Microalloying third-generation car spring flat steel and preparing method thereof

Abstract

The invention relates to a microalloying third-generation car spring flat steel and a preparing method thereof. The microalloying third-generation car spring flat steel comprises, by weight percentage, 0.48%-0.60% of C, 0.4%-0.8% of Si, 0.60%-1.00% of Mn, 0.80%-1.20% of Cr, 0.01%-0.05% of Nb, 0.0005%-0.003% of B, not larger than 0.025% of P, not larger than 0.025% of S, not larger than 0. 25% of Cu, not larger than 0.35% of Ni, not larger than 0.02% of Ti and the balance Fe. The preparing method includes the steps of blast furnace molten iron production, molten iron desulphurization, converter smelting, LF refining, RH vacuum treatment, square billet protection pouring, square billet heating, rolling, cooling bed slow cooling and fixed-size shearing. According to the microalloying third-generation car spring flat steel and the preparing method, niobium and boron microalloying and the silica content more suitable for the spring steel high elasticity ultra-low decarburization trend are adopted, the proper clean steel smelting process, rolling process and slow cooling control technology are adopted in a combined manner, and the high-end car spring flat steel having uniform texture, good hardenability, reasonably-matched comprehensive mechanicalness and good hardenability is developed.

Description

technical field

[0001] The invention relates to a leaf spring, in particular to a microalloyed third-generation spring flat steel for automobiles and a preparation method. Background technique

[0002] With the demand for lightweight development of automobiles, the strength of spring flat steel used in automobiles continues to increase, and the development trend of needing a high-strength spring flat steel to replace ordinary spring flat steel below 1500MPa is becoming more and more obvious. In addition, after the strength of the spring flat steel material is improved, its toughness deteriorates, making it prone to fracture, which affects vehicle safety. At the same time, the hardenability becomes poor, which is not conducive to the production and manufacture of leaf springs with variable cross-section thickness specifications, and cannot meet the development needs of heavy-duty commercial vehicles.

[0003] As the most important elastic component of the shock absorption sy...