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介绍了隔离开关壳体铸件在水压试验过程中应力(应变)电测法试验。结果表明,在标准试验压力下壳体各个测点应力(应变)-水压线性相关,壳体完全处于弹性变形且残余应变很小,未产生屈服。试验得出应力较大的3点均处于壳体相贯线部位,与理论设计分析相符。强度评定结果表明,壳体铸造工艺合理,强度完全满足安全设计要求。最后对壳体应力与破坏后断口组织结构分析可知,断口为脆性断裂和塑性断裂的混合断裂模式,随应力增大,金相组织中微小缩松仍是诱发断裂源。
This paper introduces the test of stress (strain) electric measurement in the process of hydrostatic test of the isolating switch shell castings. The results show that under the standard test pressure, the stresses (strains) at each measuring point of the shell are linearly related to the water pressure. The shell is completely in elastic deformation and the residual strain is small, and no yielding occurs. The test shows that the stress of 3 points are in the shell intersecting line, in line with the theoretical design analysis. Strength assessment results show that the shell casting process is reasonable and fully meet the safety requirements of the design. Finally, the structural analysis of the fracture surface after stress and failure of the shell shows that the fracture is a mixed fracture mode of brittle fracture and plastic fracture. As the stress increases, the micro-shrinkage in the microstructure still induces the fracture source.