03Н18К8М5Т steel (VKS-170; ЭК21)
Designation
| Name |
The value |
| Designation GOST Cyrillic |
03Н18К8М5Т |
| Designation GOST Latin |
03H18K8M5T |
| Transliteration |
03N18K8M5T |
| The chemical elements |
03Н18Co8Mo5Ti |
| Name |
The value |
| Designation GOST Cyrillic |
ВКС-170 |
| Designation GOST Latin |
BKC-170 |
| Transliteration |
VKS-170 |
| The chemical elements |
WCoС-170 |
| Name |
The value |
| Designation GOST Cyrillic |
ЭК21 |
| Designation GOST Latin |
EK21 |
| Transliteration |
EhK21 |
| The chemical elements |
- |
Description
03Н18К8М5Т steel is used: for the production of bodies of rocket motors, the shafts of helicopters, welded hulls, engines, pressure vessels of large dimensions, body parts for submarines, submersibles, high-load disc turbines, gears and parts gears, spindles.
Note
Maraging steel with higher structural stability in the temperature range from cryogenic to +450 °C.
Standards
| Name |
Code |
Standards |
| Classification, nomenclature and general norms |
В20 |
OST 1 90005-91 |
| Sectional and shaped rolling |
В32 |
TU 14-1-4479-88, TU 14-1-3404-82, TU 14-1-3140-81 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Al |
Ti |
Mo |
Co |
| TU 14-1-3140-81 |
≤0.03 |
≤0.01 |
≤0.01 |
≤0.1 |
≤0.3 |
≤0.1 |
17.7-19 |
The rest |
≤0.15 |
0.2-0.4 |
4.2-5 |
7.5-8.5 |
Fe is the basis.
According to TU 14-1-3404-82, the chemical composition is given for steel grade 03Н18К8М5Т-ВД (ЭК21-ВД, ВКС170ВД). Estimated content of modifiers and deoxidizers: magnesium, cerium, hafnium, germanium and boron is established by the supplier's technological instructions and their residual content in the metal is not determined by chemical analysis. A residual chromium content of up to 0.30% is allowed. In the finished product, deviations in chemical composition are permissible: for silicon and manganese, provided that their sum is not more than 0.20% for sulfur and phosphorus, provided that their sum is not more than 0.020%, for nickel by minus 0.20% .
According to TU 14-1-3140-81, the chemical composition is given for steel grade 03N18K8M5T-VD (EC21-VD, VKS170-VD). Estimated content of modifiers and deoxidizers: magnesium, cerium, hafnium, germanium and boron is established by the supplier's technological instructions and their residual content in the metal is not determined by chemical analysis. In the finished product, deviations in chemical composition are allowed: for silicon and manganese, provided that their sum is not more than 0.20%, sulfur and phosphorus, provided that their sum is not more than 0.020%, in nickel by minus 0.20 %.
According to TU 14-1-4479-88, the chemical composition is given for steel grades 03N18K8M5T-VD (EC21-VD) and 03N18K8M5T-ID (EC21-ID). In the finished product deviations in chemical composition are allowed: for silicon and manganese, provided that their amount will not be more than 0.20%; on sulfur and phosphorus, provided that their sum will not exceed 0.020%; for nickel minus 0.20%. A residual chromium content of up to 0.30% is allowed. The calculated content of modifiers and deoxidizers: magnesium, cerium, boron, etc. is established by the supplier's technological instructions and their residual content in the metal is not determined by chemical analysis.
Mechanical characteristics
| Section, mm |
sT|s0,2, MPa |
σB, MPa |
y, % |
kJ/m2, кДж/м2 |
HRC |
| Gradation of performance properties of the finished heat-treated parts for OST 1 90005-91 |
| - |
- |
1570-1810 |
- |
- |
45.5-48.5 |
| Bars hot rolled as supplied on the other 14-1-3404-82 (in the state of delivery indicate the direction of cutting out of samples) |
| - |
- |
≥1570 |
≥35 |
≥340 |
- |
| - |
- |
≥1570 |
≥50 |
≥490 |
- |
| Bars hot rolled on the other 14-1-3140-81. In the state of delivery indicated in the cutting direction of the samples. Quenching in water from 1150-1200 °C (aging for 1 h) + Quenching in water from 930-950 °C (aging for 1 h) + Quenching in air 780-800 °C (delay of 1-3 h) + Aging at 500-550 °C (exposure for 2-8 hours), air cooling |
| Образец 15х15 |
≥1470 |
≥1570 |
≥35 |
≥340 |
- |
| Образец 15х15 |
≥1470 |
≥1570 |
≥50 |
≥490 |
- |
| Bars and rods, hot rolled, forged and strip forged on the other 14-1-4479-88. In the state of delivery specified steel grade and the cutting direction of the samples. Quenching in water from 1150-1200 °C (aging 1 HR) + Triple quenching quenching in water from 930-950 °C (aging for 1 h) + Quenching in air 780-800 °C (delay of 1-3 h) + Aging at 500-550 °C (exposure for 2-8 hours), air cooling |
| 15 |
- |
≥1570 |
≥35 |
≥340 |
- |
| 15 |
- |
≥1570 |
≥50 |
≥490 |
- |
| 15 |
- |
≥1570 |
≥40 |
≥392 |
- |
| 15 |
- |
≥1570 |
≥50 |
≥490 |
- |
| The rolled bars on the other 14-1-3404-82. The longitudinal samples. Annealing in air 780-800 °C (aging 1 HR) + Aging at 490-510 °C (exposure for 2-8 hours), air cooling |
|
≥1471 |
≥1570 |
≥50 |
≥490 |
- |
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 |
| y |
The relative narrowing |
| kJ/m2 |
Toughness |
| HRC |
Rockwell hardness (indenter diamond spheroconical) |
Physical characteristics
| Temperature |
Е, ГПа |
r, кг/м3 |
a, 10-6 1/°С |
| 20 |
197 |
8120 |
80-11 |
A description of the physical symbols
| Name |
Description |
| Е |
The normal elasticity modulus |
| r |
Density |
| l |
Coefficient of thermal conductivity |
Technological properties
| Name |
The value |
| Macrostructure and contamination |
The macrostructure of the steel valley not to have shrinkage in looseness, bubbles, cracks, inclusions, brown, bundles, visible without using the magnifying devices. |
