Abstract
Micro forging using the superplasticity was tried, at austenitic stainless steal SUS304. The grains were refined by thermomechanical treatment with reverse transformation of strain induced martensite to austenite. The average grain size was about 250 nm. In the micro forging, Vickers indentation added to surface to grinded and polished flat die were used. The grain refined material, on the surface of the sample, it was possible to add a quadrangular pyramid. Bottom line of quadrangular pyramid were about 50 μm, and height was about 10 μm. On the other hand, it was not able to be carried out this process.
