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利用C形缺口试样,研究Nb-B微合金化齿轮钢的渗碳热处理畸变。结果表明,由于细小的Nb(C,N)析出相在奥氏体晶界起钉扎作用,Nb-B微合金化渗碳齿轮钢的原奥氏体晶粒平均尺寸明显细于20CrMoH钢和22CrMoH钢。微量B使20CrMoH钢和22CrMoH钢的淬透性提高,理想淬透直径DI值增大,渗碳淬火畸变率增加;Nb微合金化细化晶粒,细晶粒齿轮钢的渗碳淬火畸变相对较小;Nb-B微合金化可实现淬透性提高而渗碳淬火畸变不显著增加。
The C-notch specimen was used to study the carburizing heat treatment distortion of Nb-B microalloyed gear steel. The results show that the average austenite grain size of Nb-B microalloyed carburized gear steel is significantly smaller than that of 20CrMoH steel due to the pinning effect of precipitated Nb (C, N) precipitates on austenite grain boundaries. 22CrMoH steel. The microhardness B increased the hardenability of 20CrMoH steel and 22CrMoH steel, the ideal quenching diameter DI value increased, and the distortion rate of carburizing and quenching increased. The carburizing and quenching distortion of Nb microalloyed and fine grain gear steel was relatively Smaller; Nb-B microalloying can achieve increased hardenability and carburizing quenching distortion does not increase significantly.