Effects of high-temperature hardness and oxidation on sticking phenomena occurring during hot rolling of two 430J1L ferritic stainless steels

Effects of high-temperature hardness and oxidation on sticking phenomena occurring during hot rolling of two STS 430J1L ferritic stainless steels were investigated in this study. Hot-rolling simulation test was conducted using a high-temperature wear tester. The sticking started from the initial nucleation stage in which the rolled materials were stuck onto the roll specimen surface, proceeded to the growth stage in which stuck fragments grew further, and reached the saturation stage. The modified 430J1L steel had a smaller number of sticking nucleation sites and slower growth rate than the conventional 430J1L steel because of higher high-temperature hardness, thereby leading to less serious sticking. When the simulation test was conducted at 1070 °C, Cr oxides were formed on the surface of the rolled materials, and thus the sticking was drastically reduced because of the increased surface hardness of the rolled materials. In order to prevent or minimize the sticking, thus, it was suggested to improve high-temperature properties of stainless steels in the case of hot rolling at 900-1000 °C, and to promote the formation of oxides in the case of hot rolling at temperatures higher than 1000 °C.