ASTM B474 is a widely recognized standard that specifies the requirements for Electric-Fusion-Welded (EFW) pipes made from Nickel-Chromium-Iron Alloy, commonly known as UNS N08020 or Alloy 20. This alloy is particularly valued for its outstanding resistance to corrosion, especially in environments exposed to sulfuric acid and other aggressive chemicals. Its composition includes nickel, chromium, and iron, with added elements like copper and molybdenum to further enhance its durability and performance in harsh conditions.
One of the key advantages of ASTM B474 UNS N08020 EFW Nickel Alloy Pipe is its excellent corrosion resistance, which makes it ideal for use in chemical processing, petrochemical, food and beverage, and pharmaceutical industries. The alloy also offers good weldability, making it suitable for electric-fusion welding techniques that ensure strong and consistent joints. In addition, it provides high mechanical strength combined with good ductility, allowing it to perform reliably under various stress conditions.
The chemical composition of Alloy 20 typically includes:
- Nickel (Ni): 32–38%
- Chromium (Cr): 19–21%
- Iron (Fe): Balance
- Molybdenum (Mo): 2–3%
- Copper (Cu): 3–4%
Other trace elements such as carbon, manganese, silicon, phosphorus, sulfur, and columbium are also present in small quantities.
This type of pipe is commonly used in applications such as storage tanks, mixing vessels, heat exchangers, process piping, pickling equipment, and specialized chemical and pharmaceutical systems. The EFW manufacturing process ensures a uniform and high-quality weld, resulting in a seamless and durable product.
Pipes produced under ASTM B474 must pass a series of rigorous tests, including tensile testing, hardness testing, chemical composition analysis, hydrostatic testing, and non-destructive examination. These tests guarantee that the material meets strict quality standards and performs reliably in demanding environments.
Below is an overview of some common material grades covered under ASME SB474 / ASTM B474:
| Material Grade | Description |
|----------------------|-------------|
| UNS N02200 | Pure Nickel |
| UNS N02201 | Nickel-Copper Alloy |
| UNS N04400 | Nickel-Molybdenum Alloy |
| UNS N06002 | Monel 400 |
| UNS N06022 | Incoloy 825 |
| UNS N08825 | Inconel 625 |
| UNS N10276 | Hastelloy C-276 |
| UNS N10665 | Hastelloy B-3 |
| UNS N10675 | Hastelloy C-22 |
| UNS N08026 | Alloy 26 |
| UNS N06030 | Inconel 600 |
| UNS N06200 | Inconel 620 |
| UNS N06230 | Inconel 625 |
| UNS N06600 | Inconel 600 |
| UNS N06601 | Inconel 601 |
| UNS N06625 | Inconel 625 |
| UNS N06985 | Inconel 985 |
| UNS N08020 | Alloy 20 |
Available sizes range from 1/2'' to 48'', with wall thicknesses ranging from SCH5 to SCHXXS. Ends can be either beveled or plain, and the length is customizable based on customer needs. Standard export packaging is provided, but custom options are available upon request.
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