50 years of the original super duplex stainless steel, Ferralium 255

Published: 29th April 2019 | Issue 48

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Long before 32750 (F53) and 32760 (F55) existed there was Ferralium 255. Developed by Langley Alloys in the mid-1960s, it was launched in 1969. Since then, it has been widely used in valves for the most demanding applications, where resistance to aggressive mediums such as seawater, selected chemicals and acids can only be bettered by considerably more expensive alloys.

The virtues of duplex and super duplex stainless steels are now well known, having been in commercial existence since the 1960s. Whilst they were seen as relatively exotic alloys then, this family of alloys has achieved widespread acceptance, combining the most favourable properties of both austenitic and ferritic stainless steels. With strengths 2-3x greater than the 3xx stainless steels, and far superior corrosion resistance, they quickly became the go-to alloys for emerging applications in Oil & Gas and chemical processing through the 1960s and 1970s.

Langley Alloys was created in 1938, a venture between High Duty Alloys and Hawker Siddeley. Originally developing copperbased alloys for wartime aerospace and marine end uses, our foundry produced valves and components in a wider range of alloys. This includes the development of the forerunner of today’s CD4MCuN cast grade stainless steels, still widely used today for valve bodies and bonnets.

That Ferralium 255 is the closest super duplex alloy in bar and plate form to the cast grade CD4MCuN should come as no surprise. Originally, copper was seen as an unwelcome addition to steels, associated with ‘red shortness’ where ingots would break apart during hot working.

However, with Langley Alloys improvements to metallurgical understanding and process control, the benefit of copper additions became appreciated. It is known to enhance corrosion resistance in chlorine containing environments i.e. seawater, as well as sulphuric acid. Ferralium 255 has the highest copper addition of any super duplex stainless steel, resulting in its superior corrosion performance.

Patented in 1967 and marketed as Ferralium 255 in 1969, it has been further refined to improve mechanical properties – it is the only super duplex to achieve 85ksi yield strength.

The improved strength and corrosion resistance means that it is specified by the likes of Stamicarbon and Toyo Engineering for valves in chemical process plants, along with the leading Oil & Gas major customers.

Langley Alloys can proudly claim the title of ‘The Home of Super Duplex’, as the inventor of the original super duplex stainless steel and leading distributor. We now stock the widest range of Ferralium 255, 32750 (F53), 32760 (F55) and 2205 (F51/F60) in up to 40 different bar diameters. Plus, as Sandvik’s distribution partner, we can offer unrivalled depth of stock, to meet your project requirements.

Tel: 01782 610 250
Email: sales@langleyalloys.com
Web: www.langleyalloys.com

Telephone:	01782 610250
Email:	sales@langleyalloys.com
Website:	www.langleyalloys.com
	More information on the Langley Alloys Limited BVAA Member Directory Page

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