Superhigh strength steel plate with yield strength more than 960Mpa and method for producing same

Abstract

The invention provides a super-strength steel plate comprising the following constituents (by weight percent): C 0.08-0.18%, Si<=0.6%, Mn 0.5-2.0%, Al <=0.018%, N<=0.008%, B<=0.0025%, Ca 0-0.006%, P<=0.015%, S<=0.005%, Ni <=1.0%, Cr<=0.8%, Cu<=0.5%, Mo<=0.6%, Ti 0.01-0.03%, V<=0.1%, Nb 0.01-0.1%, balancing Fe and unavoidable foreign substance. The invention also provides the preparing process.

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. 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 (10°C / s), and its tensile strength can onl...

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Problems solved by technology

[0009] 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 causes long decarburization time during steelmaking , the labor productivity of the steelmaking furnace is low; patents JP 60121219, JP 89025371, JP 59159932 and GB 2132225 all adopt the tempering process, which adds a process and increases the cost of the process

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