High toughness low carbon bainite thick steel plate and its production method

Abstract

The invention offers a high tensile strength low carbon bainite coarse plate and its manufacturing method. Its compositions (Wt%) are C 0.04%-0.08%, Si 0.1%-0.5%, Mn 1.4%-1.85%, Nb 0.015%-0.060%, Ti 0.005%-0.03%, B 0.0005%-0.0030%, Cu 0.10%-0.60%, Ni 0.05%-0.6%, Al 0.015%-0.05%, rest Fe and other inevitable impurity. The invention adopts low cost Mn element as the main additional element, fully applies the changing action of Cu, Ni, Nb, B to the bainite. The steel has low carbon content, good low temperature toughness. The turning temperature is under -80 centigrade degree. Welding performanc e is good and simple. Forming is good. TMCP+RPC technique is adopted to improve steel tensile strength, reduced cost. The product can widely apply in engineering machinery, digging machinery, heavy-duty car, and marine facilities field, and etc.

Description

technical field [0001] The invention belongs to the field of metal materials, and in particular relates to a high-strength toughness low-carbon bainite thick steel plate and a production method thereof. Background technique [0002] The low-carbon bainite steel developed in the early stage has low Mn content, high content of Cr and Ni elements, high cost of steel, and unsatisfactory effect on promoting the bainite transformation of the entire structure, so the strength level of the steel is not high, and the production raletively hard. [0003] Wuhan Iron and Steel Group Corporation has an application number of 97109312.1, a Chinese patent named "Copper-boron low-carbon and ultra-low-carbon bainite high-strength steel", whose tensile strength can reach 590N / mm 2 Above grade, it contains about 0.5% Cu, but does not contain Ni. If the heating temperature is not appropriate, cracks and other defects are easy to appear on the surface of the steel plate, and the thickness of the...

AI Technical Summary

Problems solved by technology

This technology is only suitable for yield strength 800N / mm 2 However, the content of Nb and Ti elements is relatively high, and the weight percentages are 0.091 and 0.08 respectively, which brings great technical difficulties to continuous casting production, which is not conducive to large-scale industrial continuous casting production, and the excess of Nb and Ti after combining with N Ti also causes a decrease in impact toughness

This technology uses a higher billet heating temperature, which will affect the low temperature toughness of the steel