Rebar or steel reinforcing bar (rod, GOST 5781-82, GOST R 52544-2006) used for reinforcementdiffers by the type of profile:

• plain
• periodic profile (grooved)

Depending on the mechanical properties  the rebar rod is differentiated into classes: AI (A240), AII (A300), AIII (A400), AIV (A600), AV (A800), AVI (A1000). The rods of the rebar class:

• AI - plain
• AII, AIII, AIV - periodically profiled.

The index then includes “t” (for thermally hardened rebar steel) and “v” (strengthened by drawing). Periodically profiled reinforcing bar is a circular steel rod two longitudinal and transverse projections ledges. For each class of the rebar there are specified steel grades:

• AI (A240) - St3kp (ps, sp);
• AII (A300) - St5sp (ps), 18G2S;
• AIII (A400) - 35GS, 25G2S, A500S, A400S, 32G2RPS;
• AIV (A600) - 80S, 20HG2S;
• AV (A800) - 23H2G2T;
• AVI (A1000) -22H2G2AU, 22H2G2R, 20H2G2SR.

Thermomechanicaly strengthened rebar steel of the steel grade A400 and A500S is produced by West-Siberian Metallurgical Plant (WSMP) using St3 steel as a base and is a substitute for steel grades 35GS, 25G2S.

Thermally strengthened periodically profiled steel rods of the diameter 6-40mm - the so called “thermic” is used for the construction of strategic reinforced concrete structures, GOST 10884-81. According to the standard this rebar is made out of these types of steel:

• AtIII - St (sp, ps);
• AtIV, AtIVK - 20GS, 25G2S, 35GS, 28S, 10GS2, 08G2S, 25S2P;
• AtV(K and SK) - 20GS, 20GS2, 08G2S, 10GS2, 28S, 25G2S, 35GS, 25S2R, 20HGS2;
• AtVII - 30HS2.

In the nomenclature of these classes of rebar the letters correspond to “K” (increased resistance to corrosive fracturing under stress) and “S” (weldable). Minimum size of the rebar of any class - 6(mm), maximum size - 80(mm), all that is below or above these sizes can be made by special order to factories-producers. The size of the periodically profiled rebar (corrugated) corresponds to the diameter of the plain rod (excluding the protrusions from corrugation).