稀土微合金化对热管用无氧铜管坯成分及组织的影响

Effects of Microalloying with Rare Earth on Composition and Microstructure of Oxygen-free Copper Tube Blank for Heat Pipe

目的解决连铸连轧无氧铜管坯成分与组织控制问题。方法通过稀土净化除杂与微合金化作用,对无氧铜熔铸成分控制、水平连铸和行星轧制工艺开展深入研究。结果稀土添加后铸坯中P的质量分数由添加前0.0095%降低至0.00145%~0.00182%,降低了80.8%;O的质量分数由0.0045%降低至0.0013%~0.00183%,降低了59.3%;铸坯晶粒尺寸由稀土添加前的2200μm细化到到650μm,细化了70.4%;三辊行星组织轴向平均晶粒为16μm,周向平均晶粒为21μm。结论稀土微合金化能够有效控制热管用无氧铜铸坯的成分;稀土微合金化明显细化了铸坯的晶粒组织,使无氧铜轧制变形组织更加均匀。

The work aims to solve the problems on controlling composition and microstructure of oxygen-free copper tubes by continuous casting and rolling.The controlling of cast composition,horizontal continuous casting and planetary rolling process of oxygen-free copper tube were studied in-depth by purification and microalloying with rare earth.The results showed that the mass fraction of P and O in the casting blank added with rare earth was reduced from 0.0095%to 0.00145%-0.00182%by 80.8%and from 0.0045%to 0.0013%-0.00183%by 59.3%respectively.Moreover,the grain size of cashing blank added with rare earth was refined from 2200μm to 650μm by 70.4%.The axial average grain size of the three-roller planetary structure was 16μm and the circumferential average grain size was 21μm.The microalloying with rare earth can effectively control the composition of the oxygen-free copper for heat pipe.It apparently refines the grain size structure and makes the deformation microstructure of oxygen-free copper rolling more uniform.