ASTM A179/A192 Boiler Tubes: High-Pressure Seamless Tubing for Steam & Heat Exchangers.
Seamless Tubes (21.3–711mm OD, 2.3–40mm WT) with 360–530 MPa Tensile Strength.
Certified to ASTM A179 (low-carbon) and ASTM A192 (medium-carbon), these tubes handle 12–40 MPa steam pressure in boilers, condensers, and superheaters up to 650°C (1,202°F). Available in 5.8–12m fixed lengths with bevelled/threaded ends, they achieve ±1% OD precision via cold-drawn manufacturing.
Key Features:
- Temperature Resilience: -20°C to 650°C (-4°F to 1,202°F)
- Pressure Rating: 15–55 MPa (2,175–7,975 psi)
- Certifications: ASME SA179, EN 10216-2, ISO 9330-2
Technical Specifications
Dimensional Tolerances (GB3087/GB5310)
| Parameter | Tolerance | Standard |
|---|---|---|
| OD ≤180mm | ±1% (min ±0.5mm) | GB3087 |
| OD >180mm | ±1% | GB5310 |
| WT 3–20mm | +15%/-12.5% | GB3087 |
| WT >20mm | ±12.5% | GB5310 |
Mechanical Properties (DIN 17175)
| Grade | Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|---|
| St35.8 | 360–480 MPa | ≥235 MPa | ≥25% | ≤80 HRB |
| St45.8 | 410–530 MPa | ≥255 MPa | ≥21% | ≤85 HRB |
Material Composition & Manufacturing
Chemical Analysis (St35.8 Example)
- Carbon: ≤0.17%
- Silicon: 0.10–0.35%
- Manganese: 0.40–0.80%
- Phosphorus: ≤0.030%
- Sulfur: ≤0.030%
Production Process:
- Cold Drawing: Reduces OD to ±0.5mm precision (EN 10216-2).
- Stress Relieving: Heated to 650°C (1,202°F) for residual stress removal.
- Testing: Eddy current + hydrostatic tests at 1.5×MAOP.
Applications & Competitive Advantages
- Power Plant Superheaters:
- 76mm OD, 8mm WT St45.8: 540°C steam at 25 MPa (ASME B31.1).
- Chemical Heat Exchangers:
- 114mm OD, 10mm WT A179: 40 MPa glycol circuits (EN 13480-3).
- Industrial Boilers:
- 219mm OD, 16mm WT St35.8: 15 MPa saturated steam generation.
Advantages vs. Competitors:
- Oxidation Resistance: 0.5mm/year scaling rate at 600°C (ASTM G54).
- Weldability: Preheat to 200°C (392°F) for crack-free GTAW joints.
Quality Assurance & Packaging
- NDT Protocols:
- Ultrasonic Testing: ASTM E213 for flaws ≥0.3mm depth.
- Hardness Testing: 10-point Rockwell B per 50 tubes.
- Surface Protection:
- Phosphated + oiled (ISO 9712) or black varnish.
- Export Packaging:
- Wooden crates with PVC sleeving (max 5-ton bundles).
Packing And Delivery
