| The four tubes were offen leaked by the high temperature wear-corrosion which had a great effect on Circulating Fluidized Bed Boiler's operating safely and has resulted in enormous economic loss. Thereby, to solve this significant technical problems, more and more attentions and researching were given. Thermal spraying for protecting and repairing is the current research focus. Thereinto, arc spray has been showed tremendous advantages in this field because it is economical, efficient and convenient.In his article, the working conditions and the failure mechanism of the four tubes in Boiler have been studied. On the base of these researchs, two kinds of cermet cored wires are devised-Fe-based/Cr3C2 and Fe-based/Cr3C2/B-Fe. By arc spray methods, excellent coatings are acquired.Coating microstructures were assessed using scanning electron microscopy(SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Adhesive strength, hardness and the thermal shocking resistance of coatings were tested. The results show that two kinds of cored wires exhibit wonderful. They show excellent mechanic properties, with high adhesive strength and micro-hardness, their thermal shocking resistance is also good. In this article, comparative studies in the abrasive wear behavior of coatings and 20g steel have been made. Characteristics and mechanism of abrasive wear were analyzed. The results of test show that abrasive wear resistance of CrCB and CrC4 coatings are bettrer. The abrasive wear resistance of CrCB and CrC4 was respectively 16 times and 10 times higher than those of 20g. The erosion tests at elevated temperature show that coating's erosion behavior is between plasticity and fragility. CrC3 coating has better erosion resistance at high temperature. At the same time, the hot-corrosion resisitance of coatings and 20g were tested, it is known that all these coatings have better corrosion resisitance ability than 20g steel at 650℃.
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