Ultra-high strength steel with yield strength level of 1100MPa-1200MPa and production method of steel

Abstract

The invention provides ultra-high strength steel with yield strength level of 1100MPa-1200MPa and a production method of the steel. The chemical constituents (weight percentage) include: 0.15-0.18% of C, 0.20-0.25% of Si, 0.85-1.25% of Mn, 0.20-0.60% of Cr; and 0.45-0.65% of Mo, 0.035-0.060% of V, 0.015-0.020% of Nb, 0-0. 55% of Ni, 0-0.035% of Cu, 0.01-0.06% of Al, no more than 0.015% of P, no more than 0.01% of S, no more than 0.008% of N, the balance of Fe and unavoidable impurities. The production method includes: smelting and casting into casting blank; and heating the casting blank to 1150-1250 DEG C, wherein the final rolling temperature is 860-920 DEG C, the coiling temperature is 650-750 DEG C, the quenching heating temperature is 880-930 DEG C, the thermal insulation time is 20-90min, the tempering heating temperature is 100-450 DEG C, the thermal insulation time is over 90min. Slow cooling or air cooling is conducted to room temperature. For the steel plate produced with the constituents and the technology, the yield strength is 1150-1230MPa, the tensile strength is 1250-1340MPa, the elongation is 11-13.5%, and the impact power value at minus 40 DEG C is 21-34J.

Description

technical field [0001] The invention relates to a method for manufacturing iron and steel materials, in particular to an ultra-high-strength steel with a yield strength of 1100MPa-1200MPa and a method for manufacturing the same. Background technique [0002] Increasing the strength of materials to reduce the weight of components is the development direction of structural steel. In recent years, a large number of high-strength steels have been used to replace traditional high-strength steels in fields such as construction machinery, automobiles, and coal machinery, and the steel grades used are getting higher and higher. Using high-strength steel to manufacture structural parts of construction machinery, booms of cranes, beam structures of automobiles and car bodies of dump trucks and other mobile equipment components will significantly reduce the weight of equipment, reduce fuel consumption, and improve work efficiency. The economic benefits are very considerable. [0003]...

AI Technical Summary

Problems solved by technology

Using online quenching + tempering process to produce ultra-high-strength steel hot-rolled coils with a yield strength of 1100MPa-1200MPa, the main difficulty lies in the need to achieve a sufficient cooling rate to obtain an ideal quenched structure, so the ability of cooling equipment after rolling is extremely high; in addition , due to the online quenching process, the final cooling temperature is relatively low, the requirements for the capacity of the coiler are high, and the equipment loss is relatively large; It is difficult to guarantee, and the requirements for Kaiping equipment capacity are extremely high

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