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根据GB/T 4334-2008,通过H2SO4-CuSO4腐蚀法对304H不锈钢进行晶间腐蚀实验,观察其在不同温度、时间下的敏化情况,利用光学显微镜和扫描电镜研究析出相情况,应用分析测量图像软件测量晶界宽度,根据Avrami经验方程,分析304H不锈钢的时效析出动力学。结果表明:在600~750℃温度区间,敏化较严重,尤其650℃时效时,敏化最严重。304H不锈钢高温析出相变化规律为:温度一定时,随着时间的延长,晶界碳化物析出增加,尺寸增大;时间一定,温度升高时,晶界碳化物析出先增加,当温度达到850℃时,碳化物析出减少。650℃等温析出动力学曲线以及时效10 h的晶界宽度变化,均反映了这种变化。
According to GB / T 4334-2008, the 304H stainless steel was subjected to intergranular corrosion test by H2SO4-CuSO4 etching method to observe its sensitization under different temperature and time. The conditions of the precipitated phase were studied by optical microscope and scanning electron microscope. Image software measures the grain boundary width and analyzes the aging precipitation kinetics of 304H stainless steel according to the Avrami empirical equation. The results showed that the sensitization was more serious at 600-750 ℃, especially at 650 ℃. The results show that when the temperature is constant, the precipitation of carbides will increase and the size will increase with time. When the temperature rises, the precipitation of carbides first increases. When the temperature reaches 850 ° C, carbide precipitation decreased. The kinetic curves of isothermal precipitation at 650 ℃ and the change of grain boundary width at 10 h aging all reflect this change.