American Petroleum Institute Standards

Casing and tubing specifications

oil and gas industry – steel Pipes for oil and gas well casing or tubing

This international standard applies to the following fittings that comply with  API Spec 5B:

——Short round Thread casing (STC);

——Long round thread casing (LC);

——Bend-shaped thread casing (BC);

——Direct connection casing (XC);

——Non-thickened tubing (NU);

——Externally thickened tubing (EU);

——Integral joint oil pipe (IJ).

• terms, definitions, symbols and abbreviations
• Terms and Definitions

For the purposes of this International Standard, the terms and definitions for heat treatment operations given in astm A941 and the following terms and definitions apply.

• accessories accessory Material

Standard seamless oil, casing, or seamless thick-walled pipe, mechanical pipe, or bar billet, hot forging for manufacturing accessories.

• API Thread API threadsThreads as per API Spec 5B.
• vehicle capacity carloadThe number of pipes loaded on a railway car when shipped by the pipe manufacturer.
• casing casingA pipe is lowered from the surface into a drilled wellbore to serve as a lining.
• Casing and Tubing Accessories casing and tubing accessory

A pipe section used in a pipe string to provide mechanical and pressure integrity within the pipe string and to assist in achieving other functions required of the pipe string.

Examples of accessories: conversion joints, reducing nipples, short connections, oil flow pipe couplings, sand blowing joints, etc.

NOTE: Annexes include other pipe products not specifically covered by this International Standard or other products not covered by ISO (API) specifications.

• Connectors connectionPipe component Threaded connection assembly.
• controlled cooling controlled cooling

Cooling from high temperature in a predetermined manner to avoid hardening, cracking or internal damage, or to obtain the desired microstructure or mechanical properties.

• Coupling couplingA cylindrical body with internal threads used to connect two threaded pipes.

Coupling semi-finished products coupling blankA blank without threads from which a coupling is produced.

4.1.10   Coupling blank coupling stockSeamless thick-walled pipes or mechanical pipes for the production of semi-finished couplings.

4.1.11)   defect defectAn imperfection large enough to justify rejection of a product under the provisions of this International Standard.

4.1.12    electric welded pipe Electric-welded pipe

A pipe with a longitudinal weld seam without filler metal, either resistance welded or induction welded. During manufacture, the edges are welded together by mechanical pressure, with the heat input being generated by electric current or resistance.

4.1.13    Controlled tightening handling tightTight enough that the coupling cannot be removed without a pipe wrench.

4.1.14    Furnace batch heatMetal produced by a single cycle process of smelting one batch of materials.

4.1.15   Melting analysis heat analysisChemical composition analysis of a representative heat batch as reported by the steel mill.

4.1.16   Disadvantages imperfectionDiscontinuity in the wall or on the surface of a product that can be detected by one of the NDE methods in Table C.61 or Table E.61 of this International Standard

4.1.17    test inspectionThe process of measuring, inspecting, testing, thread checking or other comparison of unit products according to corresponding requirements.

4.1.18   Inspection lot inspection lotA limited number of products produced under conditions of consistent properties to be inspected.

4.1.19    Inspection lot sample inspection lot sampleOne or more products selected from an inspection lot that can represent the inspection lot.

4.1.20   Inspection lot size inspection lot sizeThe number of products in an inspection lot.

4.1.21    Step quenching interrupted quenchingWhen the temperature of the quenched tube is significantly higher than the temperature of the quenching medium, it is removed from the quenching medium and then quenched again.

4.1.22    code1 label 1A dimensionless designator for size or specified outside diameter, used when ordering tubing.

4.1.23    Code2 label 2A dimensionless designator for weight per unit length, used when ordering tubing.

4.1.24    Root lengthA pipe conforming to the range requirements of Table C.30 or Table E.30 of this International Standard may be plain-ended, threaded, or threaded and coupled.

4.1.25    linearity Defects Linear imperfectionImperfections include but are not limited to seams, laps, cracks, plug scores, cuts and gouges.

