摩托车发动机曲轴断裂原因分析-失效分析与预防.PDF

2009 2 February, 2009 4 1 Vo.l 4, No. 1 , , , (广东出入境检验检疫局技术中心, 广州 510623) [ ] 6 350 km , , , , [] ; ; [] T 413. 3+ 1 [] A [] 1673-6214( 2009) 01-0035-04 Failure Analysis on Crankshaft in aM otorcycle Engin e TAN Ying, CAO Biao, CHEN M ing, MO M ing-zhen (Guangdong Entry-Ex it Insp ection Quarantine Technology Center, Guangzhou 510623, China) A bstrac t: The crankshaft in amotorcycle engine fractured after the service of 6350 km. The fracture cause of the crankshaftwas an- alyzed by facture surface observation, surfacemark analysis, chemical composition analysis, metallographic exam ination and hard- ness testing. The results show that there ex isted electricalburn at the bottom of the crankshaft locating slot, whichwas caused by e- lectrode contact before fixing the locating pin. Therewas stress concentration at the electrically burned zone. As a result, cracks in-i tiated from the electrically burned zone under the effect of service load, and finally, the crankshaft fractured. K ey w ord s: crankshaft; fatigue fracture; electrode burn 2, 0 , AB , A , , , , , 3/4, 45b, [ 2] , , , ; B, , , , A, , [2-3] B AB [ 1] ,