GOST 9941-81 12X18H12T Seamless Stainless Steel Tube: Specifications
Nov 06, 2025
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What is GOST 9941-81 12X18H12T?
GOST 9941-81 is the standard for seamless stainless steel pipes, covering both cold-worked and hot-worked manufacturing processes. Grade 12X18H12T is a titanium-stabilized austenitic stainless steel specified by this standard; the addition of titanium allows for the control of carbon content during service and ensures that the pipes retain good resistance to intergranular corrosion after welding or exposure to temperatures in the 450–850°C range. This grade corresponds to AISI 321 (UNS S32100), GB 06Cr18Ni11Ti, JIS SUS321, and DIN X6CrNiTi18-10 (W.Nr. 1.4541).
12X18H12T stainless steel Equivalent materials
GOST 9941-81 applies to seamless tubes for general service and for petrochemical, power and heat-exchange equipment.
| Standard | Grade designation |
|---|---|
| GOST 9941-81 / GOST 5632 | 12X18H12T |
| ASTM | AISI 321 / UNS S32100 |
| GB | 06Cr18Ni11Ti |
| JIS G3463 | SUS321TP |
| EN 10088 / DIN | X6CrNiTi18-10 / 1.4541 |
GOST 9941-81 12X18H12T Chemical composition
| Element | Requirement |
|---|---|
| Carbon | 0.12 max |
| Silicon | 0.80 max |
| Manganese | 2.00 max |
| Phosphorus | 0.035 max |
| Sulfur | 0.020 max |
| Chromium | 17.00 - 19.00 |
| Nickel | 11.00 - 13.00 |
| Titanium | 0.50 - 0.70 |
Mechanical Properties (at Room Temperature)
| Property | Value (Metric) | Value (Imperial/Other) |
| Tensile Strength (σb) | ≥ 529 MPa | ≥ 54 kgf/mm² |
| Yield Strength (σ0.2) | ≥ 196 MPa (Typical) | ≥ 20 kgf/mm² |
| Elongation (δ5) | ≥ 37% | - |
| Hardness (HB) | ≤ 179 | (Annealed state) |
Requirements & Dimensional Tolerances
| Feature | Requirement |
| Delivery Condition | Heat treated (Solution Annealed) and Pickled |
| Surface Finish | Free from cracks, scales, laps, and deep pits. Minor scratches/dents within tolerance are allowed. |
| Curvature (Straightness) | ≤ 1.5 mm per 1 meter length (for wall thickness > 0.5 mm) |
| Outside Diameter (OD) Tolerance | ±0.8% to ±1.2% (depending on precision class) |
| Wall Thickness (WT) Tolerance | ±10% to ±12.5% (depending on precision class) |
What is the difference between 12X18H12T and 12X18H10T?
The nickel content differs: 12X18H12T has a higher nickel content (11–13%), whereas 12X18H10T typically contains 9–11%. This higher nickel content provides superior microstructural stability, as well as greater ductility and toughness-particularly in environments involving extremely low temperatures or prolonged exposure to high heat. Additionally, 12X18H12T offers slightly better resistance to intergranular corrosion and improved workability.
GOST 9941-81 12X18H12T Stainless Steel Tube Applications
Chemical and petrochemical industries: Transport of highly corrosive media.
Power engineering: Heat exchanger tubes and boiler tubes.
Nuclear industry: Piping in nuclear reactor systems.
Aerospace: Exhaust systems and heat-resistant components.
For further details, please provide the following information:
Required outer diameter and wall thickness; intended application or operating temperature; and any requirements for certifications or test data (such as hydrostatic testing or ultrasonic inspection).
Delivery Condition
In accordance with the standard, the material is typically supplied in a **heat-treated (solution annealed) and pickled** condition. The tube surface should be free of scale and exhibit a matte, grayish-white finish (2B or industrial finish).
FAQ
Q1: What does 12X18H12T correspond to in ASTM terms?
A1: It corresponds to AISI 321, UNS S32100, and in EN terms to X6CrNiTi18-10 (W.Nr. 1.4541).
Q2: Why is titanium added to 12X18H12T?
A2: Titanium is a strong carbide former; it combines with carbon so that chromium remains in solid solution, reducing susceptibility to intergranular corrosion after welding or after service at 450-850 degree C.
Q3: What heat treatment is applied?
A3: The tube is supplied solution annealed; a stabilization treatment around 850-900 degree C may be applied when maximum intergranular corrosion resistance is required.
Q4: What dimension range does GOST 9941-81 cover?
A4: Outside diameters from 6 mm to 610 mm and wall thicknesses from 0.5 mm to 30 mm, depending on the manufacturing route.
Q5: Is 12X18H12T suitable for welded construction?
A5: Yes, the stabilized chemistry is specifically intended for welded assemblies, and the grade is widely used for welded heat-exchanger tubing in petrochemical service.
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