材料期刊网

31CrMoV9是欧洲牌号的高淬透性合金钢，属于近几年国产化过程中新研制的钢种。为比较国内外成品钢质量的差距，提高中国该钢种的冶炼水平，选取不同产地的31CrMoV9钢，对其中的非金属夹杂物进行研究。电解钢样观察其中夹杂物的外观形貌，并对钢样进行金相观察和利用高温共聚焦显微镜观察钢样的组织变化。研究发现，单一成分的夹杂物多为长条状，而复合夹杂物多为球形。研究过程所选取的中国生产的钢材与德国钢材在夹杂物的数量和形态控制上存在差距，中国生产的钢材单位面积内夹杂物的数量更多，夹杂物的大小不均匀，形态控制不理想。就成分而言，德国钢材的夹杂物成分主要是以Al2O3、CaO、MnS等组成的复合夹杂物，而中国钢材的夹杂物存在着成分的波动性。共聚焦显微镜试验过程中发现，在升温过程中夹杂物会发生球化现象，降温过程中，钢样开始形成马氏体组织的温度有所不同，中国钢样为580℃，德国钢样为450℃，这与其本身晶体的成分有关，最后的组织为马氏体+碳化物颗粒+残余奥氏体。

31CrMoV9 is a medium carbon steel with high hardenability characteristic in the European brandz,which belongs to the newly developed of China in recent years. In order to compare the quality of steel at domestic and abroad, and improve the level of China's iron and steel making,nonmetallic inclusions in 31CrMoV9 steel produced by different manufactures have been studied by different detection and analysis methods. On the basis of study on inclusion in steel by use of sample electrolyzing method and the change of inclusion and microstructure of steel during heating and cool-ing period have been observed by confocal scanning laser microscope. The results show that the inclusions of a single component are long strips,while the composite inclusions are spherical. There are gap in the control of the inclusion be-tween Domestic and German steel. The inclusions size of the Domestic steel are not uniform,the shape control are not ideal,and the distribution of the inclusions are not uniform. In terms of composition,the inclusions of German steel are mainly composed of Al2O3,MnS and CaO,while the inclusion of Domestic steel have the volatility of the components. In the process of heating up by confocal scanning laser microscope,the long strip of MnS tended to be spherical,and the inclusion were observed the dissolved in the steel,and the volume of the inclusion were smaller than before. The temperature that formatted martensite were different which related to the composition of the crystal. German steel is 450℃and Domestic steel is 580℃. The final microstructure is martensite+carbide particles+retained austenite.