Improvement of the joint quality in the high-frequency induction welding of pipes by edge modification

High-frequency induction welding (HFIW) is among the most commonly used methods for producing roll formed pipes. In this paper, weld quality is evaluated through examining the weld properties, in order to obtain the effect of edge preparation on improvement of weld quality. Temperature distribution in the weld zone is studied through the groove shape of the weld joint, and the other parameters such as current, frequency, and linear speed, considered constant, are equal to 1400 A, 150 kHz, and 25 m/min respectively. The mechanical and metallurgical properties of the weld metal were evaluated by tensile test and metallography. The appropriate temperature distribution resulted from modifying the shape of the connecting edges, leading to a reduction of 27% in the mean size of the grains in the weld zone. The results also show that by increasing the temperature of welding, the heat-affected area expands and the other areas decrease. When the results of the metallography tests of the weld zone were compared, a more uniform weld width was observed in the welded specimens with modified edges. The results also showed an 18% decrease in the weld width in specimens, compared with the specimens without edge preparation.