.254 Smo Precipitated The Study Of The Law And Its Performance

With content of6%molybdenum,254SMO possesses high corrosion resistance, and it is applied to chlorine environment widely. Due to its high content of alloy element especially molybdenum, harmful phases are prone to be precipitated, and254SMO is easy to be oxidized and difficult to hot working.In this paper, precipitation law, mechanical and corrosion resistance property, hot working behavior and anti-oxidation property are studied, and their mechanisms are investigated by the method of mechanical test, micaostructure analysis, thermal simulation, corrosion test under sepecified condition, etc. Finally, the best heat treatment and hot working parameter are recommended. The study lays a foundation for the research and development of254SMO and other super-austenitic stainless steel. The main conclusions are as follows:1. The precipitations of254SMO are rather complicated, and with high content of molybdenum. The δ phase and χ phase are shown as the main precipitation, and small amount of other phase such as M23C6, Cr2N, laves phase are also existed. The precipitated temperature of δ phase and%phase are respectively reached as1150℃and1050℃, and precipitation curves of δ phase and χ phase are received by the method of stress relaxation tests, and peak of precipitation are separately shown as975℃and975℃2. The deposition of harmful phase shows significant effect on the properties of254SMO. The plasticity, toughness and corrosion resistance are greatly reduced by appearance of precipitations. Stress corrosion cracked is affected apparently by the bulk precipitation at1100℃and1150℃. Microstructure. mechanical and corrosion resistance property can be get at solution temperature for1200℃3. With version of temperature, the best thermoplastic is changed within in a narrow range1200-1250℃. Thermoplastic is seriously impacted by precipitation especially that is large block rich in molybdenum. The mechanics soften is dynamitic recrystalization, and the activation energy is about508.7kJ. In addition, the mechanics of hot deformation is analysis, and hot deformation equation is calculated.4. The poor oxidation resistance and higher temperature-sensitive of254SMO are found. According the paper work, the oxide is mainly molybdenum oxide, and then is tri-iron trioxide and ferric oxide. The foremost course lead to the bad oxidation resistance property is oxidation and volatilization of molybdenum, and oxidation is intensified by decomposition of ferric oxide at1050-1100℃...