2Cr12NiMo1W1V钢螺栓表面裂纹分析

Analysis on Surface Crack of 2Cr12NiMo1W1V Steel Bolt

2Cr12NiMo1W1V钢螺栓在调制后发现其表面存在多条轴向裂纹。通过对裂纹进行宏观观察、断口宏观及微观分析、化学成分分析、硬度检查以及金相分析等,并结合实际生产工艺,最终确定了螺栓的开裂原因。分析结果表明:2Cr12NiMo1W1V钢螺栓开裂主要是因为其表面存在锻造折叠缺陷,缺陷处形成裂纹源区,淬火时在淬火应力的作用下,由折叠缺陷进一步扩展形成裂纹。

Several cracks were found on the surface of bolts made form 2Cr12NiMo1W1V steel after quenching and tempering process.The cracking causes of the bolt was analyzed by the macrostructure observation of the crack,the macrostructure and microstructure analysis of the fracture,chemicalcomposition analysis,hardness test and metallurgical structure examination,combining with the production process.Based on these experimental results,the final cracking reason of bolt was determined.The results indicated that the cracking of the bolt was mainly due to there were diatribution forging fold defects in the surface before quenching and tempering process.The forging fold defect became cracking source when quenching,and extended to crack under the stress of quenching.