GOST 9941 20KH23N18 (20X23H18) Stainless Steel Seamless Tube | AISI 310S
GOST 9941-22 20KH23N18 (also written as 20X23H18) stainless steel seamless tube is a high-temperature austenitic stainless steel tube designed for heat-resistant and corrosion-resistant service. Equivalent to AISI 310S / UNS S31008, this chromium-nickel alloy offers excellent oxidation resistance and structural stability at elevated temperatures.
Manufactured in accordance with GOST 9941-22, these seamless stainless steel tubes are widely used in furnaces, heat treatment equipment, petrochemical plants, and high-temperature industrial systems.
What Is GOST 9941-22?
GOST 9941-22 is the Russian standard specification for seamless stainless steel tubes used in corrosion-resistant and heat-resistant applications.
It defines:
-
Chemical composition requirements
-
Mechanical properties
-
Manufacturing processes
-
Dimensional tolerances
-
Testing and inspection procedures
GOST 9941 tubes are commonly specified for CIS, Russian, and Eastern European industrial projects.
Material grade – 20KH23N18 / 20X23H18
20KH23N18 (20X23H18) is a high-alloy austenitic stainless steel containing:
-
Chromium ~23%
-
Nickel ~18%
-
Low carbon content
This composition provides:
-
Excellent resistance to oxidation up to 1000°C
-
Good resistance to scaling
-
Stable austenitic microstructure
-
Good weldability
The grade is commonly considered equivalent to AISI 310S.
Equivalent Grades
| Standard | Grade |
|---|---|
| GOST | 20KH23N18 / 20X23H18 |
| AISI | 310S |
| UNS | S31008 |
| EN | 1.4845 |
| ASTM | A312 TP310S |
Common search terms:
-
20X23H18 equivalent
-
20KH23N18 vs 310S
-
GOST 9941 stainless steel tube
Chemical Composition (Typical %)
| Element | Content |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Chromium (Cr) | 22.0 – 25.0 |
| Nickel (Ni) | 17.0 – 20.0 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.00 |
High chromium ensures oxidation resistance, while high nickel stabilizes the austenitic phase at elevated temperatures.
Mechanical Properties (Room Temperature)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 520 MPa |
| Yield Strength | ≥ 210 MPa |
| Elongation | ≥ 40% |
At elevated temperatures, 20KH23N18 maintains good creep resistance and structural stability.
High Temperature Performance
20KH23N18 / AISI 310S seamless tubes are suitable for:
-
Continuous service up to 1000–1050°C
-
Intermittent exposure up to 1100°C
-
Furnace components
-
Heat exchangers
-
Thermal processing equipment
Compared with 304 or 316 stainless steel, 310S offers significantly better oxidation resistance.
Manufacturing & Heat Treatment
Product Type: Seamless stainless steel tube
Manufacturing: Hot finished / Cold drawn
Heat Treatment: Solution annealed
All tubes are supplied clean, scale-free, and fully compliant with GOST 9941-22 requirements.
Size Range
-
Outside Diameter: 6 mm – 426 mm
-
Wall Thickness: 1.0 mm – 40 mm
-
Length: Random or fixed
-
Custom sizes available
Inspection & Testing
GOST 9941 seamless tubes undergo:
-
Chemical analysis
-
Mechanical testing
-
Hydrostatic testing
-
Non-destructive testing
-
Dimensional inspection
Mill Test Certificates available upon request.
Applications
-
Industrial furnaces
-
Petrochemical plants
-
Heat treatment systems
-
Power generation
-
High-temperature exhaust systems
-
Kilns and thermal reactors
20KH23N18 stainless steel seamless tubes are ideal for severe high-temperature industrial environments.
GOST 9941-22 AISI 310S Stainless Steel Seamless Tube
FAQ
What is 20X23H18 equivalent to?
20X23H18 is equivalent to AISI 310S and UNS S31008.
Is 20KH23N18 suitable for high-temperature service?
Yes, it is designed for oxidation resistance up to approximately 1000°C.
What is the difference between 310 and 310S?
310S has lower carbon content, improving weldability and reducing carbide precipitation.
