Abstract: Extrusion container is the most important tooling in large steel tube extrusion process. Traditional design approaches such as multi-layered extrusion container would meet great challenges for large extrusion container. Steel wire wound extrusion is proposed. Due to accelerated creep behavior and stress relaxation of steel wire under high temperature, the primary difficulty of applying steel wire winding to the design of extrusion container is to solve the conflict between preheating and protection of the wire from high temperature. The key problems of wire wound containers including preheating, steel wire protection and control of prestress distribution are analyzed. Two solutions to preheating are proposed including hot billet preheating and electrical heating rods. The problems, solutions, advantages and disadvantages are discussed respectively. A novel prestressing method “thermal induced prestress” is proposed. By preheating the inner cylinder and middle cylinder to over 350 ℃ and keeping the temperature of the outer cylinder and steel wire below 80 ℃, prestress is generated by the difference of thermal expansions due to temperature difference. Based on the idea, a prototype model with the diameter of 170 mm is manufactured. Temperature distribution and prestress measurement show that the proposed design could fulfill the requirements and could offer as an alternative to conventional types of extrusion containers.

Key words: Extrusion container, Hot extrusion, Large diameter and thick-walled steel tube, Steel wire winding