Method for manufacturing low-cost super-high intensity steel plate with yield strength of over 960 MPa for wide process operation window

Abstract

The invention relates to a super-high intensity steel plate with yield strength of over 960 MPa. The steel plate comprises the following chemical constituents in percentage by weight: 0.12 to 0.14 percent of C, 0.3 to 0.4 percent of Si, 1.45 to 1.6 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.002 percent of S, 0.02 to 0.04 percent of Al, 0.38 to 0.42 percent of Cr, 0.28 to 0.32 percent of Ni, 0.35 to 0.41 percent of Cu, 0.35 to 0.45 percent of Mo, 0.015 to 0.025 percent of Ti, 0.02 to 0.03 percent of Nb, 0.0012 to 0.002 percent of B, less than or equal to 0.004 percent of N, less than or equal to 0.002 percent of O and the balance of iron and inevitable impurities. Production methods include conventional rolling and thermo-mechanical control process (TMCP) rolling.

Description

technical field [0001] The invention relates to a method for manufacturing iron and steel materials, in particular to an ultra-high-strength steel plate and a method for manufacturing the same in a laboratory. Background technique [0002] Internationally, a number of patents have been formed on the manufacturing method of ultra-high-strength steel plates with a yield strength above 700MPa. In the patents JP60121219 and JP 89025371 of Sumitomo Metal, the high-strength steel produced by tempering process has a silicon content of ≤0.015%, a nickel content of 1.00%-3.50%, and a chromium content of 0.40%-1.20%. In the high-strength steel plate patent of Sumitomo Metal (JP 59159932), the method of directly quenching and tempering after hot rolling is adopted, and in the composition design, the range of titanium used is as low as 0.003-0.010%. In NIPPONKOKANKK's "production of high-strength thick steel plate" patent (GB2132225), the rate of direct quenching after hot rolling is c...

AI Technical Summary

Problems solved by technology

[0007] Based on the above comparative patents, it can be seen that these patents have one or more of the following deficiencies: ① A relatively high content of expensive alloy elements is added, and the cost of steel is high

For example, the nickel added in JP 60121219 and JP 89025371 is 1.00% to 3.50%, and the chromium content is 0.40% to 1.20%; the nickel content in WO 200039352 is not less than 1.0%; ②The process is complicated and the process cost is high

For example, the carbon content in the patent WO 9905335 is as low as 0.05-0.10%. Too low carbon content results in long decarburization time during steelmaking, heavy deoxidation task of molten steel, and low productivity in this process link; and if the strength specified in the standard is to be achieved , more precious alloys must be added to compensate for the strength drop caused by low carbon content

③The strength level of the steel plate is low

Such as patent WO 200039352 and patent 98812446.7, the tensile strength can only reach more than 890MPa, and the tensile strength of patent 98802878.6 can only reach more than 900MPa

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