摘要
某大型注塑机哥林柱在服役过程中发生早期断裂,采用断口形貌观察、化学成分分析、非金属夹杂物分析、显微组织观察和力学性能测试等方法,对其断裂原因进行了分析,并提出了改进措施。结果表明:哥林柱的断裂性质为韧性断裂;在热应力、后续热处理不当造成的组织应力以及持续往复拉伸外力的共同作用下,裂纹在心部缩孔残余和带状偏析应力集中处萌生并扩展,最终导致哥林柱的断裂;采取严格控制原材料的化学成分、适当提高正火温度、增大锻造比、适当延长预热保温时间、适当延长淬火保温时间等措施后,未再发生该类型失效。
The early fracture of the tie bar of a large-scale injection molding machine occurred during service.The fracture cause was studied by fracture morphology observation,chemical composition analysis,non-metallic inclusion analysis,microstructure observation and mechanical property test,and some improvement measures were put forward.The results show that the fracture characteristic of the tie bar was ductile fracture.Under the combined action of thermal stress,microstructure stress caused by improper subsequent heat treatment and continuous reciprocating tensile force,the cracks initiated from the stress concentration of shrinkage cavity residue and banded segregation in the core,and propagated,finally leading to the fracture of the tie bar.After strictly controlling the chemical composition of raw materials,properly increasing the normalizing temperature,increasing the forging ratio,properly prolonging the preheating holding time,and properly prolonging the quenching holding time,such failure did not happen again.
作者
于娜红
陈旭
YU Nahong;CHEN Xu(FAW Wuxi Fuel Injection Equipment Research Institute,Wuxi 214063,China;Wuxi Institute of Supervision&Testing on Product Quality,Wuxi 214101,China)
出处
《机械工程材料》
CAS
CSCD
北大核心
2020年第6期67-71,共5页
Materials For Mechanical Engineering
关键词
哥林柱
韧性断裂
缩孔残余
带状偏析
tie bar
ductile fracture
shrinkage cavity residue
banded segregation