4.1.26   Manufacturing plant manufacturer

Depending on the context, it refers to one or more of the following Manufacturers: pipe manufacturing plant, pipe processing plant, thread processing plant, coupling manufacturer, pup joint manufacturer, accessory manufacturer.

4.1.27   Nonlinearity non-linear imperfection

Including but not limited to pits and round bottom die stamping defects.

4.1.28    tube pipeA general term for casing, tubing, plain-end casing liner and pup joints.

4.1.29   Pipe Manufacturing Plant pipe millThe manufacturer, Company or group of Companies that operates the pipe manufacturing facility.

4.1.30   Plain end casing liner plain-end casing linerusually has a Wall thickness greater than that specified in J55 and is supplied unthreaded.

4.1.31    Processing Plant processorManufacturers, companies or groups that can process heat-treated pipes produced by pipe Factories.

4.1.32    product productIndividual pieces or batches of pipes, couplings, accessories, coupling blanks or coupling semi-finished products, as applicable.

4.1.33   Short section pup-jointCasing, tubing or plain end casing liner shorter than length range 1.

4.1.34    Pup-joint materialStandard oil, casing, or thick wall pipe, mechanical pipe, or bar stock for manufacturing short joints.

4.1.35    buyer purchaserThe party responsible for confirming order requirements and making payments for a product.

4.1.36   Quenching crack quench crackCracks are caused by stress generated during the transformation of austenite to martensite in steel.

Note: This transformation is accompanied by an increase in volume.

4.1.37    Seamless pipe seamless pipeforged steel pipe products without welds.

NOTE: It is made of hot-worked steel and, if necessary, may be subsequently cold worked or heat treated, or a combination of these processes, to produce the required shape.shape, size and performance.

4.1.38   Steel plate Skelp is a hot rolled steel strip used to make EW pipes.

4.1.39    special end processing special end-finish

Threads whose thread form and characteristics, manufacturing specifications, dimensions, joint tightening and performance are outside the scope of this International Standard.

4.1.40    Thread protector Thread protectorCaps or bushings used to protect threads and Seals during handling, transportation and storage.

4.1.41    YouTube tubingA pipe lowered into a well for producing or injecting fluid.

4.1.42    Upper critical temperature upper critical temperature Ar₃The temperature at which austenite begins to transform into ferrite during cooling.

• Symbols and abbreviations

BC	Trapezoidal thread casing joint
Cv	Charpy V-notch impact test minimum absorbed energy
CVN	Charpy V-notch
D	Specified outer diameter of pipe
d	Calculate inner diameter
EMI	Electromagnetic inspection
EU	External thickened oil pipe joint
EW	Electric welding process
FBH	Flat bottom hole
HBW	Brinell hardness test with tungsten carbide ball
HBS	Brinell hardness when tested with a steel ball
HRC	C scale Rockwell hardness
ID	the inside diameter of
IJ	Integral joint oil pipe joint
k	Constant used to calculate elongation
LC	Long round thread casing joint
N	〈Heat treatment process〉Full length normalizing
N&T	Normalizing + tempering
NDE	Nondestructive Testing
NU	No thickening of the oil pipe joint
OD	Outer diameter
psl	Product specification level
Q	Quenching + tempering

• Size and weightdeviation
• Outside diameter,D

the followingdeviationApplicable to pipe outer diameter D:

Code 1	Outer diameter (D）deviation
＜4-1/2	±0.79mm (±0.031in)
≥4-1/2	+1%D~-0.5%D

• Wall thickness,t

Specified wall thickness of pipedeviation-12.5%. Specified wall thickness of coupling blankdeviationAs specified in the order.

