渗碳钢的深冷强化

Study on Cryogenic Strengthening of Carburized Steel

采用透射电镜研究了深冷处理对ＳＡＥ４８２０渗碳钢ＴＥＭ组织的影响。用Ｘ射线衍射法对表层残留奥氏体和残余应力作了定量分析。结果表明，深冷处理可促使残留奥氏体向马氏体转变，淬火马氏体回火后析出高度弥散的超微细碳化物，降低残余压应力。残留奥氏体由５０６％降为３４８％。

The effect of cryogenic treatment on the TEM microstructure of SAE4820 carburized steel was studied by means of Transmission Electron Microscope(TEM).The residual compressive stress and retained austenite were analyzed quantitatively by XRay Diffraction.The results showed that the retained austenite translated partly into martensite,ultrafine carbides precipitated in asquenched martensite and the residual compressive stress decreased by cryogenic treatment.The residual austenite reduced from 50.6% to 34.8%,and the tangential/axial residual compressive stress from 200.6259.6MPa to 82.694.4MPa.