Resistance to wear ratio high tensile strength steel with excellent low temperature toughness of welding heat affected zone and base metal and its manufacturing method

摘要

The low tensile ratio and high tension steel plate in the invention satisfies the scheduled chemical component composition; and in the microscopic constitution of t/4(t: thickness of the plate) position, in the whole constitution, ferrite fraction is 60-80 area %, insular martensite fraction is below 5% (containing 0%); the rest is composed by mixture structure of bainite structure; the average grain diameter of the ferrite is below 14 [mu]m; the vickers hardness Hv of the second phase is 265-40; according to the constitution, although welding by thermo-energetic input, the low-temperature flexibility of HAZ is excellent; and the low-temperature flexibility of the parent metal (steel plate) is excellent too.