Reduction of oxide scale on hot-rolled steel by hydrogen at low temperature

This study was carried out with an intention to remove the oxide scale on hot-rolled steel by gaseous reduction instead of traditional acid pickling method with an aim to reduce the pollution. The reduction of iron oxide scale by hydrogen–argon mixture was studied by thermogravimetric tests in the temperature range of 370–550 °C. The rate controlling process was discussed according to the Avrami–Erofe'ev equation generalized method. The analysis suggests that the reduction of scale is controlled by two- and/or three-dimensional growth of nuclei in the whole temperature range investigated. The apparent activation energy exhibit a sudden decrease from 78.8 to 31.8 kJ/mol at temperature higher than 410 °C. Morphological structure of the reduced scale was investigated by scanning electron microscope.