High-strength and high-plasticity dual-phase steel and manufacturing method thereof

Abstract

The invention relates to high-strength and high-plasticity dual-phase steel and a manufacturing method thereof. The dual-phase steel comprises the chemical components in percentage by weight: 0.07-0.19% of C, 0.10-0.50% of Si, 1.00-2.30% of Mn, less than or equal to 0.020% of P, less than or equal to 0.015% of S, less than or equal to 0.008% of N, 0.02-0.07% of Al, less than or equal to 0.40% of Mo, less than or equal to 0.06% of Nb, and the balance of Fe and other inevitable impurities. According to the invention, by controlling the soaking temperature, slow cooling speed, slow cooling temperature, quick cooling temperature and the like of the continuous annealing process, the high-strength and high-plasticity dual-phase steel with martensite, epitaxial ferrite and residual ferritic structure can be manufactured; and continuous annealing line with a high-speed and high-hydrogen gas jet cooler is adopted, so that the content of alloy elements in the steel can be reduced, and the shaping and welding properties of steel plates can be ensured.

Description

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AI Technical Summary

Benefits of technology

This patented technology uses specific compositions or processes that control how quickly heated during processing occurs while maintaining its final shape after being cooled down. By continuously annealed without stopping at certain temperatures, this results in strong duplex steels made from both martensites (ferrites), epiconductors, and residuals). These materials have excellent properties such as good toughness and resistance against corrosion damage caused by external factors like rain water. They also provide improved impact absorption compared to traditional methods used before they were developed due to their low density.

Problems solved by technology

This patents describes two technical problem areas related to producing strong duplex steels (DP) without sacrificial metal ingredients like chromium which contribute towards increasing their tensile stress points and reducing cracks' growth rates under heavy load conditions. Current methods involve adding expensive elements called copper into these alloys, resulting in decreased impact toughness and increased brittleness temperature resistance. Additionally, current techniques involving heat treatment alone cannot achieve desired levels of mechanical properties simultaneously due to limitations associated with controlling the chemistry balance between different phases within double-layer austenotical crystal structure.

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