Hot rolling martensite steel plate with tensile strength higher than 1000Mpa and its production method

Abstract

The invention relates to a hot- roled martensite steel with strength for extension higher than 1000 Mpa, the component (with percent by weight) comprises: C 0.08-0.20, Si<=0.8, Mn 0.5-2.0, Al 0.010-0.060, N<=0.008, P<= 0.020, S<=0.005, one or more than one of Ti 0.01-0.03, V<=0.10 and Nb 0.01-0.05; Ca 0.001%-0.005%, added when sulfur content >=0.003; left is Fe and inavoidable foreigh matter. The main process parameters are as follows: cooling said steel with speed not less than 20 degree / s to cooling temeprature between 150 Deg. C to Ms, stopping cooling and batching to make metallic band; or cooling with speed not less than 20 degree / s to 650- 750 Deg. C, setting for 2- 10 seconds, and cooling with speed not less than 50 degree / s to cooling stop temperature of 150 Deg. C- Ms, and batching to make metallic band.

Description

technical field [0001] The invention relates to a method for manufacturing iron and steel materials, in particular to a hot-rolled ultra-high-strength martensitic steel plate and a method for manufacturing the same. Background technique [0002] There are many varieties of automotive steel. Traditional low-strength steel (LSS) and high-strength steel (HSS) mainly include interstitial-free steel (IF), high-strength interstitial-free steel (IF-HS), ordinary carbon mild steel (MILD), and isotropic steel ( IS), bake-hardening steel (BH), carbon-manganese steel (C-Mn) and low-alloy high-strength steel (HSLA), dual-phase steel (DP), transformation-induced plasticity steel (TRIP) and other three types of parts Low strength grade varieties. With the development of the automobile industry, the requirements for vehicle safety are getting higher and higher, and the weight of vehicles is also required to be lighter and lighter to improve fuel economy. The requirements for the strength...

AI Technical Summary

Problems solved by technology

[0017] It can be seen from the above comparative patents that these patents have one or more of the following deficiencies: ① A certain amount of expensive alloying elements, such as Cu, Ni, Cr, Mo, etc., are added, and the cost of steel is high

For example, 1.00-3.50% Ni and 0.40-1.20% Cr are added to JP60121219 and JP 89025371; the nickel content in WO200039352 is not less than 1.0%; the copper content in Japanese patent JP 4176822A is 0.5-2%; ②The process is complicated and the process cost is high

The carbon content in Japanese patent JP 4176822A is ≤0.01%, which belongs to ultra-low carbon steel. Too low carbon content results in long decarburization time during steelmaking, low labor productivity of steelmaking furnace, and ferroalloy materials added in steelmaking process. The carbon is also relatively low, and the cost of low-carbon ferroalloys is also high. In addition, special ladles and refractory materials are used when smelting low-carbon and ultra-low-carbon steels, which also increases smelting costs; patents JP 60121219 and JP 89025371 both use The tempering process is added, a process is added, and the cost of the process is increased

③The strength level of the steel plate is low

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