Preparation of W-C-Fe cermet lined steel pipes by SHS-centrifugal process

A cermet lined steel pipe was prepared by the self-propagating high-temperature synthesis (SHS) centrifugal process. In the process, Fe₂0₃, WO₃, Al and C were used as the staring mixture in order to synthesize a cermet lined coating after the mixture ignited and combusted. The phases in the synthesized coating were examined by X-ray diffraction (XRD). The of the coating and the substrate/coating bonding interface and the distribution of elements adjacent to the interface were analyzed by scanning electron microscopy (SEM) and energy dispersion spectroscope (EDS). The hardness of the coating was measured. The resuits show that a metallurgical bonding interface is formed between the coating and the substrate pipe. The coating is mainly composed of Fe₃W₃C, and there is a little WC, W₂C, Fe₃C and Fe in the coating. The phases in the coating possess a gradient distribution along the depth of the coating. The grains near the substrate are fine but those far from the substrate are coarse dendrite crystals. The microhardness of the coating is 13,50±1.6 GPa, which is 7-8 times higher than that of the substrate.