A kind of steel for construction machinery with yield strength ≥ 960mpa and its production method

Abstract

Provided is engineering machinery steel with the yield strength being larger than or equal to the 960 MPa grade. The engineering machinery steel comprises the components of, by weight, 0.04%-0.20% of C, 0.15%-0.40% of Si, 1.0%-10% of Mn, 0.01%-0.08% of N, 0.010%-0.050% of Ti, 0.01%-0.06% of Als, 0-0.020% of P, 0-0.010% of S and 0.05%-3% of Cr. Production steps comprise smelting and vacuum treatment, steel tapping, casting for blank forming, heating, a hot rolling process, and cold rolling. The engineering machinery steel provided by the invention is larger than or equal to 960 MPa in yield strength, larger than or equal to 15.0% in elongation, not lower than 60 J in -20 DEG C AKV and very excellent in matching of strength and toughness, and has an impact fracture with a dimple characteristic. Adaptive N is added to the chemical components so as to ensure the strength of the steel, and adding of Mo, V, Nb and other expensive microalloy elements is cancelled. Rolling technology of the engineering machinery steel is simple and easy to operate, cold control is not needed in the rolling process, and heat treatment is not needed as well.

Description

technical field [0001] The invention relates to low-alloyed steel and a production method thereof, in particular to steel for engineering machinery with yield strength ≥ 960 MPa and a production method thereof. Background technique [0002] Steel for construction machinery with a yield strength of 960MPa produced by Chinese domestic iron and steel enterprises is mostly produced by quenching and tempering process. In order to improve hardenability, a large amount of alloying elements are generally added, and the cost is relatively high. At present, this kind of domestic high-strength steel has not been fully localized. The application in the field of construction machinery is mainly occupied by some imported steel plates from abroad. For higher-strength high-strength steel, it is completely dependent on imports. The main grades are WELDOX from the Swedish Alklund Steel Works. A series of high-strength steel plates, the yield strength of this series of steel plates can reach 1...

AI Technical Summary

Problems solved by technology

[0004] It is known from searching the supply technical conditions of 900~960MPa grade high-strength structural steel that V, Nb, Ni, Mo, etc. are usually added as necessary alloying elements for this grade of steel plate, and are produced by quenching and tempering processes. At present, there is no Published reports on hot-rolled plus cold-rolled steel sheets of this strength grade

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