金属热处理 ›› 2022, Vol. 47 ›› Issue (7): 277-282.DOI: 10.13251/j.issn.0254-6051.2022.07.048

• 测试与分析 • 上一篇    下一篇

柴油发动机活塞连杆机构失效原因分析

焦丽, 商海昆, 何剑丰, 王国亮, 冯涛, 王嘉, 扈钰涛   

  1. 河北华北柴油机有限责任公司, 河北 石家庄 050081
  • 收稿日期:2021-11-12 修回日期:2022-04-20 出版日期:2022-07-25 发布日期:2022-08-12
  • 作者简介:焦 丽(1975—),女,高级工程师,主要研究方向为金相分析与检测以及零部件的失效分析,E-mail:1025496268@qq.com

Failure analysis on piston connecting rod mechanism of diesel engine

Jiao Li, Shang Haikun, He Jianfeng, Wang Guoliang, Feng Tao, Wang Jia, Hu Yutao   

  1. Hebei Huabei Diesel Engine Co., Ltd., Shijiazhuang Hebei 050081, China
  • Received:2021-11-12 Revised:2022-04-20 Online:2022-07-25 Published:2022-08-12

摘要: 某柴油发动机活塞连杆机构在使用过程中发生故障,拆解后发现缸套、活塞和连杆均发生不同程度的断裂失效。通过断口宏观检验和微观分析、化学成分分析和显微组织检验等手段,结合零件生产工艺流程进行综合分析。结果表明,连杆是引发此次连锁故障的肇事件,缸套与活塞为受牵连件。连杆表面存在由喷丸工艺不当造成的折叠缺陷,因应力集中而诱发了材料最初的疲劳损伤;同时显微组织不良在一定程度上弱化了连杆的整体强度。在复杂的循环应力及较大的惯性力作用下,连杆发生高周疲劳断裂,并引发缸套、活塞的相继损坏。

关键词: 活塞连杆机构, 喷丸, 折叠缺陷, 疲劳断裂

Abstract: A malfunction of piston connecting rod mechanism of diesel engine occurred during use. After dismantling, various degrees of fractures were found that on the cylinder, piston and connecting rod. The comprehensive analysis was carried out by means of macro and micro examination of the fracture, chemical composition and microstructure analysis in combination with the production process. The results show that the connecting rod was the failure maker, and the cylinder and piston belong to secondary fracture in this cascading failure. The folding defects on the surface of the connecting rod caused by improper shot peening process, which induces the initial fatigue damage because of the stress concentration. Meanwhile the undesirable microstructure weakens the strength of the connecting rod in a certain degree. The connecting rod high cycle fatigue fracture and the cylinder and piston damage one by one under the action of cyclic stress and the inertia force.

Key words: piston linkage mechanism, shot peening , folding defect, fatigue fracture

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