The forging process makes irons more consistent by avoiding the shrinkage and inconsistency of air pockets which occur during the cooling of liquid metal in the casting process. Forgings start out as billets of soft carbon steel. Billets are heated, stretched, bent, pressed into shape through several molds and then hand ground and finished before the chroming process.
Check out the embedded videos to learn more from the experts at Mizuno and Miura Golf.
Masao Nagai, head of Mizuno Global R&D, discusses how the forging process eliminates hot and dead spots, resulting in more consistent iron heads:
Adam Barr narrating how Miura turns forgings into works of art: