800MPa-grade heavy-gauge hot-rolled high-strength steel plate roll with excellent low-temperature toughness for cold forming and manufacturing method thereof

Abstract

The invention discloses an 800MPa-grade heavy-gauge hot-rolled high-strength steel plate roll with excellent low-temperature toughness for cold forming and a manufacturing method thereof. The steel comprises the following chemical components in percentage by weight: 0.03% to 0.10% of C, 0.05% to 0.25% of Si, 1.0% to 2.0% of Mn, not more than 0.015% of P, not more than 0.005% of S, 0.03% to 0.09% of Nb, 0.08% to 0.22% of V, 0.08% to 0.20% of Ti, 0.08% to 0.20% of Mo, not more than 50ppm of N, not more than 40ppm of O and the balance of Fe and inevitable impurities, wherein the steel is manufactured by the six steps of element smelting, continuous casting, direct loading and heating, rolling, ultra-fast cooling and winding and natural slow cooling. Through the adoption of a low-cost design route, the 800MPa-grade heavy-gauge hot-rolled plate rolls with excellent low-temperature toughness, cold forming performance and welding performance are developed and stably produced in batches, and the products are widely applied to the light-weight field of special vehicles such as dump trucks, trailers, semi-trailers and the like.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and relates to a method for manufacturing a low-cost hot-rolled steel coil, in particular to a thick-gauge hot-rolled high-strength steel coil for 800MPa grade cold forming with excellent low-temperature toughness and a manufacturing method thereof. Background technique [0002] With the country's urbanization construction, increasing investment in infrastructure, and the continuous deepening of environmental protection and over-limit and overloading policies, the development of the special-purpose vehicle industry is facing new opportunities and challenges, and lightweight will become its inevitable development. Studies have shown that: for every 1% reduction in the weight of special vehicles, fuel consumption can be reduced by 0.6% to 1%, while reducing exhaust emissions and protecting the environment. To reduce the weight of the vehicle body, in addition to the selection of l...

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Problems solved by technology

Patent document CN108004475A published "a 900MPa-level hot-rolled nano-precipitation strengthened high-strength and high-toughness steel and its manufacturing method", using 0.10-0.20% C to match the composition system design of Nb, V, Ti, and Mo to obtain a yield strength of ≥800MPa , The hot-rolled high-strength steel with impact energy ≥ 50J at -40°C has better overall performance, but the overall alloy cost is relatively high, and the C content is greater than 0.10%, which is different from the ultra-low carbon design idea described in this patent

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