International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In this paper the results of modelling of radial-shear rolling process of austenitic stainless steel AISI-321 are presented. The simulation in Simufact Forming program complex was performed. The conditions of simulation for radial-shear mill SVP-08 of Rudny industrial Institute were adopted. The various parameters of stress-strain state (effective plastic strain, effective stress, mean normal stress and Lode-Nadai coefficient) and also microstructure evolution with rolling force were considered. It is revealed that radial-shear rolling is an effective process for obtaining of high quality round billets from stainless steels of austenitic class.

The research paper presents the improvement on the mechanical and service properties of the austenitic stainless 0.07% C-17% Cr-9% Ni-0.7%-Ti steel in the fully austenitic state obtained by equal-channel angular pressing (ECAP) at the temperatures of 200 °C and 400 °C. Subgrain oriented structure in the Cr-Ni-Ti steel after ECAP significantly enhances the strength characteristics of steel at satisfactory plasticity. The fatigue limit of steel after ECAP at T = 200 ° C is higher than that after ECAP at T = 400 ° C, increasing in comparison with the initial state by 2.2 and 1.7 times, respectively. It was revealed that severe plastic deformation by ECAP increases the friction coefficient of the material by the 1.1 and 1.7 times at T = 200 ° C and 400 ° C, respectively. Despite this, the wear rate after ECAP at T = 200 ° C and 400 ° C decreases by 7 and 40 times, respectively, compared to initial state.

Austenitic stainless steels are widely used for various industrial, construction and biomedical application because of their high resistance to uniform corrosion and suitable mechanical properties. However, they are prone to local corrosion in aggressive halides environments. In contrast of corrosion resistance research in chloride containing environments, there have been few investigations into the effect of fluorides on passivity breakdown and pitting corrosion of stainless steels. This article focuses on the effect of fluoride added to chloride solution on corrosion resistance of AISI 316L stainless steel. Evaluation is based on results of exposition immersion tests performed in 0.9 % NaCl, 0.9 % NaCl + 0.05 % NaF and 0.9 % NaCl + 0. 5 % NaF solutions (42 days) and on results of cyclic potentiodynamic polarization tests performed in the same solutions.