【摘要】 20CrMoH钢汽车轴齿锻造毛坯等温正火处理时,由于轴齿截面变化复杂,在奥氏体化后等温正火前的冷却过程中各截面冷却速度不一致,使显微组织差异性加大,各截面硬度不均匀,切削后表面状态也不一致,严重影响了产品质量。本文针对这一问题进行了工艺和理论方面研究,给出了确保各截面冷却条件一致的冷却速度及控制各截面的冷却速度的理论方程,采用最佳工艺处理后轴齿的组织均匀、力学性能稳定。更多还原

【Abstract】 When carburizing automobile pinion parts made of 20CrMoH steel were treated by isothermal normalization,the cooling rates at various sections during the cooling process before isothermal normalizing and after austenitization were in disparity because of complexities of the pinion sections,which lead to diversity of microstructure and non-homogeneity of hardness at different sections.The machined surface state was also non-uniform,which affected products quality severely.To solve the problems,both process and theory studies were carried out.A theoretical equation for controlling cooling rates and ensuring consistent cooling rates at different sections was worked out,and optimized process was adopted with which homogeneous structure and stable properties were obtained.更多还原