Spread and roll force in rod rolling

AbstractAn investigation of spread during hot rod rolling of titanium-base materials and mild steel has been carried out for a production-type series of passes. The results show that for diamond to diamond, square to diamond, and diamond to square sequences the spread characteristics are different from those for a square to oval type pass. A method of predicting spread from a simple empirical formula is shown to give results accurate to within ±4% and is applicable to ‘stiff’ or ‘elastic’ mills. Concurrent measurements of roll force were made and from these a method of force calculation has been developedfrom Sims's theory of hot flat rolling. This enables the rollforce to be predetermined on any mill for passes of the same general configuration as described and requires simply a knowledge of the ingoing bar section, the dimensions of the pass, and the deformation strength of the rolled material.