High strength steel with yield strength to be 900-1000MPa grade and production method of high strength steel

Abstract

The invention discloses a high strength steel with yield strength to be 900-1000MPa grade and a production method of the high strength steel. The high strength steel is prepared from the following components in percentage by weight: 0.07-0.15 percent of C, 0.10-0.30 percent of Si, 0.80-1.60 percent of Mn, 0.20-0.70 percent of Cr, 0.10-0.45 percent of Mo, 0.10-0.50 percent of Ni, 0.010-0.030 percent of Nb, 0.010-0.030 percent of Ti, 0.010-0.050 percent of V, 0.0005-0.0030 percent of B, 0.02-0.06 percent of Al, 0.001-0.004 percent of Ca, 0.002-0.005 percent of N, P no larger than 0.020 percent, S no larger than 0.010 percent, O no larger than 0.008 percent and the balance of Fe and inevitable impurities, wherein Ceq accounts for 0.42-0.52 percent and is equal to C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15; Mo+0.8Ni+0.4Cr+6V is no less than 0.8 percent and no larger than 1.3 percent; Ti/N is no less than 3.7 and no larger than 7.0, and Ca/S is no less than 1.0 and no larger than 3.0. According to the production method disclosed by the invention, processes of online quenching and tempering are adopted, so that the yield strength of the produced steel plate is 900-1080MPa, the tensile strength is 950-1200MPa, the elongation is larger than 10 percent, and the impact energy at the temperature of 40 DEG C below zero is larger than 27J.

Description

technical field [0001] The invention relates to a high-strength steel with a yield strength of 900-1000 MPa and a production method thereof. The obtained high-strength steel has a yield strength of 900-1080 MPa, a tensile strength of 950-1200 MPa, an elongation of >10%, and an impact energy of -40 ℃. >40J, the microstructure is tempered martensite. Background technique [0002] The use of high-strength easy-to-weld structural steel to manufacture components of mobile equipment such as the beam structure of construction machinery, the boom of cranes, and the body of dump trucks will reduce the weight of the equipment, reduce fuel consumption, and improve work efficiency. With the intensification of international competition, it has become a trend to use high-strength and easy-to-weld structural steel to manufacture components of mobile equipment such as port machinery, mining machinery, excavator, loader beam structure, crane boom and dump truck body. Due to the develo...

AI Technical Summary

Problems solved by technology

Chinese patent CN102134680A introduces a production method of high-strength steel with a yield strength of 960MPa, which adopts a lower carbon content design and a higher Cr content, C: 0.07% ~ 0.09%, Cr: 1.05 ~ 1.15%, the patent does not contain Nb, Ti, V microalloying elements, high Cr content, not conducive to welding

[0004] The composition design in the prior art does not control the comprehensive properties of plasticity and toughness of joints, nor does it consider the genetic improvement of the strength and toughness of finished steel plates by controlling inclusions and structural properties

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