A kind of high-strength steel with fatigue stress amplitude ≥400mpa and production method

Abstract

The invention discloses high-strength steel with the fatigue stress amplitude equal to or larger than 400 MPa. The high-strength steel with the fatigue stress amplitude equal to or larger than 400 MPacomprises the components, by weight, 0.12% to 0.18% of C, 0.10% to 0.40% of Si, 1.20% to 1.60% of Mn, smaller than or equal to 0.015% of the sum of P and S, 0.10% to 0.45% of Cr, 0.42% to 0.75% of Mo, 0.05% to 0.20% of Ni, and 0.045% to 0.100% of the sum of Nb, Ti ,V and B. A method comprises the production steps of carrying out smelting as clean steel, then carrying out continuous casting to form blanks, and carrying out hot rolling on the blanks till the thickness of each blank reaches the finished product thickness; carrying out quenching; carrying out backfire; and carrying out natural cooling to the room temperature. According to the high-strength steel with the fatigue stress amplitude equal to or larger than 400 MPa and the method, on the conditions that the yield strength ranges from 900 MPa to 1, 000 MPa, the tensile strength is larger than or equal to 1, 000 MPa, and the elogation A is larger than or equal to 15%, the microstructure is finer through microalloy control, and the fatigue stress limit of the steel is larger than 400 MPa which is at least 20 MPa higher than 380 MPa as required by the present requirements. No breaking happens to the high-strength steel with the fatigue stress amplitude equal to or larger than 400 MPa after a common fatigue test is carried out, and a new window is opened for the fatigue life design of an existing component.

Description

technical field [0001] The invention relates to a steel plate for engineering machinery and a production method thereof, in particular to a high-strength steel with a fatigue stress amplitude ≥ 400 MPa and a production method thereof, and is suitable for hot-rolled steel with a steel plate thickness of 16-50 mm. Background technique [0002] The construction machinery industry is an important part of the machinery industry, and high-strength structural steel occupies an important position in the construction machinery manufacturing. In recent years, due to the rapid development of the construction machinery industry, there has been a strong demand for high-strength structural steel materials, and higher requirements have been put forward for the comprehensive performance of such materials. At present, the high-strength structural steel with a yield strength of 960MPa is favored by the domestic construction machinery industry. Its application in the construction machinery ind...

AI Technical Summary

Problems solved by technology

[0009] The present invention is to solve the high-strength steel existing in the prior art in 10 7 Stress problems under cyclic fatigue conditions, providing a high-strength steel with a guaranteed yield strength of 900-1000MPa, tensile strength ≥ 1000MPa, elongation A ≥ 15%, and fatigue stress amplitude ≥ 400MPa and its production method

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