GB 28883-2012Composite seamless steel tubes for pressure (English PDF)

5.1 Diameter and wall thickness

5.1.1 steel should nominal diameter and a nominal wall thickness (thickness of the inner layer thickness) delivery. According to the demand side, the supply and demand sides negotiated, steel Tube nominal diameter, and may be the minimum wall thickness (thickness of the inner layer thickness), nominal inside diameter (d) and the nominal wall thickness dimensions or other ways of delivery.

5.1.2 steel pipe nominal outside diameter and wall thickness should be consistent with GB/T 17395 of. According to the demand side, the supply and demand sides negotiated, can supply GB/T 17395 pipe size than predetermined.

When the pipe by a nominal inside diameter and nominal wall thickness of the delivery, the dimensions are determined by supply and demand sides negotiated.

NOTE. Unless otherwise indicated, the standard wall thickness (S) comprises a nominal wall thickness and a minimum wall thickness, the outer diameter (D) comprises a nominal diameter and an outer diameter is calculated.

5.1.3 steel pipe according to nominal diameter and nominal wall thickness delivery, the nominal outside diameter and nominal wall thickness tolerances shall comply with the requirements in Table 1.

Outer diameter steel pipe according to the nominal wall thickness and minimum delivery, the nominal outer diameter tolerance shall be as specified in Table 1, the wall thickness tolerance is twenty two%

And a nominal inside diameter steel pipe according to the nominal wall thickness delivery, the nominal diameter allows for deviation of ± 1% d, nominal thickness deviation should be allowed symbol Co specified in Table 1.

The thickness of the base layer, said well pipe (S1) for the nominal wall thickness should be 50% to 90%, double the nominal thickness (S2) of the nominal thickness should be 10% to 50%.

According to the buyer requirements, the agreement between manufacturer, can supply a predetermined tolerance than the size of the steel pipe.

Table 1 Compound seamless pipe nominal diameter and nominal wall thickness in millimeters tolerance

Classification code for producing a pipe size tolerances embodiment WH Hot-rolled (extrusion) Steel Pipe the outer diameter (D) <=80 ± 0.40 > 80 to 325 S<=35 ± 0.75% D S > 35 ± 1% D > 325 ± 1% D Nominal wall thickness (S) or base layer thickness (S1) 12.5-10% S or 12.5-10% S1 Complex nominal thickness (S2) - -10% S2 WC Cold-rolled (pull) Steel Pipe Nominal outside diameter (D) <=80 ± 0.30 > 80 ~ 219 ± 0.75% D > 219 to 325 S<=35 ± 0.75% D S > 35 ± 1% D > 325 ± 1% D Nominal wall thickness (S) or nominal thickness of the base layer (S1) S<=3 ± 0.30 S > 3 ± 10% S or ± 10% S1 Complex nominal thickness (S2) - -10% S2 Other manufacturing methods of producing a composite pipe, which size is determined by the tolerances negotiated supply and demand.

5.2 Length

5.2.1 Length of the steel pipe is generally 4000mm ~ 12000mm

By agreement between the manufacturer and specified in the contract, deliverable 12000mm length greater than or less than, but not less than 4000mm 1000mm the steel pipe. But less than 4000mm 1000mm shorter than the steel pipe, the number should not exceed 10% of the total number of batch delivery.

5.2.2 According to the demand side, the supply and demand sides negotiated, and in the contract, the pipe length can be cut to length delivery. It allows partial cut length Difference is 20 0mm.

5.3 Curvature

5.3.1 curvature per meter pipe shall be as follows.

a) When the thickness S<=15mm, no greater than 1.5mm/m;

b) a wall thickness of 15mm \u003cS<=30mm,不大于2.0mm/m;

c) the wall thickness S > When 30mm, is not greater than 3.0mm/m.

5.3.2 nominal diameter of not less than 127mm of steel, the entire length of the bend should not be greater than 0.1% of the length of pipe.

5.3.3 According to the buyer requirements, the agreement between manufacturer, and in the contract, the degree of curvature per meter and the full length of the pipe can be bent to other Provisions.

5.4 Uneven thickness and roundness

According to the demand side, the supply and demand sides negotiated and specified in the contract, roundness and wall thickness of the pipe shall not exceed the outside diameter is not public 80% of the difference between the wall thickness and tolerances.

5.5 Tip shape

Pipe and pipe end faces at both ends should be perpendicular to the axis, the cutout burrs should be removed.

5.6 Weight

Pipe delivery according to the actual weight.

6.2 Manufacturing Methods

6.2.1 Steel Smelting

Water should be coarse steel steel vacuum refining or electroslag remelting method of smelting. Supply and demand sides through consultation, and in the contract, the recoverable Other smelting methods higher requirements. When the demand side to specify a particular method of smelting, should be specified in the contract.

A method of manufacturing a tube 6.2.2 Metallurgically fused composite seamless steel tube shall use the two metallurgical fused together producing a composite manner. According to the buyer requirements, and specified in the contract, also producing a composite tube according to another method of seamless pipe.

A method for producing a steel pipe 6.2.3 Metallurgical fusion complex should be seamless steel hot extrusion (rolling), cold drawn (rolled) seamless manufacturing method. According to the demand side, and note in the contract Ming, two grades may be explosively formed by seamless tubes, and other methods for producing nested.

