New Alloy Enables Efficient Welding of Aluminum Components
Laser remote welding processes have previously been used only for steel materials. A new monolithic alloy from Constellium now also enables fast and efficient laser remote welding of aluminum components and sheets, especially for the automotive industry.
Laser remote welding processes are known from the processing of steel. This special laser beam welding process works with so-called scanner mirrors and enables a fast approach to different positions from a distance of up to 1 meter. This makes the welding process considerably faster and more efficient, as individual points no longer have to be controlled separately. What works well for sheet steel, on the other hand, has not yet been used for the aluminum alloys of the 6000 series used in automotive engineering, since the process takes significantly longer for hardenable aluminum and requires filler materials that prevent hot cracks.
The process takes more time because the laser wire has an explicit starting point, moves to the end of the seam and has to control each individual position. This takes up to five times longer than with steel parts. In order to guarantee strength and avoid cracks, a filler material is also required for remote laser welding of aluminum alloys.
Cold Forming and Warm Hardening
With a new alloy, Constellium now enables fast and efficient laser remote welding for aluminum. The aluminum experts further developed their proven alloy for automotive interior applications with Formalex Remote, thus creating the prerequisite for the laser remote process: A heat-curable, monolithic alloy that allows welding without filler materials. The material, originally in the cold-hardened T4 state, is first formed and welded by laser. Afterwards, comparable to a standard 6000 alloy, it hardens in a KTL drying oven at about 180 °C for 20 minutes. This heat treatment in the paint drying oven ensures a particularly high level of strength.
One Tool for Two Materials
Until now, car manufacturers had to use different equipment for laser welding of steel and aluminum. The new alloy has the advantage that one and the same laser tool can be used for welding both materials. Since no filler material is required any more, the welding process is significantly less susceptible to malfunctions and thus considerably more favorable. Another advantage is the significantly higher welding speed that can be achieved with the new aluminum alloy.
In contrast to the 5000 alloy, the new alloy combines properties that make it both soft enough for cold forming and allow subsequent warm hardening. In addition, the aluminum alloy has a significantly better seam quality: While conventional 5,000 mm materials are susceptible to the formation of process pores, which reduce the quality of the seams, the new alloy produces smooth seams on both sides.
Thanks to the new alloy Formalex Remote, laser remote welding can also be used for hardenable aluminum sheets for the first time. The process achieves speeds comparable to those of welding steel, which was long regarded as the sole material for laser welding from a distance. The warm hardening also enables a particularly high strength, similar to a conventional 6000 alloy.
Although perfectly sealed joints between aluminium and aluminium alloys are increasingly demanded by many industries, friction stir welding is already successfully solving this problem. More information about friction stir welding can be found here: Friction-Stir Welding Effectively Seals Aluminum Parts
This article was first published by konstruktionspraxis
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