ASTM B283 C70620 Copper Weld Neck RF Flange

The ASTM B283 standard refers to the specifications for copper and copper alloy seamless and welded pipe, fittings, and flanges. C70620 is a specific alloy designation under the copper family.
UNS C70620 alloy is an alloy of copper (the largest single base metal) and nickel, with or without other elements, of which zinc may not exceed 1%. When other elements are present, nickel is second only to copper in individual content compared to the others. As with other copper alloys, it is necessary to distinguish between wrought alloys processed into semi-finished products and cast alloys produced by various casting processes. Copper-nickel alloys with the addition of manganese are important in electrical engineering. The addition of iron significantly increases the corrosion resistance of copper-nickel alloys in flowing seawater and other corrosive waters.
Copper alloys have very good resistance to seawater, brines, organic compounds, salts, dilute non-oxidizing acids, etc. UNS C70620 is a copper-nickel-iron alloy with a low manganese content that has excellent resistance to seawater and brackish water. Of all commercial copper alloys, CuNi 70/30 (C71500) has the best resistance to aqueous corrosion. It is resistant to acid solutions and highly resistant to stress corrosion cracking and impact corrosion. In addition, CuNi70/30 provides greater strength for higher pressures.
It's important to note that this type of steel needs proper heat treatment to achieve its full mechanical properties and should be used with care to prevent cracking during welding or fabrication processes. Always consult the specific manufacturer's guidelines for best practices and application recommendations.
A "WN RF" flange refers to a type of flange. "WN" stands for "weld neck," which means that the flange is attached to a pipe by welding onto a weld neck that extends from the pipe. "RF" stands for "reduced face," indicating that the flange has a reduced diameter at the flange face, which provides better fluid flow characteristics than a full face flange.

The hot strength of copper increases with the addition of only a small amount of nickel. The mechanical properties are improved by the addition of iron, not only at room temperature, but also at elevated temperatures. 10% nickel. For example, CuNi10Fe1Mn can be used for pressure vessel structures up to 300°C, and CuNi30Mn1Fe up to 350°C. Above these limiting temperatures, the strength decreases significantly, especially the creep strength and creep strain limit.

In general, heat treatments are only used for copper-nickel alloys for soft annealing and stress relief. The temperature of the recrystallization annealing can vary in a wide range between about 620 and 900°C, depending on the degree of cold working, the nickel content and other components. High temperatures are associated with short annealing times (continuous annealing), low temperatures with long annealing times (static annealing). Stress relief annealing is carried out at 280 to 500°C. It is recommended to anneal in an atmosphere excluding air or slightly reducing to avoid pickling in an annealing atmosphere containing air.

• Chemical Processing Industries
• Pharmaceutical Manufacturin
• Petrochemical Industry
• Power Generation
• Marine Applications
• Nuclear Industries