• Laser Solutions
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• v.3 no.2
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• pp.45-51
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• 2000

In this paper, the possibilities and the limits of the laser seam welding were studied to utilize the advantageous properties of amorphous metal foils. For the conventional welding method, the high heat transfer makes the crystallized zone of the work material unavoidable. The laser is able to weld the amorphous metal without a crystallized zone, because heat transfer is limited within a very small restricted volume. The crystallized zone is restricted in the neighbor of welding spot and not in the melting area. This can be proved directly by the etching and indirectly by the tensile shear test, micro hardness test and bending test. The overlapping of welding bead could form the formation of wider and thicker amorphous zone.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.71-73
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• 2006

Magnesium alloys are becoming important material for light weight car body, due to their low specific density but high specific strength. However they have a poor weldability, caused high oxidization tendency and low vapor temperature. In this study, the laser welding performance of magnesium alloys was investigated for automobile application. The materials were rolled magnesium alloy sheet contains 3%Al and 1%Zn. To evaluate the weldability, we examined the appearance of welding bead. The mechanical property was measured for welded specimen by tensile test. And formability was checked with the Erichsen tester. For the results, the performance of weld in laser welding was enough for press forming such as car body. But it was recommended to use filler wire for reduce the under fill.

• Journal of Ocean Engineering and Technology
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• v.10 no.1
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• pp.36-46
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• 1996

This paper deals with determinig the proper friction welding condition and analyzing various mechanical properties of friction welded joints of sintered carbide tool materials(K20, P25, and SKDX5 for the blade part of drill or press punch) to alloy steel (SKH4, SCM440 for the shank part of drill or press punch), the alloy steel to aluminum(A6061 for the interlayer material between the blade part and the shank) and sintered carbide tool materials to alumminum. And also acoustic emission test will be carried out during fiction welding to evaluate the weld quality.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.803-808
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• 2000

This thesis studied whether friction welding of SPSS, localized torsion bar material could be accomplished or not. And then optimum welding conditions were examined and leaded through tensile, impact, torsion and hardness test after postweld heat treatment of the actual field condition. Obtained results were as follows; Linear relationship was existed between heating time and total upset, and a quadratic equation model could be made between tensile strength and heating time. Optimum welding conditions with fine structure were as follows in case total upset(U)=8.5mm; the number of rotations(n)=2,000 rpm, heating pressure($p_1$)=80MPa, upset pressure($p_2$)=200MPa, heating time($t_1$)=4sec, upset time($t_2$)=3 sec.

• Journal of Welding and Joining
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• v.28 no.4
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• pp.49-54
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• 2010

Stainless steel sheets are widely used as the structural material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the GMAW (gas metal arc welding). For fatigue design of GMA welded joints such as fillet and plug, ring type joint, it is important to obtain optimum design factor information on GMA welded joints. in this paper, analysis approach for fatigue test using design of experiment are evaluated optimum factor in GMA welded joint type and geometrical parameters of materials. Using these results, that factors applied to fundamental information for fatigue design.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2053-2058
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• 2008

Extruded aluminium panels have been widely used for railway vehicle structures because of their light specific weight and other merit. In the past, GMAW (Gas Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding) were mainly used to join aluminium panels. But recently friction stir welding (FSW) is widely used. due to its lots of advantage. In this study aluminium A6005-T6 which are used for car body structures was chosen. The influence of main parameters such as : pin rotating speed, welding speed, shoulder diameter, pin length and tilting angle on mechanical properties was examined. Optical microscope observation, micro hardness test and tensile test were carried out. Tensile strength of the stir welded plates is 74% of that of the base material.

• Bulletin of the Society of Naval Architects of Korea
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• v.10 no.2
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• pp.3-8
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• 1973

In a recent year, welding is known as a most powerful process in production of pipe. For the conventional purpose, pipe is welded in axial direction to minimize the welding cost. And for the high pressure pipe, welding is done in helical direction to increase a allowable hoop stress. An analytical welding temperature distributions in a metal tube are obtained as a two dimensional case in quasi-stationary state. Numerical values which have been obtained by the analytical investigation shows a good agreement with the isocromatic lines which have been appeared at oxidized zone along the welds. Therefore it is thought that the analytical result can be used in estimating the heat effect upon the material such as a residual stress and strain, metallurgical change and etc..

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.386-391
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• 2002

Stainless rolling stocks are usually fabricated by spot welding process without painting. Indentation on the surface of the car body after spot welding injures the beauty of the stainless rolling stocks. In this study, electrode tips to reduce the indentation are developed and applied to the actual spot welding works. The developed tips are composed of head, nut hole far cooling water, body and resistance material. They provide large surface contact area with the base materials during spot welding and enhance the current density by necking. Experimental results using the developed tips show that small indentation and sufficient tensile shear strength is produced due to large contact area and enhanced current density.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.85-90
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• 2014

In this paper, the transient thermal and residual stress analysis of the welding of 9% Ni steel plates using the FEA software ABAQUS are presented. The 9% Ni steel plates are welded manually with welding consumables of 70% Ni based Inconel type super-alloys (YAWATA WELD B (M)), producing a multi-pass/multi-layer butt weld. For these materials, temperature dependant mechanical and thermal material properties are used in the analysis. The back gouging is considered in welding process simulation. The FE thermal results are validated by comparing the real fusion profile and heat affected zone (HAZ). In addition, the continuous indentation test was conducted to measure the strength of base metal, HAZ and weld metal.

• Journal of Welding and Joining
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• v.9 no.2
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• pp.37-43
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• 1991

In order to analyze the mechanical phenomena of three dimensional elato-plastic behavior caused by welding of thick plate, it is necessary to solve exactly the three dimensional unstationary heat conduction problem considering the moving effect of heat source and the temperature-dependence of material properties. In this paper, the three-dimensional unstationary heat conduction problem is formulated by using an isoparametric finite element method. Thereafter, the transient temperature distributions, according to time, of thick plate during welding are defined from the results calculated by the developed computer program.