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为了研究逆转变奥氏体在应力和低温条件下的稳定性,通过透射电子显微镜对淬火+回火(QT)和淬火+两相区淬火+回火(QLT)处理9Ni钢中逆转变奥氏体进行形貌观察.结果发现QT处理钢中逆转变奥氏体以块状形态存在;QLT处理钢中逆转变奥氏体以块状和薄膜状存在,薄膜状逆转变奥氏体分布在板条边界上.通过X射线衍射对液氮浸泡前后逆转变奥氏体含量和其碳含量的变化进行测量,发现QLT工艺处理后在液氮中稳定存在的逆转变奥氏体的含量要高于QT工艺.通过三点弯曲试验、单轴拉伸和压缩试验研究其机械稳定性,发现拉应力和压应力均能促使逆转变奥氏体转变,大部分残留奥氏体分布在晶内.
In order to study the stability of retrograded austenite under stress and low temperature conditions, the transformation of austenite in 9Ni steel by quenching + tempering (QT) and quenching + two-phase quenching and tempering (QLT) The results showed that the retrograde austenite existed in massive form in QT treated steel and the reverse transformed austenite existed in massive and thin film in QTT treated steel, Strip boundary.The X-ray diffraction was used to measure the content of reverse-transformed austenite and its carbon content before and after immersion in liquid nitrogen.It was found that the content of reverse-transformed austenite which was stable in liquid nitrogen after QLT treatment was higher than QT process.Through three-point bending test, uniaxial tension and compression test to study its mechanical stability, it is found that both tensile stress and compressive stress can promote reverse transformation austenite transformation, most of the retained austenite distribution in the crystal.