Steel 12MKH
	
	
Designation
	
		
			| Name | 
			The value | 
		
	
	
		
			| Designation GOST Cyrillic | 
			12МХ | 
		
		
			| Designation GOST Latin | 
			12MX | 
		
		
			| Transliteration | 
			12MH | 
		
		
			| The chemical elements | 
			12MoCr | 
		
	
	Description
	12MKH steel is used: for the manufacture of superheater pipes, pipelines and collector installations high pressure; forgings of parts for steam boilers and steam pipes; parts, cylinders of gas turbines; various parts operating at temperatures up to +510 °C; as a base layer in the manufacture of hot-rolled dual-layer corrosion-resistant sheets.
Note
Steel pearlitic class.
Temperature intense scaling +570 °C.
Standards
	
		
			| Name | 
			Code | 
			Standards | 
		
	
	
		
	| Sectional and shaped rolling | 
	В22 | 
	GOST 1133-71, GOST 2590-2006, GOST 2591-2006 | 
	| Sheets and stripes | 
	В23 | 
	GOST 19903-74, GOST 103-2006, GOST 19903-90 | 
	| Sheets and stripes | 
	В33 | 
	GOST 4405-75, GOST 10885-85, TU 108.1263-84, TU 14-1-642-73, TU 24-10-003-70, TU 14-1-5093-92 | 
	| Pipes steel and connecting parts to them | 
	В62 | 
	GOST 550-75, TU 14-3-463-2005 | 
	| Sectional and shaped rolling | 
	В32 | 
	GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 14955-77, GOST 20072-74, TU 14-11-245-88 | 
	| Metal forming. Forgings | 
	В03 | 
	OST 5Р.9125-84, TU 0306.018-80 | 
	| Bulls. Blanks. Slabs | 
	В31 | 
	TU 14-1-1263-75 | 
	
Chemical composition
	
		
			| Standard | 
			
C | 
 
S | 
 
P | 
 
Mn | 
 
Cr | 
 
Si | 
 
Ni | 
 
Fe | 
 
Cu | 
 
V | 
 
Ti | 
 
Mo | 
 
W | 
		
	
	
		
	| GOST 20072-74 | 
	
0.09-0.16 | 
≤0.025 | 
≤0.03 | 
0.4-0.7 | 
0.4-0.7 | 
0.17-0.37 | 
≤0.3 | 
The rest | 
≤0.2 | 
≤0.05 | 
≤0.03 | 
0.4-0.6 | 
≤0.2 | 
	
Fe is the basis. 
 According to GOST 20072-74, when steel is scrap-process, the content of Cu ≤ 0.30%. Tungsten is allowed up to 0.20%, vanadium up to 0.050%, titanium up to 0.030%. When smelting steel by the method of electroslag remelting, the mass fraction of sulfur should not be more than 0.015%. 
 According to TU 108.1263-84, steel should be smelted in an open-hearth furnace or an electric arc furnace. It is permitted to process steel at the OSRP.
Mechanical characteristics
	
		
			
| Section, mm | 
 
sT|s0,2, MPa | 
 
σB, MPa | 
 
d5, % | 
 
y, % | 
 
kJ/m2, кДж/м2 | 
 
Brinell hardness number, MPa | 
		
	
	
		
	| Steel hot-rolled sheet, heat treated in the delivery condition (transverse specimens) | 
	
| 5-25 | 
≥235 | 
≥440 | 
≥24 | 
- | 
≥579 | 
- | 
	| Leaves section 20-160 mm | 
	
| 130-160 | 
≥195 | 
≥340 | 
≥18 | 
≥32 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥280 | 
≥445 | 
≥32 | 
≥67 | 
- | 
- | 
	| Sheet double layer in the delivery state according to GOST 10885-85 (samples transverse) | 
	
| 12-40 | 
≥221 | 
≥420 | 
≥24 | 
- | 
≥588 | 
- | 
	| Leaves section 20-160 mm | 
	
| 130-160 | 
≥215 | 
≥390 | 
≥18 | 
≥32 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥250 | 
≥450 | 
≥20 | 
≥62 | 
- | 
- | 
	| Sheet. Quenching in water from 900-920 °C + Vacation at 670-720 °C, air cooling (samples transverse) | 
	
| 4-60 | 
≥235 | 
≥440 | 
≥24 | 
- | 
≥579 | 
≥182 | 
	| Leaves section 20-160 mm | 
	
| 60-130 | 
≥215 | 
≥390 | 
≥18 | 
≥32 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥290 | 
≥480 | 
≥20 | 
≥57 | 
- | 
- | 
	| Sheet. Quenching in water from 900-920 °C + Vacation at 670-720 °C, air cooling (samples transverse) | 
	
| 61-125 | 
≥235 | 
≥440 | 
≥18 | 
≥32 | 
≥481 | 
- | 
	| Leaves section 20-160 mm | 
	
| 60-130 | 
≥235 | 
≥440 | 
≥18 | 
≥32 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥250 | 
≥450 | 
≥23 | 
≥62 | 
- | 
- | 
	| Forgings for parts resistant to the ICC. Normalization at 910-930 °C, air cooling + Vacation at 670-690 °C, air cooling | 
	
