304不鏽鋼晶界穩定化熱機處理製程之研究

• Main Authors: Tsao, Po-chun, 曹博鈞
• Other Authors: 黃宏欣
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/10374144149602586700

碩士 === 正修科技大學 === 機電工程研究所 === 98 === When stainless steel SUS 304 is under hot plastic processing or welding at the temperature between 550℃ and 900℃, and followed by air-cooling, the precipitation of chromium carbide will be found at the grain boundaries. The phenomenon is called the sensitizing effect of SUS 304. The sensitizing effect will reduce the strengths of SUS 304. Many efforts on eliminating the sensitizing effect are found in the literature. In this study, the thermo-mechanical treatment is applied to increase the mechanical and annealing twins of polycrystalline SUS304 austenitic microstructure. The twin mechanism, produced mainly by shear deformation, will generate a large number of jogging sectors. In addition, the grain boundary energy of the twin mechanism is much lower than that of the original austenite grain boundaries. Thus, the twin mechanism can effectively suppress the sensitization of SUS304. In this study, the shipments of SUS 304 are stabilized by the thermo-mechanical treatment, and then sensitized at a temperature of 850℃. The grain boundaries will be inspected to investigate the effects of the thermo-mechanical treatment. Oxalic acid electrolytic is screened to choose a suitable thermal-mechanical treatment for the grain boundary stabilization. Then sulfuric acid etching solution are used to quantify iron sulfide corrosion test results.