Welding Metallurgy of
01 Jan 1987-
About: The article was published on 1987-01-01 and is currently open access. It has received 991 citations till now. The article focuses on the topics: Welding.
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TL;DR: In this article, the authors dealt with the fatigue life assessment of the transverse fillet weld and transverse weld on weld fatigue specimen of the offshore steel S460G2+M with a thickness of 10 mm.
Abstract: This study deals with the fatigue life assessment of the transverse fillet weld and transverse fillet weld on weld fatigue specimen of the offshore steel S460G2+M with a thickness of 10 mm. These specimens were joined using gas metal arc welding (GMAW) with ER80S-N1 filler metal of 1.0 mm in diameter and mixed gases of 80% Ar + 20% CO2 as the consumables. Upon the welding completion, some of the fatigue specimens are treated using high-frequency mechanical impact device called pneumatic impact treatment (HFMI/PIT). The treatment procedure uses 90Hz of frequency, 6 bars of pneumatic pressure and 2 mm pin radius with aims to enhance the lifespan of the specimen. These fatigue specimens are classified in as-welded and HFMI/PIT. The fatigue test was conducted to all fatigue specimens until failure using a 250KN Instron fatigue machine with a constant amplitude loading, a stress ratio of 0.1 and stress loading from 55% to 75% of the yield strength of the base material. The fatigue data were evaluated based on the International Institute of Welding (IIW) evaluation procedures. Further, the fatigue life comparison between the as-welded and HFMI/PIT of both fatigue specimens also with the FAT class recommendation of the IIW for transverse fillet weld is plotted in the S-N curve diagram. Based on the assessment, it is found that the HFMI/PIT fatigue specimens attained higher fatigue life than the as-welded of both fatigue specimens. The most significant of fatigue life improvement after the HFMI/PIT is the HFMI/PIT transverse fillet weld. These treated welds obtained 256 MPa of FAT class which is 79 % higher than FAT class recommended by the IIW for the transverse fillet weld. Besides, the multi-pass welds on the groove weld of the transverse fillet weld on welds are found to contribute to a lower fatigue life of this specimen due to the existing weld defects on the fractured surface of the groove weld.
4 citations
Cites background from "Welding Metallurgy of"
...The amount of metallurgical destruction in the HAZ also would depend on the volume of heat input, the peak temperature reached, distance from fusion zone, time at elevated temperature, cooling rate, and the metal’s thermal properties [8]....
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TL;DR: In this article, the effects of groove angle on tensile and impact strength of the joints were investigated and it was concluded that the 50° groove angle is the best groove design and less number of welding electrodes is required to fill this joint compared with 60° or 70° angle.
Abstract: Objective: To investigate the effects of groove angle on tensile and impact strength of the joints. Methods: To achieve above objective various groove designs having included angle of 50°, 60° and 70° were prepared using a shaper. The weld grooves were completely filled using shielded metal arc welding process. All the weld joints were subjected to visual inspection, dye penetration test and radiographic test. Then tensile and impact specimens were removed from these joints. The tensile and impact specimens were machined in accordance with ASTM E8M-09 and ASTM E23-12C specifications. The tensile and impact strength was evaluated using universal testing machine. Findings: The tensile strength of the specimen having groove angle as 50° is 513.68 MPa which is more than that of the specimen having 60° and 70° groove angle. The tensile strength of base material used is 540 MPa. It is clear that the tensile of the joint is less than base material used. The joint efficiency obtained is 95.12% which is the highest compared with other joint i.e. 60° and 70°. It is further observed maximum impact strength achieved is 53.45 Joule at 50° groove angle. The tensile and impact strength provided by the joint having groove angle as 70° is 471.29 MPa and 39.15 J respectively which is minimum amongst all the joints produced.It can be concluded that 50° groove angle is the best groove design. Moreover less number of welding electrodes is required to fill this joint compared with 60° or 70° groove angle. Hence it is more economical also. Application: This research is useful for industries which are engaged in fabrication work for designing of correct and economical welding grooves.
