Ural State Federal University named after B. N. Eltsin (Ekaterinburg, Russia):

Borovykh M. A., Post-graduate, Chair of Physics, e-mail: makboro@e1.ru
Chikova O. A., Dr. Eng., Prof., Chair of Physics, e-mail: chik63@mail.ru
Vyukhin V. V., Cand. Eng., Senior Researcher, Scientific Center of Physics of Metal Liquids, e-mail: v.v.vyukhin@urfu.ru

The results of examination of the crystal of structure of samples made of 32G1, 32G2 and 35HGF are presented. These samples were selected from hot-rolled pipes in the conditions of Sinarsky pipe plant. The steel study was conducted to justify the selection of the steel grade on the basis of the relationships «structure-properties». The method of EBSD analysis (Electron Backscatter Diffraction) has been used for this purpose. The size of effective ferrite grain and orientation of the crystallites are determined; information about local mechanical stresses according to the cards of the Taylor and Schmid factors is obtained. It was found that arising of local distortions in metal crystal lattice and large-angle (non-special) crystal boundaries are the cause of development of inter-crystalline corrosion in the examined ferrite steels. Heat treatment procedure has the effect on grain size and histogram of crystalline disorientation. It is concluded that fine grain, large proportion of low-angle grain boundaries, less local mechanical stress, and, therefore, high plasticity and high corrosion resistance relating to hydrocarbons are typical for steel grade 32G2.

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