2상 조직을 갖는 고 Mn 스테인리스강의 기계적 성질, 감쇠능 및 내식성

Abstract

The mechanical properties, damping capacity and corrosion resistance of austenitic stainless steels were investigated using specimens with different volume fractions of retained and reversed austenite, by deformation and reverse annealing treatment after deformation, respectively. The results obtained from this study are as follows: The two phase structure of martensite and retained austenite was obtained by deformation with different temperature and degree of deformation..The two phase structure of martensite and reversed austenite was obtained reverse annealing treatment with different temperature and time after deformation .The ultra fine reverse austenite with less than 0.5㎛ in size was obtained by reverse annealing in the temperature range of 500-700℃. As the volume fraction of retained and reversed austenite has increased, hardness and strength have rapidly decreased, while elongation has increased.With regard to each austenite, reversed austenite has indicated higher value of hardness and strength, while elongation has suggested a lower value due to the strengthening caused by grain refinement. Hardness, strength and elongation were affected greatly by reversed austenite than retained austenite. With the increase of deformation degree, the volume fraction of retained austenite and damping capacity was decreased; with an increase of reveres annealing temperature, reversed austenite and damping capacity was rapidly increased. With the volume fraction of retained and reverse austenite, damping capacity was increased rapidly. At the same volume of retained and reveresed austenite, damping capacity of reversed austenite was higher then the retained austenite. Thus, the damping capacity was affected greatly by reversed austenite. Pitting corrosion has arisen mainly on martensite phase in 202 stainless steel with two phases of austenite and martensite. Pitting current density has decreased with an increase of volume fraction of austenite. Consequently, pitting corrosion at martensite has occurred largely with an increase of volume fraction of austenite. Pitting corrosion was affected by volume fraction of austenite.