70

Substitute: 65G

Springs, springs and other parts, which require enhanced strength and elastic properties, as well as wear resistance.

Classification

Country Section Category
CIS, Russia, Ukraine Structural steel Spring-spring structural steel

Chemical composition

Standard Fe, % Si, % Mn, % Cr, % Cu, % Ni, % P, % C, % S, %
GOST 14959-79 97.31–98.66 0.17–0.37 0.5–0.8 < 0.25 < 0.2 < 0.25 < 0.035 0.67–0.75 < 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 2.06 7810
100 11.5 68 0.483
200 12.3 52 0.487
300 13 37
400 13.8 29 0.521

Mechanical properties at 20 °C

Rolling Standard Size, mm Tension Classifiers $$\sigma _{U}$$, $$MPa$$ $$\sigma_{P}$$, $$MPa$$ $$\psi$$, % d5, % Treatment
Rod GOST 14959-79 < 80 1030 834 30 9 Tempering 830 ° C, oil, leave 470 ° C
The tape is hardcore. GOST 2284-79 cold-work 740–1130
The tape is annealed. GOST 2284-79 annealing 440–740 10

Brinell hardness number

Rolling Standard Classifiers Value, HBW
Alloy GOST 14959-79 raw 269
The plates GOST 1577-93 annealing, fat 229

Technological Properties

Weldability Flake Susceptibility Propensity to temper brittleness
Not applicable for welded structures insensitive not inclined

Critical point temperatures

Ac1, K Ac3(Acm), K Ar3(Arcm), K Ar1, K
730 743 727 693

Analogues

USA Germany European Union Bulgaria
G10700 1.1249 (Cf70) C70D 70

Standards

Standard Description
GOST 14959-79

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
d5 % Elongation at break
$$\sigma _{U}$$ $$MPa$$ Ultimate tensile strength
$$\sigma_{P}$$ $$MPa$$ Proportionality limit
$$\psi$$ % 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