Non-ferrous materials are a small part of the total piping materials, and they are used in a very aggressive environment. Non-ferrous material contains no iron or in a very insignificant amount.
These materials are more expensive than ferrous metals. Some of the non-ferrous material used in Process Industries are listed below. The non-ferrous materials are also known as exotic material.
- Copper and Copper Alloys
- Nickel and Nickel Alloys
- Aluminum and Aluminum Alloys
- Titanium and Titanium Alloys
- And Zirconium and Zirconium Alloys
Copper and Copper Alloys
- Good thermal conductivity and good corrosion resistance
- Brasses, Bronzes (Cu-Sn) and Cupronickels (Cu-Ni) are some of the examples of the copper alloy
- Cupronickels have the highest corrosion resistance among Cu alloys
- Cupronickels are used for heat exchanger tubing and seawater application
- It can be used as a cladding material with carbon steel in heat exchanger tube sheets.
Nickel and Nickel Alloys
- Good resistance to oxidation and corrosion
- Monel 400 and Hastelloy are a well-known example of nickel alloys
- These alloys are used in piping systems, pressure vessel, turbine blades, valves, and power plant accessories that handle steam at very high pressure and temperature
- Nickel alloys are frequently used as a cladding material with carbon steel
Aluminum and Aluminum Alloys
- Good thermal conductivity
- It is most workable metal
- Highly resistant to atmospheric conditions
- But When coupled with more noble materials it is subject to galvanic attack
- And Loses strength rapidly above 175°C
- Aluminum and Aluminum Alloys rarely used in process piping
- However, it is used as an external cladding material to protect the insulation from water ingress.
Image – Geo Thermal
Titanium and Titanium Alloys
- High strength to weight ratio
- Similar to SS, Titanium Oxide is formed on the surface which prevents corrosion
- Titanium and Titanium Alloys has resistant to nitric acid, which is very corrosive in nature. Hence, it is used in this kind of process environments.
- However, to Weld Titanium and Titanium Alloys, the inert atmosphere is required.
- It starts losing its strength above 400°C
- Titanium is also used as a clade material with carbon steel to reduce the cost of equipment
Zirconium and Zirconium Alloys
- Zirconium and Zirconium Alloys are used, where strong acids and alkalis are present, where other materials cannot be used due to the very aggressive environment.