Effect of Homogenization Treatment on Microstructure and Eutectic Precipitates in Ce-Containing 15Cr-22Ni-1Nb Austenitic Heat-Resistant Stainless Steel

The effects of homogenization temperature and time on microstructure and eutectic precipitates in Ce-containing heat-resistant stainless steel are studied. The increase in the homogenization temperature and time promotes the diffusion of alloying elements and the transition from dendrite structure to austenitic grain. Laves phase particles are fully dissolved after the homogenization of the ingots regardless of the cerium contents and homogenization temperature and time, except for the case of the homogenization at 1130 & DEG;C for 4 h. Honeycomb Laves phases gradually dissolve and become clusters of small blocky during homogenization treatment. The amount of eutectic NbC dissolved into the matrix is increased with the increase in the homogenization temperature and time. The solubility of niobium and carbon in austenite is increased with increasing the cerium content, which is beneficial to the dissolution of eutectic NbC. The distribution homogeneity of alloying elements in the austenitic matrix is increased with the increase in the cerium content. The homogenization temperature for reaching full diffusion of alloying elements into austenitic matrix is decreased with increasing the homogenization time. The decrease in the secondary dendrite arm spacing by cerium addition is favorable to the homogenization of alloying elements during homogenization treatment. This work shows key findings on the homogenization processing of Ce-containing 15Cr-22Ni-1Nb austenitic heat-resistant stainless steel. Laves phase particles are fully dissolved after the homogenization regardless of the cerium contents and homogenization temperature and time, except for the case at 1130 & DEG;C for 4 h. The decrease in the secondary dendrite arm spacing by cerium addition is favorable to the homogenization of alloying elements.image & COPY; 2023 WILEY-VCH GmbH