Impact of process gases on scale formation when heating tool steels

Abstract Three steel grades, 1.2322, 1.2379 and 1.8550, were heated using a natural gas/oxygen and a hydrogen/oxygen mixture and scale formation on these steels was determined gravimetrically and examined by microprobe analysis. No differences in the structure and composition of the scale were observed when using a hydrogen-heated instead of natural gas-heated furnace. Even though a thicker scale layer must be expected when using natural gas instead of hydrogen, no differences in terms of decarburization were found between the process gases used.