6.3 Delivery status

Steel should be delivered to heat treatment. The heat treatment temperature should be suitable for the base layer and multi-layer of two materials in order to obtain optimum physical and chemical properties. Heat Treatment process should be specified in the quality certificate.

According to the demand side, the supply and demand sides negotiated, and in the contract, the composite can supply seamless steel tubes other states.

6.4 Mechanical Properties

6.4.1 Tensile Test

6.4.1.1 pipe shall be the base or the whole (including the base layer and a clad layer) Tensile test at room temperature. When tested in accordance with the base layer, the tensile mechanical Properties to comply with Table 4; when tested according to the overall tensile mechanical properties of the corresponding base layer shall be as specified in Table 4 grades.

6.4.1.2 When a tensile test of the base material, a clad material should be completely removed.

6.4.1.3 Pipe outside diameter less than 219mm, the substrate or the entire longitudinal tensile test should be sampled along the pipe.

An outer diameter of 219mm steel pipe, steel pipe when the size of the base layer is sufficient transverse cross-section sample preparation, Primary lateral tensile steel should be done Tensile test. Base transverse tensile test should be taken diameter cylindrical test pieces of 10mm; steel base layer when taken insufficient size 10mm when the sample should be used having a diameter of 5mm or 8mm in transverse cross-section may be larger sample size. Transverse cross-section specimens to be Taken from the pipe end without collapsing. When the size of the base layer is insufficient to intercept 5mm steel cylindrical test, the steel pipe should be done the entire longitudinal base or Stretching test.

Table 4 Mechanical Properties of Base

No. Grade

Tensile properties

The impact absorbing energy (KV2) tensile strength Lower yield strength or regulation Given proof strength Percentage elongation Portrait Landscape Portrait Landscape not less than Not less than 110335 ~ 49020524224027 2 20G 410 ~ 550 245 24 22 40 27 3 20MnG 415 ~ 560 240 22 20 40 27 4 16Mn 490 ~ 670 320 21 19 40 27 5 15MoG 450 ~ 600 270 22 20 40 27 6 12CrMoG 410 ~ 560 205 21 19 40 27 7 15CrMoG 440 ~ 640 295 21 19 40 27 8 12Cr1MoVG 470 ~ 640 255 21 19 40 27

6.4.2 Impact test

6.4.2.1 Base pipe shall impact test at room temperature, impact absorption energy should meet the requirements in Table 4.

6.4.2.2 Table 4 Impact absorbing energy full size specimens V-notch Charpy absorbed energy required value. When a small size red when the sample was hit, the minimum sample size smaller Charpy V-notch impact absorption energy requirement value should absorb impact energy full size specimens required value Multiplied by the coefficient decreasing Table 5.

Table 5 Sample small size decreasing impact absorption energy coefficient

Sample Size Sample Size (width × height)/(mm × mm) decreasing coefficient Standard sample 10 × 10 1.00 Small specimens 10 × 7.5 0.75 Small specimens 10 × 5 0.50 6.4.2.3 pipe outer diameter smaller than 219mm, the impact test sample along the vertical or horizontal steel; as contract without special provisions, arbitration sample it should be taken longitudinally along the pipe. An outer diameter of 219mm steel pipe, steel pipe along the lateral impact test sample.

Whether taken along a vertical or horizontal steel, impact specimens shall be of a standard size, width 7.5mm or 5mm in width as much as possible A larger sample size. When the size of the base layer is insufficient Steel 5mm preparing impact specimens, impact test is not required.

6.5 Hydraulic Test

Steel hydraulic test should be carried out by the root. The hydraulic pressure test according to formula (1) is calculated, the maximum test pressure of 20MPa. At a test pressure, Regulator not be less than 10s, pipe leakage is not allowed.

p = 2SR/D (1)

Where.

P --- test pressure in megapascals (MPa), when p 0.6 ~ 0.8 > 0.8 Quality carbon steel, low alloy steel 101217 Alloy 81015

6.8 Macro examination

Pipe should do low magnification inspection. Macroscopic cross section leaching test are not allowed on the test piece was visually visible white spots, inclusions, bubbles subcutaneous, FanPi and stratification.

6.9 Non-metallic inclusions

Pipe test should be done non-metallic inclusions. Steel A method according to nonmetallic inclusions in the rating 10561-2005 GB/T , which is A, B, C, D of the various types of inclusions fine lines and coarse level of system level are to be no greater than 2.5, DS inclusions should be less than 2.5; A, B, C, the total number of fine lines and coarse level based population level D of each of various types of inclusions should be no greater than 6.5.

6.10 Grain size

Base steel grain size should be four or finer, and grain size on two test pieces and the maximum level difference between the minimum level should not exceed three.

6.11 Microstructure

6.11.1 Primary steel microstructure shall be as follows.

a) high-carbon steel and low alloy steel should ferrite and pearlite;

b) 15MoG, 12CrMoG, 15CrMoG should be ferrite and pearlite, granular bainite allowed, the presence of a phase change allowed Pro Incomplete critical temperature transformation products between AC1 ~ AC3 (such as yellow granular structure);

c) 12Cr1MoVG should ferrite and granular bainite or ferrite and pearlite or a granular bainite ferrite and pearlite, Sorbite allowed, it does not allow the presence of incompl...