Duplex Stainless steel tubes
The microstructures inside duplex stainless steels are approximately 50 per cent austenite and 50 per cent ferrite, and consequently duplex products share the physical properties of both ferritic and austenitic grades. Duplex stainless steels are resistant to the cracking caused by chloride stress corrosion in austenitic grades, and have improved resistance to localised corrosion. This family of stainless steels has roughly twice the yield strength of their counterpart austenitic grades which means we can use it to design thinner gauge tubing. Higher hardness values provide better wear resistance for high precision tubes.
Duplex steels are easily welded and formed, similar to austenitic grades. Depending on chromium, nickel and molybdenum content, duplex stainless steels are divided into four main categories: lean duplex, duplex, super duplex and hyper duplex. This family of alloys has great advantages in both material and engineered fabrication costs.
Typical applications for this alloy group include heat exchanger tubes, umbilicals, structural tanks, pulp and paper making equipment, pipes and fittings, and seawater handling systems.
Fine Tubes manufactures duplex stainless steel tubes in the following alloys:
- Duplex • UNS S31803
- Super Duplex • UNS S32750
- Super Duplex • UNS S32760
To view more technical information on the alloys we most commonly manufacture, please click the alloy link above. You can also download the technical datasheet in our Downloads section.
Note: Microstructure image courtesy of Oxford Instruments Ltd.