20G

After improvement — rivet-duty; after carburizing or cyanide — piston pins, friction discs, finger springs, cam rollers, bolts, nuts, gears, worms and other parts with high surface hardness and wear resistance. No heat treatment — welded sub-frame, shoes, scarves.

Classification

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

Chemical composition

Standard Fe, % Si, % Mn, % Cr, % Cu, % Ni, % P, % C, % S, %
GOST 4543-71 97.42–98.96 0.17–0.37 0.7–1 < 0.3 < 0.3 < 0.3 < 0.035 0.17–0.24 < 0.035

Information on suppliers

Physical characteristics

Temperature, °C $$E\cdot 10^{9}$$, $$MPa$$ $$\alpha\cdot 10^{6}$$, $$K^{-1}$$ $$\varkappa$$, $$\frac{W}{m\cdot K}$$ $$\rho$$, $$\frac{kg}{m^3}$$ $$c\cdot 10^{-3}$$, $$\frac{J}{kg\cdot K}$$
20 204 7820
100 12.5 78
200 13.4 67 0.525
300 14.4 48
400 15.1 0.554
600 15.2 0.689

Mechanical properties at 20 °C

Rolling Standard Size, mm Tension Classifiers $$\sigma _{U}$$, $$MPa$$ $$\sigma_{P}$$, $$MPa$$ $$\epsilon_L$$, % $$\psi$$, % Treatment
Rod GOST 4543-71 25 450 275 24 50 Normalization 880 ° C, air
The plates GOST 1577-93 440 27 Normalization
The plates GOST 1577-93 400 28 Annealing

Brinell hardness number

Rolling Standard Classifiers Value, HBW
Alloy GOST 4543-71 annealing 1790
The plates GOST 1577-93 normalization 197

Technological Properties

Weldability Flake Susceptibility Propensity to temper brittleness
no limits not sensitive not inclined

Critical point temperatures

Ac1, K Ac3(Acm), K Ar3(Arcm), K Ar1, K Mn, K
723 830 830 680 420

Analogues

USA Germany
H15211 1.1169 (20Mn6)

Standards

Standard Description
GOST 4543-71

Description of chemical elements

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

Description of physical characteristics

Parameter Units of measurement Description
$$E\cdot 10^{9}$$ $$MPa$$ Elastic modulus
$$\alpha\cdot 10^{6}$$ $$K^{-1}$$ Coefficient of thermal (linear) expansion (range 20°C–T)
$$\varkappa$$ $$\frac{W}{m\cdot K}$$ Coefficient of thermal conductivity (the heat capacity of the material)
$$\rho$$ $$\frac{kg}{m^3}$$ The density of the material
$$c\cdot 10^{-3}$$ $$\frac{J}{kg\cdot K}$$ The specific heat of the material (range 20°C–T)

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

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