• Journal of Welding and Joining
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• v.4 no.3
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• pp.32-42
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• 1986

In this study, the influence of carbon equivalents on friction welds of dissimilar steels was investigated. Four types of carbon steels with 10mm diameter were welded to a high-speed tool steel SKH 9. Main experimental results could be summarized as follows (1) Under constant friction pressure, the friction time increased almost linearly with the increasing burn-off length, while the forge length decreased almost linearly. (2) The maximum hardness in carbon steels increased almost linearly with the increasing carbon equivalent, but was much lower than that in the high speed steel. (3) After quenching and tempering of dissimilar steel friction welds, the hardness in carbon steel weldments became similar as that in the base metal, while the hardness in SKH 9 weld was still higher that of the base metal. (4) Relative movement in the friction phae occurred not at the interface of the weldments, but in the high speed steed steel near the interface. (5) For considered material combinations and welding parameters, most of fractures in tension and twisting tests occurred in the base metal. And welds with so high strength could produced in a wide range of welding parameters.

• Journal of Welding and Joining
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• v.10 no.1
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• pp.35-42
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• 1992

In this study, the stress concentration phenomenon for the dissimilar joints(ceramic-metal) bonded by thermal treating using a soft-insert metal(copper) was investigated with the aid of FEM(finite element method) under the load condition of uniform tension. The analysis was carried out by the supposing that stress states are plane stress or plane strain and elastic or elastic-plastic. And the Von Mises yield criterion and the incremental theory as plastic flow were adopted in this analysis. As the summarized results obtained, the stress concentration phenomenon was severer as the soft insert metal was thicker, in plane strain than in plane stress and in elastic-plastic state than in elastic state. Furthermore, the inducing mechanism of stress concentration was well expressed by the constraint forces(Fc) generated between the soft and the hard material.

• Journal of Welding and Joining
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• v.31 no.5
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• pp.64-70
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• 2013

The joining of Ti and SUS304 dissimilar metals is one of the effective measures to save rare metal. But Ti and SUS304 have differences in materials properties, and Ti and Fe intermetallic compounds such as TiFe and $TiFe_2$ are easily formed in weld fusion zone between Ti and SUS304. Nevertheless, in this study, full penetration lap dissimilar welding of Ti and SUS304 using single-mode fiber laser with ultra-high welding speed was tried, and it was found out that ultra-high welding speed could control the generation of intermetallic compound. To recognize the formation of intermetallic phase in the weld fusion zone and the compound zone of interface weld area were observed and analyzed using energy dispersive X-ray spectroscopy (EDX). And it was confirmed that the ultra-high welding speed could reduce amount of intermetallic compounds, but the intermetallic compounds were existed in the weld fusion zone under the all conditions.

• Journal of Welding and Joining
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• v.25 no.4
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• pp.1-3
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• 2007

• Coupled systems mechanics
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• v.7 no.5
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• pp.627-634
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• 2018

Laser beam welding is more advantageous compared to conventional methods. Titanium/Aluminium dissimilar alloy thin sheet metals are difficult to weld due to large difference in melting point. The performance of the weldment depends upon interlayer formation and distribution of intermetallics. During welding, aluminium gets lost at the temperature below the melting point of titanium. Therefore, it is needed to improve a new metal joining techniques between these two alloys. The present work is carried for welding TI6AL4V and AA2024 alloy by using Nd:YAG Pulsed laser welding unit. The performance of the butt welded interlayer structures are discussed in detail using hardness test and SEM. Test results reveal that interlayer fracture is caused near aluminium side due to low strength at the weld joint.

• Journal of Welding and Joining
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• v.31 no.4
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• pp.54-61
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• 2013

This paper reports mild steel(SPHC) and stainless steel(STS304) sheets commonly used for railroad cars or commercial vehicles such as in the automobile and shipbuilding industries. The sheets are used in these applications, which are mainly fabricated using the shielded metal arc welding(SMAW) of dissimilar materials. It also reports an interesting application of Laser Induced Breakdown Spectroscopy(LIBS) in order to determine the elemental composition diffusion of SPHC and STS304. Arc blow produced by magnetic force during the electric arc welding prevents the formation from a sound weldment. In particular, the mechanical properties of the joint are influenced by not only by geometrical and mechanical factors but also the welding conditions for the arc welded joint. Therefore, the mechanical properties and performance are evaluated by performing a physicochemical component analysis. And they increase in accordance with content of elements and microstructure in mild steel. As results, appropriate range for magnetic fields could be achieved. Therefore, the effect of magnetic force in a butt weld of mild steel plates was investigated by comparing to the measured data.

