Improvement of Filler Wire Dilution Using External Oscillating Magnetic Field at Full Penetration Hybrid Laser-Arc Welding of Thick Materials

Abstract

Hybrid laser-arc welding offers many advantages, such as deep penetration, good gap bridge-ability, and low distortion due to reduced heat input. The filler wire which is supplied to the process is used to influence the microstructure and mechanical properties of the weld seam. A typical problem in deep penetration high-power laser beam welding with filler wire and hybrid laser-arc welding is an insufficient mixing of filler material in the weld pool, leading to a non-uniform element distribution in the seam. In this study, oscillating magnetic fields were used to form a non-conservative component of the Lorentz force in the weld pool to improve the element distribution over the entire thickness of the material. Full penetration hybrid laser-arc welds were performed on 20-mm-thick S355J2 steel plates with a nickel-based wire for different arrangements of the oscillating magnetic field. The Energy-dispersive X-ray spectroscopy (EDS) data for the distribution of two tracing elements (Ni and Cr) were used to analyze the homogeneity of dilution of the filler wire. With a 30 • turn of the magnetic field to the welding direction, a radical improvement in the filler material distribution was demonstrated. This would lead to an improvement of the mechanical properties with the use of a suitable filler wire.

Influence of shielding gas on filler wire mixing at laser hybrid welding of thick high strength steels

“…In these studies, the magnet was operated on the top side during wire-feed LBW in partial penetration mode. With a magnet operating at the bottom side to prevent sagging as well as to improve the filler wire mixing at single-pass HLAW of steel plates with a wall thickness of 20 mm and above was demonstrated in previous studies [16,17]. Therefore, an AC magnet was positioned under the workpiece and operated at a magnetic flux density of approx.…”

Influence of oscillating magnetic field on the keyhole stability in deep penetration laser beam welding

“…In previous studies dealing with laser beam based welding by use of an oscillating magnetic field, it could be shown that the melt flow dynamic could be influenced positive to e.g. reduce the porosity of laser beam welded aluminum die casting [17] or to improve the transport of the filler wire elements at hybrid laser arc welding through formation of a vortex within the melt pool [18]. This study deals with the influence of an external oscillating magnetic field during highpower laser beam welding on the keyhole stability and on the laser beam incident angle.…”

The Effects of HLAW Parameters for One Side T-Joints in 15 mm Thickness Naval Steel

“…Friction stir welding (FSW) seems to relieve some of these problems [16]. In this context, HLAW processes with a laser source seem to be a promising technology to join HSLA steels in shipbuilding [2,21].…”