轿车螺旋悬挂弹簧用钢的研究开发

从冶金生产工艺、微观组织、拉伸和冲击断裂行为、疲劳断裂机制及弹减抗力等方面对引进轿车中应用较多的螺旋悬挂弹和钢50CrV4进行了研究。研究结果表明，随着回火温度升高，试验钢的强度和硬度降低、塑性和韧性增加；对试验钢断裂行为的分析表明其对应力状态和应变速率敏感，在中温回火后具有较高的抵抗动态变形和断裂的能力；试验钢对表面缺陷和表层硬性夹杂物敏感；中温回火后由于具有细小的微观组织和碳化物，因而具有较好的弹减抗力。通过改进冶金生产工艺、热处理和弹簧加工工艺生产的螺旋悬挂弹簧满足引进轿车的要求，已批量生产。

RESEARCH AND DEVELOPMENT OF HIGH STRENGTH STEEL USED FOR CAR SUSPENSION COIL SPRING

CrV4 steel, which is widely used in imported automobiles, was studied from the point of metallurgical processing, microstructure, tensile and impact fracture behavior, fatigue property and sag resistance property. It is shown that with the increase of tempering temperature, the strength and hardness decrease and the ductility and toughness increase. The steel is sensitive to stress state and strain rate and has a higher dynamic deformation and fracture resistance when tempered in medium temperature range. The steel is also sensitive to surface defect and surface layer inclusion. Owing to finer microstructure and carbide, the steel has a considerable sag resistance property. The suspension coil spring manufactured from this steel meet the needs of imported automobiles.