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gears, mill rolls, rods, heavy duty shafts, axles, tires, light duty springs and springs, plowshares, fingers track link and clutch transmissions, body injectors and other parts operating friction.

Classification

Country	Section	Category
CIS, Russia, Ukraine	Structural steel	Carbonaceous quality structural steel

Chemical composition

Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	As, %	P, %	C, %	S, %
GOST 1050-88	97.225–98.81	0.17–0.37	0.5–0.8	< 0.25	< 0.3	< 0.3	< 0.08	< 0.035	0.52–0.6	< 0.04

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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	210			7280
100		11	68		0.479
200		11.9	55		0.487
300		12.7
400		13.4	36		0.525
500		14	32		0.571
600		14.5
700		14.8
800		12.5
900		13.5
1000		14.4

Mechanical properties at 20 °C

Rolling	Standard	Size, mm	Tension	Classifiers	$$\sigma _{U}$$, $$MPa$$	$$\sigma_{P}$$, $$MPa$$	$$\epsilon_L$$, %	$$\psi$$, %	Treatment
Metal rolling	GOST 1050-88	< 80			650	380	13	35	Normalization
Tape				annealing	440–740		13
Tape				cold-work	740–1080

Brinell hardness number

Rolling	Standard	Classifiers	Value, HBW
Metal rolling	GOST 1050-88	hot rolling	255
Metal rolling	GOST 1050-88	calibrated, cold-work	269
Metal rolling	GOST 1050-88	annealing, calibrated	229
Metal rolling	GOST 1050-88	annealing, hot rolling	217

Technological Properties

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

Critical point temperatures

Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K	Mn, K
725	755	750	690	320

Analogues

USA	Germany
G10550	1.0535 (C55)

Standards

Standard	Description
GOST 1050-88

Description of chemical elements

Element	Units of measurement	Description
Fe	%	Iron
Si	%	Silicon
Mn	%	Manganese
Cr	%	Chrome
Cu	%	Copper
Ni	%	Nickel
As	%	Arsenic
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(Ac_m)	K
Ar₃(Arc_m)	K
Ar₁	K
Mn	K