Meilong is a supplier of welded and redrawn, seamless and redrawn
coiled tubing which are made from corrosion-resistant austenitic,
duplex, super duplex stainless steels and nickel alloy grades. We
have been specializing in manufacturing coiled tubing used in the
oil and gas industry.
Tubing for Control Lines
A direct hydraulic control umbilical provides direct hydraulic
control of each valve on a subsea christmas tree, through a bundle
of tubes from the topsides hydraulic power unit (HPU) to the subsea
tree. No electrical power or signal is required. Actuation of
valves is by the supply of hydraulic power to the relevant tube.
This is accomplished by opening the relevant valve on the manifold
located on the topsided HPU. This type of umbilical is limited to
subsea production systems with short offsets to the host and few
trees.
Thanks to the experience and expertise gained in the production and
inspection, the tubes supplied by Meilong fully meet stringent
quality requirements of the oil & gas industries. The tubing
deployed in the umbilicals used in aggressive subsea and downhole
conditions.
Tubing for Chemical Injection
One of the main challenges in the upstream processes of the oil and
gas industry is to protect pipeline and process equipment against
waxes, scaling and asphalthane deposits. The engineering
disciplines involved in flow assurance play an essential part in
mapping the requirements that reduce or prevent loss of production
due to pipeline or process equipment blockage. Steel tubing from
Meilong is applied to umbilicals and chemical injection systems
play an effective role in chemical storage and delivery at an
optimizing flow assurance.
Our tubing is characterized with integrity and quality to be
specially used in subsea conditions in the industries of oil and
gas extraction.
Duplex 2205, Chemical composition
| Element | Composition, % |
| Chromium | 22.0-23.0 |
| Nickel | 4.5-6.5 |
| Molybdenum | 3.0-3.5 |
| Manganese | 2.00 max. |
| Silicon | 1.00 max. |
| Carbon | 0.030 max. |
| Sulfur | 0.020 max. |
| Phosphorous | 0.030 max. |
| Nitrogen | 0.14-0.20 |
Application: High mechanical strength and good resistance to
localized cracking & chloride stress corrosion.
Tensile strength, min.: 90ksi (620MPa)
Yield strength, min.: 65ksi (450MPa)
Elongation in 2 in., min.: 25%
Hardness, max.: Brinell 290, or Rockwell C 30.5
Duplex 2205, Characteristics and properties
Nominal Outside Diameter in. | Nominal Wall Thickness in. | Minimum Burst Pressure psi | Minimum Collapse Pressure psi |
| Min. | Min. | Min. | Min. |
| 0.250 | 0.035 | 27,391 | 17,441 |
| 0.250 | 0.049 | 38,348 | 23,028 |
| 0.250 | 0.065 | 50,870 | 28,442 |
| 0.375 | 0.035 | 18,333 | 12,222 |
| 0.375 | 0.049 | 25,667 | 16,489 |
| 0.375 | 0.065 | 34,048 | 20,930 |
| 0.375 | 0.083 | 43,476 | 25,371 |
| 0.500 | 0.035 | 13,777 | 8,091 |
| 0.500 | 0.049 | 19,288 | 12,798 |
| 0.500 | 0.065 | 25,586 | 16,444 |
| 0.500 | 0.083 | 32,672 | 20,233 |
| 0.625 | 0.035 | 11,035 | 4,990 |
| 0.625 | 0.049 | 15,449 | 9,903 |
| 0.625 | 0.065 | 20,494 | 13,478 |
| 0.625 | 0.083 | 26,169 | 16,722 |
Application
Duplex 2205 seam welded pressure tubing in the heat treated
condition is typically used in oil and natural gas wells for
chemical injection applications. In such applications, it is
commonly referred 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. However, the tubing can also
be used for control line tubing applications including
hydraulically actuated surface-controlled subsurface safety valves.
For control line applications, the tubing is generally deployed by
strapping it to the outside of the production casing. The tubing is
frequently supplied as 5,000 to 35,000 ft. coils on a wooden or
steel reel, depending on size.
