Anti-corrosion breakthrough for offshore application by Parker

March 26, 2013

Oil and gas process design projects targeting extreme resistance to corrosion and extended service lifetimes have been boosted by a new metal processing technology. The advance comes from the Instrumentation Products Division of Parker Hannifin – the global leader in motion and control technologies – which is the first company to make fluid instrumentation products manufactured in the specialist alloy 6Mo and conforming to the stringent material quality specifications of the NORSOK M-650 standard.

The Norwegian petroleum industry is pioneering higher standards for equipment manufacturers and the NORSOK M-650 standard verifies that a manufacturer has the competence and equipment to produce reliable products from a number of specialist materials. Parker is the only instrumentation fittings company to have secured this level of product conformity, which applies to all the small bore instrumentation valves, manifolds, tubes and fittings it manufactures from 6Mo, a standard material with 22 years’ service in the North Sea.

Parker is one of the world's largest suppliers of instrumentation for offshore applications, and 6Mo super austenitic stainless steel alloy has become the most popular design choice for new North Sea oil and gas instrumentation engineering projects. Compared to standard 300 series and duplex stainless steel, the material offers much greater resistance to chloride-induced pitting, crevice corrosion and stress corrosion cracking, making it ideal for applications demanding long in-service life in hostile environments. The alloy contains a minimum content of 6% molybdenum, and has a pitting resistance equivalent (PRE) of at least 40.

One of the first bodies to investigate the quality of materials such as 6Mo was the Norwegian petroleum industry, which discovered that the current international standards for this material were not stringent enough. The introduction of NORSOK M-650 follows an earlier standard which defined appropriate processing methods for various materials – including 6Mo – used in the manufacture of pipes, but these methods are not suited to the production of small bore instrumentation components such as fittings, valves and manifolds.

Underlying its commitment to producing products that make a significant contribution to safety, Parker wanted to ensure that its 6Mo instrumentation products are the best available and could be offered with much reduced testing and qualification due to the Norsok M-650 requirements. The company sources this material from highly reputable mills, and took the decision to implement all necessary changes to ensure even higher levels of quality and traceability during product manufacture. To achieve this, the company first had to write a new material and manufacturing specification and collaborate with its suppliers to ensure that they could produce the necessary raw material.

Next, Parker modified its 6Mo manufacturing processes, test methods and quality management systems to comply with the requirements of the NORSOK M-650 standard. Part of this procedure involves validation by an interested third party, so Parker worked closely with a leading Norwegian energy company during this time. Although the new manufacturing process is patent pending and commercially confidential, it involves special treatment stages that guarantee the quality and consistency of the raw material