A high-strength steel plate with excellent low-temperature toughness and its manufacturing method

Abstract

The invention discloses a high-strength steel plate with excellent low-temperature toughness and a manufacturing method thereof. The steel plate is prepared from the components of C, Si, Mn, P, S, Cr,Nb, V, Ti and B as well as the balance of Fe and impurities; in addition, the contents of the components are required to meet the following relationship: the sum of Nb and Ti is smaller than or equalto 0.06. The manufacturing method is characterized in that the content of C is reduced in the components of steel grades, and precious metal Ni is not added; the heating temperature, the rolling temperature and the cooling rate of a casting blank are controlled by adopting a TMCP process, so that the casting blank is fully austenitized; and Nb and Cr alloys are fully dissolved into austenite, sothat good structure properties are obtained and the strength and the low temperature impact toughness of a steel plate are improved. For the steel plate provided by the invention, the yield strength ReL at normal temperature is greater than or equal to 900 MPa, tensile strength Rm is greater than or equal to 1000 MPa, the elongation percentage A is greater than 13 percent, and impact energy KV2 atthe temperature of 40 DEG C below zero is greater than 200 J; and the high-strength steel plate is suitable for main bearing steel members such as lazy arms of engineering machinery, platform steel members, pressure bearing tank bodies of containers, suspenders of bridges and the like, and has good economic benefits and social benefits.

Description

technical field [0001] The invention relates to the technical field of steel manufacturing, in particular to a high-strength steel plate with excellent low-temperature toughness and a manufacturing method thereof. Background technique [0002] High-strength and tough ship plate steel is generally controlled rolling or normalizing heat treatment by adding microalloying elements. With the development of society and technological progress, bridges, containers, construction machinery, ship plates and other industries have put forward more requirements for the performance of their own steel plates. . The steel plate is required to have higher strength to reduce the weight of the steel plate, and the steel plate is required to have good low-temperature impact toughness to expand the use field and application environment of the material. At the same time, the composition design of the steel plate is required to ensure the balance of strength elements and anti-sensitivity coefficien...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to propose a high-strength steel plate with excellent low-temperature toughness and a manufacturing method thereof, so as to solve the problems of high carbon content, high alloy content, long manufacturing process, large energy consumption, and high manufacturing cost of the steel plate of the existing load-bearing steel member, The thickness specification of the steel plate is 10~30mm, and the heat treatment process is eliminated in the process. The yield strength ReH≥900MPa at room temperature, the tensile strength≥1000MPa, the elongation A>13%, and the impact energy KV at -40℃ 2 >200J, with excellent low temperature toughness and high strength, suitable for the construction of steel structures for ships and ocean engineering

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