Laser welded blanks (LWBs) enable carmakers to reduce the weight of a monolithic part. At the same time, the strength or safety performance of the part can be maintained or improved, depending on the combination of steels selected.

Key advantages of LWBs include:

• Material optimization
• Improved technical performance without increasing weight
• Simplification of the OEM’s production processes
• Weight and thickness reductions for the complete assembly
• Butt-joining to avoid overlaps
• Safety improvements

During the blanking step, laser welded blank shapes can be arranged to make maximum use of the steel. Known as ‘nesting’, this technique increases the number of parts that can be made from one sheet of material. Less steel is required, and less scrap is produced.

The right steel grade is in the right place, in the right thickness to create a tailor-made solution for each part.

Depending on the shape, scrap rates can be as low as seven percent. With lower scrap rates, cost efficiency is increased significantly.

ArcelorMittal Tailored Blanks can work with an OEM’s design department to determine if a part is suitable for nesting. The assessment includes an assessment of the technical requirements for the part and a cost analysis to achieve the most economical solution.

Using LWBs, the technical performance of a part can be enhanced significantly without adding to the weight of the vehicle.
Examples of improved technical characteristics include:

• Higher stiffness
• Better energy absorption
• Improved crash behavior

OEMs can simplify their production processes with LWBs thanks to:

• Reduced number of parts
• Reduction in the number of stamping and assembly tools required
• Shorter manufacturing process

By ensuring the right material is in the right place, in the right thickness, LWBs can significantly reduce the weight of a part.

The following image shows the example of a door ring. The LWB solution on the right can be up to 20 percent lighter than the multi-part door assembly shown on the left.

The development of LWBs has had a direct impact on improving automobile safety since they were first introduced in the 1990s. This is because LWBs combine the energy absorption and anti-intrusion properties of different grades of steel in one part.

Evolution of LWB use:

• In the 1990s, most vehicles on the road in Europe had a two-star Euro NCAP safety rating. The average vehicle included two LWB parts and comprised five percent advanced high strength steel (AHSS).
• During the 2000s, the first vehicle to achieve a five-star Euro NCAP rating included 22 LWB parts and was comprised of 45 percent AHSS.
• During the 2010s, the combination of LWB and hot stamping has further reduced the weight and cost of vehicles, and improved safety significantly. Of the 69 Euro NCAP ratings published in 2017, 44 vehicles (64 percent) achieved a five-star rating.
• ArcelorMittal’s S-in motion^® studies have demonstrated the safety benefits and weight savings LWBs can provide in today’s production vehicles.

Example: Improved crash performance with hot stamped LWB door ring