Ultrahigh strength steel with 960MPa of yield strength and production method thereof

Abstract

The invention provides ultrahigh strength steel with 960MPa of yield strength and a production method thereof. The steel comprises the following chemical components by weight percent: 0.07-0.09% of C, 0.15-0.25% of Si, 1.00-1.20% of Mn, 1.05-1.15% of Cr, 0.15-0.20% of Mo, 0.01-0.06% of Al, no more than 0.02% of P, no more than 0.01% of S, no more than 0.008% of N and the balance of Fe and inevitable impurities. The production method comprises the following steps: smelting and casting are performed to obtain a casting blank, and the casting blank is heated to 1150-1250 DEG C; the finish rolling temperature is 840-900 DEG C; the finish cooling temperature is 640-700 DEG C; and quenching and tempering are performed, the quenching heating temperature is 880-920 DEG C, the heating preservation time is 20-60 minutes, the tempering heating temperature is 150-450 DEG C, and the heating preservation time is 90-180 minutes. The obtained material meets the performance requirement of the 960MPa grade ultrahigh strength steel and has good elongation rate and impact toughness.

Description

technical field [0001] The invention belongs to the technical field of high-strength steel production, and relates to an ultra-high-strength steel with a yield strength of 960MPa and a production method thereof. 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 the fields of construction machinery, automobiles, coal machinery, etc., and the grades of steel 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] Steel plates...

AI Technical Summary

Problems solved by technology

[0004] At present, the 960MPa grade high-strength steel designed and produced at home and abroad is characterized by the addition of more precious alloy elements in the chemical composition, and the alloy cost is relatively high.

In addition, if the TMCP direct rolling process is used to produce ultra-high-strength steel plates with a yield strength of 960 MPa, the requirements for the capacity of the rolling mill and Kaiping equipment are extremely high, and it is difficult to ensure the uniformity of the plate shape and the length and width of the coil.

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