工程科学学报，第38卷，第6期：787-794,2016年6月 Chinese Journal of Engineering,Vol.38,No.6:787-794,June 2016 DOI:10.13374/j.issn2095-9389.2016.06.007:http://journals.ustb.edu.cn 水冷铜模与砂模铸造M2钢显微组织对比 赵志刚2)区，仇圣桃2”，朱荣) 1)北京科技大学治金与生态工程学院，北京1000832)钢铁研究总院连铸技术国家工程研究中心，北京100081 ☒通信作者，E-mail:zhaozhigangl19@126.com 摘要采用实验室25kg高频真空感应炉熔炼M2钢，并用水冷铜模和砂模均浇铸为横截面100mm×50mm的M2钢铸锭， 研究冷却速度对M2钢二次枝晶间距、渗透率、碳化物和晶粒尺寸及分布的影响.研究结果表明：2钢凝固过程中，快的冷却 速度能有效减小二次枝晶间距、渗透率、晶粒和网状碳化物的尺寸，同时可以改善晶粒和网状碳化物的分布和均匀性：砂模和 水冷铜模M2钢铸锭的平均二次枝晶间距分别为42.5m和21.6μm,平均冷却速度为1.06Ks和12.50K·s,平均渗透 率分别为0.13um2和0.035μm2.快的冷却速度能有效减轻中心碳偏析程度，砂模和水冷铜模模铸的M2钢铸锭中心碳化物 面积分数分别为0.46和0.30，且其较各自的平均值分别增大38.7%和2.2%：水冷铜模铸锭平均晶粒尺寸(43.1u)较砂模 铸锭的平均晶粒尺寸(72.6μm)减小约40.7%，铸锭中心晶粒尺寸减小43.2%，且水冷铜模铸锭的晶粒尺寸较砂模铸锭均 匀.文中获得了M2钢凝固过程中晶粒尺寸与冷却速度的关系式 关键词高速钢：模铸：冷却速度：显微组织 分类号TF763·.3 Comparison between the microstructures of M2 steel cast by the water-cooled copper mould and the sand mould ZHAO Zhi-gang,QIU Sheng-tao2,ZHU Rong) 1)School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China 2)National Engineering Research Center of Continuous Casting Technology,Central Iron and Steel Research Institute,Beijing 100081,China Corresponding author,E-mail:zhaozhigangl19@126.com ABSTRACT M2 steel was melted by a 25 kg high-frequency vacuum induction furnace and was cast to ingots with a cross section of 100 mm x 50 mm by the water-eooled copper mould and the sand mould.The effects of cooling rate on the ingot's secondary dendrite arm spacing (A2),permeability,and size and distribution of grains and carbides were studied.The results show that fast cooling rate can effectively decrease the A2,permeability and size of grains and network carbides,and improve the distribution and uniformity of network carbides and grains during solidification.The A2 values of ingots cast with the sand mould and the water-cooled copper mould are 42.5 um and 21.6 um,the cooling rate is 1.06 Ks and 12.5Ks,and the permeability is 1.3x10-um2 and 3.5x 10-2 um',respectively.Fast cooling rate can effectively reduce the center carbon segregation degree.The area fraction of carbides is 0.46 and 0.30 respectively at the center of ingots cast with the sand mould and the water-eooled copper mould,and increases by 38.7% and 2.2%respectively compared with their average values.The average grain size of ingots cast with the water-cooled copper mould and the sand mould is 41.3 um and 72.6 um,respectively.Comparing with the sand mould ingot,the grain size at the center of the water-cooled copper mould ingot reduces by 43.2%,and the grain size of the water-cooled copper ingot is more uniform.The relation- ship between grain size and cooling rate was presented in this paper. KEY WORDS high speed steel:moulding:cooling rate:microstructure 收稿日期：2015-一1207工程科学学报，第 38 卷，第 6 期: 787--794，2016 年 6 月 Chinese Journal of Engineering，Vol． 38，No． 6: 787--794，June 2016 DOI: 10． 13374 /j． issn2095--9389． 