Shiraz University Iranian Journal of Materials Forming 2383-0042 4 2 2017 10 01 The Effect of Hot Deformation Parameters on Grain Size Refinement in a Martensitic Stainless Steel 25 36 4290 10.22099/ijmf.2017.4290 EN R. Mohammadi Ahmadabadi Amirkabir university of technology M. Naderi Department of Mining and Metallurgical Engineering, Amirkabir University of Technology J. Aghazadeh Mohandesi ِDepartment of Mining and Metallurgical Engineering, Amirkabir University of Technology J. Cabrera Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, ETSEIB, Universidad Politécnica de Catalunya Journal Article 2017 04 29 The grain size refinement of AISI 422 martensitic stainless steel in the temperature range of 950-1150 ºC was investigated by hot deformation tests. The deformed specimens were held at deformation temperature with delay times of 5 to 300s after achieving a strain of 0.3. The austenite grains exhibit a considerable growth at temperature higher than 1050˚C, while the grain coarsening is negligible at lower deformation temperatures. Therefore, it is a difficult task to achieve a fine grain structure at these high deformation temperatures. In the second stage of this work, the grain growth behavior of the deformed alloy at temperature range of 940-1020 ºC was investigated to obtain a fine austenite grain in the final deformation step. A uniform and fine-grain structure, with average grain size less than 30 µm, can be obtained by considering the appropriate temperature and strain per pass. At 1020˚C a relatively fine and uniform recrystallized grain, mean grain size of about 28 µm, is obtained with an applied strain of 0.4, while at 980˚C after strain of 0.2 a nearly equiaxed grain with the same mean grain size is achieved. https://ijmf.shirazu.ac.ir/article_4290_fe9ce8486f741bead5b936ccd6e85c4f.pdf