某型柴油机高压油管断裂失效分析及改进

为解决某型柴油机高压油管漏油率较高问题,分析故障油管断裂部位、断口形貌特征、金相组织、振动测试结果及受力,确定高压油管断裂的主要原因为墩头及过渡区域设计不合理,导致其疲劳破坏而发生脆性断裂;优化高压油管结构与管型,改进管夹布置方式,增加油管稳定性;改进油管镦头尾部结构,增大锁紧螺母与镦头贴合面装配应力.振动及耐久试验证...

Failure analysis of high-pressure pipe for a diesel engine and its improvement

In order to solve the problem of a high fuel leakage rate of the high pressure pipe of a diesel engine, fracture location, fracture surface morphology and metallographic, the vibration and the stress are investigated. The results show that the fracture is caused by unreasonable design of the pipe heading joint which leads to fatigue failure and brittle fracture. The structure and pipe type of high-pressure tubing are optimized, the arrangement of pipe clips is improved, and the stability of tubing is increased;the structure of upsetting head tail is improved, and the assembly stress between locking nut and upsetting head is increased.The results of vibration and durability test show the average number of failure cycles of the improved high pressure tubing is increased by 70.94%, which meets the requirements of fatigue life, and the improved scheme is effective and the pipe is successfully applied to the market.