High tensile strength 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 0.052%-0.08%, Si 0.1%-0.5%, Mn1.65%-1.90%, Nb 0.015%-0.060%, Ti 0.005%-0.03%, B 0.0005%-0.003%, Mo 0.25%-0.50%, Cu 0.62%-0.85%, Ni 0.42%-0.80%, Al 0.015%-0.05%, and 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, Mo, Ni, Nb, B to the bainite. The steel has low carbon, good low temperature toughness, welding performance, and forming performance. Its Nb and Ti element is low. And it is fit for large-scale industrialization continuous casting production. The TMCP+ RPC+T technique is adopted to make tensile strength over 900N/mm2 high intensity and tenacity steel. Adopting lower steel blank heating temperature can economize energy and improve steel low temperature toughness. The product can 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, in particular to a low-carbon bainite thick steel plate with high tensile strength and a production method thereof. Background technique [0002] In the past, quenching and tempering methods were mostly used to produce high tensile strength steel grades, which have high content of chemical elements, long production cycle, high carbon equivalent, poor welding performance and high production cost. [0003] 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. [0004] The Chinese patent of "a relaxation-precipitation-controlled phase transition technology for the production of high-strength low-alloy steel" applied by Beijing University of Science a...

AI Technical Summary

Problems solved by technology

This technology only uses controlled rolling and controlled cooling + tempering process in the production process, the strength level of steel is relatively low, and its tensile strength is 900N / mm 2 Level below, and the thickness of the steel plate is generally below 10mm