The number that decides whether an open die forging is any good doesn’t appear on most drawings. It’s the forging reduction ratio, the amount the cross-section was actually reduced from the starting billet, and it determines how thoroughly the original solidification structure got broken down and reworked. A cast billet has coarse grain, some porosity, and non-metallic inclusions strung out in whatever orientation solidification left them. Forging fixes that by deformation, but only in proportion to how much deformation there was. Push a billet through a substantial reduction and the cast structure is genuinely worked out, the porosity closes, the inclusions are elongated and dispersed, and the grain refines throughout the section. Take a shortcut with minimal reduction, machining most of the shape rather than forging it, and the part is dimensionally correct with a partly unreworked cast structure sitting in the middle of it. Ultrasonic testing on the finished shaft may well find what’s left in there. Open die forging manufacturers in India should be able to state the reduction ratio for a given part rather than treating the forging as a shaping exercise. Sharma Technocast forges shafts and rings open die with heat treatment, machining, and ultrasonic testing in-house. For open die forging requirements, contact Sharma Technocast directly. contact@sharmatechnocast.com +91 9726666123