Low cost yield strength 700MPA level non-tempering processing high strength steel plate and manufacturing method thereof

Abstract

The invention discloses a low cost yield strength 700MPA level non-tempering processing high strength steel plate, which is characterized by, in terms of mass, comprising 0.05-0.10% of C, 0.1-0.4% of Si, 1.5-2.0% of Mn, less than 0.015% of P, less than 0.01% of S, 0.3-0.8% of Cr, 0.09-0.15% of Ti, 0.04-0.08% of Nb, less than 0.005% of N, less than 0.002% of O, and balance of Fe and unavoidable impurities. The manufacturing method of the steel plate comprises technological steps of smelting, rough rolling, fine rolling, reeling and cooling to obtain the steel plate with yield strength of 700-780MPa, tensile strength of 800-860MPa and elongation Delta larger than or equal to 18%. The yield strength 700MPA level non-tempering processing high strength steel plate simultaneously has abrasive resistance and better low temperature toughness, toughness and crispiness transition temperature is at around negative 40 DEG C, specific energy of shock at normal temperature can reach as high as 120J.

Description

technical field [0001] The invention relates to a method for manufacturing a low-cost non-quenched and tempered high-strength steel plate with a yield strength of 700 MPa, and belongs to the technical field of hot-rolled high-strength steel plate production. Background technique [0002] At present, the 700MPa strength grade steel produced by different enterprises adopts the idea of ​​alloying, and different enterprises adopt different alloy compositions and alloy amounts. With the development of society and economy, the iron and steel industry is facing more and more pressure to save resources, save energy and protect the environment. At present, the production of 700MPa steel at home and abroad not only increases the cost of steel, but also increases the difficulty of recycling steel in the later stage due to the increase of alloy elements, especially rare elements, such as frequently added Mo. [0003] The production of 700Mpa steel at home and abroad adopts different pr...

AI Technical Summary

Problems solved by technology

Most of the metallographic structure of the high-strength strip steel in this application is a multi-phase structure of fine bainite and a small amount of ferrite. The low finish rolling temperature has caused great difficulty in on-site production. The control of bainite content also very difficult

Single high Ti treatment, the microalloying effect is greatly reduced, and the precipitation of TiN is difficult to control during casting

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