摘要
聚苯乙烯装置硬脂酸锌进料罐搅拌轴在使用中多次发生断裂和弯曲变形,通过对失效件进行宏观检查、化学成分分析、金相分析、硬度分析、冲击性能试验和扫描电镜观察等多种检测,分析了搅拌轴的断裂性质和失效原因,并根据分析结果提出建议措施。分析结果表明:搅拌轴断裂性质为低应力多疲劳源型高周疲劳断裂,断裂的主要原因是轴表面涂层分布不均匀,未进行调质热处理,轴断裂处台阶根部无倒角且无涂层,搅拌轴长期工作在单向弯曲交变载荷工况,极易在变径处形成应力集中区和多个环向表面疲劳裂纹源,疲劳裂纹以较低的速率缓慢扩展导致轴最终断裂失效。
The agitator shaft of the Zinc stearate feed tank in the polystyrene unit broke and bent many times in usage,by means of macroscopic inspection,chemical composition analysis,metallographic analysis,hardness analysis,impact test,SEM observation and so on for failure parts,the fracture properties and failure reasons of agitation shaft were analyzed,and according to the results of the analysis,the suggestion and measures were proposed.The analyzing results showed that the agitator shaft fatigue was a high cycle fracture with low stress and multiple fatigue sources,the main causes of shaft fracture were uneven distribution of coating on shaft surface,the lack of quenched-tempered heat treatment,no chamfering and no coating at the root of step at shaft fracture,and long-term operation of agitator shaft under one-way bending alternating load.It was easy to form stress concentration zone and multiple circumferential surface fatigue crack sources at the variable radius location,and the fatigue crack propagated slowly at a low rate,which leaded to the final fracture failure of the shaft.
作者
魏培生
解志刚
祝加轩
王波
张云来
WEI Peisheng;XIE Zhigang;ZHU Jiaxuan;WANG Bo;ZHANG Yunlai(Research Institute of Dushanzi Petrochemical Corporation of PetroChina,Dushanzi 833699,China)
出处
《新技术新工艺》
2022年第10期86-91,共6页
New Technology & New Process
关键词
搅拌轴
低应力
高周疲劳断裂
涂层
调质热处理
交变载荷
应力集中
agitator shaft
low stress
high cycle fatigue fracture
coating
quenched-tempered heat treatment
alternating load
stress concentration
