Experimental Study on Improved YUS701 Steel Used for High Level Waste Storage Tanks

Abstract

Type 1.4833 austenitic heat-resistant steel used in glass curing container storage tank of high level nuclear radioactive waste treatment has safety risks in long-term use at high temperature condition， and can not meet the needs of higher strength and better toughness and plasticity at high temperature condition of steel used in next generation storage tank. According to the application conditions of the storage tank， 0.12% Nb element is added to the original composition of YUS701 steel 25Cr-13Ni-2Si-0.8Mo-0.25N for the inner cover of the silicon steel ring cover annealing furnace ， appropriately reduce the content of C and Si elements. Electroslag remelting smelting process is adopted to control the deformation rate and temperature during forging and rolling. Finally， solid solution heat treatment at 1 150 ℃ is carried out to prepare the forgings of the improved YUS701 steel. The experimental results show that the improved YUS701 steel has good mechanical properties at room temperature. At 1 000 ℃， the yield strength exceeds 65 MPa and the tensile strength reaches about 100 MPa. After thermal cycle of simulated high temperature glass solid solution pouring， the impact absorption energy reaches more than 155 J， which can meet the performance requirements of the next generation of steel for storage tanks.

Keywords

• high-level radioactive waste； glass curing body； heat resistant steel； improved yus701 steel