Hot-rolled steel for car friction plate and preparation method of hot-rolled steel

Abstract

The invention discloses hot-rolled steel for a car friction plate. The hot-rolled steel comprises the following chemical compositions by mass percent: 0.45-0.75 percent of C, 0.10-0.30 percent of Si, 0.60-1.20 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.006 percent of N, 0.05-0.50 percent of Cr, 0.015-0.050 percent of Als, less than or equal to 0.005 percent of Ti, 0.01-0.03 percent of V and the balance of Fe and inevitable impurities. The invention further discloses a preparation method of the hot-rolled steel for the car friction plate. The hardness of the hot-rolled steel is controlled within 18-25 HRC, the hardness of the steel annealed at 600-850 DEG C is still kept at 14-18 HRC, and the hot-rolled steel has favorable cold working forming performance and does not crack in the blanking and forming process.

Description

technical field [0001] The invention relates to a hot-rolled strip steel manufacturing technology, in particular to a hot-rolled steel material for an automobile friction plate and a preparation method thereof. Background technique [0002] Automobile friction plate is an important part of the automobile braking system and one of the vulnerable parts of the automobile. The current processing procedure includes blanking steel sheet, flattening, grinding, and then sintering a layer of copper-containing friction material on the ground steel base. The working environment and processing technology of automobile friction discs require that the steel base has good hardenability, wear resistance, and high strength, etc., and especially requires that the steel base still have a hardness of 14-18HRC after sintering at 600-800°C. In addition, automobile friction discs also have high requirements on the thickness accuracy and surface of the steel belt, with the thickness accuracy requi...

AI Technical Summary

Problems solved by technology

However, since there are no stable and high-temperature-resistant carbides in the steel, after the material is annealed at high temperature, the hardness of the product will drop greatly and unevenly, which does not meet the existing process requirements

If the hardness of the existing hot-rolled steel sheet before annealing is further increased to more than 30HRC, it is easy to crack during the stamping process

In addition, the roughness Ra of the hot-rolled strip steel is above 1.0um, which does not meet the requirement of the existing technology that the surface roughness of the steel base is less than 0.30um

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