Other common names: Alloy 400

Monel 400 – Nickel-Copper Alloy

Monel 400 is a Nickel-Copper alloy with high strength and excellent corrosion resistance in a range of acidic and alkaline environments and especially suitable for reducing conditions. It also has good ductility and thermal conductivity.

Monel 400 is a nickel-copper alloy (about 67% Ni – 23% Cu) that is resistant to sea water and steam at high temperatures as well as to salt and caustic solutions. Alloy 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. 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 alloy is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. As would be expected from its high copper content, alloy 400 is rapidly attacked by nitric acid and ammonia systems.

Monel 400 has great mechanical properties at subzero temperatures, can be used in temperatures up to 1000° F, and its melting point is 2370-2460° F. However, alloy 400 is low in strength in the annealed condition so, a variety of tempers may be used to increase the strength.

Relevant Standards

Monel 400 is covered by the following standard:

• BS 3075
• 3076 NA 13
• DTD 204B
• ASTM B164

Equivalent Materials

Equivalent materials to Monel 400 are:

• W.NR 2.4360
• W.NR 2.4361
• UNS N04400
• AWS 040

    

In what forms is Monel 400 Available at SAGAR STEELS?

• Sheet
• Plate
• Bar
• Pipe & Tube (welded & seamless)
• Fittings (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)
• Wire

What are the characteristics of Monel 400?

• 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 at 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
• Good mechanical properties from sub-zero temperatures up to 1020° F
• High resistance to alkalis

Chemical Composition, %

Corrosion Resistant Monel 400

Alloy 400 is virtually immune to chloride ion stress corrosion cracking in typical environments. Generally, its corrosion resistance is very good in reducing environments, but poor in oxidizing conditions. It is not useful in oxidizing acids, such as nitric acid and nitrous. Nevertheless, it is resistant to most alkalis, salts, waters, food products, organic substances and atmospheric conditions at normal and elevated temperatures.

This nickel alloy is attacked in sulfur-bearing gases above approximately 700° F and molten sulfur attacks the alloy at temperatures over approximately 500° F.

Monel 400 offers about the same corrosion resistance as nickel but with higher maximum working pressures and temperatures and at a lower cost due to its superior ability to be machined.

Applications of Monel 400

Monel 400 typically finds application in:

1. Marine Engineering
2. Chemical Processing
3. Hydro-carbon Processing
4. Heat Exchangers
5. Valves
6. Pumps
7. Marine engineering
8. Chemical and hydrocarbon processing equipment
9. Gasoline and freshwater tanks
10. Crude petroleum stills
11. De-aerating heaters
12. Boiler feed water heaters and other heat exchangers
13. Valves, pumps, shafts, fittings, and fasteners
14. Industrial heat exchangers
15. Chlorinated solvents
16. Crude oil distillation towers

---

Monel® K-500 / N05500

Other common names: Alloy K500

Monel K500 is a Nickel-Copper alloy that is precipitation hardenable, due to the additions of Aluminium and Titanium. It combines the corrosion resistance of Monel 400 but gives the added advantage of extra strength and hardness (as a result of its age hardening ability).

Monel K500 is a precipitation-hardenable nickel-copper alloy that combines the excellent corrosion resistance characteristic of Monel 400 with the added advantage of greater strength and hardness. These amplified properties, strength and hardness, are obtained by adding aluminum and titanium to the nickel-copper base and by a thermal processing used to effect precipitation, typically called age hardening or aging. When in the age-hardened condition, Monel K-500 has a greater tendency toward stress-corrosion cracking in some environments than Monel 400. Alloy K-500 has approximately three times the yield strength and double the tensile strength when compared with alloy 400. Plus, it can be further strengthened by cold working prior to precipitation hardening. The strength of this nickel steel alloy is maintained to 1200° F but stays ductile and tough down to temperatures of 400° F. Its melting range is 2400-2460° F.

Relevant Standards

Monel K500 is covered by the following standards:

• BS 3075
• 3076 NA 18

Equivalent Materials

Equivalent materials to Monel K500 are:

• W.NR 2.4375
• UNS N05500
• AWS 041

   

Specifications

In what forms is Monel K500 Available at SAGAR STEELS?

• Bar
• Rod

Corrosion Resistant Monel K-500

The corrosion resistance of alloy K-500 is substantially equivalent to that of alloy 400 except that when in the age-hardened condition, nickel alloy K-500 has a greater tendency toward stress-corrosion cracking in some environments. Monel K-500 has been found to be resistant to a sour-gas environment. The combination of very low corrosion rates in high-velocity sear water and high strength make alloy K-500 particularly suitable for shafts of centrifugal pumps in marine service. In stagnant or slow-moving sea water, fouling may occur followed by pitting but this pitting slows down after a fairly rapid initial attack.

