EFFECTS OF ALLOYING ELEMENTS ON STICKING BEHAVIOR OCCURRING DURING HOT ROLLING OF MODIFIED FERRITIC STS430J1L STAINLESS STEELS

Abstract

In this study, effects of alloying elements on the sticking behavior occurring during hot rolling of five kinds of modified ferritic STS430J1L stainless steels were investigated by analyzing high-temperature hardness and oxidation behavior. Hot-rolling simulation tests were conducted by a high-temperature wear tester that could simulate actual hot rolling. The simulation test results revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation. Since the hardness continuously decreased as the test temperature increased while the formation of Fe-Cr oxides in the rolled steel surface region increased, the sticking of five steels was evaluated by considering both high-temperature hardness and oxidation. The addition of Zr, Cu, or Si had a beneficial effect on the sticking resistance, while the Ni addition did not make much difference to the sticking. Particularly, in the Si-rich steel, Si oxides formed first in the initial stage of the high-temperature oxidation, worked as initiation sites for Fe-Cr oxides, accelerated the formation of Fe-Cr oxides, and thus, decreased the sticking by over 10 times in comparison with the other steels.