GB/T 24187-2009 English PDF (GB/T24187-2009)

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GB/T 24187-2009: Cold-drawn precision single welded steel tubes
GB/T 24187-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.75
H 48
Cold-drawn precision single welded steel tubes
ISSUED ON. JUNE 25, 2009
IMPLEMENTED ON. APRIL 01, 2010
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Classification and code ... 6 
4 Ordering content ... 7 
5 Dimensions, shape, weight and tolerance ... 7 
6 Technical requirements ... 10 
7 Test methods ... 14 
8 Inspection rules ... 15 
9 Packaging, marking and quality certificate ... 16 
Appendix A (Normative) Bell-mouth test of steel tubes for automotive ... 17 
Appendix B (Informative) Requirements for the inner surface of high-cleanliness
steel tubes for refrigeration ... 19 
Appendix C (Informative) Steel tube’s outer plating requirements ... 21 
Appendix D (Normative) Test method for residues of internal surface
cleanliness ... 23 
Cold-drawn precision single welded steel tubes
1 Scope
This standard specifies the classification and code, dimension, shape, weight
and allowable deviation, technical requirements, test methods, inspection rules,
packaging, marking and quality certificates of cold-drawn precision single
welded steel tubes.
This standard is applicable to the cold-drawn precision single welded steel
tubes which are used in the manufacture of condensers, evaporators, fuel pipes,
lubricating oil pipes, electric heating pipes, cooler pipes and general pipe fittings
in such industries as refrigeration, automotive, electric heating and so on
(hereinafter referred to as “steel tube”).
2 Normative references
The provisions in following documents become the provisions of this standard
through reference in this standard. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this standard;
however, parties who reach an agreement based on this standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 222 Permissible tolerances for chemical composition of steel products
GB/T 223.3 Methods for chemical analysis of steels and alloys - The
diantipyryl methane phosphomolybdate gravimetric method for the
determination of phosphorus content by
GB/T 223.58 Methods for chemical analysis of steels and alloys - The
sodium arsenite-sodium nitrite titration method for the determination of
manganese content
GB/T 223.59 Iron, steel and alloy - Determination of phosphorus content -
Bismuth phosphomolybdate blue spectrophotometric method and antimony
phosphomolybdate blue spectrophotometric method
GB/T 223.61 Methods for chemical analysis of iron, steel and alloy - The
ammonium phosphomolybdate volumetric method for the determination of
phosphorus content
GB/T 223.62 Methods for chemical analysis of iron, steel and alloy - The
butyl acetate extraction photometric method for the determination of
phosphorus content
GB/T 223.63 Methods for chemical analysis of steels and alloys - The
sodium periodate for the determination of manganese content
GB/T 223.64 Iron, Steel and alloy - Determination of manganese content -
Flame atomic absorption spectrometric method
GB/T 223.67 Iron, steel and alloy - Determination of sulfur content -
Methylene blue spectrophotometric method
GB/T 223.68 Methods for chemical analysis of iron steel and alloy - The
combustion potassium iodate volumetric method for the determination of
sulfur content
GB/T 223.72 Methods for chemical analysis of iron, steel and alloy - The
alumina chromatographic separation-barium sulfate gravimetric method for
the determination of sulfur content
GB/T 223.74 Methods for chemical analysis of iron, steel and alloy - The
combustion gravimetric/gas-volumetric method for the determination of
combined carbon content
GB/T 223.79 Iron and steel - Determination of multi-element contents - X-
ray fluorescence spectrometry (Routine method)
GB/T 228-2002 Metallic materials – Tensile testing at ambient temperature
(eqv ISO 6892.1998)
GB/T 241 Metal materials - Tubes - Hydrostatic pressure test
GB/T 242 Metal materials - Tube - Drift-expending test (GB/T 242-2007, ISO
8493.1998, IDT)
GB/T 244 Metallic materials - Tube - Bend test (GB/T 244-2008, ISO
8491.1998, IDT)
GB/T 246 Metal materials - Tube - Flattening test (GB/T 246-2007, ISO
8492.1998, IDT)
GB/T 2102 Acceptance packing marking and quality certification of steel tube
GB/T 4336 Standard test method for spark discharge atomic emission
spectrometric analysis of carbon and low-alloy steel (Routine method)
GB/T 10125 Corrosion tests in artificial atmospheres - Salt spray tests (GB/T
10125-1997, eqv ISO 9227.1990)
GB/T 11605 Methods of humidity measurement
GB/T 16488 Water quality - Determination of petroleum oil, animal and
vegetable oils - Infrared photometric method
GB/T 20066 Steel and iron - Sampling and preparation of samples for the
determination of chemical composition (GB/T 20066-2006, ISO 14284.1996,
IDT)
GB/T 20123 Steel and iron - Determination of total carbon and sulfur content
Infrared absorption method after combustion in an induction furnace (routine
method) (GB/T 20123-2006, ISO 15350.2000, IDT)
GB/T 20126 Unalloyed steel - Determination of low carbon content - Part 2.
Infrared absorption method after combustion in an induction furnace (with
preheating) (GB/T 20126-2006, ISO 15349-2.1999, IDT)
3 Classification and code
3.1 Dimensional accuracy
a) Ordinary accuracy, codenamed PA;
b) Advanced accuracy, codenamed PC.
