Investigation Of Liquid Induction Carbonitriding Technique

In order to improve hardness and wear resistance of the surface of metal materials, traditional surface treating methods are also the main methods. To develop a high efficiency, low energy consumption, environmentally friendly surface treatment method has is our goal. Liquid induction saturation technique is a new treatment of thermochemical processing technique. Liquid induction saturation technique in solution was applied for surface modified of medium carbon steel. We build a device of liquid induction saturation. The feasibility of rapid carburizing and carbonitriding saturation in formamide and triethanolamine was discussed. The influence of the current and time to the thickness of the layer was mainly analyzed, the best parameter of technics was applied through a lot of experiments. The morphology, structure of surface modifition layer was observed by SEM. The composition of surface modification layer is observed by EDS. The thickness of saturation layer was measured.The results indicated that applied high frequency power in triethanolamine, could not achieve carburizing,nitriding in medium carbon steel. Induction heating current and time are important process parameters of the formation of the layer. Using a large current to heat the sample to the temperature of infiltration, then with small current to keep the temperature of the two-stage heating method is not only to prevent overheating of the sample, but also to obtain a total of diffusion layer. Under the conditions fixed in the current, the thickness of the layer increased with treated time. The layer is dense and uniform including the outer white layer, inner white layer and buffer layer. White layer contains carbon, nitrogen. Different segments of the current heating, the heating current and heat current is not much difference, or the red-hot state of the sample surface is difficult to maintain. When the heating current is 425A, heat current is 280A, a layer with the thickness of 80μm will available with 6 mintues treated. And the thickness of the white layer is 34.5μm, the maximal hardness is 592HV.