ATOS 80 용접재의 기계적 특성에 관한 연구

Abstract

In this study, mechanical properties were investigated and compared such as tensile strength test, hardness test and impact test in ATOS 80 high-strength steel with welded specimens using a flux-cored arc welding in accordance with welding conditions. The results were obtained as follows; 1. In the welding conditions, similar tensile strengths show for both 4-pass and 5-pass methods under unconstrained conditions; however, the tensile strength in 4-pass is much higher than that in 5-pass way under constrained conditions due to less heat-effected area. Also, it was found that amount of protective gas showed similar values​​ such as 15ℓ/m and 20ℓ/m and it was thought that both 4-pass and 5-pass methods are considered as appropriate welding conditions. 2. It was found that the stable hardness in amount of 15ℓ/m shielding gas could be obtained more than amount of 20ℓ/m shielding gas. 3. Under unconstrained welding conditions, the highest impact value appears at amount of 20ℓ/m shielding gas with the 4-pass method; however, under constrained welding conditions, the lowest impact value show at amount of 20ℓ/m shielding gas with the 5-pass method because the welding area was vulnerable from the turbulence phenomenon. 4. Through tensile test, Vickers hardness test and the Charpy impact test results, the mechanical properties in the ATOS high strength steel were investigated and the properties could have slightly different value under working environment. It was thought that the welding method at amount of 20ℓ/m shielding gas with the 4-pass method could be considered as most optimal ways under unconstrained welding conditions.