钢中奥氏体晶粒度是影响机械性能的重要因素之一,对冲击韧性、强度、塑性以及切削加工性等也部起着很大的影响。因而在钢材质量鉴定时,测定晶粒度是重要的试验指标。我国冶金部颁发的“冶标YB 25-59钢中奥氏体的测定方法”标准,规定了二种显示钢中奥氏体本质晶粒度的方法,即在930±10℃温度下保温八小时渗碳处理及保温三小时进行氧化处理的方法。前者依靠渗碳处理后在奥氏体晶粒边缘析出渗碳体网络来显示奥氏体晶粒度,而后者则借助于晶粒边缘的氧化来显示 Austenite grain size in steel is one of the important factors affecting the mechanical properties of the impact toughness, strength, plasticity and machinability also play a significant impact. Thus in the steel quality identification, the determination of grain size is an important test indicators. China’s Ministry of Metallurgical issued “Standard YB 25-59 austenitic steel determination method ” standard, provides two kinds of methods to show the intrinsic austenite grain size, that is, at 930 ± 10 ℃ temperature Eight hours of carburizing and heat insulation three hours for oxidation treatment method. The former relies on the carburizing network precipitated at the austenite grain boundaries after carburizing to show the austenite grain size while the latter is shown by the oxidation of the grain boundaries