Hardness analysis of 7075 rheo squeeze casting parts treated with different solution temperature

Hardness test is the most simple and easy method in mechanical property test. In order to replace some mechanical property tests with hardness test, many engineering applications and production have adopted some more accurate empirical conversion relationship between hardness and strength. Practice has proved that there is an approximate relationship between hardness and strength of metal materials. Because the hardness value is determined by the initial plastic deformation resistance and the continuous plastic deformation resistance, the higher the strength of the material, the higher the plastic deformation resistance, the higher the hardness value. Hardness and strength are commonly used in production to measure the quality of heat treatment system and whether the parts can meet the process or use requirements. After a certain strengthening process is carried out on metal materials, with the increase of strength, the general hardness also increases correspondingly. In order to reduce the inspection process and part of the test materials, the method of hardness measurement and metallographic analysis are used to analyze the advantages and disadvantages of the solution treatment process.

The Brinell hardness values of 8 # and 12 # samples after solution treatment at different solution temperatures are obtained. After each sample is polished, three points are taken for hardness test, and then the average value of three hardness values is taken. The testing instrument is hbe-3000a electronic Brinell hardness tester, with a diameter of 10mm steel ball, a pressure of 1500kgf and a pressure holding time of 30s. As shown in the figure is the curve distribution of Brinell hardness value with temperature after solution treatment of 8 # and 12 # samples.

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