Abstract:
This thesis was to analyze the welding heat input of ASME SA-192 finned tube steel and optimization of parameters for High Frequency Resistance Welding (HFRW), T joints welding. The Central Composite Design (CCD) analyzes the determination of optimum factors for welding: current 13 kVolt, voltage 9 Amp, and frequency 250 rpm. The first specimen group assigned the heat to the
weld from 200 to 290 J/mm revealed that the influence of heat on the microstructure. The specimens have no melting. The hardness of the specimens has been heated up, resulting in a higher surface hardness value. The hot affected area has a narrow area. The tensile and fatigue test results showed that when the specimen was subjected to a slight repetitive load then the specimens are damaged
immediately. This does not pass Ultimate Tensile Strength (UTS) standard because there is a tear between the fin and the tube. In another group, the heat to the weld 350 to 540 J/mm was found that the influence of heat on the microstructure. There is a complete melting between the fin and the tube. The Grain resolution. The width of the weld, where this area is most heated, also increases the tensile stress. High surface hardness value but the area that has been affected with heat has decreased hardness. All specimens pass UTS standard. Besides, the research found that the strength of the specimens must be considered the tensile stress along with the fatigue value. Moreover, this research proposes parameters suitable for the effect of the heat of the workpiece to determine the optimum melting width and weld depth