The dummy block is a critical element for extrusion quality and press performance. A dummy block is in direct contact with the billet. Its’ successful operation depends on a number of factors. For example, press alignment (both thermal and physical), proper pre-determined expansion size and expansion rate, lubrication, maintenance and so on. The most important factor in the effective
operation of any dummy block is its’ efficient interaction with a round, straight, thermally, and therefore dimensionally, stable container. The lifetime of the dummy block is strongly dependent on the right combination of expansion angle, hoop strength of ring expansion and yield strength of the block holder.