Fatigue Strength of High Mn Non-Magnetic Steel and Its Microscopic Characteristics

Abstract

Fatigue behavior of high manganese non-magnetic austenitic steel (HM steel) was studied through the rotating bending fatigue tests using plain specimens with a partial shallow notch by means of the successive-taken replica method. This behavior was compared with that of an austenitic stainless steel (SUS304). The experimental results showed that the fatigue limit of HM steel was the same as that of SUS304, and distinct knee point was observed in S-N curve of both materials. It was found that the fatigue cracks of these materials initiated at grain boundaries or in its neighborhood. It was apparently observed that some non-propagating micro-cracks existed in the specimen surface of HM steel subjected to the stress cycling of fatigue limit by 107 cycles, while no micro-crack existed in the specimen of SUS304 subjected to the same stress condition. © 1994, The Society of Materials Science, Japan. All rights reserved.