E⋅109
MPa
α⋅106
K−1
ϰ
Wm⋅K
ρ
kgm3
σU
MPa
σP
MPa
ϵL
ψ
KCU⋅103
Jm2

20H12VNMF (EP428, 25P2VNMF)

High loaded parts.

highly loaded parts for steam and gas turbines, long operating at temperatures up to 600 ° C .; martensitic steel grade

Classification

Country	Section	Category
Country	Section	Category
CIS, Russia, Ukraine	Heat resistant steels and alloys	Heat resistant high alloy steel

Chemical composition

Standard	Fe, %	Si, %	Mn, %	Cr, %	Ni, %	V, %	P, %	C, %	S, %	Mo, %	W, %
Standard	Fe, %	Si, %	Mn, %	Cr, %	Ni, %	V, %	P, %	C, %	S, %	Mo, %	W, %
GOST 5632-72	82.715–86.98	< 0.6	0.5–0.9	10.5–12.5	0.5–0.9	0.15–0.3	< 0.03	0.17–0.23	< 0.025	0.5–0.7	0.7–1.1

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Physical characteristics

Temperature, °C	$E\cdot 10^{9}$ , $MPa$	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$\rho$ , $\frac{kg}{m^3}$
Temperature, °C	$E\cdot 10^{9}$ , $MPa$	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$\rho$ , $\frac{kg}{m^3}$
20	212			7850
100	207	10.6	25	7830
200	202	10.9	25	7800
300	196	11.2	26	7780
400	190	11.4	26	7760
500	181	11.7	27	7730
600	167	11.9	27	7700
700		12		7670
800		12.1

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
Rod	GOST 5949-75				740	590	15	50	590	Hardening of 1010-1060 ° C, the oil, leave 660-670 ° C, air
Rod	GOST 18968-73				740	590–755	15	50	590	Normalized and tempered

Brinell hardness number

Rolling	Standard	Classifiers	Value, HBW
Rolling	Standard	Classifiers	Value, HBW
Rod	GOST 5949-75	annealing	229
Rod	GOST 18968-73	normalization, average vacation	229–269

Technological Properties

Weldability
Weldability
Difficult to weld

Critical point temperatures

Ac₁, K	Ac₃(Ac_m), K
Ac₁, K	Ac₃(Ac_m), K
800	860

Analogues

USA
USA
616

Standards

Standard	Description
Standard	Description
GOST 5632-72
GOST 5949-75

Description of chemical elements

Element	Units of measurement	Description
Element	Units of measurement	Description
Fe	%	Iron
Si	%	Silicon
Mn	%	Manganese
Cr	%	Chrome
Ni	%	Nickel
V	%	Vanadium
P	%	Phosphorus
C	%	Carbon
S	%	Sulfur
Mo	%	Molybdenum
W	%	Tungsten

Description of physical characteristics

Parameter	Units of measurement	Description
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

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

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