Designation
| Name |
The value |
| Designation GOST Cyrillic |
18ХГ |
| Designation GOST Latin |
18XG |
| Transliteration |
18HG |
| By chemical elements |
18CrMn |
Description
18KHG steel is used: for the production of carburized parts of small sections, working on friction; details of pipeline valves are designed to cut non-aggressive media (water, steam, air, nitrogen, inert gases, fuel oil, oil, oil distillers, diesel fuel, diesel oil, crude oil and petroleum products); tubes for plants of chemical and petrochemical plants with nominal pressure PN=19.6−98 MPa (200−1000 kgf/cm2). Details of pipe fittings are made of rolled, forged blanks and forgings (requires heat treatment: quenching in oil and tempering in air or in oil).
Note
Steel structural quality chromatorgraphy.
Standards
| Name |
Code |
Standards |
| Sheets and strips |
В23 |
GOST 103-2006 |
| Bars and shapes |
В22 |
GOST 1133-71, GOST 8319.0-75, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006 |
| Bars and shapes |
В32 |
GOST 4543-71, GOST 7417-75, GOST 8560-78, GOST 14955-77, TU 14-1-2118-77, TU 14-11-245-88, TU 14-1-1271-75, TU 14-1-5228-93, TU 14-136-367-2008 |
| Blanks. Of the workpiece. Slabs |
В31 |
OST 3-1686-90, TU 14-1-4944-90 |
| Classification, nomenclature and General rules |
В30 |
OST 64-155-75 |
| Thermal and thermochemical treatment of metals |
В04 |
ST ЦКБА 026-2005 |
| Steel pipes and fittings to them |
В62 |
TU 14-3-251-74 |
| Tape |
В34 |
TU 14-4-795-77 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Cu |
V |
Ti |
Mo |
W |
| GOST 4543-71 |
0.15-0.21 |
≤0.035 |
≤0.035 |
0.9-1.2 |
0.9-1.2 |
0.17-0.37 |
≤0.3 |
Rest |
≤0.3 |
≤0.05 |
≤0.03 |
≤0.15 |
≤0.2 |
Fe is the basis.
According to GOST 4543-71 the content in high-quality steel is regulated: P≤0,025%; S≤0.025%; Сu≤0.30%; in high-grade steel: P≤0,025%; S≤0.015%; Сu≤0.25%.
Mechanical properties
| Section, mm |
t отпуска, °C |
sT|s0,2, MPa |
σU, MPa |
d5, % |
y, % |
KCU, kJ/m2 |
HB, MPa |
| Blank pieces of pipe armature at ST CKBA 026-2005. Quenching in oil with 865-895 °C (exposure for 2.5-4.0 hours depending on thickness and weight of the workpiece) + Vacation, air cooling or oil (longitudinal samples) |
| ≤15 |
200-220 |
≥735 |
≥880 |
≥10 |
≥40 |
- |
277-321 |
| ≤80 |
650-700 |
≥440 |
≥635 |
≥16 |
≥45 |
≥588 |
197-235 |
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 |
| Склонность к отпускной хрупкости |
Inclined. |
| Flock-sensitive sensitivity |
Sensitive. |
