18Ni马氏体时效钢原始奥氏体晶界显示方法

利用光学显微镜(蔡司)，在室温下，通过配制不同成分、浓度浸蚀剂和化学浸蚀方法，对经不同温度处理后的18Ni马氏体时效钢的原始奥氏体晶界显示方法进行了系统研究。结果表明：采用腐蚀性强、浓度高的浸蚀剂只能获得18Ni马氏体时效钢的金相显微组织，而采用体积比为4%的硝酸酒精溶液，对800~925 ℃固溶空冷后的18Ni马氏体时效钢试样进行化学浸蚀，能清晰地显示出18Ni马氏体时效钢试样原始奥氏体晶界，并可以进行准确的晶粒度级别数评定。

Display method of original austenite grainboundary of 18Ni maraging steel

The etchants with different composition and concentration were prepared at room temperature. The display method of original austenite grain boundary of 18Ni maraging steel after treatment by chemical etching at different temperatures was studied using optical microscope(Zeiss).The experimental results showed that only the metallographic microstructure of 18Ni maraging steel could be obtained when the etchant with strong corrosivity and high concentration was adopted. However, as 4% (volume fraction) nitric acid alcohol solution was used for chemical etching, the original austenite grain boundaries of the 18Ni maraging steel samples could be clearly observed after solution and air cooling at 800-925 ℃. Moreover, the grain size grades could be evaluated accurately.