Seamless Redrawn Capillary Coiled Tubing SS316L 1 8 Capillary Tube

Seamless and redrawn capillary tubing made from SS316L without orbital welds

Meilong Tube specially manufactures seamless and redrawn, welded and redrawn coiled tubing which are made from corrosion-resistant austenitic, duplex, super duplex stainless steels and nickel alloy grades. The tubing is used as hydraulic control lines and chemical injection lines specially serving oil and gas, geothermal industry.

Typical Size of Capillary Tubing

Outside diameter of control lines is mainly 1/4’’ (6.35mm).

Wall thicknesses: 0.035’’ (0.89mm), 0.049’’ (1.24mm), 0.065’’ (1.65mm)

Control line tubing is available in lengths from 400 feet (122 meters) to 32,808 feet (10,000 meters). No orbitally butt welds.

Other specifications (1/8’’ to 3/4’’) are available on request.

Importance of Capillary Tubing

Each one tubing coil is a completely continuous length without orbital welds.

Each one tubing coil is hydrostatic tested at minimum 10,150 psi.

The test can be witnessed on site by the third party inspectors (SGS, BV, DNV).

Other tests are eddy current test, chemicals, flattening, flaring, tensile, yield, elongation, hardness for the material quality.

Application Description for Capillary Tubing for SSSV

A safety valve is a valve that acts as the protector of your equipment. Safety valves can prevent damage to your pressure vessels and even prevent explosions at your facility when installed in pressure vessels.

A safety valve is a type of valve that automatically actuates when the pressure of the inlet side of the valve increases to a predetermined pressure, to open the valve disc and discharge the fluid. The safety valve system is designed to be a fail-safe so that a wellbore can be isolated in the event of any system failure or damage to the surface production-control facilities.

In most cases, it is mandatory to have a means of closure for all wells capable of natural flow to the surface. The installation of a subsurface safety valve (SSSV) will provide this emergency closure capability. Safety systems may be operated on a fail-safe principle from a control panel located on the surface.

The SCSSV is controlled by a ¼” stainless steel control line that is attached to the outside of the well tubing string and installed when the production tubing is installed. Depending on the wellhead pressure, it may be necessary to keep as much as 10,000 psi on the control line to keep the valve open.

Other Applications

Capillary coiled alloy tubing for chemical injection

Bare and encapsulated hydraulic control line coiled alloy tubing for subsea safety valves

Velocity strings, work strings, and steel tube umbilicals

Geothermal coiled alloy tubing

Alloys for Control Lines Capillary Tubing

Control Line Capillary Tubing Features

Close dimensional tolerances

Considerably enhanced mechanical properties

Superior surface finish

High cleanness of inside surface

Controlled ovality, eccentricity

Chemical compositions of SS316L for Capillary Tubing

SS316L is an austenitic chromium-nickel stainless steel with molybdenum and a low carbon content.

Corrosion Resistance

Organic acids at high concentrations and moderate temperatures

Inorganic acids, e.g. phosphoric and sulphuric acids, at moderate concentrations and temperatures. The steel can also be used in sulphuric acid of concentrations above 90% at low temperature.

Salt solutions, e.g. sulphates, sulphides and sulphites

Caustic environments

Austenitic steels are susceptible to stress corrosion cracking. This may occur at temperatures above about 60°C (140°F) if the steel is subjected to tensile stresses and at the same time comes into contact with certain solutions, particularly those containing chlorides. Such service conditions should therefore be avoided. Conditions when plants are shut down must also be considered, as the condensates which are then formed can develop conditions that lead to both stress corrosion cracking and pitting.

SS316L has a low carbon content and therefore better resistance to intergranular corrosion than steels of type SS316.

Tubing Process and Packing

Seamless- pierced, redrawn, annealed (multi-pass circulation process)

Welded- longitudinally welded, redrawn, annealed (multi-pass circulation process)

Packing- Tubing is level wound coiled on the metal / wooden drums or spools.

All drums or spools are packed in wooden crates for easy logistic operation.