Rolling characteristics of Bi-2223 tapes

Nov. 30 19:05-19:20

*Xiaobo Ma1, Shengnan Zhang1, Jianqing Feng1, Chengshan Li1, Jianfeng Li1
Northwest Institute For Non-ferrous Metal Research1

Rolling plays a very important role in the preparation of Bi-2223 tape by powder in tube (PIT) process. Through the study of the rolling process of single-filamentary Bi-2223/AgAu tape, it is found that tape width increases with the increasing of the deformation extent, reduction ratio per pass, roll diameter, tape strength and friction coefficient. The deformation of the filaments at different positions of multi-filamentary tape is inhomogeneous. According to the deformation extent of filaments, the cross section of the tape can be divided into thress areas, namely easy deformation zone, difficult deformation zone and free deformation zone. Increasing reduction ration per pass and roll diameter can increase the density and width of cores in different regions. However, the higher reduction ration per pass is, the more rough silver/ superconducting interfaces are. The results show that, using 300 mm rolls, 21-28% reduction ratio per pass not only ensure the full deformation of cores in each deformation zone, but also obtain a smooth silver/ superconducting interface, so a higher Jc is obtained.

Keywords: Bi-2223/AgAu tapes, Filaments width, Different deformation zone, Roller diameter