sheet piling of iron or steel, whether or not drilled, punched or made from ass[r]

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The resistivity and microstructure of heavily drawn Cu‐Nb alloys

The resistivity and microstructure of heavily drawn Cu‐Nb alloys

A combined resistivitytransmission electron microscopy(TEM) study has been done on heavily drawn Cu‐20 vol % Nb alloys (so‐called i n s i t u alloys). The results show that electron scattering at Cu‐Nb interfaces makes the major contribution to resistivity in heavily drawn wire. The dislocation contribution is small and constant at deformation strains greater than around 4, apparently as a result of dynamic recovery/recrystallization of the Cu matrix which occurs during room‐temperature drawing. Results of this study and other recent TEM dislocation studies indicate that the dislocation density in heavily drawn Cu‐20 vol % Nb material does not exceed 10 1 1 cm − 2 . It is demonstrated here that the 10 1 3 ‐ cm − 2 dislocation density predicted by the
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Dissimilar friction stir welding of duplex stainless steel to low alloy structural steel

Dissimilar friction stir welding of duplex stainless steel to low alloy structural steel

Table 4 summarises the results for the 10 specimens that did fracture, with figure 7 displaying the S-N (stress-life) data points plotted in double logarithmic scale. This same figure features results typical of a low alloy steel FSW joint produced at welding speeds of 250 mm/min and 300 rpm, and tested at 90% of YS. 36 Although

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A REVIEW ON EFFECT OF PREHEATING AND/OR POST WELD HEAT TREATMEMT (PWHT) ON MECHANICAL BEHAVIOUR OF FERROUS METALS

A REVIEW ON EFFECT OF PREHEATING AND/OR POST WELD HEAT TREATMEMT (PWHT) ON MECHANICAL BEHAVIOUR OF FERROUS METALS

The study of the previous work reviews that effective preheat and/or post heat are the primary means by which acceptable heat affected zone properties , minimum potential for hydrogen induced cracking and minimum residual stresses are created. Some researchers concluded that microstructure of the HAZ is responsible for the property deterioration of weld and cold cracking susceptibility and also recommended that heat treatment is not always necessary, technical problems associated with conventional steel materials welding can be eliminated without preheating and post heating treatments by applying some specific welding process and consumables. Some of the researchers observed that the increase of preheating and/or PWHT coarsened the microstructures of weld and HAZ and significantly influenced the properties of the weld joints. Few of the researchers advised the way for welding of specialized type of ferrous metals .While studying the effects of pre-and post weld Heat Treatment on mechanical properties, some researchers observed that toughness decreases after stress relieve operation on other hand toughness increases if only PWHT is applied. Welding stresses can be reduced by 21- 32% by using new welding technique i.e. parallel heat welding process (PHW).Some researchers said that residual stresses increases with increase in preheat temperature and also recommended that it is impossible to obtain a full residual stress distribution in welded structures by means of experimental methods but this disadvantage can be solved by means of computational analysis.
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Cavitation Erosion Resistance and Wear Mechanism Model of Flame-Sprayed Al 23 –40%TiO 2/NiMoAl Cermet Coatings

Cavitation Erosion Resistance and Wear Mechanism Model of Flame-Sprayed Al 23 –40%TiO 2/NiMoAl Cermet Coatings

shown in Fig 2 and Fig 3, it is possible to indicate a typical lamellar microstructure of sprayed coatings [12,26] consisting of metal oxide particles, porosity and partly melted or unmelted particles, which results in an uneven surface with micro-cracks in the ceramic phase. This network of microcracks is caused by the quenching stresses during the cooling of the ceramic lamella. Cracks in the ceramic phase are an inherent phenomenon occurring at the LVOF deposition of ceramic particles [4]. However, the coating cross-section shows no presence of cracks penetrating through the coating thickness, which could negatively influence the coating wear properties. Results of the chemical composition spot analysis (Fig 3) reveals that the brighter splats were sprayed with the metallic powder and mainly consist of Ni and Al, Mo, O, Ti. On the other hand, the darker splats consist of chemical elements such as Ti, Al and O and were made from the Al 2 O 3 –40%TiO 2 ceramic powder.
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Cold Steel   John Styers pdf

Cold Steel John Styers pdf

He is part of a team, trained to do his job in a coldly calculated war of scientific weapons and mass destruction. But the touted push button warfare has limitations, and they demand the individual's ability to meet his enemy face to face, steel to steel, hand-to-hand. Whether he is a radar operator, a communications man or a truck driver, he must be prepared to defend his own life in any eventuality. Close combat has been skillfully developed into a science of self-preservation - and the advance of death-dealing devices does not preclude the necessity for a basic knowledge of hand to hand principles and confidence in their application. A Warning Word...
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The Structural Behaviour of Concrete Filled Steel Tubular columns

The Structural Behaviour of Concrete Filled Steel Tubular columns

Cold formed steel sections offer flexibility and versatility in producing a variety of cross section shapes, which are obtained by bending relatively thin metal sheets using either a cold rolling or a press braking process at room temperature. Cold formed thin walled members offer several advantages of economy and efficiency, including a high strength for a light weight, a relatively straight forward manufacturing process and an ease of transportation and erection.

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Characteristics of Resistance Spot Welding for 1 GPa Grade Twin Induced Plasticity Steel

Characteristics of Resistance Spot Welding for 1 GPa Grade Twin Induced Plasticity Steel

For the last few decades, formability and weldability of steels have been intensively investigated to increase the productivity and the safety in automotive companies. Recently, steel which has both high ductility and high tensile strength is required to reduce vehicle weight. Twin induced plasticity (TWIP) steel has high tensile strength as well as improved ductility and is applicable to automobiles. Since, TWIP steel is an austenitic alloy which contains high content of Mn, it would have different resistance spot welding characteristics comparing with dual phase (DP) steel. In this work, TWIP steel, the newly developed steel, was introduced. To identify the resistance spot welding characteristics of 1 GPa grade TWIP steel, the experiments for both DP and TWIP steels were conducted. Resistance and power signals were measured to analyze the welding characteristics. The suitable welding ranges were also obtained with the lobe diagrams for these steels. In order to analyze the weld, shear tension and hardness tests, and a microstructure analysis were conducted. Both steels show a different microstructure in base metal, heat affected zone, and nugget. Because of the different microstructures between the two steels, the two steels showed different hardness distribution and tensile shear strength in the weld. Also, the differences in dynamic resistance signal, welding power signal, and welding heat input are shown between the two steels. These distinctions in microstructure and welding process characteristics caused the difference in suitable welding range. As well, this study provides guidelines to the application of DP and TWIP steels in resistance spot welding for vehicle manufacturing process. [doi:10.2320 / matertrans.M2012167]
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