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

Abstract

The invention discloses high-carbon cold-rolled automobile diaphragm spring steel. The high-carbon cold-rolled automobile diaphragm spring steel is prepared from the following constituents in percentage by weight: 0.70-0.90% of C, 0.15-0.35% of Si, 0.50-1.00% of Mn, P smaller than or equal to 0.008%, S smaller than or equal to 0.002%, 0.010-0.030% of Alt, 0.10-0.30% of V, 1.20-2.00% of Cr, 1.20-2.00% of Ni, 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 a 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 after cutting, cold rolling, quenching, tempering, and inspection for standby. The steel disclosed by the invention is rolled and thermally treated to achieve high strength, high elasticity, high limit of yielding, high fatigue limit resistance, low-temperature toughness and longer service life, and can be used for manufacturing various vehicle clutch assemblies, especially the large engineering machinery at the low temperature environment.

Description

technical field [0001] The invention relates to steel for springs, in particular to steel for automobile cold-rolled diaphragm springs 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 low, and it is easy to be brittle in low temperature environments, which cannot meet the requirements of large construction machinery vehicles used in low temperature environments for diaphragm springs. ...

AI Technical Summary

Problems solved by technology

It has low fatigue performance and elastic limit, and low spheroidization rate after annealing

In addition, because of the high Si content in the steel, such as the production of wide-band steel, the risk of fracture will be greater in the post-processing shearing stage and cannot be used.

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