Steel 20KH12VNMF (ЭП428; 20KH12VNMF-sh (ЭП427-W))
Designation
| Name |
The value |
| Designation GOST Cyrillic |
20Х12ВНМФ |
| Designation GOST Latin |
20X12BHMF |
| Transliteration |
20H12VNMF |
| The chemical elements |
20Cr12WНMoV |
| Name |
The value |
| Designation GOST Cyrillic |
ЭП428 |
| Designation GOST Latin |
EP428 |
| Transliteration |
EhP428 |
| The chemical elements |
- |
| Name |
The value |
| Designation GOST Cyrillic |
20Х12ВНМФ-Ш (ЭП427-Ш) |
| Designation GOST Latin |
20X12BHMF-Sh (EP427-Sh) |
| Transliteration |
20H12VNMF-Sh EhP427-Sh |
| The 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 stripes |
В23 |
GOST 103-2006 |
| Sectional and shaped rolling |
В22 |
GOST 1133-71, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006 |
| Sheets and stripes |
В33 |
GOST 4405-75 |
| Classification, nomenclature and general norms |
В30 |
GOST 5632-72 |
| Sectional and shaped rolling |
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 |
| Bulls. Blanks. Slabs |
В31 |
OST 108.020.03-82, OST 3-1686-90 |
| Steam pipelines. Regulators. Superheaters |
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 |
The 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 |
The 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 characteristics
| Section, mm |
σB, MPa |
y, % |
Brinell hardness number, MPa |
| The bars as supplied on the other 14-1-3697-84 |
|
450-640 |
≥45 |
140-187 |
Description mechanical marks
| Name |
Description |
| Section |
Section |
| σB |
Limit short-term strength |
| y |
The relative narrowing |
Physical characteristics
| Temperature |
Е, ГПа |
r, кг/м3 |
l, Вт/(м · °С) |
a, 10-6 1/°С |
| 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. |
| Forging temperature |
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. |
| Workability by cutting |
In the annealed condition with HB 187 and blower SB=610 MPa Kn b.St.=0.6 |
