microstructural evolution and mechanical properties inhigh frequency resistance welding (hfrw) of 2.25cr-1mo ferrite-pearlite steels andferritic steels 409

In this research, the effect of high-frequency resistance welding (hfrw)parameter on microstructure and mechanical properties on dissimilar joints between 2.25cr-1mo ferritic steeland as spirally (helically) finned tube of industrial fin tube boiler has been investigated. ferritic steels containing cr and mo have found widespread use in steam pressure systems in the power generation and petrochemical industries. current frequency range normally used for high-frequency welding 400, 000 hz. with this technique, the fin is wound on edge around the tube spirally and a continuous weld is obtained. as well as international standard for tests of high frequency resistance welded fins according to astm used for metallography fusion weld, tensile strength and hardness. the various sample of metallographic results and mechanical properties indicate that the average width of the weld bond and diffusion between the fin and the tube shall be a minimum of 90 percent depend on optimum welding parameter, fin tipand tube tipposition of resistance welding, pressure setting with squeeze rollerand pitch fpi (fin per inch) todissimilar joints between chromium-molybdenum low alloy steels tube and chromium high alloy steels of coil strips.