The design of fluid instrumentation systems for use in harsh and corrosive environments has been boosted by an optimised grade of 6Mo tubing. The mechanical characteristics of the ‘Parker Grade’ 6Mo tubing have been optimised to ensure integrity of connections made using instrumentation compression type fittings from the Instrumentation Products Division of Parker Hannifin.
Containing at least 6 percent molybdenum, 6Mo alloy is a super-austenitic stainless steel. The material is more resistant to chloride-induced pitting, crevice attack and stress corrosion cracking than standard 300 series or duplex stainless steel, making it ideal for offshore applications demanding durability and reliability in a hostile environment. Parker produces 6Mo versions of various types of instrumentation tube fittings, together with a series of 6Mo tubing clamps, and can also machine instrument valves and manifolds in the material.
Many instrumentation system designers specify two ferrule compression fittings for the assembly of small-bore tubing, with the 6Mo version of Parker’s A-LOK design proving a popular choice for today’s offshore projects. As with all two ferrule fittings, the rear ferrule needs to be harder than the tube it is gripping so that it ‘bites’ into the tube material during assembly helping to create a reliable, pressure-tight seal. Parker hardens the rear ferrule of 6Mo A-LOK fittings using its unique Suparcase process, which provides market-leading corrosion resistance.
Parker Grade 6Mo instrumentation tubing is available in a wide range of imperial and metric sizes up to 25mm OD, and its 6Mo A-LOK two ferrule compression fittings are suitable for the majority of topside applications involving pressures up to 413 bar.