Precipitation Behavior of σ Phase in ER316L Austenitic Stainless Steel and Its Wire Rod High-Speed Wire Rolling

The effects of solid solution temperature and strain rate on the precipitation behavior of σ phase in ER316L austenitic stainless steel were investigated by solid solution treatment and high-temperature compression test. Based on the testing results, the rough and medium rolling parameters in high-speed wire rolling process of wire rod were designed and the high-speed wire rolling of wire rod was done. The microstructure and tensile properties of the wire rod were studied. The results show that the microstructure of the tested steel consisted of austenite phase and σ phase. The content of σ phase increased with decreasing solid solution temperature or increasing strain rate. In order to prevent the large precipitation of σ phase, the strain rate should keep slow and the rolling temperature should be set at 1 000℃ and above during the rolling of the tested steel. The volume fraction of σ phase in the wire rod rolled by the designed process was lower than 3%, the average tensile strength was 640.2 MPa and the average elongation was 48.7%; the wire rod illustrated a relatively good drawing performance.