Balka stalnaya used, Dnepropetrovsk region.

An I-beam is a standard profile of structural elements made of black rolled steel. It is important that an I-beam beam is approximately 7 times stronger and 30 times stiffer than a square profile beam with a similar cross-sectional area. Double-beam beams are one of the most important materials in all construction industries. This is connected with a large number of subspecies of I-beam beams differing in their characteristics.
We offer a full range of I-beams.

GOST 8239-89 — I-beam with a slope of the inner faces of the shelves;
Klassov:
(//tractor-service.com)
10; 12; 14; 16; 18; 18a; 20; 20a*; 22; 22a*; 24; 24a*; 27; 27A*; 30; 30A*; 33; 36; 40; 45; 50; 55; 60;

GOST 19425-74 — two-beam special beams (C letter: M ― for suspended tracks; Ш — for reinforcing mine shafts); 140
классов:

14C; 20C; 20Sa; 22C; 27C; 27Sa; 36C; 18M; 24M; 30M; 36M; 45M.