Broder Metals: Increase in Demand for F55 / UNS S32760 Material

Broder Metals Group Ltd is a steel and nickel alloy distributor carrying a wide range of cobalt alloy, nickel alloy, and stainless steels for the value and pump industry. Recently we have been seeing increased demand for F55 (UNS S32760), not only in the Annealed condition, but also the cold drawn version, Condition S.

F55 (UNS S32760) is a super duplex stainless steel with a roughly equal split of austenite and ferrite microstructure, which provides a high mechanical strength along with good ductility. Corrosion resistance properties are excellent in a variety of environments: this material provides high resistance to pitting, crevice corrosion resistance, stress corrosion cracking, corrosion fatigue and erosion. It performs very well in chloride stress-corrosion situations and is good for sulphide stress corrosion resistance. It also has low thermal expansion and higher heat conductivity than austenitic only steels, while weldability and workability is good.

Most people in the industry will be aware of the benefits from using F55 (UNS S32760) material in ball, needle, gate and butterfly valves, stems, grade actuators, gearboxes, and other applications such as in heat exchangers, desalination plants, and utility and industrial systems to name just a few.

Material supplied in the A (annealed) Condition provides a minimum of 550 MPa 0.2% Yield Strength with a minimum 750 MPa Ultimate Tensile Strength. Hardness is a maximum 290 HBW (31 HRC), which conforms to the requirements of NACE MR0175.

What may be less well known is the benefits obtained from deliberate application defined amounts of cold work to convert Condition A material to Condition S (Strained). Obviously, the chemistry-induced benefits of corrosion resistance remain, but mechanical performance is enhanced with an increase in Yield Strength (minimum of 550 MPa increased to a minimum of 720 MPa) and Ultimate Tensile Strength (minimum of 750 MPa increased to 860 MPa minimum). Hardness increases to a maximum of 335 HBW (36 HRC), while there is a slight trade-off in elongation which drops from a minimum of 25% to a minimum of 16% (measured across 50 mm or 4D).

We obviously carry a full range of sizes in Condition A sizes and can quickly convert to Condition S with low temperature Charpy Impact test properties, to suit our customer’s requirement. Our core sizes are 12.7mm (1/2 “) to 101.6mm (4”) diameter.