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GB/T5310-2017 Seamless tube for high pressure boiler

Short Description:

High-quality carbon structural steel, alloy structural steel, and stainless heat-resistant steel seamless steel pipe for high-pressure and above steam boiler pipes in GB/T5310-2007 standard. Material mainly is Cr-Mo alloy and Mn Alloy, Such as 20G, 20MnG, 20MoG, 12CrMoG, etc

  • Payment: 30% deposit, 70% L/C or B/L copy or 100% L/C at sight
  • Min.Order Quantity: 1 PC
  • Supply Ability: Annual 20000 Tons Inventory of Steel Pipe
  • Lead Time: 7-14 days if in stock, 30-45 days to produce
  • Packing: Black Vanishing, bevel and cap for every single pipe; OD below 219mm need to pack in bundle, and each bundle no exceed 2 tons.
  • Product Detail


    Product Tags


    Mainly used for high pressure and high temperature service of boiler(Superheater tube, reheater tube, air guide tube, main steam tube for high and ultra high pressure boilers). Under the action of high temperature flue gas and water vapor, the tube will oxidize and corrode. It is required that the steel pipe has high durability, high resistance to oxidation and corrosion, and good structural stability.

    Main Grade

    Grade of high-quality carbon structural steel: 20g、20mng、25mng

    Grade of alloy structural steel: 15mog、20mog、12crmog、15crmog、12cr2mog、12crmovg、12cr3movsitib, etc

    In different standard there are different Grade

    GB5310 : 20G  = EN10216 P235GH


    Material C Si Mn P S Cr MO NI Al Cu Ti V
    P235GH ≤0.16 ≤0.35 ≤1.20 ≤0.025 ≤0.025 ≤0.3 ≤0.08 ≤0.3 ≤0.02 ≤0.3 ≤0.04 ≤0.02
    20G 0.17-0.24 0.17-0.37 0.35-0.65 ≤0.03 ≤0.03 - - - - - - -
    Material Tensile Strength Yield Extension
    20G 410-550 ≥245 ≥24
    P235GH 320-440 215-235 27
    360-500 25
    Material Test
    20G: Flattening Hydraulic Impact Test NDT Eddy Grazin size Microscopic structure
    P235GH Flattening Hydraulic Impact Test NDT Electromagnetic Drift expanding Leak tightness


    Wall Thickness and Outter Diameter:

    If there is no special requirements, pipe gonna be delivery as  norminal outter diameter and norminal wall thickness. As follow sheet

    Classification designation

    Method of manufacture

    Size of pipe


    Normal grade

    High grade

    W H

    Hot Rolled(extrude) pipe

    Norminal outter Diameter



    士 0.40


    57 〜325







    >325 〜6。。

    + 1%D or + 5.Take lesser one一2


    + 1%D or + 7,Take lesser one一2

    Norminal Wall Thickness






    + 12.5%S







    + 12.5%S -10%S



    Thermal expansion pipe

    Norminal outter Diameter





    Norminal Wall Thickness



    + 20%S


    + 15%S



    Cold drawn(rolled)


    Norminal outter Diameter




    >25.4 〜4()


    >40 〜50


    >50 〜60




    Norminal Wall Thickness









    The usual length of steel pipes is 4 000 mm ~ 12 000 mm. After consultation between the supplier and the buyer, and fill in the contract, it can be delivered steel pipes with a length greater than 12 000 mm or shorter than I 000 mm but not shorter than 3 000 mm; short length The number of steel pipes less than 4,000 mm but not less than 3,000 mm shall not exceed 5% of the total number of steel pipes delivered

    Delivery weight:
    When the steel pipe is delivered according to the nominal outer diameter and nominal wall thickness or the nominal inner diameter and nominal wall thickness, the steel pipe is delivered according to the actual weight. It can also be delivered according to the theoretical weight.
    When the steel pipe is delivered according to the nominal outer diameter and minimum wall thickness, the steel pipe is delivered according to the actual weight; the supply and demand parties negotiate. And it is indicated in the contract. The steel pipe can also be delivered according to the theoretical weight.

    Weight tolerance:
    According to the requirements of the purchaser, after consultation between the supplier and the purchaser, and in the contract, the deviation between the actual weight and the theoretical weight of the delivery steel pipe shall meet the following requirements:
    a) Single steel pipe: ± 10%;
    b) Each batch of steel pipes with a minimum size of 10 t: ± 7.5%.

    Test Requirement

    Hydraustatic Test:

    The steel pipe should be tested hydraulically one by one. The maximum test pressure is 20 MPa. Under the test pressure, the stabilization time should be not less than 10 s, and the steel pipe should not leak.

    After the user agrees, the hydraulic test can be replaced by eddy current testing or magnetic flux leakage testing.

    Nondestructive Test:

    Pipes that require more inspection should be ultrasonically inspected one by one. After the negotiation requires the consent of the party and is specified in the contract, other non-destructive testing can be added.

    Flattening Test:

    Tubes with an outer diameter greater than 22 mm shall be subjected to a flattening test. No visible delamination, white spots, or impurities should occur during the entire experiment.

    Flaring Test:

     According to the requirements of the purchaser and stated in the contract, the steel pipe with outer diameter ≤76mm and wall thickness ≤8mm can be done flaring test . The experiment was performed at room temperature with a taper of 60 °. After the flaring, the flaring rate of the outer diameter should meet the requirements of the following table, and the test material must not show cracks or rips

    Steel Type



    Outter diameter flaring rate of steel pipe/%

    Inner Diameter/Outter Diameter


    >0.6 〜0.8


    High-quality carbon structural steel




    Structural alloy steel




    •The inner diameter is calculated for the sample.

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