Nickel based self-fluxing alloy coating extends the service life of furnace wall tubes at waste incineration plants due to its excellent corrosion resistance and heat resistance. With our system, fusing of such coatings is performed by induction heating, which offers improved efficiency and reliability of products. Compared with conventional plasma, flame, and HVOF thermal-sprayed coatings, induction-fused coatings provide a far stronger metallurgical bond at the interface, while minimizing the inclusion of pores. In addition, the tubes are less costly than those with welded coatings, and the process reduces the distortion of the products, facilitating easier final assembly. A successful experimental application of 11 units (four, six-meter pipes per unit) revealed virtually no corrosion on the exposed surfaces, and showed an improved water heating efficiency over that of the original mortar-coated tubes. Over 200 such units are now being employed in four incinerators in Taiwan, and further installations are in progress.

This study focuses on two major advantages of induction heating over flame heating in the treatment of coated boiler tubes. In both cases the induction heating process is simple, fast and effective. Firstly, we will show how the use of induction heating results in exceptionally thick and hard coatings with low porosity. Having high corrosion and wear resistant properties, the products can satisfy industry's needs for reliable coatings with a long service life. Next, the study will detail how a pipe with the coating already applied can be simultaneously bent by induction heating while the coating is melted and fused to the pipe. The result is a thicker, more even and reliable coating than that accomplished by the flame sprayed method on a bent pipe. The process is not only less cumbersome, but again provides a superior product for the market.