Since their development in the 1960’s, super duplex stainless steels have found particular favour in the Oil and Gas market, especially when exploration moved offshore and into deeper and more hostile environments. Deeper wells equal higher pressures and longer strings, demanding higher strength materials, whilst sour wells containing sulphur need the corrosion resistance of this family of alloys.
A significant application of super duplex stainless steel seamless tubes developed since the 1990’s is in subsea control umbilical, carrying methanol, hydraulic and chemical injection fluids to deep installations, often at high pressures. Such subsea engineering systems will also include pumps, valves and other equipment interconnected across the seabed. Such systems are then linked to the surface by Floating Production, Storage and Offloading (FPSO) vessels.
More recently, the demand for drinking water has driven the construction of desalination plants, converting seawater into fresh drinking water. Super duplex piping is typically used on the inlet side of the units, whilst duplex piping may be acceptable on the outlet side as the risk of corrosion diminishes.
As well as the above applications, super duplex stainless steel fittings, pipes and flanges are used in many different chemical processing applications; fertiliser manufacturing; flue gas desulphurisation (FGD) systems and marine scrubbers; shipping, water treatment; industrial processing and general engineering.
Fortunately, with such demand, Langley Alloys is well-placed to provide a complete piping packages services – combining our stock of super duplex piping with fittings and flanges sourced from our partners or machined in-house. A selection of images from recent projects is shown below.
Super duplex pipe (seamless) is typically supplied to ASTM A790, or ASTM A928 (welded pipe).
Super duplex flanges are typically supplied to ASTM A182.
Super duplex fittings are typically supplied to ASTM A815.
In addition, we can machine bespoke fittings from our super duplex stainless steel bar stock that meets ASTM A479.