中文摘要：

9Cr马氏体耐热钢在发生α→γ相变前的升温过程中其膨胀-温度曲线的斜率发生了偏折,偏折点处的温度为660℃左右。采用相同的升温速率将该钢样品升温至600、660和750℃三个温度,保温15min后水淬,利用金相显微镜和扫描电镜分析各样品中组织的差异。研究结果表明,9Cr钢加热至660℃和750℃的样品中析出相的数量较600℃明显增加,因此钢中碳氮化物在偏折点温度处的大量析出是膨胀曲线斜率发生明显改变的原因。

英文摘要：

A turning of the slope at about 660 ℃ was found on the dilation-temperature curve of 9Cr martensitic heat resistant steel during heating process before α→γ phase transformation.In the present work,the steel samples were heated at the same heating rate from room temperature to 600,660 and 750 ℃,respectively,held for 15 min and then water-quenched.Optical microscope and scanning electron microscope were used to examine the microstructure difference of the three samples.The results show that there are much more precipitations in the samples heated to 660 and 750 ℃ than that heated to 600 ℃.Therefore,it could be concluded that the large amount of carbonitride precipitations in the steel at the turning point lead to the slope change on the dilation-temperature curve.