调质钢晶粒度检测方法的研发

Research and Development of Grain Size Detection Method for Quenched and Tempered Steel

本文是针对调质钢晶界难以腐蚀,晶粒度难以准确测量而研发的一种检测方法。根据金属学原理,金属材料在低于临界点Ac1温度热处理,实际晶粒大小不会发生变化;同时在非保护气氛炉里热处理,往往会伴随表面氧化脱碳。利用脱碳法可以得到清晰的调质钢实际晶界,便于晶粒度的准确测定。试验结果表明:利用试样表面脱碳方法,用4%硝酸酒精溶液就可以腐蚀出真实、清晰、完整的实际晶粒度;操作过程简单,无环境污染。本方法已经在检测中使用,效果良好。而且实验表明,钢材在低于Ac1的温度热处理后,晶粒大小不会发生变化。

This paper is a detection method developed for quenched and tempered steel, which is difficult to corrode the grain boundaries and difficult to accurately measure the grain size. According to the principle of metallology, the actual grain size will not change when the metal material is heated at a temperature lower than the critical point Ac1;at the same time, heat treatment in a non-protective atmosphere furnace is often accompanied by surface oxidation and decarburization. The actual grain boundaries of quenched and tempered steel can be obtained clearly by the decarburization method, which facilitates the accurate measurement of grain size. The test results show that the real,clear and complete grain boundaries can be obtained by the decarburization method on the surface of the sample, and4% nitric acid alcohol can corrode. The operation process is simpler, and there is no environmental pollution. This method has been used in the detection, and the effect is good.Experiments show that the grain size of the 20 steel sample after heat treatment at a temperature lower than Ac1 does not change.