EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF WELDING PARAMETERS ON WELD GEOMETRY AND MICROSTRUCTURE OF GMAW BUTT-WELDED PIPE JOINTS
Abstract
This paper investigates the influence of welding current, travel speed, and arc voltage on the weld geometry of S235JRH steel butt-welded pipe joints with GM-70S filler wire. The experimental plan was arranged according to a Taguchi L9 orthogonal array to reduce the number of trials while preserving the ability to evaluate the main effects of the welding parameters. The results show that increasing the welding current from 90 A to 100 A increases the thermal energy supplied to the joint, resulting in an increase in welding width from 5.8 mm to 7.8 mm and penetration depth from 1.7 mm to 3.2 mm. In addition, increasing the travel speed from 4.6 mm/s to 5.0 mm/s reduced the weld reinforcement height from 1.7 mm to 1.2 mm.
Arc voltage also significantly affected weld formation, particularly weld width. Under welding condition M07 (100 A, 4.6 mm/s, 20 V), the weld exhibited relatively large width and reinforcement height, reaching 7.8 mm and 1.8 mm, respectively. Microstructural analysis showed that the weld metal mainly consisted of ferrite and bainite, satisfying the mechanical property requirements of the pipe butt-welded joint.
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