A kind of ultra-high-strength spring steel with excellent hydrogen-induced delayed fracture resistance and production method thereof

Abstract

The invention discloses an ultra-high-strength spring steel with excellent hydrogen-induced delayed fracture resistance and a production method thereof. The tensile strength is ≥ 2300 MPa, and the chemical composition includes the following weight percentages: C 0.75%-0.85%, Si 1.60%- 2.00%, Mn 0.40%~0.60%, Cr 0.80%~1.00%, V 0.20%~0.30%, Nb 0.03%~0.05%, Mo 0.10%~0.30%, Re 0.01%~0.03%, Al 0.015~0.040% , N 0.005%~0.008%, P≤0.015%, S≤0.015%, O≤0.0015%, the rest is Fe and other unavoidable impurities; and Al / N≥3.5%, 29.1C+5.2Si+1.8Mn+ 3.5Cr+2.6V+0.8Nb+4.9Mo≥36%; produced by electric furnace smelting-LF furnace-vacuum degassing-continuous casting-blanking-wire rolling, the present invention avoids the use of a large amount of The precious metal element Ni and the Cu element which is very easy to cause brittle cracking of steel and copper, under the interaction of C, Si, Mn, Cr, V, Nb, Mo, Re, N, are produced at low cost under a specific process to obtain anti-corrosion. Ultra-high-strength spring steel with tensile strength ≥ 2300MPa, and has excellent delayed fracture resistance and fatigue performance.

Description

technical field [0001] The invention belongs to the technical field of spring steel, and in particular relates to an ultra-high-strength spring steel with excellent hydrogen-induced delayed fracture resistance and a production method thereof. Background technique [0002] Lightweight technology is the future development trend of automobiles. As one of the safety components of automobiles, springs are constantly required to increase the design stress of springs in order to reduce their own weight. In the future, springs will develop toward high stress, light weight, and long life. However, the properties of materials used to manufacture high-stress springs are already at their limits. It is imperative to further increase the service stress of springs and develop new materials with high strength and toughness. [0003] In recent years, the development of high-strength spring steel is a hot topic. Chinese patent CN 103725984 A discloses a high-toughness high-strength spring st...

AI Technical Summary

Problems solved by technology

[0006] At present, the tensile strength of high-strength spring steel used at home and abroad is basically between 1800-2000MPa. Steel grades of 2000-2100 grades have been developed and tried on high-end cars, but higher grades of ultra-high-strength and tough steel grades have not yet begun develop

However, some spring companies increase the strength of existing steel types by reducing the tempering temperature, which will lead to poor plasticity and toughness, and a decrease in fatigue life.

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