曹新民

(广西机电职业技术学院建筑工程系)

摘 要：利用直读光谱仪、拉伸试验机、布氏硬度计和扫描电镜对开裂的Z形臂进行了检测。结果表明，Z形臂的成分、组织、性能均满足技术要求。断口的微观组织由胞状晶和树枝晶、气孔以及等轴形韧窝组成，分析发现，Z形臂在铸造过程中形成的冷隔缺陷，是导致开裂的主要原因。通过采取控制浇注时间和浇注温度以及增加冒口的措施，取得了良好的效果。

关键词：起重机；Z形臂；冷隔；ZG35SiMn2MoV钢；胞状晶

中图分类号：TG111.91;TG142  文献标志码A

DOI：10.15980/j.tzzz.2020.07.011

Failure Analysis of Crane Z arm Fracture

Cao Xinmin

(Civil Engineering Department, Guangxi Technological College of Machinery and Electricity)

Abstract: The cracked Z arm was tested by direct reading spectrometer, tensile tester, Brinell hardness tester and scanning electron microscope. The results show that the composition, structure and performance of Z arm meet the technical requirements. The micromorphology of the fracture presents cellular crystal, dendrite, pore and equiaxed dimple. The Z arm is not fully fused in the casting process, resulting in the formation of cold shut, which is also the main reason of the cracking. Through the control measures of limiting pouring time, measuring pouring temperature and adding riser, effective improvement could be achieved.

Key Words: Crane, Z arm, Cold Shut, ZG35-SiMn2MoV Steel, Cellular Crystal