GB/T 35072-2018Corrosion resistant alloy bimetal fittings for petroleum and natural gas industries (English PDF)

3.1 Terms and definitions

The following terms and definitions apply to this document.

3.1.1 Purchaser

The owner includes its agents, inspectors and other authorized representatives.

3.1.2 Manufacturer

A factory or company responsible for the production of composite fittings and marking the products in accordance with the requirements of this standard.

3.1.3 Metallurgical composite

Through the composite process of hot rolling, explosion, surfacing, etc., the contact interface between the corrosion resistant alloy and carbon steel or low alloy steel forms atomic interdiffusion And the formation of the combination.

3.1.4 Backing layer

The mechanical load or pressure bearing part of the composite plate, composite pipe or composite pipe is made of carbon steel or low alloy steel.

3.1.5 Inner cladding

A portion of the corrosion-resistant alloy material bonded to the surface of the carbon steel or low-alloy steel base material by metallurgical composite means.

3.1.6 Similar composite pipe fittings

A set of elbows, tees, reducers, or caps with the same code.

3.1.7 Outer arc side

The outer portion of the curved section of the elbow.

3.1.8 Inner arc side

The inner part of the curved section of the elbow.

3.1.9 Straight pipe segment

Straight pipe section at the end of the pipe.

3.1.10 Corrosion-resistant alloy composite pipe fittings

According to the principle of corrosion resistance of the base material and the anti-corrosion of the inner coating material, carbon steel or low alloy steel is used as the base material and corrosion-resistant alloy. The inner layer composite pipe fittings, referred to as composite pipe fittings.

3.1.11 Corrosion resistant alloy

A general term for corrosion-resistant alloy materials such as stainless steel and nickel-based alloys used in the manufacture of composite sheets, mother tubes and composite tubes.

3.1.12 Mother tube

Metallurgical composite straight pipe for the manufacture of corrosion resistant alloy composite pipe fittings.

3.1.13 Unbound

The bond between the base layer and the corrosion-resistant alloy layer is not bonded.

3.1.14 Acidic environment

H2S partial pressure greater than or equal to 0.3 kPa and can cause SSC to occur in carbon steel or low alloy steel materials as specified in ISO 15156-2 Single-phase or multi-phase fluid environments containing media such as oil, natural gas, and water in the form of HIC failure.

3.1.15 Shear bond strength

The cut required for the unit contact area where the inner coating of the metallurgically bonded composite sheet, the composite tube or the composite tube is separated from the base layer Toward stress.

3.1.16 Anti-pitting equivalent number

It is used to reflect and predict the pitting resistance of corrosion-resistant alloys, based on the content of Cr, Mo, W and N in the chemical composition of the alloy. Come to fix.

Note: See ISO 15156-3 for detailed information.

3.2 Symbols and codes

The following symbols and codes apply to this document.

A---90° elbow center to end length, in millimeters (mm);

B---45° elbow center to end length, in millimeters (mm);

C---three-way center to end length (tube), in millimeters (mm);

D, D1---the outer diameter of the end of the composite pipe, in millimeters (mm);

D---the nominal inner diameter of the end of the composite pipe, in millimeters (mm);

Dmax---the maximum outer diameter of the cross section of the composite pipe, in millimeters (mm);

Dmin---the minimum outer diameter of the cross section of the composite pipe, in millimeters (mm);

Dn---the nominal outer diameter at the cross section of the composite pipe fitting, in millimeters (mm);

Dp---The nominal outer diameter of the pipe connected to the composite pipe, in millimeters (mm).

DN---the nominal diameter of the composite pipe fittings of the metric unit, which is a non-measured value in millimeters (mm);

E, E1---The length from the back to the end of the cap, in millimeters (mm);

e---The extension length of the coating in the groove of the welded end of the composite pipe fitting, the unit is mm (mm);

H---the length of the end face to the end face of the reducer, in millimeters (mm);

M---three-way center to end length (outlet), in millimeters (mm);

O---ellipticity;

P---composite pipe fitting test to calculate the minimum strength in MPa (MPa);

Q---Composite pipe fitting position tolerance, end face verticality, the unit is mm (mm);

Rm---tensile strength;

Rt0.5---the yield strength of the total elongation of 0.5%;

S---corrosion sample area in square millimeters (mm²);

t---The nominal wall thickness of the inner cladding of the composite pipe fitting, the unit is mm (mm);

tB---the nominal wall thickness of the base layer of the composite pipe fitting, the unit is mm (mm);

Tcorr---corrosion test time in days (d);

Tp---the nominal wall thickness of the pipe connected to the composite pipe or the nominal wall thickness of the base pipe of the composite pipe, in millimeters (mm);

U---shape tolerance, composite pipe flatness, in millimeters (mm);

Vcorr---average corrosion rate in millimeters per year (mm/a);

sigmab---the actual tensile strength of the composite pipe base material (when the actual tensile strength of the composite pipe base material is less than the name of the connecting pipe For the minimum tensile strength, calculate according to the nominal minimum tensile strength of the connecting pipe), the unit is MPa (MPa);

phi---design verification test coefficient;

deltaW---the mass loss of the corrosion sample in grams (g);

rho---The density of the corrosion sample material in grams per cubic centimeter (g/cm³).

