Laser welded blanks are known to bring added value in vehicle design by generating weight reductions and/or improving crash performance. An added advantage is that they optimize material utilization. This can bring significant cost and emission reductions in the supply chain.
For example, monolithic parts that have a scrap rate above 20 percent can be replaced by laser welded blanks. As the video below shows, the monolithic part can be replaced by two sub-blanks which are laser welded together. The laser welded blank has exactly the same performance and behavior during stamping and in the car, but requires much less steel. This generates savings at all parts of the steel production process, from the blast furnace to laser welding.
Optimizing steel usage with advanced nesting opens the door to significant cost reductions for OEMs without affecting the part’s mechanical properties. And it significantly reduces scrap which increases sustainability.
Nesting is commonly used to produce blanks. However, there is room to make this process more efficient and more sustainable for some specific parts. ArcelorMittal has completed a study into an A-pillar to showcase the potential benefits of combining laser welded blank technology and nesting optimization.
A common nesting configuration has been observed at OEMs who produce A-pillar blanks. The configuration places the monolithic blanks face-to-face on the line. The net weight of each monolithic blank is 5.6 kilograms. But due to wastage, 10.6 kg of steel is required to produce each part. Effectively, 48 percent of the steel in the coil is scrapped and recycled. This considerable volume of scrap must be handled and transported for recycling.
Using advanced nesting, OEMs can create two sub-blanks instead of a single monolithic blank. That enables the position of the blanks to be optimized on the sheet and reduces the amount of steel required.
After blanking, the sub blanks are laser welded together to form one part. The position of the weld can be varied, depending on the part’s design. The mechanical properties of the part remain unchanged compared those of a monolithic blank. The net final weight of the part also remains unchanged.
The advanced nesting optimization process provides a range of benefits. For the A-pillar alone, material usage is reduced by almost 30 percent. Cost is also reduced by around €1.00 per car due to the material savings.
And if the volume of steel utilised can be reduced by 30%, the nested LWB solution provides a corresponding 30 percent reduction in CO2 emissions. That emissions reduction is accessible immediately.
Steel is already the leading solution for automotive applications due to its excellent strength-to-weight ratio, cost effectiveness, and inherent recyclability. The combination of advanced nesting and laser welded blanks enhances the sustainability of steel even further by ensuring that scrap is minimised.
While the scrap material can be fully recycled, producing it in the first place generates emissions. By minimising the amount of steel that is required to create a part, these emissions are avoided. And using less steel also reduces costs for automakers as the scrap material does not need to be handled or transported.