ROLLED STEEL PRODUCT EXCELLENT IN WEATHERABILITY AND FATIGUE RESISTING CHARACTERISTIC AND METHOD OF PRODUCTION THEREOF

摘要

A simple method of producing at a low cost a rolled steel product which is used for a steel structure member such as a bridge and a steel tower to be installed on a seashore where there is a possibility of a corroded steel product and a fatigued joint due to scattered sea salt particles and in an area where snow melting salt is used, which is excellent in weatherability and fatigue resisting characteristic, which is a building construction steel product containing 0.02 to 0.20 wt.% of C and trace amounts of Ni, Cu and Mo as added essential elements, and which has a Ni/Cu concentration ratio of not less than 0.8, not larger than 2 mu m of inner oxidation layer in the steel product surface and concentrated layers of Ni, Cu and Mo not smaller than 2 mu m deep on the inner oxidation layer.