SA179 Cold-Drawn Seamless Steel Tubes
Material and Composition
The material is low-carbon steel (carbon content ≤0.06%) with a densified microstructure achieved through cold-drawing.
Key Performance Characteristics
Thermal Conductivity: Thermal conductivity reaches 45-50 W/(m·K), significantly higher than ordinary carbon steel pipes, making it ideal for heat exchange applications.
Mechanical Strength: Tensile strength ≥ 325 MPa, yield strength ≥ 180 MPa, maintaining structural stability even under high-temperature conditions.
Dimensional Accuracy: Outer diameter tolerance controlled within ±0.10 mm, wall thickness deviation not exceeding ±10%, ensuring sealing performance during equipment assembly.
Surface Quality: After acid pickling and phosphating, surface roughness Ra ≤ 0.8 μm, effectively reducing fluid resistance.
Corrosion Resistance
The material demonstrates superior performance in sulfide stress corrosion environments compared to 304 stainless steel, which is a key factor in its long-term application in petrochemical equipment.
Production and Certification
According to product data from Baidu Aiqicha, domestic leading manufacturers have passed international certifications such as ASME and PED. Their SA179 steel tubes can operate continuously for over 100,000 hours at 450℃.
SA-210 Gr.A1 Seamless Steel Tubes
Standard and Composition
The material follows ASME SA-210/SA-210M, an ASME standard for seamless steel tubes used in boilers and superheaters.
Chemical Composition
Carbon (C): ≤0.27% (provides strength but reduces toughness and weldability if excessive).
Manganese (Mn): 0.29%–0.93% (enhances strength, toughness, and hot workability).
Silicon (Si): ≥0.10% (used for deoxidation and strength improvement, aids oxidation resistance).
Phosphorus (P) and Sulfur (S): ≤0.035% (excess reduces toughness, causing hot/ cold brittleness).
Mechanical Properties
Tensile Strength: ≥415 MPa (resists fracture under high stress).
Yield Strength: ≥255 MPa (prevents irreversible deformation under normal pressure).
Elongation: ≥30% (ensures energy absorption during impact or overload).
Inspection and Testing
Visual Inspection: Checks for cracks, folds, laps, delamination, and scale defects. Surface imperfections (e.g., scratches, dents) must meet allowable limits.
Dimensional Accuracy: Measures outer/inner diameter, wall thickness, and length. Tolerances strictly controlled for high-pressure/high-temperature applications.
Mechanical Tests: Includes tensile tests (yield strength, tensile strength, elongation) and impact tests (low-temperature toughness).
Non-destructive Testing: Uses ultrasonic and eddy current testing to detect internal/external defects.
Applications
Used in power plant boilers (water walls, economizers, low-temperature superheaters, headers, and steam pipes) requiring high-temperature/high-pressure resistance and excellent heat transfer.
Chemical Composition Comparison
| Element | ASME SA179 / SA179M | ASME SA-210 Gr.A1 |
|---|---|---|
| Carbon (C) | 0.06–0.18% | ≤0.27% |
| Manganese (Mn) | 0.27–0.63% | 0.29–0.93% |
| Silicon (Si) | ≤0.37% (no lower limit specified) | ≥0.10% (explicit deoxidation requirement) |
| Phosphorus (P) | ≤0.035% | ≤0.035% |
| Sulfur (S) | ≤0.035% | ≤0.035% |
| Other Elements | No Cr, Ni, Mo alloy requirements | No Cr, Ni, Mo alloy requirements |
Mechanical Properties Comparison
| Property | ASME SA179 / SA179M | ASME SA-210 Gr.A1 |
|---|---|---|
| Tensile Strength | ≥325 MPa | ≥415 MPa |
| Yield Strength | ≥180 MPa | ≥255 MPa |
| Elongation | ≥35% | ≥30% |
| Hardness | ≤72 HRB | ≤79 HRB |