Investigation of cold drawing process of thin-walled ribbed steel tube

Abstract

Cladding tube is an important part of nuclear power components. This paper presents a simulation and experimental study on the cold drawing process of one kind of cladding tubes, namely thin-walled ribbed steel tube. Three kinds of drawing processes are studied: single pass drawing, tube sinking and fixed-plug combined drawing process, and two pass fixed-plug drawing process. The finite element (FE) simulation model considering Johnson-Cook constitutive equation is established to analyze the effective stress, effective plastic strain, and contact force in different drawing processes. Different out diameter (OD) and wall thickness (WT) 316L stainless steel (SS) tubes are used to investigate the forming process of the ribbed tube. Furthermore, experiments with the same parameter settings are compared with the simulations. It is found that the simulation and experimental results are in good agreement, the ribs height highly depends on the tube OD and WT. The results show that the formation of tube ribs is caused by the extrusion of the drawing die. In addition, during the forming of the tube ribs, inner grooves will be formed on the inner wall of tube, and the fixed-plug drawing process can effectively reduce the depth of the inner groove. Finally, the microstructure and hardness of the ribbed tube at different position are investigated. This work provides a reference for the integrated forming process of the ribbed tube.