The purpose of this study is to research into which characteristic is shown according to a change in filler metal in case of CO2 gas arc welding by using Automobile Structural Steel(ATOS80). The major characteristics of this study were experimented by having Bevel angle as 50°, Root gap as 3mm, Filler metal as Solid wire & Flux wire, and the projected length of wire as 15mm. This study made the welded test specimens for the KS specification in advance suitably for the conditions, thereby having comparatively analyzed with the data value that was obtained through tensile test, hardness test, impact test and Macro Structure Detecting. Arranging the results that analyzed finally, the tensile strength and the hardness appeared to be excellent in case of welding with flux wire. The impact strength was indicated to be superior in case of welding with solid wire.

In GMAW welding used mostly at the scene of a welding industry, welders can not see control panels in internal welds of vehicles and tanks, and can not adjust the current and voltage properly during the welding, which is caused by distance from the working area. Therefore, welders have to move to control the current and voltage by stopping welding. This, however, can result in the welding defects by momentary cooling. In this research related to the existing GMAW welding methods and the manners with the remote control torch their performances were evaluated by comparing and analyzing the welds of V-type butt using SM50A 6 mm and welding structural rolled steels. As the result of conducting the visual inspection and bending test one by one against the V-type butt welds, the amount of spatter by the remote control torch method showed reducing effects about five times lower and it had a performance that did not affect the weld defects by displaying suitable effects on the bending test of welds. Consequently, the experimental study on the possibility of replacement and compatibility with the existing commercial welder for the remote control torch was performed.

The purpose of this study is to determine more variables in welding characteristics of ATOS(steel for automobile structure) 80 high tensile steel available in market, and in terms of welding using GMAW(gas metal arc welding), this study seeks to examine how welding characteristics of ATOS 80 may vary depending on protrusion length of wire electrode. The major characteristics of this study can be summed up as follows, this study analyzed welding characteristics of ATOS 80 by changing the protrusion length of wire electrode (10㎜, 15㎜ and 20㎜) in welding section, and also used visual inspection and radiograph test to examine observations of major defects on welding section.

The purpose of this study is to determine more variables in welding characteristics of ATOS(Steel for Automobile Structure) 80 high tensile steel available in market, and examine how welding characteristics of ATOS 80 vary depending on changes in improvement angle of welding sections. In regard to major characteristics of this study, it focused on analyzing welding characteristics of ATOS 80 by changing improvement angle of welding sections into 40°, 50° and 60° and by changing root gap into 2㎜ and 3㎜. And it also used radiograph test to examine observations of major defects on welding section.

개조한 가스 금속 아아크 용접공정을 이용하여 SiC/AI 금속기 복합재료를 제조하고 그 특성을 조사하였다. AI 모재위에 강화입자의 크기와 부피분율을 변화하여 다양한 SiC/AI 복합재료층을 제조하였고, 만들어진 복합재료층의 특성은 미세조직관찰과 미소경도시험을 통하여 이루어졌다. 복합재료층의 두께는 약 7-8mm로 측정되었고 균일한 강화입자의 분포도를 얻을 수 있었다. 분산입자의 부피분률은 Ar가스의 유량에 의하여 조절하였고 분산입자의 부피분률이 증가하고 크기가 작아짐에 따라 기지의 수지상 응고조직은 더욱 미세화되었다. 복합재료의 부피경도는 분산입자의 부피분률이 감소함에 따라 낮아졌으나 입자 크기에는 크게 변화가 없는 것으로 나타났다.