Some studies on the electromagnetic aspects governing the
magnetically impelled arcs through experimentation, finite element simulation
and statistical analysis
Affiliations: [a] Research Scholar, Department of Electrical and
Electronics Engineering, National Institute of Technology, Tiruchirappalli –
620 015, India | [b] AGM, Welding Research Institute, BHEL, Tiruchirappalli
– 620 014, India | [c] DGM, Welding Research Institute, BHEL, Tiruchirappalli
– 620 014, India | [d] Department of Electrical and Electronics Engineering,
National Institute of Technology, Tiruchirappalli – 620 015, India
Abstract: In this study, Magnetically Impelled Arc Butt welding (MIAB)
laboratory setup for welding carbon steel tubes of small wall thickness is
designed and developed. Magnetically Impelled Arc Butt welding is an efficient
two phase process which is used in highly automated factory production lines in
high volume industries such as automotive manufactures. In this process, an
electric arc generated between aligned and properly gapped pipes are made to
rotate along the peripheral butt ends. This arc swiftly rotates along the
peripheral edges of the tubes to be welded due to the electromagnetic force
resulting from the interaction of the arc current and the externally controlled
magnetic field created by magnetic systems. The arc acts as a heating source
providing the required heat to the butt ends of the pipes. Further an
application of force on the pipe along the axial direction sets the weld. The
electromagnetic force responsible for the arc rotation is governed by the
magnetic flux density in the gap, the arc current and the arc length (gap
size). To be precise the radial magnetic flux density is a critical factor in
arc rotation and weld quality. Preliminary trials are conducted to understand
the process parameters. Tubes with 45 mm Outer Diameter with 3 mm thickness are
used for conducting the investigations. Further, for the first time an attempt
is made to analyze the effects of weld input parameters such as welding
current, welding voltage, magnetic coil voltage and magnetic coil current on
the arc speed in MIAB welding process using software package STATA. The aim of
this study also is to explore the distribution of the magnetic flux density in
the tube gap region using finite element code ANSYS .The analysis emphasizes
that the most significant factor that governs the arc speed is magnetic coil
current (that creates magnetic flux density) and the welding current.
Keywords: Magnetically Impelled Arc Butt (MIAB) welding, T11 tubes, lab model, magnetic coil design, STATA, finite element analysis.
