Hot rolling diaphragm spring steel for automobile and production method of hot rolling diaphragm spring

Abstract

The invention discloses hot rolling diaphragm spring steel for an automobile and a production method of the hot rolling diaphragm spring steel. The hot rolling diaphragm spring steel comprises the following components by weight percentage: 0.40-0.60% of C, 0.15-0.35% of Si, 0.70-1.20% of Mn, less than or equal to 0.015% of P, less than or equal to 0.008% of S, less than or equal to 0.050% of Alt, 0.10-0.30% of Mo, 0.70-1.20% of Cr, 0.10-0.50% of V and less than or equal to 0.005% N. The production method comprises the processing steps of desulfurating, smelting, refining, conducting vacuum treatment, continuously casting to form a blank, conducting segmented thermal insulation according to temperature, heating the casting blank, rolling, coiling, slowly cooling, shearing a steel band, annealing, molding, quenching, tempering and waiting for application. According to the hot rolling diaphragm spring steel and the production method, the production cost is low; a load of a rolling mill can be reduced; the comprehensive mechanical property is excellent; a steel coil is heated uniformly in the annealing process; the uniformity of a metallurgical structure is ensured; a tempered sorbite structure is obtained by heat treatment of the quenching and the tempering; the steel is separated out by compound precipitation of microalloys, such as Cr, Mo and V in the steel; and high strength and good wear-proof property of the steel are ensured.

Description

technical field [0001] The invention relates to steel for springs, in particular steel for hot-rolled diaphragm springs for automobiles 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 the automobile diaphragm spring steel. After searching, the Chinese patent name is "high strength toughness and high hardenability spring tube material", and the patent application number is CN200510018800.7. The composition and mass percentage of C: 0.48~0.55%, Si: 0.17~0.37%, Mn: 0.70~1.00%, Cr: 0.8~1.1%, B: 0.001~0.004%, Ni≤0.35%, Cu≤0.25%, P≤0.03%, S≤0.03%, and the rest is Fe. Due to the addition of B, and the control level of P and S content is not high, although it has a certain economical efficiency, the post-processing performance is poor, and it cannot meet the requirements of steel for automobile diaphragm ...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a hot-rolled diaphragm spring steel for automobiles and its manufacturing method, which can overcome the poor uniformity of steel coil structure and mechanical properties after annealing, poor surface quality and insufficient cold working performance, and obtain high strength, high elastic limit, Hot-rolled diaphragm spring steel for automobiles with high yield limit and high fatigue resistance limit performance and production method thereof

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