There are very few comparisons of materials
that cover the full range of material options, from standard to titanium,
including the copper alloys, and the duplex stainless steels. This Website
will provide comparisons covering mechanical properties,
performance in various corrosion conditions
as well as costs associated with valve manufacturing.
The review will draw on Shipham’s extensive experience of manufacturing
valves in most of the materials considered, as well as making reference
to published literature from a variety of sources.
cheaper than the exotic stainlesses
The materials include cast iron, carbon steel, 316 stainless, 6Mo, duplex and super-duplex stainless steels, nickel alloys and titanium as well as a selection of high performance nickel-aluminium bronzes. The common corrosion types will be covered..
excellent anti fouling properties
Additionally, the pressure-temperature characteristics of Nickel-aluminium Bronze will be discussed. On the one hand, everyone knows that Class 150 has a maximum operating pressure of “about 20 bar” and some are aware that for bronze alloys there is a maximum of 15.5 bar. The truth lies somewhere between these two limits. There is no standard that both maximises the potential of NAB as well as recognising its limitations, enabling an economic and a safe design.
High Pressure Ratings
In conclusion, NAB is shown to be particularly useful for seawater service, despite elevated temperature and sulphide environment limitations. The main advantages are that:
• It is cheaper than the exotic stainlesses, and so cost effective;
• Its performance on general corrosion, pitting and cavitation is comparable to
superduplex alloys and significantly better than the standard
alloys;
• It also has beneficial properties of good heat conduction,
does not gall,
and has excellent anti fouling properties
• It can have a pressure temperature rating well above the bronze standards.