Duplex F61

General Properties

Super Duplex F61 is a high-performance stainless steel, highly valued for its exceptional behavior in aggressive chemical environments. In particular, it offers excellent resistance to acids such as sulfuric, phosphoric, and nitric acid.
In addition, in chloride-containing environments like seawater, this alloy demonstrates remarkable resistance to pitting and crevice corrosion. The critical pitting temperature exceeds 50°C, making it highly suitable for demanding applications.

Furthermore, Super Duplex F61 stands out with excellent ductility and high impact resistance, both at ambient and sub-zero temperatures. It also shows outstanding resistance to abrasion, erosion, and cavitation, making it ideal for dynamic applications.

Corrosion resistance:

UNS S32550 performs excellently in most corrosive environments, often outperforming the 2205 duplex alloy. It offers enhanced protection in acidic environments, including the presence of sulfuric, phosphoric, nitric acids, and organic acids such as acetic and formic acid.
However, it is important to note that strongly reducing environments should be avoided to maintain optimal alloy performance.

Physical Properties:

• Melting temperature: 1385 – 1443°C
• Density: 7.81 g/cm³
• Specific gravity: 7.81
• Tensile modulus of elasticity: 200 GPa

Mechanical Properties:

Welding

Super Duplex F61 offers good weldability, typical of duplex stainless steels. While it is not as easy to weld as austenitic steels, its low thermal expansion coefficient significantly reduces post-weld distortion and residual stresses.
All standard welding methods are applicable, yielding excellent results when proper procedures are followed.

Heat Treatment

Like other duplex stainless steels, Super Duplex F61 cannot be hardened through conventional heat treatment. However, hardening can be achieved via solution annealing followed by rapid cooling, after heating to approximately 1100°C.