Influence of Heating Temperature on Edge Crack in Hot Rolling of 36%Ni-Fe Alloy

For the purpose of edge crack control in hot rolling of 36%Ni-Fe alloys, a high temperature tensile test and laboratory-scale hot rolling experiment were carried out. Intergranular oxidation has been considered to be one of the major factors in edge cracking. Edge cracks which initiate from intergranular oxidation grow to the inner side along coarse grain boundaries as the thickness reduction ratio increases. The depth of intergranular oxidation increases at higher reheating temperatures. However, recrystallization occurs at the crack tip, and this has the effect of suppressing crack growth. This suggests that promoting recrystallization during hot rolling by increasing the reheating temperature, rather than inhibition of intergranular oxidation as such, is effective for suppressing edge cracking.