Weldability without restrictions.

manufacture of valves class A-V (A800), designed for reinforcement of ordinary and prestressed concrete structures


Country Section Category
CIS, Russia, Ukraine Structural steel Low alloy structural steel for welded structures

Chemical composition

Standard Fe, % Si, % Mn, % Cr, % Ti, % Cu, % Ni, % Al, % P, % C, % S, %
GOST 5781-82 94.82–96.625 0.4–0.7 1.4–1.7 1.35–1.7 0.02–0.08 < 0.3 < 0.3 0.015–0.05 < 0.045 0.19–0.26 < 0.045

Information on suppliers

Mechanical properties at 20 °C

Rolling Standard Size, mm Tension Classifiers $$\sigma _{U}$$, $$MPa$$ $$\sigma_{P}$$, $$MPa$$ $$\epsilon_L$$, % Treatment
Fittings GOST 5781-82 1030 785 7

Technological Properties

no limits


BSt 420 S


Standard Description
GOST 5781-82

Description of chemical elements

Element Units of measurement Description
Fe % Iron
Si % Silicon
Mn % Manganese
Cr % Chrome
Ti % Titan
Cu % Copper
Ni % Nickel
Al % Aluminium
P % Phosphorus
C % Carbon
S % Sulfur

Description of mechanical properties

Parameter Units of measurement Description
$$\sigma _{U}$$ $$MPa$$ Ultimate tensile strength
$$\sigma_{P}$$ $$MPa$$ Proportionality limit
$$\epsilon_L$$ % Elongation at break (longitudinal)

Designation of types of weldability

Parameter Units of measurement Description
no limits Welding is performed without heating and without subsequent heat treatment
Boundedly welded Welding is possible with heating up to 100–120 °C and subsequent heat treatment
Difficult to weld For obtaining quality welded joints, additional operations are required: heating up to 200–300 °C for welding, heat treatment after welding — annealing
Not applicable for welded structures