• weight

quantity	deviation
Single	+6.5%~-3.5%

18 144 kg (40 000 lb) or more	-1.75%
Vehicle load less than 18 144kg (40 000lb)	-3.5%
18 144kg (40 000lb) or more for order quantities	-1.75%
Order quantities less than 18 144kg (40 000lb)	-3.5%

• Tighten the triangle mark

For all sizes and grades of trapezoidal thread casing andH40, j55, K55 and M65 steel gradesSpecifications (Code 1)For round Threaded casings of size 16 and larger, the tightening triangle mark shall be printed on the outer surface of both ends of each pipe. Upon agreement between the purchaser and the manufacturer, the triangle mark may be replaced by a 10 mm (3/8 in) wide and 76 mm (3 in) long horizontal white paint strip.KunisukeTrapezoidal thread casingOn tighteningA triangle or horizontal white strip should be set at the site end near the triangle or horizontal painted strip.A 25 mm (1 in) wide and 610 mm (24 in) long vertical white paint mark; in addition, a 25 mm

Vertical white paint markings 1 in (1 in) wide and 100 mm (4 in) long.

For groups 1 and 3, the triangle marking should only be done using method 2 or 4.hammer Pressure.

ForGroup 2 (for Grades C90 and T95 only), the triangle mark shall be used only with the third methodHammer Pressure.

For Group 2 (except Grades C90 and T95) and Group 4, the triangle marking shall be done using only the third or fourth method.Hammer Pressure.

• Products 1.8m (6ft) or longer

One or more of the following methods should be used:

• For threaded pipe, nipples and accessories: Apply a paint-printed band around the product at a distance not greater than 0.6m (24in) from the coupling or internal thread end.
• For plain end pipe or “male-male” pipe products: Apply a paint-printed band around the product at a distance not greater than 0.6m (24in) from either end.
• Couplings: Paint the entire outside surface of the coupling including the corresponding coupling color band.
• If the pipe is supplied with special gap couplings or the pipe and coupling are of different steel grades(Except H40, J55 and K55 which are allowed in 9.2.1

For steel grades other than 300 mm2, pipes and couplings shall be painted in accordance with the above provisions a), b) and c).

• Disassembled coupling
• Paint the entire outside surface of the coupling, including the corresponding color band.
• Special clearance coupling

The color of the steel grade from which the coupling is made is painted on the coupling, and a black stripe is also painted around the center of the coupling.

• Puppet sections and accessories less than 1.8m (6ft) in length

Paint the entire outer surface, including the corresponding color band, except for the threads.

• Steel grade color code

The colour and number of colour bands for each steel grade are shown in Table C.66 or Table E.66.

• coating and protection
• coatings – All Groups
• protective coating during transportation

Unless otherwise specified on the purchase agreement, pipes and couplings shall be provided with an External coating to prevent rusting during transportation. Measures should be taken to ensure that the coating is smooth, dense and as non-flaking as possible. The coating grade shall be sufficient to protect the pipe for at least3 months capability. Unless otherwise specified on the purchase order, coupling stock may be supplied without external coating (bare) except for any protective coating that may be applied over the die-stamped marking.

If bare pipe or special coating is required, it should be noted on the order. If special coating is required, the order should further indicate whether the pipe is coated along the entire length or uncoated within a certain distance from the pipe end. Unless otherwise specified, uncoated pipe ends are usually coated with a layer of oil to prevent rust during transportation.

Note: 13Cr type pipes are susceptible to local pitting when stored in a humid environment. Special attention should be paid to coating, shipping and storage.

• Coating for long term storage

after consultation between the purchaser and the manufacturer, pipes stored for a long time, especially in a marine environment, may require internal and external protective coatings to prevent corrosion.

The following shall apply:

• In the long-term storage marine environment agreed upon by the purchaser and the manufacturer, the corrosion protection of the coating should be effective; minor surface discoloration should be acceptable in the long-term storage marine environment;
• It is not necessary to remove the protective coating before the pipe is lowered into the well. c) It is important to apply the coating correctly. The following parameters should be evaluated:

– dryness of the pipe;

– cleanliness of the pipes;

– coating temperature;

——Coating thickness.