Study on the application for electromagnetic controlled molten pool welding process in overhead and flat position welding

Abstract

In fusion welding, gravity makes a molten metal flow downward and it sometimes causes an irregular shaped weld bead and weld defects such as an undercut. To solve this problem, the authors propose a new electromagnetic controlled molten pool welding process method which controls the molten metal flow by using upward electromagnetic forces, and the applicability of this method to industry is examined. In flat position welding with excessive heat input, the molten metal tends to sag down and an undercut defect is likely to occur. It is found that the upward electromagnetic force given by adjusting the conditions of magnetic field can lift the molten metal up, resulting in the remarkably improved shape of a penetration bead. It is further found that, even in overhead position welding, a well shaped penetration bead without undercuts is obtained by adjusting the welding touch angle as well as magnetic field conditions.

Effect of Magnetic Field Induce Arc in Autogenous TIG Welding of 304 Stainless Steel Butt Joint

“…Therefore, the melted metal falls for the weld pool area to shrink. This is corroborated by previous studies, which stated that welding with high heat input conditions leads to a molten sag down and an undercut [12].…”

“…Nomura et al [11] stated that the welding arc could be controlled using an external magnetic field, leading to a deeper weld penetration than conventional TIG welding. Shoichi et al [12] examined the effect of EMF on TIG welding with filler for 2 welding positions of 1 G and 4 G. The results showed that the use of an external magnetic field with a certain position leads to a force in the direction of gravity or made against it (antigravity) to reduce the impact of welding defects, such as undercut. Baskoro et al [13] examined TIG welding using a dynamic magnetic field.…”

Impact of electromagnetic stirring on the gas metal arc welding of an MAR-M247 superalloy

“…Large angle grain orientations can increase the energy required for the development of hot cracks, thereby effectively hindering their expansion. Currently, ESM magnetic eld control technology has been developed for metal welding, including stainless steel [35][36][37][38][39], alµminµm alloys [32,[40][41][42][43], and magnesiµm alloys [44][45][46][47], but it has not been employed for welding of the MAR-M247 superalloy. Therefore, in this study, the effects of GTAW with an EMS device on the mechanical properties and microstructure of the MAR-M247 superalloy are explored.…”

Device Design for Electric Arc Electromagnetic Constriction

“…In fusion welding, gravity causes the liquid metal in the weld pool to follow the direction of gravity, which can cause irregularities and defects in the weld bead. With the use of an electromagnetic control in the weld pool, it was possible to even the appearance of the bead, both in flat and overhead positions, combining the intensity of the electromagnetic field and the inclination of the GTAW torch [5].…”