A Ni-Cu alloy with high strength and good corrosion resistance

• Excellent resistance to hydrofluoric acid
• Excellent resistance to sea water for marine applications
• High strength metal with good toughness at high temperatures
• Cryogenic usability
• In-depth information on grades 400 and K500
• Datasheets available for Monel 400 and Monel K500
• Weld neck flange features and benefits

Strength & Saltwater Resistance
Monel® socket head cap screws are made from a nickel-copper alloy that exhibits high strength, toughness and good corrosion resistance. Renowned for the saltwater corrosion resistance, Monel is the go-to material by the navy. It is often used in many other marine applications for its combination of high strength and seawater resistance. Monel screws are even resistant to rapid moving seawater and will last many years in saltwater conditions.
 
Strength and Toughness from Cryogenic to 1000°F
Monel socket head cap screws offer excellent mechanical properties over a wide temperature range from cryogenic up to 1000°F. In US Navy tear tests at temperatures as low as -320°F, Monel 400 has displayed excellent ductility and toughness. In fact, it has shown little decrease in impact resistance when tested on plates at liquid-hydrogen and liquid-helium temperatures.
 
Monel K500 is an age hardened alloy, known for extreme strength even at high temps. But it is also excellent for cryogenic service. Monel K500's tensile and yield strength increase - with little or no change to ductility and toughness - even at the temperature of liquid hydrogen.
 
Excellent Resistance to Hydrofluoric Acid
One of the most outstanding characteristics of Monel socket head cap screws is that they offer exceptional resistance to hydrofluoric acid (HF), a particularly tough acid to deal with, in all concentrations up to the boiling point. For hydrofluoric acid applications Monel screws are perhaps the most resistant of all commonly used specialty alloys.

The most common grades of Monel nickel alloy flanges are Monel 400 and Monel K500 . Gain more insight on these two grades by accessing our Monel 400 and K500 overviews or by contacting our engineering experts.

Resources: Monel Torque Spec, Flange Dimensions, Flange Bolting Chart, Monel 400, Monel K500

Flange Types Available: Blind Flanges, Lap Joint Flanges, Slip On Flanges, Socket Weld Flanges, Threaded Flanges, Weld Neck Flanges

Common Grades of Monel Weld Neck Flanges

Monel 400 

Monel 400, UNS N04400 (QQ-N-281), is a nickel-copper alloy with high strength and excellent corrosion resistance in a range of media including sea water, hydrofluoric acid, sulfuric acid, and alkalies. Monel 400 is commonly in marine engineering, chemical and hydrocarbon processing applications.

Monel 400 Specifications: BS3075NA13 (Wire), BS3076NA13 (Bar), ASTM B 164 (Rod, Bar, and Wire), ASTM B 564 (Forgings), ASME SB 164 (Rod, Bar, and Wire), ASME SB 564 (Forgings), AECMA PrEN 2305 (Wire for Rivets), SAE AMS 4675 (Bars and Forgings), SAE AMS 4730 (Wire), SAE AMS 4731 (Wire and Ribbon), DIN 17752 (Rod and Bar), DIN 17753 (Wire), DIN 17754 (Forgings), VdTÜV 263 (Sheet, Plate, Bar, and Tubing), QQ-N-281 (Plate, Sheet, Strip, Bar, Rod, Wire, and Forgings), Werkstoff 2.4360

Monel K500 

Monel K500, UNS N05500 (QQ-N-286),  is a precipitation-hardenable nickel-copper alloy that combines the corrosion resistance of Monel alloy 400 with greater strength (over 2x as strong) and hardness. It also has low permeability and is nonmagnetic to temperatures as low as -150°F (-101°C). 

Monel K500 Specifications: BS3075NA18 (Wire), BS3076NA18 (Rod and Bar), ASTM B 865 (Rod and Bar), DIN 17752 (Rod and Bar), DIN 17753 (Wire), DIN 17754 (Forgings), QQ-N-286 (Rod, Bar, Wire, and Forgings), SAE AMS 4676 (Rod and Bar), ASME Code Case 1192 (Rod and Bar), ISO 9723 (Bar), ISO 9724 (Wire), ISO 9725 (Forgings), Werkstoff 2.4375

 Mechanical Properties of Monel

Monel 400 Corrosion Data

Monel Weld Neck Flange Features & Benefits

Monel weld neck flanges are best for hazardous, high pressure applications. Weld neck flanges are easily identified by their long tapered neck. The inside of the flange is bored to match the inside diameter of the pipe in order to ensure there is no restriction in flow and also to prevent turbulence at the joint. The tapered neck provides thicker metal at the flange joint, while the neck narrows down gradually to meet the pipe where it is butt welded to the pipe. This design helps to transfer stress from the flange to the pipe, as well as diminish stress concentration at the base of the flange connection.

Monel weld neck flanges are ideal for critical applications involving high pressure, sub-zero and elevated temperatures, as well as in conditions where fluctuations cause pipe expansion/contraction.

Key Feature: Ideal for high presure applications.

Weld Neck Flange Advantages

• Ability to withstand high pressure – since pipe is welded to the neck of the flange, stress is transferred to the pipe.
• The beveled end that, when connected to a pipe, creates a trough for a strong weld.
• Most versatile flange in the ASME stable of flanges.

Weld Neck Flange Disadvantages

• More advanced welding skill is needed for installation. The inside weld must be smooth to reduce friction and the outside weld must meet code criteria.

Uses

• Severe conditions that include high-pressure, high-cyclic and hazardous fluid applications.
• Fitting-to-fitting fabrication where the flange is welded directly to a fitting, such as an elbow, without the need for a short piece of pipe, as would be required with a slip-on flange.