非调质钢曲轴感应淬火裂纹失效分析

摘要

目的：分析非调质钢曲轴感应淬火时出现裂纹的原因。方法首先统计了裂纹的分布规律，并确定了裂纹源位置，之后通过金相检验、低倍检验，从锻打工艺、材料偏析等角度对裂纹进行了原因分析。结果产生在分模面位置的裂纹，是因产品结构造成该区域材料在锻打过程中发生流速不均，当材料的框型偏析位置在锻造挤压下流动到此处时，偏析的材料产生了微细空洞，该微细空洞在后续感应淬火时成为裂纹源而引起开裂。结论该裂纹的产生与材料框型偏析有直接关系。研究对控制非调质钢曲轴生产中的裂纹缺陷，提高曲轴生产质量，具有重要应用价值。%To analyze the causes for induction hardening crack of non quenched and tempered steel crankshaft, this study firstly analyzed the crack distribution and determined the source of crack position, then analyzed the causes of cracks from the aspects of the forging process and material segregation through metallographic examination and acid corrosion test. According to the test results, crack in the position of parting surface was caused by the uneven regional material flow during forging process due to the structure of product. When the material of the box type segregation position under the forging extrusion flowed to here, micro holes were formed on the segregated materials. The micro holes became sources of crack in the subse-quent induction quenching and consequently caused cracking. Therefore, the existence of cracks is directly related to the segre-gation of the material frame. Research on crack control of non quenched and tempered steel crankshaft production has important application value for improving the production quality of crankshaft.