Description
Duplex 2205 is a duplex stainless steel. When properly heat
treated, the microstructure consists of a nearly equal mixture of
the austenitic and ferrite phases. This two-phase microstructure
produces a fine grain size which increases the yield strength. In
the final heat treated condition, alloy 2205 can achieve a yield
strength approximately twice that of austenitic alloys such as
316L, 825 and 625 which must be cold worked to achieve comparable
yield strengths. Duplex stainless steels are often classified as
lean, conventional, super or hyper based upon their pitting
resistance equivalent (PRE or PREN). Various PRE formulas are used
to rank an alloy’s resistance to chloride pitting corrosion based
upon its composition. Alloy 2205 typically has a PRE of 36 and is
considered a conventional duplex stainless steel. Alloy 2205 is
often selected for use in oil and gas production environments based
upon its higher strength and resistance to pitting, crevice and
stress corrosion cracking in chloride containing environments.
Consult ISO 15156-3, Table A.24 for the limits regarding the use of
alloy 2205 in hydrogen sulfide containing environments for oil and
gas production.
Manufacturing Process and Resultant Properties
Strip splice welds join lengths of cold rolled strip to enable long
lengths between orbital welds (greater than 14,500 ft between
orbital welds is achievable). The strip is formed into a tubular
cross section and longitudinally seam welded using the gas tungsten
arc (GTAW) process. The tubing may be welded at a larger outside
diameter, plug-redrawn to final size and subsequently heat treated.
The final material condition of the tubing is heat treated.
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. Those strip splice welds detected by ECT. Yield pressure
hydrostatic testing is performed on the heat treated tubing at
final size.
Quality Assurance
Eddy current test (ECT)
Ultrasonic test
Hydrostatic test
Chemical composition analysis
Tensile test
Hardness test
Dimension & visual inspect
Metallographic analysis
Standards and Specifications
Tubing Specification PTM-TS-011, Duplex 2205 Tubing for Control
Line Applications
ASTM A789, Standard Specification for Seamless and Welded
Ferritic/Austenitic Stainless Steel Tubing for General Service
Meets the material limits for duplex stainless steel with PREN 30
to 40 as listed in ISO 15156-3, Table A.24
Coiled Tubing Size
| Imperial size | Metric size |
OD inch | WT inch | OD mm | WT mm |
| 1/8 (0.125) | 0.028 | 3.18 | 0.71 |
| 0.035 | 3.18 | 0.89 |
| 3/16 (0.188) | 0.028 | 4.76 | 0.71 |
| 0.035 | 4.76 | 0.89 |
| 0.049 | 4.76 | 1.24 |
| 1/4 (0.250) | 0.035 | 6.35 | 0.89 |
| 0.049 | 6.35 | 1.24 |
| 0.065 | 6.35 | 1.65 |
| 0.083 | 6.35 | 2.11 |
| 3/8 (0.375) | 0.035 | 9.53 | 0.89 |
| 0.049 | 9.53 | 1.24 |
| 0.065 | 9.53 | 1.65 |
| 0.083 | 9.53 | 2.11 |
| 1/2 (0.500) | 0.035 | 12.7 | 0.89 |
| 0.049 | 12.7 | 1.24 |
| 0.065 | 12.7 | 1.65 |
| 0.083 | 12.7 | 2.11 |
| 5/8 (0.625) | 0.049 | 15.88 | 1.24 |
| 0.065 | 15.88 | 1.65 |
| 0.083 | 15.88 | 2.11 |
| 3/4 (0.75) | 0.065 | 19.05 | 1.65 |
| 0.083 | 19.05 | 2.11 |
| 1 | 0.065 | 25.4 | 1.65 |
| 0.083 | 25.4 | 2.11 |
Tubing length up to 32,808 feet (10,000 m)
For control line, chemical injection line, umbilicals
Available materials
Austenitic: 316L
Duplex: S31803, S32205
Super Duplex: S32750
Nickel alloy: N06625, N08825
Norm Equivalence
| Grade | UNS No | Euro norm | Japanese |
| No | Name | JIS |
| Alloy | ASTM/ASME | EN10216-5 | EN10216-5 | JIS G3463 |
| 316L | S31603 | 1.4404, 1.4435 | X2CrNiMo17-12-2 | SUS316LTB |
| 2205 | S31803 | 1.4462 | X2CrNiMoN22-5-3 | SUS329J3LTB |
| 2507 | S32750 | 1.4410 | X2CrNiMoN25-7-4 | |
| 625 | N06625 | 2.4856 | NiCr22Mo9Nb | |
| 825 | N08825 | 2.4858 | NiCr21Mo | |
