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用光学金相显微镜、扫描电镜等对某汽车用铝硅系合金铸造成型的发动机缸体上的渗漏裂纹进行了相关观察与分析。结果表明,渗漏裂纹产生的原因与疏松孔隙等铸造缺陷有关,在发动机运行中产生的各种应力作用下,铸造缺陷易扩大、相互连通并形成裂纹,它不断扩展并贯穿壁厚,最终导致渗漏现象。

Analysis on Crack for Engine Cylinder Body

he leakage crack on the engine cylinder body, casting by Al-Si alloys, was observed and analyzed by using optical microscope and scanning electron microscope. The result show that the causation of the leakage crack is connected with the casting defects, such as loose and pore. On the effect of the stress casing by the running engine, the casting defects would be enlarged and connected with others to form a crack. The crack would run through the engine cylinder body, and case the leakage.