Prediction of Crack-sensitivity of Continuously Cast Slabs of AISI 430 Ferritic Stainless Steel

摘要

Continuously cast slabs of ferritic stainless steels, e.g., AISI 430 grade have been known to be very sensitive to the formation of internal cracks. Thermal and mechanical stresses are generated during continuous casting of slab. The ability of the solidifying shell to absorb these stresses is determined by the solidification mode and the high temperature material properties. Lindenberg et al. have correlated the internal cracking susceptibility of ferritic stainless steel slabs with their high temperature properties. The frequency of internal cracks due to bulging and those under corners and depressions have been found to increase with ΔT_(ZDS), the difference of temperatures for zero ductility and zero strength. The solidus temperature for AISI 430 is around 1 450℃. Results of hot tearing tests carried out at different temperatures have indicated that % reduction of area for AISI 430 abruptly decreases to zero at 1 390℃. Accordingly the temperature range of 1390-1 450℃ is prone to formation of internal cracks.