2016． 06． 007; http: / /journals． ustb． edu． cn 水冷铜模与砂模铸造 M2 钢显微组织对比 赵志刚1，2) ，仇圣桃2) ，朱 荣1) 1) 北京科技大学冶金与生态工程学院，北京 100083 2) 钢铁研究总院连铸技术国家工程研究中心，北京 100081  通信作者，E-mail: zhaozhigang119@ 126． com 摘 要 采用实验室 25 kg 高频真空感应炉熔炼 M2 钢，并用水冷铜模和砂模均浇铸为横截面 100 mm × 50 mm 的 M2 钢铸锭， 研究冷却速度对 M2 钢二次枝晶间距、渗透率、碳化物和晶粒尺寸及分布的影响． 研究结果表明: M2 钢凝固过程中，快的冷却 速度能有效减小二次枝晶间距、渗透率、晶粒和网状碳化物的尺寸，同时可以改善晶粒和网状碳化物的分布和均匀性; 砂模和 水冷铜模 M2 钢铸锭的平均二次枝晶间距分别为 42. 5 μm 和 21. 6 μm，平均冷却速度为 1. 06 K·s － 1和 12. 50 K·s － 1，平均渗透 率分别为 0. 13 μm2 和 0. 035 μm2 ． 快的冷却速度能有效减轻中心碳偏析程度，砂模和水冷铜模模铸的 M2 钢铸锭中心碳化物 面积分数分别为 0. 46 和 0. 30，且其较各自的平均值分别增大 38. 7% 和 2. 2% ; 水冷铜模铸锭平均晶粒尺寸( 43. 1 μm) 较砂模 铸锭的平均晶粒尺寸( 72. 6 μm) 减小约 40. 7% ，铸锭中心晶粒尺寸减小 43. 2% ，且水冷铜模铸锭的晶粒尺寸较砂模铸锭均 匀． 文中获得了 M2 钢凝固过程中晶粒尺寸与冷却速度的关系式． 关键词 高速钢; 模铸; 冷却速度; 显微组织 分类号 TF763 + . 3 Comparison between the microstructures of M2 steel cast by the water-cooled copper mould and the sand mould ZHAO Zhi-gang1，2)  ，QIU Sheng-tao2) ，ZHU Ｒong1) 1) School of Metallurgical and Ecological Engineering，University of Science and Technology Beijing，Beijing 100083，China 2) National Engineering Ｒesearch Center of Continuous Casting Technology，Central Iron and Steel Ｒesearch Institute，Beijing 100081，China  Corresponding author，E-mail: zhaozhigang119@ 126． com ABSTＲACT M2 steel was melted by a 25 kg high-frequency vacuum induction furnace and was cast to ingots with a cross section of 100 mm × 50 mm by the water-cooled copper mould and the sand mould． The effects of cooling rate on the ingot’s secondary dendrite arm spacing ( λ2 ) ，permeability，and size and distribution of grains and carbides were studied． The results show that fast cooling rate can effectively decrease the λ2，permeability and size of grains and network carbides，and improve the distribution and uniformity of network carbides and grains during solidification． The λ2 values of ingots cast with the sand mould and the water-cooled copper mould are 42. 5 μm and 21. 6 μm，the cooling rate is 1. 06 K·s － 1 and 12. 5 K·s － 1，and the permeability is 1. 3 × 10 － 1 μm2 and 3. 5 × 10 － 2 μm2 ，respectively． Fast cooling rate can effectively reduce the center carbon segregation degree． The area fraction of carbides is 0. 46 and 0. 30 respectively at the center of ingots cast with the sand mould and the water-cooled copper mould，and increases by 38. 7% and 2. 2% respectively compared with their average values． The average grain size of ingots cast with the water-cooled copper mould and the sand mould is 41. 3 μm and 72. 6 μm，respectively． Comparing with the sand mould ingot，the grain size at the center of the water-cooled copper mould ingot reduces by 43. 2% ，and the grain size of the water-cooled copper ingot is more uniform． The relation￾ship between grain size and cooling rate was presented in this paper． KEY WOＲDS high speed steel; moulding; cooling rate; microstructure 收稿日期: 2015--12--07