电渣重熔过程冷却强度对含镁H13钢中碳化物的影响  

Effect of cooling intensity on carbides in Mg-containing H13 steel during the electroslag remelting process

作　　者：贺宝[1] 李晶[1] 史成斌[1] 王昊[1] 

机构地区：[1]北京科技大学钢铁冶金新技术国家重点实验室,北京100083

出　　处：《工程科学学报》2016年第12期1720-1727,共8页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51374022)

摘　　要：研究电渣重熔过程冷却强度对含镁H13钢凝固组织和碳化物偏析的影响.采用光学显微镜、扫描电镜、透射电镜、X射线衍射仪等分析凝固组织及碳化物的特征.研究发现,钢锭的凝固组织均为马氏体组织、残余奥氏体及一次碳化物.H13钢电渣锭中主要析出的一次碳化物为V8C7、MC、M23C6及M6C.随着冷却强度增加,电渣锭边部碳化物的尺寸减小且分布更加均匀,但是碳化物的类型不发生变化.电渣重熔过程中冷却强度增加促进钢中镁对夹杂物的变性能力,经过镁变性后生成的Mg O·Al2O3为Ti N的析出提供形核质点,Mg O·Al2O3和Ti N的复合夹杂物能够促进一次碳化物异质形核,从而细化一次碳化物.The effect of cooling intensity on the carbide segregation and solidification microstructure of an H13 as-cast ingot with Mg addition was studied during the electroslag remelting process. The solidification microstructure and the carbide characteristics of the steel were analyzed by optical microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction anal- ysis. The results show that the solidification microstructure of the ingot consists of martensite, retained austenite and primary carbides. Carbides in the electroslag remelting ingot are Vs C7, MC, M23 C6 and M6 C. With the increasing of cooling intensity, the size of carbides in the edge of the electroslag remehing ingot decreases, the distribution of these carbides becomes more homogeneous, but the types of carbides remain unchanged. Increasing the cooling intensity improves the modification of inclusions by Mg. The formed MgO. Al2O3 arising from Mg treatment provides preferred nucleation sites for TiN. These complex inclusions promote the heterogeneous nucleation of primary carbides, consequently refining primary carbides.

关 键 词：模具钢 电渣重熔 冷却 微观组织 碳化物 

分 类 号：TF744[冶金工程—钢铁冶金]