A new process for the forming of a triangular flange in hollow shafts from Ti6Al4V alloy

This paper presents an innovative process of metal forming of a hollow shaft with a flange of triangular rosette shape. The analyzed part is used in helicopters as drive transmission shaft. This product has to be a monolith; hence, it is inadmissible to connect the flange with a tube. Due to the lack of alternative methods of this part manufacturing, shafts are made by means of machining from full bar, which generates material loss exceeding 90%. The proposed method of the flange metal forming considerably lowers material and labor consumption and guarantees better resistance properties in comparison with shafts made by means of machining. The presented way is based on billet's end expanding freely protruding from a split die. Numerical analysis of the forming process of a shaft from titanium alloy Ti6Al4V was conducted in software DEFORM-3D. On the basis of the analysis results tools were designed for the process experimental verification. Stand tests were made on a three-slide forging press. The results of theoretical and experimental research are convergent and confirm the rightness of the proposed method.