Research On The Low Carbon Steel And38CrMoAl Prepared By Liquid Induction Thermochemical Process

As the high technology develops rapidly in the machinery and electronic areas, advanced layers having many properties such as high hardness and heart toughness are required in the modern world. Liquid Induction Thermochemical Process is a kind of brand new method which combines Induction heating and Thermo-chemical treatment to reduce soaking time, save energy and reduce production cost. Low carbon steel and38CrMoAl were treated in the formamide solution by Liquid Induction Thermochemical Process while the processing temperature was controlled. Section hardness distribution and depth of layers were measured. Metallograhic organization was observed. Composition on the surface and its distribution were analyzed. The influence of processing temperature and soaking time and processing in some high temperature were also analyzed. Diffusion activation energy was calculated.The results show that, a layer as the depth is19μm could be generated at550℃for20seconds. As the temperature and time increase, the layers are getting thicker and section hardness distribution becoming uniform. Low carbon steels which treated at600℃for15minutes could generate a150μm as the thickness,680HV0.3as the maximum hardness value layer while the38CrMoAl were124μm and733HV0.3. The surface structure of the layer is ζ phase. Because of the overheating during the process, abnormal organizations and black grain boundaries could be observed in some samples of low carbon steel and38CrMoAl. The surface hardness value is getting higher when treated at800℃for5minutes, the maximum of low carbon steel and38CrMoAl specimens are720HV0.3and735HV0.3. The diffusion activation energy of low carbon steel and38CrMoAl treated by liquid induction thermochemical process are40.23kJ/mol and44.86kJ/mol.