Ultrahigh-strength and high-toughness welded cast steel

Abstract

A high-strength and high-toughness welding cast steel consists of C 0.12-0.17 wt%, Si 0.10-0.50 wt%, Mn 0.8-1.2 wt%, S+P<=0.025 wt%, Ni 4.00-4.50 wt%, Cr 0.7-1.2 wt%, Mo 0.40-0.50 wt%, V 0.04-0.08 wt%, Cu 0.20-0.40 wt% and iron residue. The process is carried out by selecting electric furnace + AOD duplex smelting process, pouring and heating to obtain final product. The yield strength reaches above 800 MPa, V-shaped notch impact reaches above 55J at -20 degree. It can be used for ship, ocean and petrochemical industries.

Description

technology field; [0001] The invention relates to the field of metal materials, in particular to an ultra-high-strength and high-toughness weldable cast steel. Background technique; [0002] At present, in the field of iron and steel materials, cast steel can be divided into low-strength pearlite-ferritic steel and high-strength and ultra-high-strength quenched-tempered martensitic steel (or bainite steel) in terms of organization. Two categories. Since cast steel is a non-deformable material, it is impossible to use advanced metallurgical processes such as controlled rolling to improve its strength and toughness at the same time as rolled steel plates. At present, the traditional high-strength and ultra-high-strength quenched-tempered martensitic steel (or bainite steel) generally has a pair of contradictions between strength, toughness and weldability. In order to improve the strength, it is necessary to increase the C in the steel. And the total amount of alloying eleme...

AI Technical Summary

Problems solved by technology

[0004] It can be seen from Table 1 that the existing high-strength cast steel can reach very high strength, even exceeding 1000MPa, but its plasticity and toughness are poor, the elongation is about 10%, and the U-notch impact energy at room temperature is 30-40J; Cast steel is less weldable and even difficult to weld