抄録
After the oil crisis, the developments of off shore fields have reached to North Sea and Arctic Sea. New welded steel structures such as a caisson and an ice breaker have been in progress. Weldments of them require multi-performance characteristics including high strength, high toughness in high heat input condition, resistance for local corrosion and SSC, etc. Many kinds of steels and weld techniques have been developed to meet these demands. Weldability of steel has been largely improved by TMCP. Weld metals provide enough toughness, strength and resistance for SSC as well as steels but are inferior in resistance for cold crack. Because it is difficult to control the cooling rate during weld and CEQ of weld metal can not be reduced. The chemical compositions should be balanced between weld metal and base plate to avoid local corrosion. Recent progress of steels and welds are described.
