Monel 405 Flanges
Monel 405 Flanges (UNS N04405) Monel Flanges
Monel 405 Flanges (UNS N04405) are free-machining nickel-copper alloy flanges known for their high strength, exceptional corrosion resistance, and excellent workability. As a modified version of Monel 400 with added sulfur, Monel 405 offers superior machinability while maintaining the same corrosion-resistant performance in marine, chemical, and industrial environments.
These flanges exhibit excellent resistance to seawater, steam, alkalis, neutral salts, and various corrosive chemicals, making them ideal for applications where superior machining precision and durability are required. Monel 405 flanges perform reliably in temperatures ranging from sub-zero conditions to elevated temperatures up to 550°C.
Key Features
Free-machining grade with enhanced machinability
Excellent corrosion resistance in marine and chemical environments
High strength and toughness in high- and low-temperature conditions
Resistant to stress-corrosion cracking & pitting
Non-magnetic in annealed condition
Good thermal conductivity & electrical conductivity
Suitable for high-precision machining applications
Stable mechanical and metallurgical properties across temperatures
Specification
| Specification | Details |
|---|---|
| Standard | ASTM B164 / ASME SB164 |
| UNS | N04405 |
| Flange Types | WNRF, SORF, BLRF, Threaded, SWRF, RTJ, LJRF |
| Size Range | ½″ to 48″ |
| Pressure Class | 150#, 300#, 600#, 900#, 1500#, 2500# |
| Dimension Standards | ASME B16.5, B16.47, B16.48 |
| Manufacturing Method | Forged / Machined / Plate Fabricated |
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | N04405 |
| ASTM | B164 |
| BS / EN / DIN | No direct equivalent |
| ISO / AFNOR | – |
Available Sizes
Flange Size: ½″ – 48″
Thickness: SCH 10 – SCH XXS
Custom dimensions available upon request
Chemical Composition
| Element | % |
|---|---|
| Nickel (Ni) | 63 min |
| Copper (Cu) | 28–34 |
| Sulfur (S) | 0.025–0.060 |
| Iron (Fe) | 2.5 max |
| Manganese (Mn) | 2.0 max |
| Carbon (C) | 0.30 max |
| Silicon (Si) | 0.50 max |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 517 MPa min |
| Yield Strength | 172 MPa min |
| Elongation | 30% min |
| Hardness | 65–95 HRB |
| Density | 8.8 g/cm³ |
Physical Properties
| Property | Value |
|---|---|
| Melting Range | 1300–1350°C |
| Electrical Resistivity | 0.51 μΩ·m |
| Thermal Conductivity | 21.8 W/m·K |
| Specific Heat | 0.377 J/g·°C |
| Modulus of Elasticity | 179 GPa |
| Magnetic Character | Non-magnetic when annealed |
Types of Monel 405 Flanges
Weld Neck Flanges (WNRF)
Slip-On Flanges (SORF)
Blind Flanges (BLRF)
Socket Weld Flanges (SWRF)
Threaded/Screwed Flanges
Lap Joint Flanges
Ring-Type Joint (RTJ) Flanges
Long Weld Neck Flanges
Orifice Flanges
Custom Precision-Machined Flanges
Corrosion Resistance
Monel 405 provides outstanding resistance against:
Seawater & marine atmospheres
Neutral & alkaline salt solutions
Caustic alkalis
Mild acids
Steam & high-humidity environments
Brackish water and chlorides
Stress-corrosion cracking & pitting
It outperforms stainless steels in marine and alkaline corrosive environments.
Heat Resistance
Effective performance up to 550°C
Excellent strength retention at elevated temperatures
High oxidation resistance
Stable performance under thermal cycling
Suitable for high-temperature mechanical systems
Heat Treatment
Annealing: 850–950°C followed by controlled cooling
Stress Relieving: 500–600°C
Alloy cannot be precipitation hardened; strengthening is achieved through cold work.
Welding
Weldable using GTAW, GMAW, SMAW
No preheat required
Post-weld annealing recommended for critical service
Recommended filler: Monel 67
Note: High sulfur content may influence weld fluidity; controlled welding techniques are advised.
Fabrication
Excellent machinability due to higher sulfur content
Good forming, forging, and cutting characteristics
Hot working range: 900–1150°C
Cold working increases strength
Suitable for CNC machining, threading, and precision parts
Applications
Marine and offshore components
Valves, pumps, and seawater service flanges
Electrical & electronic components
Oil & gas instrumentation
Heat exchangers & condensers
Fuel and chemical processing pipelines
Steam generators & boiler components
High-precision machined industrial parts
Aerospace electrical connectors