Application
Alloy 825 seam welded pressure tubing in the heat treated condition is typically used in oil and natural gas wells for applications including hydraulically actuated surface-controlled subsurface safety valves, chemical injection, and instrumentation. In such applications, it is commonly referred to as control line tubing. The tubing is generally deployed by strapping it to the outside of the production casing. It may be encapsulated and can be included along with other pressure tubing or TEC and mechanical components, such as bumpers, within a flatpack. The tubing is frequently supplied as 5,000 to 35,000 ft. coils on a wooden or steel reel, depending on size.

Description 
Alloy 825 is a titanium-stabilized austenitic nickel-iron - chromium alloy with additions of molybdenum and copper. The chemical composition of the alloy is listed in Table 1. The alloy is characterized by good resistance to stress-corrosion cracking due to its nickel content (38.0 to 46.0) and satisfactory resistance to pitting and crevice corrosion.
Alloy 825 has shown good corrosion resistance in oil and gas production environments containing hydrogen sulfide, carbon dioxide and chlorides. Consult ISO 15156-3, Table A.14 for the limits regarding material type 4c in hydrogen sulfide containing environments for oil and gas production.
Draka uses expert system software to assist customers in their selection of alloys for oil and gas environments.

Manufacturing Process and Resultant Properties
Strip splice welds join lengths of cold rolled strip to enable long lengths between orbital welds (greater than 5,000 ft between orbital welds is achievable). The strip is formed into a tubular cross section and longitudinally seam welded using either the gas tungsten arc (GTAW) or laser beam welding (LBW) process. The tubing may be welded at a larger outside diameter, sunk to final size and subsequently heat treated. Heat treated tubing is joined by orbital welding to achieve the desired length. The final material condition of the tubing is heat treated. Mechanical properties, permissible variation in tubing dimensions and size dependant characteristics / properties are listed in Tables 3, 4, and 5 on reverse respectively.

Nondestructive Testing (NDT)
Eddy current testing (ECT) is performed on the longitudinally seam welded tubing and strip splice welds in the as-heat treated condition. Radiographic testing is performed on all orbital welds and those strip splice welds detected by ECT. Yield pressure hydrostatic testing is performed on the heat treated tubing at final size. 

Standards and Specifications
Tubing Specification PTM-TS-002, Alloy 825 Tubing for Control Line Applications
ASTM B704, Standard Specification for Welded UNS N06625, UNS N06219, and UNS N08825 Alloy Tubes
Meets the material limits for annealed and cold-worked, solidsolution, nickel-based alloys listed in ISO 15156-3, for Material Type 4c in Table A.14