 | 
≥235 | 
≥412 | 
≥21 | 
≥45 | 
≥579 | 
- | 
	| Leaves section 20-160 mm | 
	
| 20-39 | 
≥235 | 
≥440 | 
≥19 | 
≥35 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥235 | 
≥400 | 
≥22 | 
≥62 | 
- | 
- | 
	| Rolled steel. Normalization at 910-930 °C, air cooling + Vacation at 670-690 °C, air cooling | 
	
| ≤90 | 
≥235 | 
≥410 | 
≥21 | 
≥45 | 
≥579 | 
- | 
	| Leaves section 20-160 mm | 
	
| 40-60 | 
≥235 | 
≥440 | 
≥19 | 
≥35 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥220 | 
≥360 | 
≥22 | 
≥64 | 
- | 
- | 
	| The tubular billet (D = 80-270 mm) as supplied on THAT 14-1-1263-75. Normalization at 910-930 °C, air cooling | 
	
| 20-25 | 
≥206 | 
≥412 | 
≥21 | 
≥50 | 
≥686 | 
- | 
	| Leaves section 20-160 mm | 
	
| 20-39 | 
≥235 | 
≥390 | 
≥19 | 
≥35 | 
≥490 | 
- | 
	| Pipe with a diameter of 273 mm with a wall thickness of 28 mm. Normalizing at 920 °C, air cooling + Vacation at 680-690 °C, air cooling | 
	
| - | 
≥220 | 
≥310 | 
≥26 | 
≥64 | 
- | 
- | 
	| The tubular billet (D = 80-270 mm) as supplied on THAT 14-1-1263-75. Vacation at 670-700 °C, air cooling | 
	
| 20-25 | 
≥206 | 
≥412 | 
≥19 | 
≥45 | 
≥490 | 
- | 
	| Leaves section 20-160 mm | 
	
| 40-60 | 
≥235 | 
≥390 | 
≥19 | 
≥35 | 
≥490 | 
- | 
	| Seamless hot deformed tubes, heat-treated in the delivery condition according to GOST 550-75 | 
	
 | 
≥245 | 
≥410 | 
≥21 | 
≥45 | 
≥690 | 
≤156 | 
	| Leaves section 20-160 mm | 
	
| 130-160 | 
≥295 | 
≥440 | 
≥20 | 
≥50 | 
≥780 | 
- | 
	
| 40-130 | 
≥340 | 
≥490 | 
≥20 | 
≥50 | 
≥780 | 
- | 
	
Description mechanical marks
	
		
			| Name | 
			Description | 
		
	
	
		
	| Section | 
	Section | 
	| sT|s0,2 | 
	Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2% | 
	| σB | 
	Limit short-term strength | 
	| d5 | 
	Elongation after rupture | 
	| y | 
	The relative narrowing | 
	| kJ/m2 | 
	Toughness | 
	
Physical characteristics
	
		
			| Temperature | 
			
Е, ГПа | 
 
r, кг/м3 | 
 
l, Вт/(м · °С) | 
 
R, НОм · м | 
 
a, 10-6 1/°С | 
 
С, Дж/(кг · °С) | 
		
	
	
		
	| 0 | 
	
212 | 
7850 | 
- | 
- | 
- | 
- | 
	| 100 | 
	
206 | 
7830 | 
50 | 
240 | 
112 | 
473 | 
	| 200 | 
	
200 | 
7800 | 
50 | 
330 | 
125 | 
519 | 
	| 300 | 
	
195 | 
7760 | 
50 | 
410 | 
127 | 
565 | 
	| 400 | 
	
189 | 
7730 | 
49 | 
540 | 
129 | 
594 | 
	| 500 | 
	
179 | 
7690 | 
47 | 
640 | 
132 | 
653 | 
	| 600 | 
	
170 | 
7650 | 
46 | 
740 | 
- | 
733 | 
	| 700 | 
	
160 | 
7610 | 
44 | 
900 | 
135 | 
- | 
	| 900 | 
	
- | 
- | 
- | 
- | 
138 | 
- | 
	| 800 | 
	
- | 
- | 
- | 
- | 
- | 
888 | 
	| 1000 | 
	
- | 
- | 
- | 
- | 
- | 
1365 | 
	
A description of the physical symbols
	
		
			| Name | 
			Description | 
		
	
	
		
	| Е | 
	The normal elasticity modulus | 
	| r | 
	Density | 
	| l | 
	Coefficient of thermal conductivity | 
	| R | 
	UD. the resistivity | 
	
Technological properties
	
		
			| Name | 
			The value | 
		
	
	
		
	| Weldability | 
	Welded without any restrictions. Welding methods: SMAW, ADS under gas protection, the CCC. Recommended heating and subsequent heat treatment. | 
	| Propensity to temper brittleness | 
	Tend not. | 
	| Forging temperature | 
	Start - 1260 °C, the end - 750 °C. | 
	| Flock-sensitive sensitivity | 
	Sensitive. | 
	| Workability by cutting | 
	In the normalized and tempered condition, when blower SB 138 HB=460 MPa Kn b.St.=1.4. |