Laser beam welding of atmosphere aluminum die cast material using high frequency beam oscillation and brilliant beam sources

Abstract

In the serial production of components for automotive applications such as cooling and air-conditioning systems, aluminum die-cast materials are frequently used due to their excellent castability. The aim of providing light weight components can be approached with thin walled cross sections even for complex structural parts. However, cast components are usually connected to semifinished products such as profiles or tubes. The connections have to be mostly pressure tight. The joining technique for these applications has to be highly productive to obtain high component outcome and cost-efficient. Laser beam welding techniques are especially suitable for these tasks. Die-cast components have limited or no weldability due to their manufacturing process. This is due to entrapped gases within pores or cavities under high pressure conditions. Furthermore, the mold release agents for the die-cast process are inappropriate for obtaining homogeneous and sound weld seams. Consequently, this results in a larger number of pores in the weld seam and stochastic melt pool blow-outs, which prohibit mostly the use of the component. To solve these issues, a new welding technique, remoweld®T, has been developed at Fraunhofer IWS. This unique method has been extensively tested and used for serial-production. The decisive step was to use laser sources with brilliant beam quality in combination with a high frequency beam oscillation within the melt pool. In this paper, the technological approach will be presented. With the remoweld®T method, it was possible to obtain homogeneous weld seams with low porosity and a strongly reduced distortion for the first time. Minor component tolerances and a reproducible joining technique with a high output for serial production can be achieved

In situ observation with x-ray for tentative exploration of laser beam welding processes for aluminum-based alloys

“…Nevertheless, typical phenomena already known from the literature are shown. 1,13 In the static laser beam welding in Fig. 8, two large craters become visible immediately after the start of the process.…”

“…In the study by Dittrich et al, 1 the theory was established that the laser beam gradually slices the material. This theory needs to be verified.…”

Comparative Study of Laser-Arc Hybrid Welding for AA6082-T6 Aluminum Alloy with Two Different Arc Modes

“…Considering the physical-chemical characteristics of aluminum alloys, numerous results indicate that some obvious drawbacks such as: large welding deformation, serious joint softening, and low production efficiency would appear during the arc welding process due to the high heat input and low welding speed [3][4][5]. With features of high energy density, low heat input, high welding speed, and large depth-width ratio, laser welding can effectively solve the above problems [6][7][8][9]. However, strict accuracy in assembly is required due to the small focused spot diameter of the laser, which significantly limits its application [10,11].…”

Influence of welding parameters on electromagnetic supported degassing of die-casted and wrought aluminum

“…This has been demonstrated successfully using a laser hybrid method 2 and a beam oscillation. 6 However, the temporal prolongation of the weld pool existence is to a certain extent accompanied by the negative properties mentioned above with regard to distortion and heat input. The second approach to porosity reduction is to actively support the buoyancy behavior of the pores.…”