용접열사이클 재현에 의한 SS400강 및 STS304강의 특성 평가 - 제2보: 부식특성

Abstract

The welding methods have been applied in the most structural products from multi-field of automobile, ship construction and construction, and so on. The structure steel must have enough strength of structure. In this study, SS400 steel and STS304 steel were used to estimate the corrosion characteristics of the weld thermal cycle simulated HAZ. To evaluate the corrosion characteristics, also, the materials with two conditions were used in 3.5% NaCl. The one is to the drawing with diameter of Φ10 and the other is to the residual stress removal treatment. The electrochemical polarization test and immersion test were carried out. From test results, corrosion potential, corrosion current density, weight loss ratio and corrosion rate were measured. In the kinds of SS400 steels, corrosion potential of weld thermal cycle simulated specimens after the heat treatment showed somewhat the direction of noble potential. And in the base metal to be drawing weight loss ratio and corrosion rate occurred higher than the other kinds. In the kinds of STS304 steels, the result of base metal to be drawing was similar to results of SS400 steels, too. Two kinds of 750 ℃ and 1300 ℃ of weld thermal cycle simulation after the heat treatment were rather higher than the other kinds in weight loss ratio and corrosion rate.1. 서 론최근까지 산업 전반에 걸쳐 다방면에서 용접에 의한 열영향부에 대한 연구는 사용 재료의 기계적 물성 등을 알기 위하여 중요하게 여겨져 왔다. 현대 산업에 있어서 용접은 자동차, 조선, 건설업 등의 여러 분야에서 구조물 제작의 대부분을 차지하고 있다. 특히, 조선공업에서는 용접이 차지하는 분야는 매우 크며, 앞에서 언급한 다른 산업분야에서도 그 중요성이 크다(이토우고로우, 1982). 이때 사용되어지는 구조용 강은 구조물에 필요한 강도 범위를 유지하고 있어야 하는데, 용접부의 국부적인 성질변화에 따른 구조물의 국부적인 기계적 특성변화