Experimental investigation of the oxidation behaviour of stainless steel exposed to different air-and oxy-fuel natural gas or hydrogen combustion atmospheres and temperatures during reheating on a semi-industrial scale

In the future, steel has to be manufactured with significantly lower CO2 emissions. Consequently, heating methods other than natural gas-fired furnaces with air as an oxidiser need to be employed. This study investigates the impact of air-and oxy-fuel combustion with natural gas and hydrogen on the scaling behaviour of EN 1.4307 (AISI 304L) stainless steel. The residual oxygen, 1 to 7 %O2 d.b., and the sample core temperature, 1200 degrees C and 1300 degrees C, were varied. A discontinuous gravimetric measurement method was applied, utilising ten samples of 20 x 20 x 65 mm dimensions for each set. For atmosphere generation in a semi-industrial furnace, a multi-fuel and-oxidiser burner was used. The specific mass gain was most heavily dependent on the temperature, followed by the oxidiser and fuel. In the oxy-fuel combustion mode, the presence of residual oxygen in the atmosphere and the fuel had a negligible influence. At 1200 degrees C, switching from natural gas/air combustion to hydrogen/air combustion resulted in a 15 % increase in the specific mass gain and, when switching from natural gas/air to oxy-fuel with natural gas or hydrogen, in a 40 % increase.