There is a wide range of different types of stainless steels, all of which share the common property of resistance against corrosion. This property, combined with the low level of maintenance required when working with this type of metal are just some of the reasons it is popular in so many application areas.
This blog post will look at one type of stainless steel available in the market, duplex and super duplex stainless steel.
Duplex and Super Duplex Stainless Steel
Duplex stainless steels earn their name as they have a two-phase microstructure that consists of grains of 50% austenitic and 50% ferritic stainless steel.
This type of steel has a selection of benefits, and it is often chosen over regular ferritic or austenitic stainless steels due to its increased strength – it is about twice as strong as these metals. Due to its increased yield strength, thinner sections of duplex stainless steels can be created, providing significant weight savings. This makes duplex stainless steel a popular choice for structural applications and pressure vessels.
As with all stainless steels, duplex stainless steels benefit from this characteristic. The level of corrosion resistance depends on the grade of duplex stainless steel, and these levels are similar to the range for austenitic stainless steels.
The ferritic part of the duplex stainless steels microstructure provides this type of steel with very good stress corrosion cracking (SCC) resistance, which makes it a popular choice for hot water tanks and process plants. This is a property that standard austenitic stainless steels do not possess, and they can be susceptible to in situations of elevated temperature or humidity.
Duplex stainless steels also exhibit better ductility and toughness compared to ferritic stainless steels, but they do not provide these properties as successfully as austenitic stainless steels.
These steels are also considerably cheaper compared to the equivalent austenitic and ferritic grades. This is because duplex stainless steels have lower molybdenum and nickel contents, and therefore a lower alloy surcharge.
Super Duplex stainless steel has all of the same benefits as its counterpart, the main difference being that this metal has a higher chromium and molybdenum content, which provides it with increased corrosion resistance.
Super Duplex stainless steel is often employed in the oil and gas industry, heat exchangers, offshore platforms, chemical processing equipment, boilers, and pressure vessels.
Duplex and Super Duplex Stainless Steel from Masteel
Masteel supply a large range of different steels globally, including duplex and super duplex stainless steel.