Ultra-fine grained martensite steel plate and preparation method thereof

Abstract

The invention discloses an ultra-fine grained martensite steel plate and belongs to the technical field of alloy steel. By adopting a V / C reasonable ratio and controlled rolling, an ultra-fine grained structure is obtained under the traditional heat treatment process conditions, and the ultra-fine grained structure comprises the following chemical compositions in percentage by weight: 0.10 to 0.50 percent of C, 0.1 to 0.50 percent of Si, 0.30 to 1.50 percent of Mn, V which meet the formula shown in the specifications, less than 0.02 percent of P, less than 0.01 percent of S and the balance of Fe and inevitable impurities. On the basis, one or more alloy elements, such as 0 to 0.50 percent of Cr, 0 to 0.50 percent of Ni, 0 to 0.50 percent of Mo, 0 to 0.40 percent of Cu, 0 to 0.05 percent of Nb, 0.005 to 0.04 percent of Ti, 0.0005 to 0.003 percent of B and 0.01 to 0.06 percent of Al are added. The steel plate is subjected to controlled rolling and quenched by keeping the temperature of between 880 and 900DEG C, and the ultra-fine grained martensite structure of which the austenite grain size is less than 5 micrometers can be obtained; and moreover, the process is simple and can adapt to the current industrial production equipment and flows.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, and in particular provides an ultra-fine-grained martensitic steel plate and a preparation method thereof, in particular an ultra-fine-grained steel whose grain size of the original austenite is less than 5 microns. Background technique [0002] As we all know, grain refinement is the only way to improve the strength and toughness of metal materials at the same time, and other strengthening methods (such as solid solution strengthening, dislocation strengthening, precipitation strengthening, etc.) damage the toughness while increasing the strength. In addition, grain refinement also helps to improve service performance such as fatigue resistance and delayed fracture resistance of steel. Therefore, how to obtain fine-grained and ultra-fine-grained structures has always been a hot technical issue of concern and research and development in the steel industry. At present, quenching treatment is ...

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Problems solved by technology

The disadvantage of this method is that the process is cumbersome, and industrial production will face many difficulties; the rapid heating method uses the increase in the austenite nucleation rate during the rapid heating process to achieve the purpose of refinement, such as the induction rapid heating method and the electro-induced rapid heating method have been developed. The heating method can achieve ultra-fine grain structure, but this method requires special equipment, and there are many restrictions on the shape and size of the sample or part (see literature: Weng Yuqing et al., ultra-fine grain steel-steel structure refinement Theory and Control Technology, Beijing: Metallurgical Industry Press, 2003, p.467-520.); Low-temperature large deformation + short-time austenitization method uses a large number of defects caused by low-temperature deformation to increase the austenite nucleation rate, and at the same time Short-term heat preservation can prevent the grains from growing significantly, so as to achieve the effect of fine graining (see literature: M. Tokizane, N. Matsumura, K. Tsuzaki, T. Maki and I. Tamura. Recrystallization and formation of austenite in deformed lath martensitic structure of low carbon steels, Metallurgical and Materials Transactions A, Volume 13, Number 8, 1379-1388) However, large deformation at low temperature has high requirements for equipment capabilities, and short-time austenitization also faces many practical problems. Difficult, so the method is currently limited to laboratory research

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