锡磷青铜水平连铸坯反偏析及其对轧制边裂的影响  

Inverse segregation of tin-phosphorus bronze horizontal continuous casting billet and its effect on rolling edge crack

作　　者：王松伟 郑莲宝 宋鸿武[1] 孔凡亚[1] 徐勇[1] WANG Songwei;ZHENG Lianbao;SONG Hongwu;KONG Fanya;XU Yong(Shi-Changxu Innovation Center for Advanced Material,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Key Laboratory for Modern Metallurgy Technology(Ministry of Education),North China University of Science and Technology,Tangshan 063200,Hebei,China)

机构地区：[1]中国科学院金属研究所师昌绪先进材料创新中心,沈阳110016 [2]华北理工大学现代冶金技术教育部重点实验室,河北唐山063200

出　　处：《材料工程》2025年第3期70-82,共13页Journal of Materials Engineering

基　　金：全球共性挑战专项项目(172GJHZ2022054GC)。

摘　　要：在水平连铸过程中锡磷青铜铸坯边部由于反偏析作用形成网状分布的硬脆富Sn相,并在轧制过程中成为裂纹源,进而不断扩展诱发带材大幅度边裂。为改善此问题,通过改进石墨模具结构,调整铸坯冷却强度分布规律,减缓铸坯边部冷却过快而引起的严重反偏析现象。数值模拟和实验验证表明:模具结构优化后,铸坯侧面与模具间的气隙厚度梯度减小,糊状区的凝固收缩过程更平缓。液相面更加平直,液相与糊状区夹角减小了18.3°,铸坯中部与边部的凝固位置差减小了18.62 mm。此外,铸坯晶粒趋于等轴化,富Sn相由晶间条状转变为点状分布,反偏析程度减轻,反偏析层内富Sn相含量减少了2.3%,反偏析层厚度减小了214μm。粗轧后带材边部裂纹数量由结构优化前的21个减小至4个。During the horizontal continuous casting process,a network of hard and brittle Sn-rich phase is formed at the edges of tin phosphorus bronze casting billet due to inverse segregation,which becomes crack sources during rolling and continuously propagates to induce significant edge cracks in the strip.To solve this problem,the graphite mold structure is improved,and the cooling intensity distribution law of the billet is adjusted to slow down the serious inverse segregation phenomenon caused by excessive cooling of the billet edge.Numerical simulation and experimental verification show that after the optimization of the mold structure,the thickness gradient of the air gap between the side of the billet and the mold is reduced,the solidification shrinkage of the mushy zone is more gentle;the liquid phase surface is more straight,the angle between the liquid phase and the mushy zone is reduced by 18.3°,and the solidification position difference between the middle and the side of the billet is reduced by 18.62 mm.In addition,the billet grain tends to be equiaxial,the Sn-rich phase is transformed from the inter-crystalline stripe to the point distribution,the degree of inverse segregation is reduced.The degree of inverse segregation is reduced,the content of Sn-rich phases in the inverse segregation layer is reduced by 2.3%,and the width of the inverse segregation layer is reduced by 214μm.The number of cracks at the edge of the rough rolled strip is reduced from 21 before the structural optimization to 4.

关 键 词：锡磷青铜 反偏析 边裂 模具结构 凝固收缩 

分 类 号：TG245[金属学及工艺—铸造] TB31[一般工业技术—材料科学与工程]