| Superaustenitic stainless steel S32654containing7%molybdenum, has outstanding corrosion resistance. Therefore, it has been widely used in hostile environment where excellent corrosion resistant alloy is needed. S32654has higher contents of alloy elements than other austenitic stainless steel, which enhance its corrosion resistance, and however simutaneously strengthen the susceptibility to precipitation of second phase, leading an adverse effect on the material in the subsequent processing and application.The precipitated phase of the superaustenitic stainless steel S31254has been studied by employing metallographic microscope, scanning electron microscope(SEM) and transmission electron microscope(TEM). The results show that when treated at1200℃for60min, the microstructure of superaustenitic stainless steel S32654become a single austenitic organization without suffering from the risk of precipitation. The sensitive precipitation temperature for S32654is950℃.The morphology of those secondary phases occurring S32654is mainly multifarious, such as spindle, bamboo leaf-shaped and so on. The main secondary phases are σ phase and laves phase, except which μ phase, Chi phase and Pi phase were found. Precipitates are mainly nucleated at the grain boundary, twin boundary and even at grain interior. The particles of precipitation phase growed and the amount of precipitation phase increases with aging time increasing. However, the ability of resist corrosion of S32654is weaked with prolonging aging time. |
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