水蒸気含有雰囲気におけるオーステナイト系ステンレス鋼の高温酸化挙動

摘要

In many cases, the oxidation resistance in H_2O-containing atmosphere is required for austenitic stainless steels used at high temperature environment. In order to clarify the possibility of applying austenitic stainless steels to the high temperature environment, isothermal oxidation test were carried out at 500～900℃ in H_2O-containing atmosphere. The main results obtained are as follows ;rn(1) Oxidation rate of austenitic stainless steel was higher in the gases containing water vapor than in the air at 700～800℃.rn(2) Cr and Si were effective in improving the oxidation resistance of austenitic stainless steels in water vapor environment.rn(3) It was confirmed that the volatile cromium-containing species were present exposed to oxidizing environments containing N_2-O_2-H_2O, while no volatile species were fund in N_2-H_2O.rn(4) The oxidation resistance was improved by the grinding finish. However, the effect was lost with time in Air-50%H_2O atmosphere.rn(5) The influence of N_2, CO, CO_2, or CH_4 mixture on the oxidation containing H_2O of austenitic stainless steel were very small compared with O_2 mixture.%各種燃焼機器，内燃機関の排ガス経路部材，発電プラrnントなど，500～1000℃で使用される部位は，SUS310Srn（25Cr-20Ni）に代表されるオーステナイト系耐熱ステンrnレス鋼の主な用途のひとつである。これらの部位では，rn高温強度とともに耐高温酸化性が重要な要求特性に挙げrnられる。