Quick Summary
DIN 1629 is a German industrial standard that specifies the technical delivery conditions for seamless circular steel tubes primarily used for pressure purposes. These pipes are known for their high strength, uniformity, and ability to withstand high internal pressures, making them suitable for critical applications in boilers, heat exchangers, and pipelines.
The standard has been largely superseded by the European standard EN 10216, but the name "DIN 1629" is still widely used in industry.
1. What is DIN 1629?
DIN 1629 is a material standard that covers seamless steel pipes made from non-alloy and alloy quality steels designed for elevated temperatures. The key characteristic is that the pipes are seamless, meaning they are formed from a solid billet without a welded seam. This eliminates a potential weak point, making them ideal for high-pressure applications.
2. Key Characteristics and Applications
Seamless Construction: No longitudinal weld, offering superior strength and pressure integrity.
Pressure Resistance: Designed to contain liquids and gases under high pressure.
High-Temperature Service: The specified steel grades retain their strength at elevated temperatures.
Precise Dimensions: Governs outside diameters, wall thicknesses, and tolerances.
Typical Applications:
Power Generation: Boiler tubes, superheater tubes, and high-pressure steam lines.
Petrochemical Industry: Refinery pipelines, heat exchangers, and pressure vessels.
Mechanical and Plant Engineering: Hydraulic cylinders, high-pressure fluid systems.
Construction: For structural purposes where high strength is required (though DIN 2448/EN 10255 is more common for general structural use).
3. Steel Grades and Their Properties
DIN 1629 is divided into several parts, each covering different material grades. The most common parts are:
| Part | Former Designation | Current EN 10216 Equivalent | Key Properties & Uses |
|---|---|---|---|
| DIN 1629 Part 1 | St 35.8, St 44.8, St 52.8 | EN 10216-2 (e.g., P235GH, P265GH) | Non-alloy steels for elevated temperatures. Good weldability and formability. Common for general pressure applications. |
| DIN 1629 Part 2 | 15Mo3, 13CrMo44, 10CrMo910 | EN 10216-2 (e.g., 16Mo3, 13CrMo4-5, 10CrMo9-10) | Alloy steels with Molybdenum (Mo) and/or Chromium (Cr) for higher temperature and corrosion resistance. Used in power plants. |
| DIN 1629 Part 3 | 14MoV63, 12CrMo19-5 | EN 10216-2 | Highly alloyed steels for special high-temperature and high-pressure services. |
| DIN 1629 Part 4 | Various Stainless Grades | EN 10216-5 (e.g., 1.4301, 1.4404, 1.4541) | Seamless stainless steel tubes for corrosion resistance at high temperatures. |
Important Note: When ordering or specifying, it is now standard practice to use the EN 10216 designation. For example, instead of "DIN 1629 St35.8," you would specify "EN 10216-2 P235GH".
4. Comparison with Other Common Pipe Standards
| Feature | DIN 1629 / EN 10216 | ASTM A106 / A53 (USA Standard) | DIN 2448 / EN 10255 (Threaded Pipe) |
|---|---|---|---|
| Primary Use | High-pressure, high-temperature systems | Pressure and high-temperature service | General purpose, low-pressure, structural |
| Manufacture | Seamless (and welded for some EN grades) | Seamless (A106) / Seamless & Welded (A53) | Usually welded |
| Key Feature | Precise chemistry for creep strength | Similar to DIN 1629, widely used globally | Has a threadable wall thickness, less precise |
| Common Grades | P235GH, 16Mo3, 13CrMo4-5 | A106 Grade B, A53 Grade B | S235JRH, E235 |
5. How to Specify and Order DIN 1629 Pipes
When ordering, you should provide a complete specification. Since DIN 1629 is obsolete, it's best to use the EN 10216 standard. A typical specification looks like this:
Seamless Steel Tube - EN 10216-2 - P235GH
Standard: EN 10216-2
Grade: P235GH
Dimensions: e.g., 114.3 mm OD x 6.3 mm WT (Wall Thickness)
Length: e.g., 6000 mm (random or fixed length)
Test Category: e.g., Category III (for stringent non-destructive testing)
Delivery Condition: e.g., +N (Normalized)
Conclusion
While DIN 1629 was the foundational German standard for high-quality seamless pressure tubes, it has been successfully integrated into the European EN 10216 series. The principles of high strength, pressure integrity, and suitability for elevated temperatures remain the same. When working with these pipes today, you will almost always encounter the EN 10216 designation, but understanding its origin as DIN 1629 is crucial for historical context and communication in certain industrial sectors.
