A Comparative Study of Fish-scaling Resistance of Low Carbon Non-microalloyed and Boron-microalloyed Steels for Enameling

Abstract

Abstract. TH values of low carbon non-microalloyed and boron-microalloyed steels before and after baking were measured and microstructures of low carbon non-microalloyed and boron-microalloyed steels before and after baking were observed by scanning electron microscope as well as transmission electron microscope in order to study fish-scaling resistance of steels for enameling. Results show that cementite is the important hydrogen storage trap in low carbon steels and cementite at ferrite grain boundary is the most important hydrogen storage trap. TH value of non-microalloyed steels before baking is highest because all cementites distribute along ferrite grain boundaries. TH value of non-microalloyed steels after baking decreases due to a decrease in cementite-ferrite interfaces when cementites grow up. TH value of boron-microalloyed steels before baking is lowest because most cementites disperse in ferrite grains. TH value of boron-microalloyed steels after baking increases because cementites in ferrite grains are pushed to ferrite grain boundaries by migratory grain boundaries when ferrite grains grow up.