Composite microalloyed high-strength steel forge piece with tensile strength of 700 MPa and production method thereof

Abstract

The invention discloses a composite microalloyed high-strength steel forge piece with tensile strength of 700 MPa and a production method thereof, and relates to a low-welding crack sensitivity high-strength steel forge piece with tensile strength of 700 MPa and a production method thereof. The forge piece comprises the following chemical components in percentage by weight: 0.07-0.12% of C, 1.2-1.8% of Mn, 0.2-0.4% of Si, not more than 0.006% of S, not more than 0.015% of P, 1.3-1.8% of Ni, 0.15-0.3% of Cr, 0.2-0.4% of Mo, 0.02-0.1% of Nb, not more than 0.1% of V, not more than 0.02% of Ti, not more than 0.25% of Cu, and not more than 0.001% of B, the balance being Fe and inevitable impurities; and Pcm is not more than 0.26%. The plate thickness of the forge piece can reach up to 200 mm; and the mechanical performance of the force piece satisfies the following conditions: the yield strength is not less than 560 MPa; the tensile strength is not less than 700 MPa; the elongation is not less than 17%; and KV2 (-40 DEG C) is not less than 80 J.

Description

technical field [0001] The invention belongs to the field of high-strength low-alloy steel production, and in particular relates to a high-strength steel forging with a tensile strength of 700 MPa and low welding crack sensitivity and a production method thereof. Background technique [0002] With the rapid development of my country's metallurgical industry and major projects such as "West-to-East Electricity Transmission" and "West-to-East Gas Transmission", quenched and tempered high-strength steel and forgings are widely used in pressure steel pipes for power generation, volute casings of hydroelectric units, Natural gas storage tanks and gas storage gas tanks for complete metallurgical equipment have been widely used in the construction, and the demand is increasing year by year. The application requirements for higher strength quenched and tempered steel and its supporting forgings are also increasingly urgent. [0003] Chinese patent application number: 200910063768.2 d...

AI Technical Summary

Problems solved by technology

The low-carbon low-alloy steel products produced by the above-mentioned thin strip continuous casting method have high strength, but the main problem is that the elongation of the product is not high and the low-temperature toughness is poor

Since the hot rolling reduction rate of the thin strip continuous casting process usually does not exceed 50%, the effect of refining austenite grains by deformation is not good, so the plasticity and low temperature toughness of this type of steel are poor

Images