Warm forging: new forming sequence for the manufacturing of long flat pieces

Abstract

Warm forming of steel is an economic and ecologic alternative to the conventional hot forging technology. It offers several advantages like decreased energy input, reduced scale formation, better surface quality and closer tolerances. Warm forming is common for rotation symmetric parts but has not been applied for long flat pieces yet. The main obstacles prohibiting the transfer are the missing of a suitable preforming technology and the problems to keep the narrow temperature tolerances despite the increased number of forming operations compared to rotation-symmetric process routes. In a cooperative effort within a European consortium of forges and scientific institutes, closed-die warm forging processes for long flat pieces have been developed. To cover a wide range of longitudinal geometries, two model products, a connecting rod and a steering link, with unequal requirements towards the production process have been selected. The process developed for the steering link is discussed in this article.