AMS 4674 is a specification for Monel R405 Bars & Forgings, Monel R405 (UNS N04405) is the free-machining grade of Monel 400. Is a solid solution alloy that can only be hardened by cold working. This nickel alloy exhibits characteristics like good corrosion-resistance, good weldability and high strength.
Like Monel 400, Monel R405 bars is resistant to sea water and steam at high temperatures as well as to salt and caustic solutions. A low corrosion rate in rapidly flowing brackish or seawater combined with excellent resistance to stress corrosion cracking in most freshwaters, and its resistance to a variety of corrosive conditions led to its wide use in marine applications and other non-oxidizing chloride solutions.
This nickel steel alloy is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. As would be expected from its high copper content, alloy R-405 is rapidly attacked by nitric acid and ammonia systems.
Chemical Composition
| Elements | Content (%) |
| Nickel, Ni | 63 |
| Copper, Cu | 28-34 |
| Iron, Fe | 2.50 |
| Manganese, Mn | 2 |
| Carbon, C | 0.30 |
| Silicon, Si | 0.50 |
| Sulfur, S | 0.025 - 0.060 |
Mechanical Properties
| Properties | Metric | Imperial |
| Tensile Strength (annealed) | 550 MPa | 79800 psi |
| Yield strength (@ strain 0.200%, annealed) | 240 MPa | 34800 psi |
| Elongation at break (annealed) | 40% | 40% |
Physical Properties
| Properties | Metric | Imperial |
| Density | 8.80 g/cm³ | 0.318 lb/in³ |
| Melting point | 1338°C | 2440°F |
Characteristics
- Good machinability and is recommended for use with automatic screw machines
- Resistant to seawater and steam at high temperatures
- Excellent resistance to rapidly flowing brackish water or seawater
- Excellent resistance to stress corrosion cracking in most freshwaters
- Particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated
- Offers some resistance to hydrochloric and sulfuric acids a modest temperatures and concentrations, but is seldom the material of choice for these acids
- Excellent resistance to neutral and alkaline salt
- Resistance to chloride induced stress corrosion cracking
- High resistance to alkalis
Application
Alloy R405 is chiefly used for automatic-screw-machine stock and it not generally recommended for other applications. Screw machine stock for fasteners and similar high production run items.
- Meter and valve parts
- Fasteners
- Screw machine products