Study of Effective Transient Thermal Resistances of Different Heat Transfer Sections during Solidification of Steel Ingot

摘要

Numerical simulations of solidification process of steel ingots weighing 19, 8.5, and 3.35 ton are carried out and the calculated results are validated against temperature measurement during solidification of steel ingots. A new concept of "effective transient thermal resistance" is proposed to help analyze heat transfer resistances of mold, ingot/mold interface, solidified shell, and outer wall of mold. Consequently, the restrictive steps of heat transfer (RSHT) at different stages of solidification of steel ingots are dug out. It is found that the RSHT during solidification of steel ingots weighing 19, 8.5, and 3.35 ton are similar. At early-stage of solidification, the effective transient thermal resistances of the mold and ingot/mold interface increase rapidly. Heat transfers through the mold and ingot/mold interface, are the RSHT. At mid-stage of solidification, the effective transient thermal resistance of the outer wall of the mold is larger than that of other heat transfer sections. Heat transfer section of the outer wall of mold is the RSHT. At late-stage of solidification, the heat transfer section of the solidified shell is the RSHT due to the thickening of the solidified shell. In addition, it was found that variations of pouring temperature and mold's thickness do not change the RSHT during solidification of steel ingots.