20HGNR

Gears, pinion shafts, worms, cam clutches, rollers, bushings and other critical parts operating under impact loads.

Classification

Country Section Category
CIS, Russia, Ukraine Structural steel Alloyed structural steel

Chemical composition

Standard Fe, % Si, % B, % Mn, % Cr, % Ti, % Cu, % Ni, % P, % C, % S, %
GOST 4543-71 95.765–97.469 0.17–0.37 0.001–0.005 0.7–1 0.7–1.1 < 0.06 < 0.3 0.8–1.1 < 0.035 0.16–0.23 < 0.035

Information on suppliers

Mechanical properties at 20 °C

Rolling Standard Size, mm Tension Classifiers $$\sigma _{U}$$, $$MPa$$ $$\sigma_{P}$$, $$MPa$$ $$\epsilon_L$$, % $$\psi$$, % $$KCU\cdot 10^{3}$$, $$\frac{J}{m^2}$$ Treatment
Rod 25 1420 1370 14 60 1080 Normalization 930 ° C, air Tempering 840 ° C, oil, leave 200 ° C, air
Rod 50 1200 1110 12 62 1470 Normalization 930 ° C, air Tempering 840 ° C, oil, leave 200 ° C, air
Rod GOST 4543-71 15 1270 1080 10 50 880 Hardening and tempering

Brinell hardness number

Rolling Standard Classifiers Value, HBW
Alloy GOST 4543-71 annealing 197

Technological Properties

Weldability Flake Susceptibility Propensity to temper brittleness
Boundedly welded sensitive inclined

Critical point temperatures

Ac1, K Ac3(Acm), K Ar3(Arcm), K Ar1, K Mn, K
740 830 725 650 365

Standards

Standard Description
GOST 4543-71

Description of chemical elements

Element Units of measurement Description
Fe % Iron
Si % Silicon
B % Bor
Mn % Manganese
Cr % Chrome
Ti % Titan
Cu % Copper
Ni % Nickel
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)
$$\psi$$ % Reduction in cross section on fracture
$$KCU\cdot 10^{3}$$ $$\frac{J}{m^2}$$ Impact toughness

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

Description of temperatures of critical points

Parameter Units of measurement Description
Ac1 K
Ac3(Acm) K
Ar3(Arcm) K
Ar1 K
Mn K