Stainless Steel S31803 Metal Hydraulic Tubing Metallic Bright Capillary String

Product Details:
Place of Origin: China
Brand Name: MEILONG
Certification: ISO9001:2015, PED 97/23/EC
Model Number: 1/4'' OD x 0.065'' WT
Payment & Shipping Terms:
Minimum Order Quantity: 10000 feet
Price: Negotiable
Packaging Details: Level wound coiled on wooden spool, and wooden case packing
Delivery Time: 10 days (for our required MOQ)
Payment Terms: L/C, T/T
Supply Ability: 150000 meters per month

Detail Information

Material: Duplex S31803 Comply With NACE MR0175/ISO15156 Material: Duplex S31803 Comply With NACE MR0175/ISO15156
Tube Type: Seamless Condition: Bright Annealed
Length: Up To 10000 Meters Long Per Reel Qualification: Hydrostatic Tested
Application: Oil And Gas Fields Surface: Metallic Bright
Surface: Metallic Bright Specialty: High-pressure Hydraulic
High Light:

annealed stainless steel tubing


stainless steel coil tubing

Product Description




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.



Duplex Stainless S31803 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.



Duplex Stainless S31803 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, Duplex Stainless S31803 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. Duplex Stainless S31803 typically has a PRE of 36 and is considered a conventional duplex stainless steel. Duplex Stainless S31803 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 Duplex Stainless S31803 in hydrogen sulfide containing environments for oil and gas production.


Corrosion Resistance

S31803 duplex stainless steel is a cost effective solution for many applications where the 300 series stainless steels are susceptible to chloride stress corrosion cracking. Stress corrosion cracking occurs when stainless steels are subjected to tensile stress, while in contact with solutions containing chlorides. Increasing temperatures also increase the susceptibility of stainless steels to stress corrosion cracking.


The combination of chromium, molybdenum and nitrogen convey the good resistance of S31803 to chloride pitting and crevice corrosion. This resistance is extremely important for services such as marine environments, brackish water, bleaching operations, closed loop water systems and some food processing applications. The high chromium, molybdenum and nitrogen contents of S31803 provide corrosion resistance superior to common stainless steels, such as, 316L and 317L in most environments.


Duplex Stainless S31803, 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


Capillary String Size

Imperial size Metric size









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

Tubing Specification PTM-TS-011, Duplex Stainless 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

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


Duplex Stainless 2205, Characteristics and properties

















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








ASTM A213 A269








EN 10216-5 TC1 TP316Ti S31635 1.4571

ASTM A213 A269















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


Stainless Steel S31803 Metal Hydraulic Tubing Metallic Bright Capillary String 0

Stainless Steel S31803 Metal Hydraulic Tubing Metallic Bright Capillary String 1

Stainless Steel S31803 Metal Hydraulic Tubing Metallic Bright Capillary String 2


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