Failure analysis of a cracked diesel engine clutch spring plate
Failure analysis of a cracked diesel engine clutch spring plate
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DOI：
10.1016/j.matchar.2006.11.003
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发表时间：
2008-02
影响因子：
4.7
通讯作者：
Zhi-wei Yu;Xiao-lei Xu
中科院分区：
文献类型：
--
作者：
Zhi-wei Yu;Xiao-lei Xu
某货车使用的柴油机离合器弹簧片在进行试验时发生裂纹。裂纹从板材厚度方向的中部开始，向板材的正面和背面扩展。断口研究表明，脆性沿晶断裂是主要的破坏机制。沿晶断裂区沿板径向观察到许多平行带状组织，二次裂纹密度高，沿晶颗粒细小。金相分析表明，裂纹起始处沿板材径向存在细长的MnS夹杂物偏析和颗粒状的碳化钒。细长的MnS夹杂物的偏析导致韧性下降，夹杂物和杂质元素在晶界的共同偏析导致晶界的弱化。这些条件导致离合器弹簧片沿晶脆断。
A diesel engine clutch spring plate used in a truck cracked when testing was being performed. The crack initiated from the middle of the thickness direction of the plate and propagated toward the front and the back of the plate. Fractographic studies indicate that brittle intergranular fracture was the dominant failure mechanism. Many parallel band structures were observed along the radial direction of the plate in the intergranular fracture region; a high density of secondary cracks and fine intergranular particles were found in this banded region. Metallurgical examinations indicated segregation of elongated MnS inclusions and the presence of granular vanadium carbides along the radial direction of the plate, at the location of the crack origin. Segregation of the elongated MnS inclusions leads to a reduction in toughness, and the combined segregation of inclusions and impurity elements at grain boundaries result in weakening of the boundaries. These conditions led to the intergranular brittle fracture of the clutch spring plate.