The starting point of every forged Motegi Racing wheel is the alloy billet material. Made of T6061 high strength military grade aluminum, they range in length from 5 to 6 meters and 300 mm in diameter. Each piece has a metallurgic spec sheet that details the alloy elements that were used in the formula to make the material.
Billets are cut into precised sections that must have specific thickness, critical to the proper quality of the final forged blank. Quality-control measures are in place at each step to ensure that the product conforms to specifications.
Before an aluminum cut section can be forged, it must be expose to intense heat of up to 300 degrees Celsius in a furnace to soften the alloy material and make it ready for the molding forces of the forging machine.
Motegi Racing competition wheels are forged using a very unique rotary forging press. Rotary forging compresses the cut and pre-heated section of billet between two synchronized rotary dies with 5,000 tons of power to the desired shape of the blank. This process rearranges the aluminum molecules, aligning them in a circular pattern. This allows for compression in a concentrated area and thus affords a more efficient method of metal deformation while producing superior mechanical properties. The result is a forged blank with ultra compress grain structure to produce light weight and strong wheels.
Highly specialized CNC spinning equipment applies the force of one or more rollers to the outside diameter of the forged blank. The aluminum material is mechanically worked beyond its yield strength and flows in the desired direction over a mandrel. The rollers and mandrel are all rotating. The inside geometry of the finished product takes the shape of the mandrel while the CNC roller program determines the external shape.
After the forging operation that compress and extents the material, forging blanks are tempered in heat treatment furnaces to the fully hard T6 condition for maximum strength. Rigorous testing is conducted to ensure material properties meet or exceed the customer specifications and industry standards. The temperature is up to 400 degrees Celsius in the furnaces and can last up to 24 hours. The treatment ends by cooling the hot blanks in cold water solution that increases the mechanical properties of the material.