Research on the “shear-extrusion” process to form large-scale cut-off valve bodies

Focused on the metal plastic forming of large-scale cut-off valve bodies used by power plant boilers, and based upon a deep study of combined backward cup–forward rod extrusion, this paper presents a new forming process named “shear-extrusion”, of which the main characteristic is that it is labor saving. The new shear-extrusion process was studied by the methods of numerical analysis and simulating experiment, and the optimal process variables to be applied in the forming of valve bodies were obtained. Finally, large-scale cut-off valve bodies were formed successfully using a 10,000 kN screw press. The new process can be applied to produce not only cut-off valve bodies but also components with branches such as sluice valve bodies, tee-junctions and so on.