65Mn钢弹簧断裂原因分析

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Abstract： A 65Mn steel damping spring fractured after one year of service.The fracture cause was investigated through macroscopic observation，chemical composition analysis，hardness testing，metallographic examination， and microscopic fracture surface analysis.The results indicate that residual mill scaleon the biletsurface was not completely removed，leading to the formation of folds and micro-cracks during wire drawing. Under alternating loads，these cracks progressively propagated，eventually leading to fatigue fracture.

Keywords：spring; fracture; fold; crack; fatigue fracture

1序言

65Mn 弹簧钢具有较高的淬透性、强度、硬度和弹性，以及较好的韧性、塑性和加工性，表面脱碳倾向较小，力学性能优于碳素弹簧钢，热处理后疲劳极限可与合金弹簧钢相媲美，是广泛使用的弹簧钢之一，常用来制作各种小尺寸弹簧[1]。（剩余2757字）