Keywords: Groove Design, Impact Strength, Radiography, Shielded Metal Arc Welding, Tensile Strength
4 citations
TL;DR: In this article, the influence of the welding parameters on the economical, geometric and coarse-grained heat-affected zone of the weld beads of high-hardness steel was determined.
Abstract: High-hardness steel is widely used in the armor industry due to their mechanical properties that combines hardness and toughness, which generates a great resistance to the impact of projectiles. Almost all applications in the armor industry include the welding of its components; however, several modifications could happen in the microstructure. For instance, one main region involved in the welding performance is the coarse-grained heat-affected zone (CGHAZ), especially in high-hardness steel, due to the formation of highly brittle, non-tempered martensitic. Furthermore, studies concerning the influence of the variations in welding parameters and the addition of cold wire have not been conducted so far. In this paper, we determined the influences of the welding parameters on the economical, geometric and coarse-grained heat-affected zone of the weld beads. In addition, the influences of the cold wire are also shown. To perform the experimental procedure, two parameters were tested: the industrial parameters, used for the conventional steel welding, and the experimental parameters, obtained in this study. The welding velocity and dilution were 150% and 53% higher, respectively. Besides, the deposition rate was 100% greater for the improved parameters with a 50% reduction in the CGHAZ area.
4 citations
01 Jan 2020
TL;DR: In this paper, a computational model of dendritic growth based on the CALPHAD thermodynamic model was developed, which allows for the investigation of some practical alloys such as stainless steels.
Abstract: A computational model of dendritic growth based on the CALPHAD thermodynamic model was developed in this study. The dendrite growth was simulated using cellular automata (CA) with the equilibrium conditions in interfacial cells. The developed novel model (CA-CALPHAD) overcomes the current limitation of the published CA models, in which linearized phase diagrams are used, and allows for the investigation of some practical alloys such as stainless steels. To reduce the computational time, the study proposes a specific data structure to store the thermodynamic information and an efficient interpolation scheme to retrieve the information during the simulation. The model takes into account the curvature effect of the evolving solid/liquid (S/L) interface by incorporating the capillarity undercooling into the thermodynamic information during the simulation. The finite volume (FV) numerical scheme was used to solve the mass and heat diffusion equations. The developed CA-CALPHAD model can be used to investigate the free growth, constrained growth, and competitive growth of dendrites in response to different solidification parameters. The results of modeling include the dendrite morphology, dendrite size, solute segregation in the dendrite, dendrite growth rate, dendrite tip radius, and the spacing between primary and secondary dendritic arms. Finally, a procedure of linking the developed CA-CALPHAD model to a computational welding mechanics tool (CWM) was developed producing a holistic multiphysics model (CWM-CA-CALPHAD). Therefore, the model can be used to predict the microstructure of a weld in response to realistic welding parameters and weld joints design.
4 citations
Cites background or methods from "Welding Metallurgy of"
...Chalmer et al [9] proposed the constitutional supercooling theory, an experimentally validated theory, that describes the effect of solidification parameters on microstructure morphology....
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...< 100 >for both FFCCCC and BBCCCC materials) and/or in the direction of the maximum temperature gradient, the growth will be relatively fast [9]....
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...11 interface will be flat if TTGG VV ≥ ∆TT0 DDLL [9], where TTGG is the thermal gradient, VV is the growth rate, ∆TT0 is the equilibrium freezing range, and DDLL is the diffusion coefficient of solute atoms in liquid....
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...As a welding speed increases, the weld pool becomes longer and narrower (teardrop shape), and in contrast, the weld pool becomes elliptical as the welding speed decreases [9]....
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...According to the presented description in [9] and illustrated in Figure-1....
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References
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TL;DR: In this article, the fundamental understanding of structure-properties relationship in automotive steels resistance spot welds is discussed. And a brief review of friction stir spot welding, as an alternative to RSW, is also included.
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