900MPa grade hot rolling non-tempering thin steel sheet and preparation method thereof

Abstract

The invention relates to a 900MPa grade hot rolling non-tempering thin steel sheet and a preparation method thereof, belonging to the technical field of alloy steel. The steel sheet comprises the following chemical components in percentage by weight: 0.08-0.13wt% of C, less than or equal to 0.50wt% of Si, 1.0-2.0wt% of Mn, 0.08-0.20wt% of V, 0.08-0.15wt% of Ti, 0.15-0.40wt% of Mo, less than 0.015wt% of P, less than 0.005wt% of S, less than 0.005wt% of N, less than 0.002wt% of O and the balance of Fe and inevitable impurities. Through reasonable control of a V-Ti-Mo multielement microalloying and hot continuous rolling online TMCP (Thermal Mechanical Control Processing) process, a microstructure is obtained, wherein microalloy precipitated phases with grain size of about 5nm are dispersed and distributed on an ultra-fine grain ferrite matrix with grain size less than 5 mu m, so that the yield strength of the steel sheet can reach over 900MPa grade in a hot continuous rolling technical condition, thereby cancelling tempering thermal treatment after rolling. The steel sheet has the advantages that the production flow of the steel sheet is simplified, the energy consumption is reduced, the internal stress of the steel sheet is reduced, and the steel sheet has an important effect of improving the plate cut quality. The steel sheet can be widely applied to the field of mobile facilities such as automobiles, engineering machinery and containers.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, and in particular provides a 900MPa grade hot-rolled non-quenched and tempered thin steel plate and a preparation method thereof. Background technique [0002] At present, the application of ultra-high-strength thin steel plates in mobile facilities such as automobiles, construction machinery, and containers is increasing. For example, in the field of construction machinery, hot-rolled thin steel plates (thickness ≤ 8mm) with a yield strength of 900 MPa or more have been used in key parts such as the boom frame of long-arm concrete pump trucks, telescopic arms of large-tonnage truck cranes, and pull plates of crawler cranes. It meets the requirements of construction machinery's continuous development in the direction of high parameterization, large-scale and light weight, and plays an important role in improving equipment efficiency, reducing energy consumption and reducing self-weight. In t...

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Problems solved by technology

[0003] The production process of traditional 900MPa and above hot-rolled thin steel plates is hot rolling followed by quenching + tempering heat treatment (quenching and tempering treatment), and the structure is low-carbon martensitic structure. The production process is cumbersome, the process is long, and the energy consumption is high. The toughness and plasticity of the martensitic structure is low, and the problems of excessive internal stress and poor shape of the steel plate caused by quenching treatment have always plagued the industry

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