Influence of Testing Methods on Austenite Grain Size of 20CrNiMoH Steel
Austenite grain size is an important index to measure the quality of steel.The influence of aus-tenite grain size display method on the austenite grain size detection result of 20CrNiMoH carburized gear steel was studied.The results show that the difference of austenite grain size detected by oxidation proce-dure and direct hardening procedure is small,the austenite grain size detected by carburizing procedure is 0.2 to 0.3 grade lower than that by oxidation procedure and direct hardening procedure,and there is mixed crystal phenomenon in the grain size detected by mock carburizing procedure.The causes of mixed crystal in simulated carburizing procedure are analyzed,and the improvement measures are given to ensure that no mixed crystal phenomenon occurs in the detection of austenite grain size by simulated carburizing procedure.