从1970年开始用球铁等温淬火代45钢制造凸轮轴到现在已生产近4万根。由于稳定地控制热处理的各个工艺参数,保证在大批生产获得优质高产,合格率达100％。机械性能(在凸轮轴上取样)稳定地达到6_b>82公斤/毫米~2、a_k>2.5公斤·米/厘米~2、HRC43～47。现将如何稳定地控制球铁凸轮轴等温淬火的质量作以下报导。在首批试生产380根凸轮轴中就有80根开裂。从80根轴的裂纹规律来看,大多数是沿凸轮过渡到基轴的交界处圆角R1呈横向开裂,打断后可看见一个黑圆圈。少数形成纵向裂纹见图1。从开裂的80根中任抽13根进行硬度和磁力探伤检查,并逐根打断考验耐打程度。发现抽查的13根有11根的硬度HRC49～57,超过了技术要求(HRC43～47), Since 1970, it has been producing 40,000 camshafts from isothermal quenched ductile iron and has now produced almost 40,000 camshafts. Due to the stable control of the various heat treatment process parameters to ensure that a large number of high-quality production to obtain high-yield, pass rate of 100%. Mechanical properties (sampling on the camshaft) stably reach 6_b> 82 kg / mm2, a_k> 2.5 kg.m / cm2, HRC43-47. How to control the quality of the isothermal quenching of the camshaft now is as follows. In the first batch of 380 camshaft trial production there were 80 cracks. According to the crack rule of 80 axes, most of the cracks are transversely cracked along the corner R1 of the transition from the cam to the base axis, and a black circle can be seen after being interrupted. A small number of longitudinal cracks shown in Figure 1. Cracked from the crack in any of the 13 pumping 13 hardness and magnetic testing, and by the end of the test resistance to break the degree. It was found that 13 of the 13 samples had a HRC of 49 to 57, which exceeded the technical requirements (HRC 43-47)