High-carbon hot-rolled automobile diaphragm spring steel and production method thereof

Abstract

The invention discloses high-carbon hot-rolled automobile diaphragm spring steel. The high-carbon hot-rolled automobile diaphragm spring steel is prepared from the following constituents in percentage by weight: 0.70-0.90% of C, Si smaller than or equal to 0.10%, Mn smaller than or equal to 0.80%, P smaller than or equal to 0.008%, S smaller than or equal to 0.003%, 0.010-0.030% of Alt, 1.20-1.80% of Cr, 0.10-0.30% of V, 0.002-0.006% of Ca, and N smaller than or equal to 0.004%, and is prepared by the following production steps: molten iron desulphurization, smelting in a converter, refining in an LF (Ladle Furnace) furnace, processing in an RH vacuum furnace, continuous casting to form blanks, pit type slow cooling after cutting of cast blanks, cast blank heating, segmented hot rolling, reeling, slow cooling, annealing, quenching, tempering, and inspection for standby. The steel disclosed by the invention is quenched and tempered to achieve tensile strength of 1600-2200 MPa, HRC (Rockwell Hardness) of 47-57, high limit of elasticity, high limit of yielding, high fatigue limit resistance and longer service life, and can be used for manufacturing various vehicle clutch assemblies for large engineering machinery.

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] In the automobile clutch assembly, the diaphragm spring has a great influence on the performance and service life of the automobile clutch assembly. At present, limited by the capability level of metallurgical equipment and post-processing level, the carbon content in domestic automotive diaphragm spring steel is not high, generally within 0.65%, and the process of "hot rolling → annealing → pickling → processing → heat treatment" is often used Routing. Mainly due to its low carbon and chromium content, the mechanical properties of the product such as strength and hardness are not high, and it cannot meet the future development and use requirements of large construction machinery vehicles and other vehicle diaphragm springs. [0003] Before the present invention was proposed, t...

AI Technical Summary

Problems solved by technology

Compared with the invention steel, this kind of steel has higher strength, larger rolling load during production, and higher requirements for production equipment

In addition, because of the high Si content in the steel, such as the production of wide-band steel, there is a greater risk of shear fracture in later processing

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