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...

AI Technical Summary

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

The Weldox960 series produced by SSAB in Sweden and the Dillimax series of high-strength steel produced in Dillingen, Germany, both use high aluminum content (not less than 0.018%), which has the following disadvantages: the nozzle of high-aluminum steel is easy to nodulate during pouring, and it is easy to Bring the refractory material of the ladle nozzle into the molten steel; too much aluminum will cause a significant increase in alumina inclusions in the steel, and a longer argon blowing time is required to promote the inclusions to float up; fine aluminum nitride precipitates with finer grains of aluminum are welded on the steel plate When completely dissolved, so that the welding heat-affected zone grain coarse

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 830MPa, and the tensile strength of patent 98802878.6 can only reach more than 900MPa