What are the characteristics of Monel K500?

• Corrosion resistance in an extensive range of marine and chemical environments. From pure water to non-oxidizing mineral acids, salts and alkalis.
• Excellent resistance to high velocity sea water
• Resistant to a sour-gas environment
• Excellent mechanical properties from sub-zero temperatures up to about 480C
• Non-magnetic alloy

   

Chemical Composition of Monel K500

The compositional range for Monel K500 is provided in the table below.

Element	Content
Ni	63 % min
Cu	30 %
Fe	2 % max
Al	2.3 - 3.15 % max
Ti	0.35 - 0.85 % max

   

Fabrication with Monel K-500

Monel K-500 is readily fabricated by standard commercial procedures.

Welding alloy K-500 is best accomplished by the gas-tungsten-arc welding process. It is recommended that Monel K-500 be annealed when it is welded and that any weldments be stress relieved prior to aging.

Heavy machining of this alloy is best accomplished when the material is in the annealed condition or hot-worked and quenched condition. Age-hardened material however can be finish-machined to close tolerances and fine finishes. Therefore, the recommended practice is to machine slightly oversize, age-harden, then finish to size. During aging, a slight permanent contraction takes place, but little warpage occurs because of the low temperatures and slow cooling rates involved.

Mechanical Properties
Typical Room Temperature Tensile Properties of Annealed Material

   

Applications of Monel K500

Monel K500 typically finds application in:

• Pump Shafts
• Fasteners
• Marine Propeller Shafts
• Oil Well Tools
• Instruments
• Springs

---

Monel® R-405 / N04405

Nickel alloy 405 is a nickel-copper alloy with high toughness and strength. It also has excellent corrosion resistance in a range of media that include alkalis, sulfuric acid, hydrofluoric acid and seawater. The alloy has enhanced machinability due to its increased sulfur content. It can be slightly magnetic at room temperature, and has excellent resistance to chloride ion stress corrosion cracking.

Monel R405 is the free machining version of Monel 400. It is a nickel-copper alloy with a controlled amount of sulfur added to provide sulfide inclusions that act as chip breakers during machining. Like Monel 400, alloy R-405 is resistant to sea water and steam at high temperatures as well as to salt and caustic solutions. Monel R405 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.

Other Designations

Other designations that are equivalent to nickel alloy 405 include the following:

• ASTM B 164
• ASME SB-164
• SAE AMS 4764
• SAE AMS 7234
• QQ-N-281
• NACE MR-01-75

In what forms is Monel R405 Available at SAGAR STEELS ?

• Round Bar (ASTM specification B 164)
• Hex Bar

Corrosion Resistant Monel R-405

As with alloy 400, Monel R-405 is virtually immune to chloride ion stress corrosion cracking in typical environments. Generally, its corrosion resistance is very good in reducing environments, but poor in oxidizing conditions. It is not useful in oxidizing acids, such as nitric acid and nitrous. Nevertheless, it is resistant to most alkalis, salts, waters, food products, organic substances and atmospheric conditions at normal and elevated temperatures.

Monel 400 and R-405 offer about the same corrosion resistance as nickel but with higher maximum working pressures and temperatures and at a lower cost due to its superior ability to be machined.

What are the characteristics of Monel R405?

Characteristics are essentially the same as those of Monel 400 such as:

• 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

Chemical Composition, %

In what applications is Monel R-405 used?

Alloy R-405 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

Fabrication with Monel R-405

Monel R-405 is fabricated, pickled and heat-treated by the same procedures as for alloy 400. It is not recommended for forging. However, R-405 alloy was especially developed for good machinability and is recommended for use with automatic screw machines. The nickel –copper sulfides resulting from the sulfur in its composition act as chip breakers.

This nickel alloy also has the same procedures and processes as alloy 400 and can be joined by standard welding, brazing and soldering techniques. Just as with alloy 400, R-405 can easily be welded by gas – tungsten arc, gas metal arc, or shielded metal arc processes using appropriate filler metals. There is no need for post weld heat treatment, however, thorough cleaning after welding is critical for optimum corrosion resistance, otherwise there is the risk of contamination and embrittlement.

Physical Properties

The following table shows the physical properties of nickel alloy 405.

Properties	Metric	Imperial
Density	8.80 g/cm3	0.318 lb/in3
Melting point	1300-1350°C	2370-2460°F

 

Mechanical Properties
Nominal Mechanical Property Range of Monel Alloy R-405 Rod and Bar

The ranges shown are composites for various product sizes and therefore are not suitable for specification purposes.

---