Automotive cold-rolled diaphragm spring steel and production method thereof

Abstract

The invention relates to automotive cold-rolled diaphragm spring steel and a production method thereof. The automotive cold-rolled diaphragm spring steel comprises the following components by weight percentage: C of 0.40-0.65, Si of 0.15-0.35, Mn of 0.60-1.00, P of less than or equal to 0.010. S of less than or equal to 0.007, Alt of less than or equal to 0.040, Ni of 0.20-0.50, Cr of 0.80-1.20, V of 0.27-0.55 and N of less than or equal to 0.005, and a tempered sorbite body is adopted as a control metallographic structure. The process comprises the steps of: desulphurization, smelting, refining, vacuum processing, continuous casting into a billet, thermal insulation in segments according to the temperature, heating of the cast billet, rolling, coiling, slow cooling, cutting, first annealing, first cold rolling, second annealing, second cold rolling, formation, quenching, tempering and preparation for use. The automotive cold-rolled diaphragm spring steel has excellent comprehensive mechanical properties. Difficulties in cutting and cold rolling can be reduced due to annealing, a tempered martensite structure is obtained due to heat treatment of quenching and tempering, and sufficient strength and wear resistance of the steel can be ensured due to composite reinforcing effects of micro-alloys such as Cr, Ni and V in the steel.

Description

technical field [0001] The invention relates to steel for springs, in particular to cold-rolled steel for automobile diaphragm springs and a production method thereof. Background technique [0002] Before the present invention was proposed, there were many similar technical products related to the field of alloy structural steel manufacturing, but few aimed at automobile diaphragm spring steel, especially cold-rolled automobile diaphragm spring steel. After a preliminary search, such as the patent document of the Chinese patent "Steel strip for automobile insurance belt spring leaf and its production method" patent application number CN200510110463.4, the involved steel has the following composition and mass percentage C≤0.15%, Si≤1.00%, Mn≤2.00%, Cr: 16.00~17.00%, Ni: 6.00~8.00%, P≤0.045%, S≤0.030%, and the rest is Fe and unavoidable impurities. Compared with the present invention, the cold-rolled steel strip has more Cr and Ni added to the chemical composition, higher Si ...

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Problems solved by technology

[0005] The purpose of the needle of the present invention is to solve the problems of easy rolling fracture and cracks inside the slab which affect product quality in hot rolling, so as to provide a diaphragm spring produced with high elastic limit, high yield limit, high resistance Cold-rolled diaphragm spring steel for automobiles with high fatigue limit performance and long service life and production method thereof

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