Surface layer of WCL steel carbonitriding in fluidized bed

Recently special attention is paid to the thermochemical treatments which are performed in environments increasing the process of diffusion alloying. One of these environments is fluidized bed. Application of fluidized beds allows for intensifying the process of diffusion alloying of steel. Carbonitriding in fluidized bed makes possible to get the same diffusion layer thickness at shorter time than in conventional carbonitriding. The purpose of this paper is to determine the surface layer structure produced on WCL steel carbonitriding in fluidized bed. The authors present results of microstructure investigations, hardness and microhardness tests, fractography of the fracture surface layer and X-ray analysis. These results show that the surface layer produced on WCL steel after carbonitriding in fluidized bed consists many sublayers. Thickness of this surface layer is depending on carbonitriding temperature and time. (author)