ArcelorMittal is extending its innovative ArcelorMittal Multi Part Integration (MPI) steel solution to Japan. This expansion comes as a result of a strategic collaboration with G-Tekt, culminating in the signing of a partial ablation license agreement.

The MPI concept allows multiple vehicle components to be integrated into one large laser welded blank (LWB). A laser welded blank is a sheet of steel which combines several different grades. Each grade can have different thicknesses and/or coatings. LWBs allow a part to be engineered for optimal performance and lightweighting.

The separate grades are laser welded together to create a single sheet of steel which has the best grade in the best place for strength and deformation. Each sheet can be hot- or cold-stamped to give the part its final shape.

MPI uses the latest press hardenable steels (PHS) and laser welding technology to create a single part. The MPI part can replace up to 11 separate parts with one.

Developed by ArcelorMittal’s Global R&D teams in partnership with ArcelorMittal’s Tailored Blanks division, MPI represents a sustainable steel solution designed to simplify vehicle design and production. Specifically tailored for the manufacturing of body-in-white (BIW) structures, MPI streamlines production, reduces assembly complexity, saves weight, and shortens lead times—particularly beneficial for electric vehicles.

G-TEKT CORPORATION is a Japanese leading tier 1 supplier of automotive body structure products; its strong advantage is in a materialization of both weight reduction and higher mechanical strength of those products by making the best use of the architectural analysis of whole body structure of a vehicle, hot stamping and cold stamping technology.

This company additionally has decided to launch the development of large integrated body structure products by using AM patented Ablation technology and laser welding technology.

At the core of ArcelorMittal’s MPI process lies partial ablation, a patented technology essential for preparing hot stamping sheets for laser welding. This process ensures flawless laser welded blanks (LWB), subsequently transformed into high-strength MPI parts through hot stamping.

Press hardenable steels (PHS) are typically supplied with an aluminum-silicon (AlSi) coating which protects the underlying steel during thermal treatments and prevents corrosion. ArcelorMittal’s patented partial ablation process removes a thin strip of the AlSi coating on the edge of the blanks before they are laser-welded together.

If the coating is not removed before laser welding, the aluminum it contains can weaken the weld and cause the part to fail. Around 99% of the PHS LWBs made today utilize AlSi coated steels.

Using ArcelorMittal’s patented ablation technology, a laser beam is used to remove the aluminum-silicon (AlSi) layer on the top of the press hardenable steel (PHS). The intermetallic layer is preserved during the operation to ensure corrosion resistance. After ablation, two or more blanks are welded together to form a single PHS laser welded blank (LWB). PHS LWBs are then hot stamped to form the part.

By integrating MPI into their manufacturing processes, Japanese carmakers can streamline BIW production, optimize vehicle weight, and reduce CO₂ emissions, all while maintaining cost-effectiveness.

ArcelorMittal’s patented partial ablation technology, initially introduced in 2007, has gained widespread adoption among OEMs globally. By removing a thin strip of aluminum-silicon coating from press hardenable steels (PHS) before laser welding, this innovative process ensures the safety and durability of LWBs, contributing to significant advancements in lightweighting, safety and cost savings across the automotive industry.

The increasing demand for partially ablated laser welded blanks reflects the automotive industry’s recognition of the benefits offered by ArcelorMittal’s steel solutions and technology, the company said.