某型装甲车用履带断裂分析

装甲车训练时履带发生断裂,通过宏观检验、化学分析、力学测试、金相检验以及断口分析等手段,对取样的失效件进行综合分析。结果表明:化学成分符合国家标准规定,硬度符合相应技术要求,金相组织均为回火索氏体,未发现异常组织,断口均为韧窝,装甲车履带的失效是由于在湿软且起伏较大的路面行进时,履带所受阻力过大导致履带销变形,进而导致端联器、诱导齿、导齿盖及履带板等相关部件非正常受力,在大阻力行进过程中部件局部位置受力过大,最终导致其过载断裂。建议增加履带销的截面积,评估装甲车行进过程中履带板所受阻力,根据受力情况重新设计履带销的合适壁厚,或采用实心履带销。若实心履带销仍不能满足强度要求,或考虑装甲车的整体负重,建议更换履带销使用材料,选择强度级别更高的材料以保证履带销的整体强度。

Analysis of cracking in tracks for a type of armored vehicle

The tracks of armored vehicle broke during the training. The failure parts were comprehensively analyzed by means of macroscopic examination,chemical analysis,mechanical test,metallographic test and fracture analysis. The results showed that the chemical composition of sample could meet the regulations of national standard. The hardness was also accordant with the corresponding technical requirements. The metallographic structures were all composed of tempered sorbite,and no abnormal structure was found. The shape of fracture is dimple. When the armored vehicle moved on the wet and undulating road,the resistance of the track was overloaded,resulting in the formation of track pin. Then,the related components such as the end gear,the induction tooth,the guide tooth cover and the track shoe were abnormally stressed. The stress on some positions of these components was too high in motion with large resistance,which finally caused the overload fracture. It was suggested to increase the cross-sectional area of the track pin,evaluate the resistance of the track shoe during the motion of armored vehicle,redesign the appropriate wall thickness of the track pin according to the force,or use a solid track pin. If the solid track pin still could not meet the strength requirements,or the overall load of the armored vehicle was considered,it was recommended to replace the material used for the track pin and select a material with higher strength level to ensure the overall strength of the track pin.