55l

gears and couplings handling machines, running wheels, sliders, toothed sector and crowns, half couplings, rays, sleeve gear couplings and other parts, which are requirements of high hardness.

Classification

Country	Section	Category
Country	Section	Category
CIS, Russia, Ukraine	Steels and alloys for castings	Ordinary steel for castings

Chemical composition

Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	P, %	C, %	S, %
Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	P, %	C, %	S, %
GOST 977-88	96.995–98.88	0.2–0.52	0.4–0.9	< 0.3	< 0.3	< 0.3	< 0.04	0.52–0.6	< 0.045

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Physical characteristics

Temperature, °C	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$\rho$ , $\frac{kg}{m^3}$	$c\cdot 10^{-3}$ , $\frac{J}{kg\cdot K}$
Temperature, °C	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$\rho$ , $\frac{kg}{m^3}$	$c\cdot 10^{-3}$ , $\frac{J}{kg\cdot K}$
20			7820
100	11	68		0.479
200	11.8	55		0.487
400	13.4	36		0.525
500		32
600	14.5			0.571

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
Rolling	Standard	Size, mm	Tension	Classifiers	$\sigma _{U}$ , $MPa$	$\sigma_{P}$ , $MPa$	$\epsilon_L$ , %	$\psi$ , %	$KCU\cdot 10^{3}$ , $\frac{J}{m^2}$	Treatment
Castings		< 100			600	350	10	18	240	Normalization of 840-860 ° C, 600-630 ° C and Holidays

Brinell hardness number

Rolling	Standard	Classifiers	Value, HBW
Rolling	Standard	Classifiers	Value, HBW
Castings			159–255

Casting and technological parameters

linear shrinkage, %
linear shrinkage, %
2.2–2.3

Technological Properties

Weldability	Flake Susceptibility	Propensity to temper brittleness
Weldability	Flake Susceptibility	Propensity to temper brittleness
Difficult to weld	not sensitive	not inclined

Critical point temperatures

Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K
Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K
725	770	755	690

Analogues

Germany	USA
Germany	USA
1.0554	Gr.105-85

Standards

Standard	Description
Standard	Description
GOST 977-88

Description of chemical elements

Element	Units of measurement	Description
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
Parameter	Units of measurement	Description
$\alpha\cdot 10^{6}$	$K^{-1}$	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
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

Description of the casting and technological parameters

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
linear shrinkage	%	The difference between model dimensions and the model casting

Designation of types of weldability

Parameter	Units of measurement	Description
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
Parameter	Units of measurement	Description
Ac₁	K
Ac₃(Ac_m)	K
Ar₃(Arc_m)	K
Ar₁	K