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

Monel® lap joint flanges, like Monel 400 and K500, are made from a nickel-copper alloy and exhibit high strength, toughness and good corrosion resistance over a wide temperature range. An outstanding characteristic of Monel lap joint flanges is that they offer exceptional resistance to hydrofluoric acid, a particularly tough acid to deal with, in all concentrations up to the boiling point. For hydrofluoric acid applications Monel lap joint flanges are perhaps the most resistant of all commonly used specialty alloys.

Monel alloy 400 & K500 lap joint flanges also exhibit excellent corrosion resistance in marine applications and have reasonable corrosion resistance to sulfuric and hydrochloric acids under reducing conditions. Monel K500 lap joint flanges are over 2x as strong as Monel 400 lap joint flanges. 

Because of these characteristics, Monel lap joint flanges are often found in marine and chemical processing applications.

The most common grades of Monel 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.

ResourcesMonel Torque Spec, Flange DimensionsFlange Bolting ChartMonel 400Monel K500

Flange Types Available: Blind FlangesLap Joint FlangesSlip On FlangesSocket Weld FlangesThreaded FlangesWeld Neck Flanges


Common Grades of Lap Joint 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)

Monel 400 Chemistry

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)

Monel K500 Chemistry


 Mechanical Properties of Monel

Monel 400 Tensile Curves         Monel alloy K500 Tensile Data

Monel 400 Tensile Data   Monel K500 Tensile Data

Monel 400 Flange Pressure - Temperature Chart


 

Monel 400 Corrosion Data

Monel HF vs Nickel Alloys revised

Monel 400 HF IsoCorrosion Curve


 Monel Lap Joint Flange Features & Benefits

lap and stud combined

Lap joint flanges are unique in that they are made of two pieces, the flange itself and the stub end.

Flange

  • The backside, has a slight shoulder that is square cut at the center or pipe hole
  • The front side has a flat face with a filleted (rounded) center hole to match the filleted back face of the stub end. Here the stub end will wrap tightly around the center hole of the flange.

Stub End

  • Shaped like a short piece of pipe with a weld bevel on one. This portion of the stub end is also called the sleeve.
  • Narrow shoulder on the flange facing end called is the hub. The back face of the hub has a rounded transition (or inside fillet) that joins the hub to the sleeve

Benefits

  • Economy 
    Because a lap joint flange has a two piece configuration, it offers a way to cut cost when piping systems requires 
  • For high cost alloys the only "wetted" part is the stub end. In this situation, it is only required for the stub-end to be made of the higher cost corrosion-resistant material, where the flange itself can be the produced from lower cost steel.
  • Ease of Work
    By using lap joint flanges, work can be simplified in situations that require frequent and rapid disassemble and assembly during the operation of a plant. The ability to spin that backing flange compensates for misalignment of the bolt holes during assembly.

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