3.3 Abbreviations

The following abbreviations apply to this document.

AUT automatic ultrasonic testing (automaticultrasonictesting)

CLR crack length ratio (cracklengthratio)

CSR crack sensitivity rate (cracksensitivityratio)

CTR crack thickness rate (crackthicknessratio)

CVN Charpy V-notch

HAZ heat affected zone (heat-affectedzone)

HIC hydrogen induced cracking

MPQT manufacturing process qualification test (manufacturingprocedurequalificationtest)

MPS manufacturing procedure specification (manufacturing procedure specification)

MT magnetic particle detection (magnetictesting)

NDT nondestructive testing (nondestructive testing)

PREN resistance to pitting equivalents (pittingresistanceequivalentnumber)

PT penetration test (penetranttesting)

RT radiography (radiographictesting)

SCC stress corrosion cracking (stresscorrosioncracking)

SMYS specifies minimum yield strength (specifiedminimumyieldstrength)

SSC sulfide stress cracking

TIG tungsten inert gas shielded welding (tungsteninertgasarcwelding)

UT ultrasonic testing (ultrasonictesting)

6.1 Standard size

Except as otherwise stipulated in this standard, composite pipe fittings shall conform to the geometrical dimensions specified in GB/T 12459 or GB/T 13401, and composite pipe fitting ends. The outer diameter of the part is divided into two series, I and II. The I series is an international general series. When writing the mark, the "I" can be omitted and should be preferred. I series.

6.2 Wall thickness

6.2.1 If the wall thickness of the composite pipe is determined by the calculation and analysis method specified in 5.3, the minimum wall thickness of the base layer may be smaller than the nominal wall thickness 0.25mm. The residual wall thickness of the base layer in the isolated discontinuous partial thinning or repaired portion shall not be less than 87.5% of the nominal wall thickness.

6.2.2 The inner wall thickness of the composite pipe fittings shall not be lower than the minimum design wall thickness requirement, and the inner cladding wall thickness shall only allow positive deviation and the deviation shall not be greater than 1.0mm.

6.3 Inner diameter

The inner diameter of the composite pipe fitting within 50mm from the pipe end shall be the same as the inner diameter of the connected pipe and the inner diameter within 50mm from the pipe end. The maximum deviation allowed is ±0.5mm.

6.4 Ellipticity

For all composite fittings, the ellipticity O shall be no more than 0.5% from the end of the pipe 100 mm; for all elbows, the ellipse of the curved section The roundness O should be no more than 2.5%.

Ellipticity O is calculated according to formula (1).

O = (Dmax - Dmin) / Dn × 100% (1)

In the formula:

O --- ovality;

Dmax --- the maximum outer diameter of the cross section of the composite pipe, in millimeters (mm);

Dmin --- the minimum outer diameter of the cross section of the composite pipe, in millimeters (mm);

Dn --- nominal outer diameter at the cross section of the composite pipe, in millimeters (mm).

6.5 Tolerance

6.5.1 The limit deviation of the composite pipe size shall comply with the requirements of Figure 1 and Table 2.

6.5.2 The geometrical tolerance of composite pipe fittings shall comply with the requirements of Figure 2 and Table 3.

7.1 Grassroots

7.1.1 The base material of the composite pipe fittings shall be of the same or similar steel grade, chemical composition and mechanical properties.

For carbon steel or low alloy steel, the chemical composition and mechanical properties of the base material should meet the requirements of APISpec5L. PSL2 in 2012. Purchaser In agreement with the manufacturer, the base layer may also select carbon steel and low alloy steel materials as specified in GB/T 12459 or GB/T 13401 and meet the corresponding requirements. standard requirement.

7.1.2 If the composite pipe conveying fluid contains H2S and is in an acidic environment, the base material of the composite pipe fittings shall be determined by agreement between the purchaser and the manufacturer. And whether the welds need to meet the requirements of APISpec5L.2012 Annex H, ISO 15156-1 and ISO 15156-2.

7.2 Inner coating

7.2.1 The inner cladding of composite pipe fittings should preferably use austenitic stainless steel or nickel-based alloy specified by APISpec5LD, and should conform to the API. […]