Designation
| Name |
The value |
| Designation GOST Cyrillic |
12Х8 |
| Designation GOST Latin |
12X8 |
| Transliteration |
12H8 |
| By chemical elements |
12Cr8 |
| Name |
The value |
| Designation GOST Cyrillic |
1Х8 |
| Designation GOST Latin |
1X8 |
| Transliteration |
1H8 |
| By chemical elements |
1Cr8 |
Description
12X8 steel is used: for the manufacture of seamless pipes for petroleum refining and petrochemical industries operating at temperatures to +450 °C; the furnace and the communication pipes used in power and heat networks; of billets intended for production of tubes of the cracking units of oil refining.
Note
Steel martensitic class.
Standards
| Name |
Code |
Standards |
| Steel pipes and fittings to them |
В62 |
GOST 550-75, TU 14-3-457-76, TU 14-3-463-2005 |
| Blanks. Of the workpiece. Slabs |
В31 |
TU 14-1-583-73 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Cu |
| TU 14-3-457-76 |
≤0.12 |
≤0.03 |
≤0.035 |
0.3-0.6 |
7.5-9 |
0.17-0.37 |
≤0.4 |
Rest |
≤0.25 |
Fe is the basis.
According to TU 14-1-583-73, GOST 550-75, TU 14-3-457-76 the chemical composition is given for steel grade 12X8. In the finished rolled products, deviations in chemical composition are allowed in accordance with GOST 20072.
Mechanical properties
| Section, mm |
sT|s0,2, MPa |
σU, MPa |
d5, % |
y, % |
KCU, kJ/m2 |
HB, MPa |
| Tubular billet on the other 14-1-583-73 after annealing |
|
≥215 |
≥390 |
≥24 |
≥50 |
≥1177 |
≤170 |
| Tubes seamless cold - and warm, heat-treated in the delivery condition according to GOST 550-75 |
|
≥216 |
≥392 |
≥22 |
- |
- |
≤170 |
| Pipe kiln and communication in the delivery condition on the other 14-3-457-76 (impact strength is specified for tubes with wall thickness ≥ 12 mm and is determined for longitudinal samples) |
|
≥196 |
≥392 |
≥22 |
≥50 |
≥780 |
≤170 |
Description mechanical marks
| Name |
Description |
| sT|s0,2 |
Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2% |
| σU |
Limit short-term strength |
| d5 |
Elongation after rupture |
| y |
The relative narrowing |
| KCU |
Toughness |
| HB |
Brinell hardness number |
Technological properties
| Name |
The value |
| Macrostructure and pollution |
The macrostructure of billets, check for the etched cross templeto should not have shrinkage looseness, bubbles, delaminations, voids, cracks, inclusions and placenow visible without using the magnifying devices. The defects allowed on a point inhomogeneity, the Central porosity and segregation must not exceed 2 points (for each species), subcortical bubbles at 1 point at a depth of less than 2 mm. |
