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
Duplex 2507 is a super duplex stainless steel designed for
applications which demand exceptional strength and corrosion
resistance. Alloy 2507 has 25% chromium, 4% molybdenum, and 7%
nickel. This high molybdenum, chromium and nitrogen content results
in excellent resistance to chloride pitting and crevice corrosion
attack and the duplex structure provides 2507 with exceptional
resistance to chloride stress corrosion cracking.
Usage of Duplex 2507 should be limited to applications below 600° F
(316° C). Extended elevated temperature exposure can reduce both
the toughness and corrosion resistance of alloy 2507.
Duplex 2507 possesses excellent mechanical properties. Often a
light gauge of 2507 material can be used to achieve the same design
strength of a thicker nickel alloy. The resulting savings in weight
can dramatically reduce the overall cost of fabrication.
Corrosion Resistance
2507 Duplex is highly resistant to uniform corrosion by organic
acSuper Duplex 2507 Plateids such as formic and acetic acid. It is
alsohighly resistant to inorganic acids, especially if they contain
chlorides. Alloy 2507 is highly resistant to carbide-related
intergranular corrosion. Due to the ferritic portion of the duplex
structure of the alloy it is very resistant to stress corrosion
cracking in warm chloride containing environments. Through
additions of chromium, molybdenum and nitrogen localized corrosion
such as pitting and crevice attack are improved. Alloy 2507 has
excellent localized pitting resistance.
Characteristics
● High resistance to chloride stress corrosion cracking
● High Strength
● Superior resistance to chloride pitting and crevice corrosion
● Good general corrosion resistance
● Suggested for applications up to 600° F
● Low rate of thermal expansion
● Combination of properties given by austenitic and ferritic
structure
● Good weldability and workability
Super Duplex Stainless 2507, Chemical composition
| Element | Composition, % |
| Chromium | 24.0-26.0 |
| Nickel | 6.0-8.0 |
| Molybdenum | 3.0-5.0 |
| Manganese | 1.2 max. |
| Silicon | 0.8 max. |
| Carbon | 0.030 max. |
| Sulfur | 0.020 max. |
| Phosphorous | 0.035 max. |
| Nitrogen | 0.24-0.32 |
Application: Super duplex alloy combining excellent strength with
good corrosion resistance in high chloride and seawater
environments
Tensile strength, min.: 116ksi (800MPa)
Yield strength, min.: 80ksi (550MPa)
Elongation in 2 in., min.: 15%
Hardness, max.: Brinell 310, or Rockwell C 32
Standards and Specifications
Tubing Specification PTM-TS-011, Duplex Stainless 2507 Hydraulic
Tubing for Control Line Applications
ASTM A789, Standard Specification for Seamless and Welded
Ferritic/Austenitic Stainless Steel Tubing for General Service
All Super Duplex Stainless 2507 control line tubing offered by
MEILONG are made from a controlled-chemistry. Super Duplex
Stainless 2507 material with minimum pitting resistance equivalent
(PRE) value of 42.5
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.
Super Duplex Stainless 2507 material provides excellent corrosion
resistance in chloride-containing environments.
All Super Duplex Stainless 2507 control line tubing offered by
MEILONG are made from a controlled-chemistry. Super Duplex
Stainless 2507 material with minimum pitting resistance equivalent
(PRE) value of 42.5
Size include 1/4’’, 3/8’’, 1/2’’, 5/8’’, 3/4’’, and 1 in. outside
diameter.
Tubing nominal wall thickness meets ASTM A-789
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
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 |