• Journal of Welding and Joining
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• v.34 no.3
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• pp.61-68
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• 2016

Characteristics of dissimilar metal welds between alloy steel ASTM A387 Gr. 91 and carbon steel ASTM A516 Gr.70 made with Flux cored arc welding(FCAW) have been evaluated in terms of microstructure, mechanical strength, chemical analysis by EDS as well as corrosion test. Three heat inputs of 15.0, 22.5, 30.0kJ/cm were employed to make joints of dissimilar metals with E91T1-B9C wire. Post-weld heat treatment was carried out at $750^{\circ}C$ for 2.5 h. Based on microstructural examination, tempered martensite and lower bainite were formed in first layer of weld metal. The amount of tempered martensite was decreased and the amount of lower bainite was increased with increasing heat input and layer. Heat affected zone of alloy steel showed the highest hardness due to the formation of tempered Martensite and lower Bainite. Tensile strengths of dissimilar welds decreased with increasing heat inputs. Dissimilar welds seemed to have a good hot cracking resistance due to the low HCS index below 4. The salt spray test of dissimilar metals showed that the corrosion rate increased with increasing heat inputs due to the increase of the amount of lower Bainite.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.98-103
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• 2008

This paper is to discuss distribution of welding residual stresses of a ferritic low alloy steel nozzle with dissimilar metal weld using Alloy 82/182. Two dimensional (2D) thermo-mechanical finite element analyses are carried out to simulate multi-pass welding process on the basis of the detailed and fabrication data. On performing the welding analysis generally, the characteristics on the heat input and heat transfer of weld are affected on the weld residual stress analyses. Thermal analyses in the welding heat cycle process is very important process in weld residual stress analyses. Therefore, heat is rapidly input to the weld pass material, using internal volumetric heat generation, at a rate which raises the peak weld metal temperature to $2200^{\circ}C$ and the base metal adjacent to the weld to about $1400^{\circ}C$. These are approximately the temperature that the weld metal and surrounding base materials reach during welding. Also, According to the various ways of appling the weld heat source, the predicted residual stress results are compared with measured axial, hoop and radial through-wall profiles in the heat affected zone of test component. Also, those results are compared with those of full 3-dimensional simulation.

• Korean Journal of Materials Research
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• v.19 no.7
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• pp.369-375
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• 2009

The spot weldability of dissimilar metal joints between stainless steels (AISI316) and interstitial free (IF) steels were investigated. This study was aimed to determine the spot welding parameters for a dissimilar metal joint and to evaluate the dissimilar metal joint's weldability, including its welding nugget shape, tensileshear strength, hardness, and microstructure. The fracture surface was investigated by using a Scanning Electron Microscopy (SEM). The experimental results showed that the shape of nugget was asymmetric, in which the fusion zone of the STS316 sheet was larger due to the higher bulk-resistance. The microstructure of the fusion zone was fully martensite. In order to evaluate the microstructure further, dilution of stainless steels were calculated and imposed onto the Schaeffler diagram. The predicted microstructure from the Schaeffler diagram was martensite. In order to confirm the predicted microstructure, XRD measurements were carried out. The results showed that that initial weld nugget was composed of austenite and martensite.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.41-41
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• 2009

To evaluate the applicability of dissimilar joining between Mg and Al alloys in automobile manufacturing process, solid state joining processes such as magnetic pulse welding(MPW), friction stir welding(FSW) and friction spot joining(FSJ) were attempted successfully. MPW process has been concentrated mainly on round section tube to tube and tube to bar welds. AZ31 Mg alloy has been successfully welded to pure Al A1070 as well as to Al alloy A3003. While, for friction stir welding of dissimilar sheet joints, AZ31B/A6061 with the thickness of 2mm were used and a square butt joint with a good quality was obtained at the conditions of 0.8mm/sec of travel speed and tool rotation speed of 850rpm. The maximum tensile strength of 179 MPa, which was about 80 % of the Mg base metal tensile strength, has been obtained. Finally, friction spot joining was attempted to make a dissimilar lap joint between AZ31(0.8mm) and A6061(1mm), while the joint exhibited the same level of tensile shear strength as that of similar Mg joint.