图a、b和c分别为DZ2（连铸）钢边部、1/2半径和心部回火后的析出相形貌。由图可知，三个部位上试验钢的析出相形貌均有两种，一种是小尺寸球形或椭球形颗粒，另一种是大尺寸长棒状，由能谱图可知其为合金渗碳体。由图4 b、c可以看出，1-1#钢心部和1/2半径处合金渗碳体析出极不均匀，有很多较大尺寸合金渗碳体发生偏聚，这是由于心部和1/2半径处出现了大量的贝氏体，而贝氏体中的大角度界面较少，导致合金渗碳体析出的形核位点较少，加之1/2半径和心部冷速较慢，保温时间相对较长，容易在贝氏体中发生偏聚。

Figure A, B and C respectively show the morphology of precipitated phase after tempering DZ2 (continuous casting) steel edge, 1/2 radius and center. It can be seen from the figure that there are two kinds of morphology of precipitated phase in the test steel at the three parts, one is small size spherical or ellipsoidal particles, the other is large size long rod, which can be seen from the energy spectrum diagram as alloy cementite. Can be seen from figure 4 b, c, 1-1 # steel core and uneven at 1/2 radius alloy cementite precipitate, there are a lot of larger alloy cementite occur together, this is due to the heart and large amounts of bainite appeared at 1/2 radius, and the large Angle in the bainite interface is less, the alloy cementite precipitate nucleation sites is less, In addition, the cooling rate of 1/2 radius and the core is slow, and the holding time is relatively long, which makes it easy to produce segregation in bainite.