NORSOK_-_oil_rig.jpgThe coiled tubing (CT) industry is a major part of oil & gas upstream subsea applications.  Coiled tubing is used widely in extreme conditions in offshore environments. The North Sea is a  good example of extreme offshore applications. Extreme conditions require a special grade of seamlessstainless steel tubing known as 6 Mo (UNS S31254).  Common applications include interventions in wells or for production tubing  to extend the life of “depleted wells”.  Interventions are operations performed in oil wells during production or at the end  of a well’s useful life.  The process of intervention changes the condition of the well or its structure, and can be used for well diagnosis or to assist controlling production.

Super Austenitic Tubing Resists Pitting and Crevice Corrosion

6 Mo  is a super austenitic stainless steel with  6.0% – 6.5% molybdenum, 19.5% – 20.5% Chromium, 17.5% – 18.5% Nickel, and 0.18% – 0.22% nitrogen, providing significant resistance to pitting and crevice corrosion, which are primary concerns in North Sea applications.  In addition, 6Mo has significantly higher tensile properties as compared to  other austenitic stainless steels allowing higher working pressures.


Suppliers of 6 Mo tubing to North Sea offshore oil applications must meet specific NORSOK qualification. NORSOK (originally named “the Norwegian shelf’s competitive position”) is a set of standards developed by the Norwegian petroleum industry to ensure adequate safety, added value and cost effectiveness for development and operations in the petroleum industry and are intended to supersede oil company specifications and to serve as authorities’ regulatory references. [5]

6 mo Tubing.jpg

NORSOK Standard M-650, “Qualification of manufacturers of special materials” is used to verify that a manufacturer has sufficient competence and expertise to produce the relevant material, and the necessary manufacturing facilities and equipment to support the production of the product for the duration of the qualification period.

HandyTube has been successfully qualified by MRC Energy Piping for its 6 Mo, (NORSOK Standard “Material data sheets and element data sheets for piping”, MDS R18) seamless coil and straight length tubing up to 3.8 mm wall thickness according to NORSOK M650 Edition 4.  NORSOK qualification is a significant milestone in HandyTube’s commitment to being a valued supplier and a key resource to the oil and gas industry, providing custom solutions for critical applications.

Coiled Tubing for Pumping Chemicals to the Well as an Alternative to Wireline

In subsea applications coiled tubing is most frequently used in a chemical wash or circulating operation by pumping chemicals to the bottom of the well.  This tubing may also replace wireline to run electrical cable for transmitting data about wellbore conditions and logging if a wireline tractor is not practical for lowering the tool string.  Using coiled tube to replace wireline is common when conditions in the well are not conducive for gravity to pull the weight of the tool string into position.

Coiled Tubing Applications in Deepwater Installations with Working Pressures up to 15,000 psi Include:Coiled Tubing.png

  • Compliant Towers
  • Drill ships
  • Semisubmersibles
  • Spars
  • Tension leg platforms
  • Umbilical Control Lines
  • Hydraulic Chemical Injection Lines
  • Control Lines for Subsea Safety Valves

Seamless Straight Tubing

Seamless straight length tubing  is often used in enclosed instrumentation equipment  connecting hydraulic pumps and tools, and operating hydraulically actuated devices.  Seamless straight length tube is also used in sampling & conditioning systems, control panels, processing facilities, offshore subsea manifolds and templates in the North Sea. [3]


Among its other many applications, tubing is used to clean out boreholes, conduct cementing, assist in pressure control and many other operations that involve pumping water or oil based fluids into a well.

HandyTube has specialized in the manufacture of seamless tubing of outer diameters less than 1” (25.4mm) for over 35 years. HandyTube seamless coil and straight-length tubing is available in a number of high performance corrosion resistant stainless steel and high nickel alloys,  suitable for a variety of environmental conditions.  Straight-length tubing is ideal for ultra-high purity, military, aircraft, semiconductor, medical and general instrumentation applications.  HandyTube has worked successfully with customers worldwide to take products from a raw idea to full implementation of extensive customer-specific solutions for critical applications. Do you have HandyTube engineered solutions in your critical application? If not, visit or contact for our engineered products and services.

About HandyTube

HandyTube Corporation, a Handy & Harman Company, is a leading manufacturer of seamless, stainless steel and Nickel alloy coil and straight length tubing and is able to produce seamless tubing upwards of 6,000 feet long, and in custom sizes to best suit  your application.  Parent company Handy & Harman Ltd., based in White Plains, N.Y., is a diversified manufacturer of engineered niche industrial products with leading market positions in many of the markets it serves. Through its operating subsidiaries, Handy & Harman focuses on innovative technology and serves customers across a wide range of markets. Handy & Harman’s diverse product offerings are marketed throughout the United States and internationally. Its common stock is listed on the NASDAQ Capital Market under the symbol HNH. Website:



[4] Odfjell Well Services



* Straight length up