Reliable Steel is well known for the high-quality Super Duplex pipes that we source and stock for our discerning clients around the world. We can provide a different grades of super duplex pipes, such as A/SA 789 tube, A/SA 790 pipes.
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Super duplex stainless steel is a high-performance alloy that combines the strengths of both austenitic and ferritic stainless steels. It is known for its superior corrosion resistance, high strength, and toughness, making it suitable for demanding applications in harsh environments like offshore oil and gas, and chemical processing.
ASTM/ASME A789 and ASTM A790 are standards for super duplex stainless steel pipes and tubes, with SA789 covering both seamless and welded tubes and SA790 covering both seamless and welded pipes. These specifications are for high-performance, corrosion-resistant materials used in applications like oil and gas, chemical processing, and marine engineering, due to their excellent strength and resistance to pitting and stress corrosion cracking.
| Feature | ASTM A789 / ASME SA789 | ASTM A790 / ASME SA790 |
|---|---|---|
| Product Type | Tubing (smaller sizes, typically used for heat exchangers, boilers, etc.) | Pipes (larger sizes, generally used for fluid/gas transport and structural applications) |
| Dimensions | Based on outside diameter (OD) and wall thickness, often in Birmingham Wire Gauge (BWG) | Based on Nominal Pipe Size (NPS) and schedule numbers (e.g., Sch 40, Sch 80) as per ASME B36.10M and B36.19M |
| Manufacturing | Seamless or welded (automatic welding without filler metal) | Seamless or welded (automatic welding without filler metal) |
| Heat Treatment | Mandates a final solution annealing and rapid cooling/water quenching | Mandates a final solution annealing and rapid cooling/water quenching |
| Testing | Hydrostatic or non-destructive electric testing (Eddy Current, UT) | Hydrostatic or non-destructive electric testing (Eddy Current, UT) |
Super duplex grades, such as UNS S32750 and UNS S32760, contain higher levels of chromium, molybdenum, and nitrogen compared to standard duplex steels, providing enhanced pitting and crevice corrosion resistance (Pitting Resistance Equivalent value > 40).
Duplex stainless steel pipes and tubes are used in demanding industries due to their high durability, strength, and resistance to corrosion and stress corrosion cracking.