Technology for heating processing for car universal joint cross shaft

Abstract

The invention discloses a technology for heating processing for a car universal joint cross shaft. The technology comprises the steps that after a sealed box type multi-purpose stove is heated up to 915+ / -5 DEG C, the universal joint cross shaft is placed in the stove; after the temperature of the stove is raised up to 915+ / -5 DEG C again, carbon potential is kept at 0.5% and the constant temperature is kept for 10 min; then carburizing is officially started, the carburization temperature is 915+ / -5 DEG C, the carburization carbon potential is 1.15% and the carburization time is 160 min; the universal joint cross shaft after carburization is cooled down to 860 DEG C and the carbon potential is adjusted to 0.95%; meanwhile, ammonia gas is led and the ammonia gas flow is 4-6 ml / min; the constant temperature is kept for 10 min; then quenching oil with the oil temperature of 60-80 DEG C is injected to quench and medium speed stirring is conducted; and after quenching, the universal joint cross shaft is tempered for 100-130 min in a tempering stove of 170-190 DEG C. By improving the temperature and carbon potential of carburizing and quenching, increasing the cooling speed and leading the ammonia gas during a quenching temperature continuing period, the hardenability of the cross shaft is increased, and the performance of the car universal joint cross shaft is improved.

Description

technical field [0001] The invention relates to a heat treatment process for an automobile universal joint cross shaft, belonging to the technical field of heat treatment. Background technique [0002] The universal joint cross shaft is a key part of the car universal joint transmission device. The universal joint cross shaft must have good mechanical properties, which requires carburizing and quenching heat treatment for the universal joint cross shaft to make its surface hardness and effective hardening Layer, core hardness and metallographic structure are controlled so that it has high wear resistance and fatigue resistance under service conditions. [0003] However, the universal joint cross shaft is usually made of low-carbon alloy steel 20Cr steel. After the traditional heat treatment process, it is found that the metallographic structure of the universal joint cross shaft contains a lot of residual austenite, and the surface hardness and core hardness need to be impro...

AI Technical Summary

Problems solved by technology

[0003] However, the universal joint cross shaft is usually made of low-carbon alloy steel 20Cr steel. After the traditional heat treatment process, it is found that the metallographic structure of the universal joint cross shaft contains a lot of residual austenite, and the surface hardness and core hardness need to be improved.

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