Study On High-temperature Oxidation Character Of 20crmo Steel In The Regenerative Heating Furnace

Firstly, the special oxidation and reduction combustion atmosphere of regenerative heating furance is confirmed by analyzing of working pricinple, and the growth and property of steel's oxide layer is influenced by the special combustion atmosphere. The elements of 20CrMo steel can be oxidated and transformed into homologous oxide on the base of oxidation thermodynamic calculation, and the discontinuance growth law of 20CrMo steel's oxide layer is also discovered by the high-temperature oxidation kinetics experiment in the regenerative heating furance.Secondly, the oxide produced in the traditional furance, is loose and thick and the layers of oxide is distinct by SEM morpholoy. However, the oxide produced in the regenerative furance is compact and thin and the layers of oxide is confused, meanwhile interface undulation is discovered between inner oxide region and matrix metal, it is the intervention layer. The oxides of Fe₂O₃,Fe₃O₄,FeO,Cr₂O₃,MoO₃,FeCr₂O₄ are found in the oxide layer that is produced in different heating atmosphere by EDS, but the quantity of oxides is different in the oxide layer between traditional furance and regenerative furance, the former is less and the latter is high.Finally, the reasons for the difficuty of removing oxide of 20CrMo steel heated in the regenerative furance are generalized by analyzing the mechanics of 20CrMo steel high-temperature oxidation and researching on the high-temperature oxidation character. The oxides of Cr₂O₃,MoO₃,FeCr₂O₄ in the20CrMo steel's oxide layer strengthen the ductility and strength.The oxide layer produced in the regenerative furance is confused due to the oxidation-reduction combustion atmosphere, so there is Fe3O4 in the inner oxide layer, and also the oxide of Fe2O3 exists in the Fe3O4 layer.The complexity of oxide layer is adverse to be removed.Because of the difference of diffusion of alloying agents in 20CrMo steel and the special oxidation-reduction combustion atmosphere, there is intervention layer between inner oxide region and matrix metal, the connection area is enlarged and the connection strength is increased, so the difficulty of removing is improved.