In high-temperature pressure vessel applications, some stainless steel seamless pipes may still suffer from oxidation failure, strength degradation, or insufficient service life-even when they meet standard specifications. The key factors lie in whether the material's chemical composition control (especially silicon content), grain structure, and manufacturing grade truly satisfy the long-term operational demands under high-temperature and pressure conditions.
The EN 10216-5 1.4841 stainless steel seamless pipes we supply typically contain a relatively high silicon content (Si ≈ 1.5–2.5%), which significantly enhances oxidation resistance at elevated temperatures. Even under conditions of approximately 1000–1100°C, the material can form a stable and dense oxide protective layer, effectively preventing oxide scale spallation.In terms of grain size control, by optimizing hot working and solution annealing processes, the grain size is consistently maintained within ASTM 5–8. This ensures high-temperature strength while also improving creep resistance.
The hardness of EN 10216-5 1.4841 stainless steel pipes is generally controlled within ≤ HB 200, ensuring good workability and crack resistance. In addition, the pipes undergo standard solution annealing treatment, resulting in a uniform microstructure and fully relieved internal stresses, making them suitable for long-term service under high-temperature and pressure conditions.
We can supply seamless pipes that comply with EN 10216-5 TC2 requirements, ensuring stricter non-destructive testing (NDT) and quality control, including ultrasonic testing and leak tightness verification, thereby enhancing safety and reliability in pressure vessel applications.
Chemical Composition
| Grade | DIN 1.4841 | |
|---|---|---|
| min | max | |
| C | – | 0.015 |
| Mn | – | 2.0 |
| Si | – | 0.15 |
| P | – | 0.020 |
| S | – | 0.015 |
| Cr | 24.0 | 26.0 |
| Mo | – | 0.10 |
| Ni | 19.0 | 21.0 |
| N | – | – |
Mechanical Properties
| Grade | DIN 1.4841 | |
|---|---|---|
| Tensile Strength (MPa) min | 515 | |
| Yield Strength 0.2% Proof (MPa) min | 205 | |
| Elongation (% in 50mm) min | 40 | |
| Hardness | Rockwell B (HR B) max | 95 |
| Brinell (HB) max | 217 | |
Physical Properties
| Grade | DIN 1.4841 | |
|---|---|---|
| Density (kg/m3) | 7750 | |
| Elastic Modulus (GPa) | 200 | |
| Mean Coefficient of Thermal Expansion (m/m/0C) | 0-1000C | 15.9 |
| 0-3150C | 16.2 | |
| 0-5380C | 17.0 | |
| Thermal Conductivity (W/m.K) | at 1000C | 14.2 |
| at 5000C | 18.7 | |
| Specific Heat 0-1000C (J/kg.K) | 500 | |
| Electrical Resistivity (n.m) | 720 | |
What is the maximum continuous service temperature for 1.4841?
In an air environment, the upper limit of 1.4841's oxidation resistance reaches 1150°C. If used as a pressure-bearing component (such as a heat exchanger tube), its allowable stress at various temperatures must be determined in accordance with EN 10216-5 and the relevant pressure vessel design codes. Typically, above 900°C, its strength decreases rapidly as the temperature rises.
Applications
1. Food processing equipment, particularly in beer brewing, milk processing & wine making.
2. Kitchen benches, sinks, troughs, equipment and appliances
3. Architectural panelling, railings & trim
4. Chemical containers, including for transport
5. Heat Exchangers
6. Woven or welded screens for mining, quarrying & water filtration
Our Advantages
By utilizing precise heat treatment temperature profiles, we ensure that the grain size meets the required creep strength specifications, thereby preventing elongation and deformation of the tubes under high-temperature conditions of 1000°C.
All our 1.4841 seamless tubes are supplied as standard in accordance with the EN 10216-5 TC2 grade. This includes 100% Ultrasonic Testing (UT) and 100% Eddy Current Testing (ET).
We are able to provide our customers with a comprehensive set of Welding Procedure Specifications (WPS) as well as post-installation maintenance manuals.
Packaging and Marking:
The products shall be packaged in bundles or plywood crates, wrapped in plastic, and provided with appropriate protective measures to ensure seaworthy transport, or packaged in accordance with specific requirements.
Markings shall indicate whether the tubing is hot-worked or cold-worked, and shall include-but not be limited to-the following information: standard, grade, dimensions, heat number, and batch number.
FAQ
Q: What is "Sigma (σ) Phase Embrittlement" in 1.4841?
A: Due to its extremely high chromium content (24–26%), prolonged operation of 1.4841 within the temperature range of 600°C to 900°C leads to the precipitation of a hard and brittle sigma (σ) phase within its microstructure. When procuring this material, it is essential to ensure that the tubing has undergone a thorough solution annealing treatment (heating to 1050–1150°C followed by rapid cooling).
Q: Why are 1.4841 seamless tubes prone to cracking during the tube-expanding process in heat exchangers?
A: This is typically caused by two factors:
Work Hardening: The high silicon and alloy content of 1.4841 naturally results in a higher hardness level compared to grades such as 304 or 316L. If the solution heat treatment is incomplete-resulting in excessive hardness (exceeding 223 HBW)-cracking may occur during the tube-expanding process.
Excessive Grain Size: If the heat treatment temperature is excessively high or the holding time is too prolonged, it can lead to abnormally coarse grain structures, which subsequently reduces the material's ductility.
Q: Is 1.4841 resistant to chloride-induced Stress Corrosion Cracking (SCC)?
A: No, it is not. Although 1.4841 contains approximately 20% nickel-offering better resistance than grade 304-it still remains susceptible to the risk of stress corrosion cracking in acidic environments containing chloride ions or in high-temperature aqueous environments.