Die Design and Process Study of Zr-4 Alloy Profile Extrusion

According to the application requirements of Zr-4 profile with outer square and inner circle for small nuclear reactors, the extrusion die structure and extrusion process parameters are optimized through numerical simulation and calculation. Based on the study of alloy friction boundary conditions and heat exchange conditions, the influences of die inlet angle and working belt structure size on metal flow behavior were clarified. Combined with the analysis of related factors such as flow stress and temperature rise variation law in extrusion process, determine the structure size of the die and the process parameter range of the extrusion, use the on-site 1250T horizontal extruder to carry out the pilot scale experiment of profile extrusion, verify the results of the preliminary analysis and calculation, determine the optimal process technology plan, and trial-produce The required outer square and inner circle zirconium alloy profiles that every sizes and performances meet the design requirements. The cross-sectional size of this profile is 36mm × 36mm, the inner hole diameter is 20mm, and the length is 1500∼2500(mm). It is the first zirconium alloy profile produced by the extrusion process in China. This process can ensure the grains are broken under large deformation, and obtain profiles with good performance, uniform wall thickness and longer length. At the same time, it can also reduce material loss, improve production efficiency.