600 MPa grade TMCP steel with low yield ratio and excellent weldability

摘要

A new lower cost 600 MPa TMCP steel with high strength, good low temperature impact toughness, low yield ratio and excellent weldability has been developed successfully by design of alloy composition and thermal mechanical control process technology, and the welding heat affected zone (HAZ) have been investigated. The systematic studies show that the new developed steels gather high strength, high low temperature toughness, good seismic performance (low yield ratio) and excellent weldability, and the base steels have a good match of strength and toughness. A large number of fine acicular ferrite in HAZ can ensure that the welding plate has high strength and good low temperature impact toughness. The comprehensive performance of steel can meet fully the high-technical requirements of large-scale engineering.