Application
Alloy 825 seam welded pressure tubing in the heat treated and cold worked condition is typically used in oil and natural gas wells for chemical injection applications. In such applications, it is commonly reffered to as capillary tubing and is free-hanging (self supporting) inside the production casing. The chemicals being injected are often used to enhance production flow rates, inhibit corrosion or scaling and/or de-water. The tubing is frequently supplied as 5,000 to 35,000 ft. coils on a wooden 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 is first sunk to an intermediate outside diameter, heat treated, and joined by orbital welding to achieve the desired length. The tubing is then sunk to the final outside diameter and provided in the as-cold worked condition. 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 at intermediate size in the as-heat treated condition. Radiographic testing is performed on all orbital welds and those strip splice welds detected by ECT at intermediate size in the as-heat treated condition. Yield pressure hydro static testing is performed on the cold worked tubing at final size. 

Standards and Specifications
Tubing Specification PTM-TS-006, Alloy 825 Tubing with Enhanced Properties
ASTM B704, Standard Specification for Welded UNS N06625, UNS N06219, and UNS N08825 Alloy Tubes, except in the as-cold worked condition
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.