Name	The value
Designation GOST Cyrillic	20Х12ВНМФ-Ш (ЭП427-Ш)
Designation GOST Latin	20X12BHMF-Sh (EP427-Sh)
Transliteration	20H12VNMF-Sh EhP427-Sh
By chemical elements	20Cr12WНMoV-Mg (ЭP427-Mg)

Description

20KH12VNMF steel is used: for the production of highly loaded parts, blades of steam and gas turbines operating at temperatures up to +580 °C, parts of valves, forgings, discs, rotors for steam and gas turbines, tires, diaphragms, bolts, nuts, pins and other highly loaded parts operating at temperatures up to +600 °C; the nozzle blocks, parts of turbines and flanged connections for steam lines of thermal power plants.

Note

Steel heat-resistant martensitic class.
The recommended maximum operating temperature for a very long time — up to +600 °C. the Temperature of beginning of intensive scaling in air +750 °C.

Standards

Name	Code	Standards
Sheets and strips	В23	GOST 103-2006
Bars and shapes	В22	GOST 1133-71, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006
Sheets and strips	В33	GOST 4405-75
Classification, nomenclature and General rules	В30	GOST 5632-72
Bars and shapes	В32	GOST 5949-75, GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 14955-77, GOST 18968-73, GOST 19442-74, TU 14-1-643-73, TU 14-11-245-88
Blanks. Of the workpiece. Slabs	В31	OST 108.020.03-82, OST 3-1686-90
The steam lines. Regulators. Protopresvitera	Е26	OST 108.839.08-82, OST 108.839.10-82

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Ti	Mo	W
TU 14-1-643-73	0.17-0.23	≤0.025	≤0.03	0.5-0.9	10.5-12.5	≤0.4	0.5-0.9	Rest	-	0.15-0.3	-	0.5-0.7	0.7-1.1
GOST 5632-72	0.17-0.23	≤0.025	≤0.03	0.5-0.9	10.5-12.5	≤0.6	0.5-0.9	Rest	≤0.3	0.15-0.3	≤0.2	0.5-0.7	0.7-1.1

Fe is the basis.
According to TU 14-1-643-73, the chemical composition is given for steel grade 20Х12ВНМФ (ЭП428). In the steel grade 20Х12ВНМФ-Ш (ЭП428-Ш), the mass fraction of sulfur should not be more than 0,015%.

Mechanical properties

Section, mm	σ_U, MPa	y, %	HB, MPa
The bars as supplied on the other 14-1-3697-84
	450-640	≥45	140-187

Description mechanical marks

Name	Description
σ_U	Limit short-term strength
y	The relative narrowing
HB	Brinell hardness number

Physical characteristics

Temperature	Е, HPa	r, kg/m³	l, W/(m · °C)	a, 10^-6 1/°C
0	212	7850	-	-
20	212	7850	-	-
100	207	7830	25	106
200	202	7800	25	109
300	196	7780	26	112
400	190	7760	26	114
500	181	7730	27	117
600	167	7700	27	119
700	-	7670	-	12
800	-	-	-	121
1000	-	-	-	107
1200	-	-	-	117

A description of the physical symbols

Name	Description
Е	The normal elasticity modulus
l	Coefficient of thermal conductivity

Technological properties

Name	The value
Weldability	Steel difficult weldability. Method of welding - RDS, the necessary preheating and subsequent heat treatment.
The temperature of forging	Start - 1230 °C, the end of - 900 °C. the cross Sections up to 250 mm is subjected to annealing, one hypothermia. Sections from 250 to 400 mm - annealing and two hypothermia.
Machinability	In the annealed condition with HB 187 and blower SB=610 MPa Kn b.St.=0.6

Steel 20KH12VNMF (ЭП428; 20KH12VNMF-sh (ЭП427-W))

Designation