Superhigh strength steel plate with yield strength more than 1100Mpa and method for producing same

Abstract

The invention provides a super-strength steel plate comprising the following constituents (by weight percent): C 0.10-0.20%, Si<=0.6%, Mn 0.5-2.5%, Al <=0.03%, N 0.001-0.006%, B 0-0.0025%, Ca 0-0.006%, P<=0.015%, S<=0.005%, Ni 0.2-1.2%, Cr 0-0.8%, Cu 0-0.5% and Mo 0-0.6%, Ti 0.01-0.03%, V 0-0.1%, Nb 0.01-0.1%, balancing Fe and unavoidable foreign substance.

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 with a yield strength of 1100 MPa or more and a method for manufacturing the same. 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. For example, in the patents JP 60121219 and JP 89025371 of Sumitomo Metal, the tempering process is used to produce high-strength steel and the silicon content in the steel is ≤0.015%. , the nickel content is 1.00% to 3.50%, and the chromium content is 0.40% to 1.20%; [0003] The patent WO 200039352 applied by Exxonmobil Upstream Res is a low-temperature steel, which uses a method of low carbon content (0.03% to 0.12%) and high nickel content (not less than 1.0%) to produce high-strength steel with good low-temperature toughness. It adopts a lower cooling rate ...

AI Technical Summary

Problems solved by technology

[0011] It can be seen from the above comparative patents 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 patent WO 9905335 is as low as 0.05-0.10%, the carbon content in patent GB 2132225 is 0.04%-0.16%, and the carbon content in patent 98802878.6 is 0.02-0.10%. Too low carbon content results in long decarburization time during steelmaking , low smelting production efficiency; in patents 98812439.4 and 98812446.7, not only the quenching rate is low, but also online quenching after hot rolling is not used, which reduces production efficiency