HYDRAULIC CONTROL AND INSTRUMENTATION APPLICATIONS
STAINLESS STEEL AND HIGH NICKEL ALLOYS COILED TUBING SOLUTIONS
MEILONG is an important manufacturer in premium coiled seamless &
welded tubular solutions for oil and gas applications. In an
endeavor to increase its presence in subsea, MEILONG has extended
its offer by developing a highly innovative tubular solution for
umbilical projects.
MEILONG has developed a strong and unique expertise in premium
quality tubes to answer the most stringent specifications of its
customers. Based on this expertise in high pressure, and extremely
high pressure tubes, MEILONG’s state-of-art factory is exclusively
dedicated to the manufacturing and supply of super duplex and high
nickel alloys tubes for corrosive downhole applications and is now
ready to offer the highest specifications for your toughest
challenges.
Description
TP316L is a chromium-nickel austenitic stainless steel with an
addition of molybdenum and reduced carbon content. The addition of
molybdenum provides improved resistance to pitting and crevice
corrosion in environments containing halides such as chlorides when
compared to so-called conventional 18 chromium 8 nickel austenitic
stainless steels such as 304L. The reduced carbon content minimizes
harmful chromium carbide precipitation during welding and thereby
improves resistance to intergranular corrosion. Austenitic
stainless steels such as TP316L are susceptible to stress corrosion
cracking (SCC) in environments containing chlorides and other
halides. ANSI 316L is generally used in oil and gas production
environments which do not contain oxygen and have limited amounts
of chlorides and hydrogen sulfide. Consult ISO 15156-3, Table A.2
for the limits regarding TP316L in hydrogen sulfide-containing
environments for oil and gas production.
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.
TP316L has a low carbon content and therefore better resistance to
intergranular corrosion than steels of type TP316.
Application (seamless tubing)
TP316L seamless 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 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.
TP316L, Chemical composition
| Element | Composition, % |
| Chromium | 16.0-18.0 |
| Nickel | 10.0-14.0 |
| Molybdenum | 2.0-3.0 |
| Manganese | 2.00 max. |
| Silicon | 1.00 max. |
| Carbon | 0.035 max. |
| Sulfur | 0.030 max. |
| Phosphorous | 0.045 max. |
Application: Standard oil and gas CRA (corrosion resistant alloy)
Tensile strength, min.: 70ksi (485MPa)
Yield strength, min.: 25ksi (170MPa)
Elongation in 2 in., min.: 35%
Capillary String 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
Dimensional tolerances: ASTM A632 standard is used to define
permissible variation in tubing wall thickness and diameter.
Variation in tubing diameter:
+0.003’’ is permissible for tubing below 0.188’’ diameter and
+0.004’’ is for tubing above 0.188’’ nominal diameter
Variation in wall thickness: For both seamless and welded tubing
+10/-10% deviation is acceptable
No negative tolerance permitted on the variation on length
measurement
Orbital welds: Each one reel of tubing is a continuous length
without orbital butt welds
Pressure rating: The pressure rating shall be specified on the PO.
Material quality: The material shall be free of injurious seams,
laps, longitudinal and transverse notches or other imperfections,
which due to their nature will interfere with the use of the
material I final usage of the part.
Pressure testing: Each coil of tubing shall be hydrostatically
pressure tested at its maximum rated test pressure (specified in
purchase order or the supplied test pressure rating table) for a
minimum of 15 minutes. The test pressure of the tubing shall be
reported on the certification.
Production Process
Welded & Redrawn Tubing
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 is first sunk to an intermediate
outside diameter, heat treated, and make the same process to obtain
the desired size.
Seamless & Redrawn Tubing
Seamless extruded tube hollows are drawn or drawn / sunk to final
size to produce seamless tubing coils 500 to 2,000 ft. long,
depending upon the size. The tubing is heat treated and joined by
orbital welding to achieve the desired length. The final material
condition of the tubing is heat treated.
Standards and Specifications
ASTM A269, Standard Specification for Seamless and Welded
Austenitic Stainless Steel Tubing for General Service
Meets the material limits for 316L austenitic stainless steel
listed in ISO 15156-3, Table A.2.
Tube markings include size, material type/grade, specification,
heat number, and other information.
Quality Assurance
Eddy current test (ECT)
Ultrasonic test
Hydrostatic test
Chemical composition analysis
Tensile test
Hardness test
Dimension & visual inspect
Metallographic analysis
Duplex Stainless 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 |
Available Material Grades
| Standard | Grade | UNS | Steel No. |
ASTM A213 A269 ASME SA213 | TP304 TP304L | S30400 S30403 | 1.4301 1.4306 |
ASTM A213 A269 ASME SA213 | TP316 TP316L | S31600 S31603 | 1.4401 1.4404 |
| EN 10216-5 TC1 | TP316Ti | S31635 | 1.4571 |
ASTM A213 A269 ASME SA213 | TP321 TP321H | S32100 S32109 | 1.4541 1.4878 |
| ASTM A789 | 2205
| S31803 S32205 | 1.4462
|
| ASTM A789 | 2507 | S32750 | 1.4410 |
| ASTM B423 | Alloy 825 | N08825 | 2.4858 |
| ASTM A269 | TP904L | N08904 | 1.4539 |
| ASTM A269 | 6Moly | S31254 | 1.4547 |
| ASTM B444 | Alloy 625 | N06625 | 2.4856 |
| ASTM B165 | Alloy 400 | N04400 | 2.4360 |
