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. 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 acidswhenthey are de-aerated. As would be expected from its high copper content, alloy R-405is rapidly attacked by nitric acid and ammonia systems.

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