ThePipingMart Blog Grades Monel R-405 (UNS N04405) – Composition, Properties and Uses

Monel R-405 (UNS N04405) – Composition, Properties and Uses

Monel R-405

Monel R-405 is a nickel-copper alloy that combines the properties of both metals in one material. It has an excellent combination of strength, hardness, and corrosion resistance, making it an ideal material for various industrial applications. In this blog post, we will cover the composition, chemical properties, mechanical properties, physical properties, uses, corrosion resistance, heat resistance, and treatment methods of Monel R-405 as well as its machining and welding processes.

Monel R-405 Composition

R-405 is a Nickel-Copper alloy containing approximately 63% nickel and 33% copper with trace amounts of iron and manganese.

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

Monel R-405 Chemical Properties

This chromium-free alloy provides excellent corrosion resistance in many environments, making it suitable for use in marine applications. The presence of molybdenum also increases the overall strength and toughness of the material.

Monel R-405 Physical Properties

N04405 exhibits high tensile strength (up to 860MPa) and yield strength (up to 830MPa). The material also features good ductility (up to 20%) and impact toughness (up to 60J).

Properties Metric Imperial
Density 8.80 g/cm³ 0.318 lb/in³
Melting point 1338°C 2440°F

Monel R-405 Mechanical Properties

Additionally, it has a low coefficient of thermal expansion (10×10-6/K) which allows it to maintain its shape at higher temperatures. Its high melting point (1425°C) also makes it suitable for elevated temperature applications.

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%

Monel R-405 Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@ 20-100°C/68-212°F) 13.7 µm/m°C 7.61 µin/in°F
Thermal conductivity 21.8 W/mK 151 BTU in/hr.ft².°F

Monel R-405 Equivalent

  • AMS 4674
  • ASTM F467
  • ASTM F468
  • QQ N281

Monel R-405 Uses

Monel R-405 is widely used in various industries due to its excellent corrosion resistance in saltwater environments and its ability to resist chlorine stress cracking and pitting corrosion in chloride solutions. It is commonly used for valves, piping systems, pumps, propellers, heat exchangers, and other components that require superior corrosion protection. Additionally, it can be used as a substitute for stainless steel or titanium when these materials are not available or cost prohibitive.


Monel R-405 can be machined using conventional tools such as lathes and drills as well as more specialized tools such as end mills and reamers.


It can also be welded using standard welding techniques such as gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), shielded metal arc welding (SMAW), submerged arc welding (SAW), plasma arc welding (PAW), etc.

Heat Treatment

Heat treatment processes such as annealing or tempering can also be used on the material to increase its ductility or hardness depending on the application requirements.

Corrosion Resistance

R-405 is highly valued in the industrial and manufacturing sectors for its excellent corrosion resistance. It is composed of a combination of nickel, copper, iron, and manganese, giving it superior resistance to stress corrosion cracking and pitting from chloride ions. Monel R-405 is commonly used for applications with varying temperatures or corrosive environments like seawater, sulfuric acid, and hydrochloric acid. The affordability of this material makes it an attractive option for many industries. Its popular use is in the production of engine parts that require strength and heat resistance all while protecting against corrosion, making the Monel R-405 an ideal choice.


Monel R-405 is a versatile alloy that offers excellent mechanical properties combined with superior corrosion resistance, making it an ideal choice for many industrial applications such as valves, piping systems, pumps, etc. It can be easily machined using conventional tools while maintaining good surface finish quality without requiring further heat treatment. Welding processes like GTAW or GMAW can also be used to join pieces together while still achieving superior joint strength without any additional post-weld treatments needed. Overall this makes Monel R- 405 an incredibly useful alloy that should always be considered when looking for materials with superior physical properties coupled with great levels of corrosion protection under harsh environments like salt water or chloride solutions.

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