The continuous reduction in the oxide scale of hot-rolled steel strip in H 2 -N 2 atmosphere was simulated in laboratory. Scale specimens were reduced in 20% H 2 -N 2 or 50% H 2 -N 2 atmosphere. The sample weight losses were measured after soaking at 550, 700 and 800°C. In both atmospheres, specimen reduced at 700°C showed the minimum weight loss after soaking for 240 s. At 700 and 800°C, higher hydrogen concentration accelerated the reaction in the beginning of soaking, but had little effect once the dense-reduced iron layer formed. While at 550°C, the reduced iron kept growing in porous structure and the weight loss rate increased significantly in higher H 2 concentration.

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