Tube oxidation at flame-induction heating

The extent of tube oxidation at furnace heating, induction heating and combined flame-induction heating was studied. The flame furnace 3150 mm long was heated by natural gas. Near the furnace an inductor with a length 500 mm was installed. Tubes manufactured from steel 20 with diameters 105/95 mm were heated up to 940-980°C. At combined heating using the scheme furnace (500-600°C) - indicator (940-980°C) or at induction heating only the degree of oxidation formed (0.5-0.55)% of the total mass. At furnace heating up to 940°C oxydation reached 0.93-0.95%. Use of the scheme inductor-furnace resulted in the greatest degree of oxidation (0.85-1.36)%.