DIN 1629 Seamless Steel Pipe Product Overview
DIN 1629 Seamless Pipes are non-alloy carbon steel tubes optimized for low/medium-pressure systems in chemical plants, machinery, and structural frameworks. With grades like St37 (1.0254), St44 (1.0255), and St52 (1.0421), these pipes deliver 235–355 MPa yield strength at ≤300°C, balancing weldability and load-bearing capacity. Compliant with EN 10297-1 standards, they replace ASTM A53 and JIS G3441 in applications requiring ±0.5% OD precision and S355JR-grade structural performance.
Key Technical Specifications
1. Dimensional & Manufacturing Properties
- Size Range:
- Cold-Drawn: 10.2 mm (0.4″) – 273 mm (10.7″) OD | Wall Thickness: 1.25–25 mm
- Hot-Rolled: 273 mm – 1,220 mm (48″) OD | Wall Thickness: 10–50 mm
- Tolerances:
- OD: ±0.5% (cold-drawn), ±1.0% (hot-rolled)
- Wall Thickness: +10%/-10% (DIN 1629-1)
- Surface Treatments:
- Black (Mill Finish): Rust-resistant oxide layer for outdoor structures
- Bright Annealed: Ra ≤1.6 µm for hydraulic cylinders
2. Mechanical & Chemical Performance
Chemical Composition:
| Grade | C | Mn | P | S | Deoxidation | Key Feature |
|---|---|---|---|---|---|---|
| St37 | ≤0.17% | 0.40–1.20% | ≤0.040% | ≤0.040% | R (Rimmed) | High ductility (A5 ≥25%) |
| St44 | ≤0.21% | 0.40–1.30% | ≤0.040% | ≤0.040% | R (Rimmed) | 420–550 MPa tensile |
| St52 | ≤0.22% | 1.30–1.70% | ≤0.040% | ≤0.035% | RR (Killed) | 355 MPa yield @ 65 mm WT |
Mechanical Properties:
| Grade | Yield (MPa) | Tensile (MPa) | Elongation (%) | Hardness (HB) | Impact (J @ 20°C) |
|---|---|---|---|---|---|
| St37 | 235 (WT <16 mm) | 350–480 | ≥25 | ≤130 | ≥27 |
| St44 | 275 (WT <16 mm) | 420–550 | ≥21 | ≤160 | ≥25 |
| St52 | 355 (WT <16 mm) | 500–650 | ≥21 | ≤190 | ≥40 |
Pressure Ratings:
| OD (mm) | St52 Wall (mm) | Max Pressure @ 20°C (bar) | Burst Strength (bar) |
|---|---|---|---|
| 88.9 | 5.0 | 320 | 960 |
| 219.1 | 12.7 | 260 | 780 |
Applications by Industry
| Industry | Use Case | Grade | Key Benefit |
|---|---|---|---|
| Chemical Plants | Process water pipelines (≤30 bar) | St44 | EN 10297-1 compliance |
| Construction | Scaffolding, support columns | St37 | 25% cost savings vs. S355 |
| Material Handling | Conveyor roller shafts | St52 | 355 MPa yield handles 5-ton loads |
| Hydraulics | Low-pressure cylinder barrels | St37 + Bright Annealed | Ra ≤1.6 µm surface |
Global Standard Equivalents
| Germany (DIN) | USA (ASTM) | Europe (EN) | Japan (JIS) |
|---|---|---|---|
| St37 (1.0254) | A106 Gr. A | EN 10297-1 E235 | STKM 13A |
| St52 (1.0421) | A53 Gr. B | EN 10297-1 E355 | STKM 18C |
Certifications & Compliance
- Testing: Tensile (DIN EN ISO 6892-1), Impact (DIN EN ISO 148-1)
- Certifications: TÜV Rheinland, ISO 9001:2015, PED 2014/68/EU (Category I)
Packing And Delivery
