The ablation process
What is the story behind?
The automobile industry uses especially thin and thus, light sheet steel for car bodies to reduce the weight of vehicles. But the thinner the panel, the stronger the sheet steel has to be.
Hot-formed steel grades have substantially higher strength than cold-formed steel and are, therefore, becoming increasingly popular in vehicle manufacturing. However, there is one drawback: If whole blanks (sheet steel panels) of high-strength material are used, the vehicle’s crash performance suffers because the energy released in a collision cannot be absorbed. In short, the vehicle remains largely intact, but passengers don’t. Hence, strong is not necessarily safe.
Soutec technology for better vehicle crash performance
This is where so-called “TBs” (tailored blanks) made on laser welding systems from ANDRITZ Soutec come into play. Until now, mainly cold-forming sheets of different thicknesses were welded together as TBs to achieve minimum panel thickness and thus reduce the weight. Now the task is to combine hot-forming steel grades of different thicknesses and strengths so that the bodywork can deform in the softer and/or thinner areas during a collision, thus absorbing the impact energy. However, more than 90% of the hot-forming steel grades used in the car industry have an aluminum silicon coating (AlSi). This has the benefit of preventing a layer of scale forming during heat treatment, which would need to be removed at a high cost after press hardening.
Unfortunately, the AlSi coating makes welding more difficult and has a negative effect on the quality of the weld seam. The detrimental effect of Al diluted in the melting pool reduces weld strength effecting the crash performance negatively. The sub-blanks have to be prepared before laser welding by removing the top layer of AlSi coating.
Inline or offline ablation - we offer both depending on the requirements
ANDRITZ Soutec has conceived, developed and implemented this innovative process on its laser systems (inline ablation), but also provides stand-alone ablation systems (offline ablation).