Multipass laser hot-wire welding: Morphology and process robustness

Abstract

There are great prospects for utilizing multipass laser hot-wire welding to join thick steel sheets, especially for techniques commonly performed in single passes, e.g., laser arc hybrid welding, fall short, presenting great opportunities for vehicle industries and offshore applications. Many modern approaches for applying these techniques rely on customized wire feeding nozzles or special scanner optics to ensure proper laser–wire interactions and, in turn, robust process behavior, making them less accessible to many industries. Here, we present a modified adaption of laser hot-wire welding, utilizing more readily available equipment, including an unmodified welding source and a nozzle, presented and evaluated through means of, e.g., high speed imaging and macroscopy. This technique was found to have high process robustness, especially for sealing passes, if wire resistance heating is kept within suitable levels. It is able to both maintain proper laser–wire interaction and produce close to net-shape weld caps. Also, recommended process parameters are presented, together with a description of a potential method for suppressing solidification cracking.

Measuring the effects of a laser beam on melt pool fluctuation in arc additive manufacturing

“…In welding, Engström et al (2001) and others have shown that laser-arc hybrid techniques can be highly capable competitors to their single heat source counterparts. Näsström et al (2017) showed that excellent surface morphology of welds can be produced using laser hybrid processes and suggests that laser positioning can be used to affect the attained bead shape. An arc technique that has been shown to introduce significant benefits to GMAW is cold metal transfer (CMT).…”

Effect of Wire Preheat and Feed Rate in X80 Steel Laser Root Welds: Part 2 — Mechanical Properties

“…6, 7) and hot-wire laser welding (HWLW) (Refs. 5,8,9) have been developed to improve the welding performance. Feeding an additional wire could increase the gap tolerance (Ref.…”

“…Feeding an additional wire could increase the gap tolerance (Ref. 8) and modify the chemical composition and weld metal microstructure (Ref. 5).…”

Extension of the process limits in laser beam welding of thick-walled components using the Laser Multi-Pass Narrow-Gap welding (Laser-MPNG) on the example of the nickel-based material Alloy 617 occ

“…The materials investigated range from mild steels [15], stainless steels [10], aluminum alloys [3], or nickel-based alloys [17]. Fiber and disk lasers with maximum powers up to 16 kW are most frequently used for the development.…”