弹体表层缺陷原因分析

炮弹弹体生产中，磁粉检测发现表层缺陷。经理化检验确认，表层及基体内缺陷处含有夹杂物，通过扫描电镜观察及能谱分析，确认夹杂物中含有冶炼过程中保护渣的成分。表层缺陷是冶炼过程中保护渣卷入钢坯，钢材轧制、弹体冲拔加工时夹杂物随金属变形，切削加工时暴露到表层形成的，通过磁粉检测可以发现剔除。在基体内未暴露的缺陷无有效的检测方法检验剔除。建议完善钢材质量评估和检验方法，冶炼时及时剔除质量有波动的钢锭，弹体加工中采用有效的检测技术，选择适宜的时机进行基体缺陷的检验，以保证批量生产产品质量。

Analysis on Surface Defects of Shell Bodies

During the production of shell bodies, surface defects were found by magnetic powder inspection. Through physical and chemical examination, it was found that there were inclusions at the position of the defects. The composition of the inclusions was analyzed by SEM and energy spectrum analysis, and it was found that the inclusions had the components of the protection slag. In the process of smelting, some protection slag drifted into the molten steel, and then turned into inclusions during cooling. The inclusions deformed and some of them came to the surface and became surface defects in the process of machining. Sur- face defects can be detected and eliminated by magnetic powder inspection, but the inner inclusions in the matrix material can not be effectively detected and eliminated. The techniques for quality assessment and testing of steel products should be improved and unqualified steel ingots should be detected and abandoned. In the course of processing shell bodies, effective detection techniques should be employed and the inner inclusions should be inspected.