火炮身管在射击过程中表层微观结构的变化

The Microstructural Changes in the Surface Layer of Cannon Barrels During Firing

通过对比发射过1650枚炮弹和500枚炮弹的火炮身管来分析白层的形成和微观结构。白层的厚度与发射次数有关,也与环境、压力、温度等条件有关。在白层中确定存在奥氏体和Fe3C,另外白层内一组更广泛的碳化物也在被观察,分别是Fe2C,Fe5C2和Fe20C9。共晶体和碳化物的形成说明是液相冷却的结果,这暗示了氧化过程发生的同时产生渗碳。因此,白层形成和磨损侵蚀率之间的一些关系可以被推导出。

The white-layer formation and its microstructure were investigated through comparative analysis of two fired cannonbarrels, one launched 1650 shells and the other launched 500. The thickness of the white-layer is related to the number ofshells that were fired, as well as the function of the environment, pressure and temperature conditions. The presence of aus鄄tenite and Fe3 C in white-layer was confirmed, and much wider range of carbides were observed within white-layer, namelyFe2 C, Fe5 C and Fe20 C9 . The morphology of eutectic and carbides suggests their formation is a result of splat cooling from theliquid state. There are indications that the oxidizing process takes place concurrently with carburization. Thus some correla-tions between the white-layer formation and the wear erosion rate could be deduced.