Baoguang Sang

Numerical simulation of macrosegregation in large multiconcentration poured steel ingot

Abstract A continuum model for the transport phenomena in solidification systems is used to investigate the formation of macrosegregation in a 360 t multiconcentration poured steel ingot. A numerical scheme with explicit time stepping in solidification problems is employed to solve coupled temperature and concentration fields, and equations of momentum. The proposed scheme is tested against an experimental concentration field reported in the literature. The influences of the concentration in each ladle and the ladle pouring time upon macrosegregation are studied. The simulation results show that, with a shorter time for the last ladle, macrosegregation is not significantly reduced with MCP compared with conventional single concentration pouring. A longer ladle time produced a marked reduction in the extent of positive segregation at the top of the ingot. Any positive segregation in excess of the industrial requirement limit is shifted to the riser. If the last ladle is poured after a longer time, growth of channel segregates is initiated by local remelting.

Study on macrosegregation in heavy steel ingots

Abstract Macrosegregation in heavy steel ingots was studied through numerical and experimental studies of a 500 kg ingot. The numerical model used heat conduction coupled with thermal convection. Simulation results confirm that a small 500 kg ingot poured in a sand mould has a solidification time that is equal to that of a 10 000 kg industrial ingot cast in an iron mould. Accordingly, the sand moulded ingot exhibits more severe macrosegregation compared to the iron moulded ingot, indicating the possibility that a relatively small ingot in sand can simulate conditions in a much heavier steel ingot in a conventional iron mould. Experiment demonstrated that a 500 kg ingot exhibited all the types of macrosegregation, including A- and V-segregates and negative and positive segregation commonly found in a 65 000 kg steel ingot.

Numerical study of macrosegregation formation of ingot cast in normal sand mold and water-cooled sand mold

[Liu, Dongrong; Kang, Xiuhong; Sang, Baoguang; Li, Dianzhong] Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China. [Liu, Dongrong] Harbin Univ Sci & Technol, Sch Mat Sci & Engn, Harbin 150040, Peoples R China.;Kang, XH (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China;xhkang@imr.ac.cn