3.2 Mechanical properties
a) Ordinary steel tube, codenamed MA;
b) Soft steel tube, codenamed MB.
3.3 Surface status
The surface status and code of the steel tube are shown in Table 1. According
to the requirements of the purchaser, through negotiation between the supplier
and the purchaser, it may supply the steel tubes of other surface status than
those listed in Table 1.
Where.
W - The theoretical weight per meter of steel tube, in kilograms per meter
(kg/m);
D - The outer diameter of steel tube, in millimeters (mm);
S - The wall thickness of steel tube, in millimeters (mm).
5.4.3 For steel tubes delivered according to theoretical weight, the allowable
deviation of the actual weight of each batch from the theoretical weight shall be
± 7.5%.
5.5 Example of marking
Marking order. dimensional accuracy - specification dimension - mechanical
properties - surface type and plating post-treatment - standard number
Example 1. The soft cold drawn precision single welded steel tubes which are
copper-plated for the use of coil cooling, in ordinary accuracy, outer diameter
4.76 mm, wall thickness 0.50 mm, is marked as follows.
PA-4.76 x 0.50-MB-Cu-GB/T 24187
Example 2. The ordinary cold drawn precision single welded steel tubes which
are passivated into strip-shaped fixed length for automotive use, in advanced
accuracy, outer diameter 8.00 mm, wall thickness 0.70 mm, length 6000 mm,
outer surface galvanized layer thickness in 8 μm, is marked as follows.
PC-8.00 x 0.70 x 6000-MA-Zn 8 D-GB/T 24187
6 Technical requirements
6.1 Cold-rolled steel strip
6.1.1 Chemical composition of steel strip
6.1.1.1 For cold-rolled steel strips for steel tubes, it may use cold-rolled low-
carbon steel strips or cold-rolled ultra-low carbon steel strips. The chemical
composition (melting analysis) of steel strips shall comply with the requirements
of Table 6.
The steel tube for automotive shall be hydraulically tested. The test pressure is
calculated according to formula (2).
Where.
P - Test pressure, in Megapascal (MPa);
S - The wall thickness of steel tube, in millimeters (mm);
R - The allowable stress, the value of which is 140 MPa;
D - The outer diameter of steel tube, in millimeters (mm).
Under the test pressure, the voltage regulating time shall be not less than 5 s,
it is not allowed for the steel tube to crack or leak.
6.6 Airtightness
The steel tube shall be subjected to airtightness test one by one. The
airtightness test pressure shall be not less than 1.6 MPa, the pressure
regulating time shall be not less than 3 minutes, it is not allowed for the steel
tube to have air leakage.
6.7 Nitrogen-filled seal
According to the requirements of the purchaser, through negotiation between
the supplier and the purchaser, and as indicated in the contract, the coiled steel
tube can be filled with nitrogen gas at a pressure of not less than 0.2 MPa, then
both ends are sealed. The filled gas at the sealing part shall not leak.
6.8 Surface quality
6.8.1 The inner and outer surfaces of steel tubes shall be clean, smooth, free
of rust and stains, it shall not allow cracks, crusting, delamination, lap welding,
etc., which are harmful to the use.
6.8.2 The surface of uncoated steel tubes shall be bright and free of black spots;
for coated steel tubes, the coating shall be uniform, complete and firmly bonded.
6.8.3 The surface of the steel tube is allowed to have scratches and scribes
which have a length of not more than 50 mm and a depth not exceeding the
negative deviation of the wall thickness.
6.8.4 The burrs on the outer surface of the welded steel tube shall be removed,
the convex height of the inner surface of the weld shall not exceed 0.20 mm.
6.8.5 For the steel tubes which are hot galvanized, the surfaces are allowed to
have local rough surfaces, zinc beads or dark spots.
6.9 Inner surface cleanliness
6.9.1 The residue on the inner surface of the steel tube shall not exceed 0.16
g/m2.
6.9.2 The requirements for the inner surface of high-purity steel tubes for
refrigeration use shall be determined through negotiation between the supplier
and the purchaser, or by reference to Appendix B.
6.10 Surface coating
6.10.1 The types, status and markings of the surface coating of steel tubes are
as shown in Table 1.
6.10.2 The requirements for the coating of the outer surface of the steel tube
shall be determined through negotiation between the supplier and the
purchaser, or by reference to Appendix C.
7 Test methods
7.1 The size and shape of the steel tube shall be measured one by one by the
gage which meets the accuracy requirements, the wall thickness shall be
measured to avoid the weld.
7.2 The surface of the steel tube shall be visually inspected one by one under
full lighting conditions.
7.3 The chemical composition and mechanical properties of the steel strip shall
be based on the quality certificate of the steel strip manufacturer. When the
supplier and the purchaser agree that re-inspection or arbitration is required,
the test method of chemical composition for steel tubes shall comply with the
requirements of Table 10.
7.4 The airtightness test of steel tubes is selected by the supplier from the
following ways.
a) Connect one end of the steel tube to the barometer, lead in dry gas from
the other end. After reaching to the specified pressure, cut off the gas
source, stabilize the pressure to the specified time, check whether the
pressure in the steel tube is reduced. When performing this test, it shall
ensure the sealing at the joint at the steel tube ends.
b) Lead in dry gas into the steel tube. After reaching to the specified pressure,
place the steel tube below water. Within the specified time, it shall not
produce air bubbles due to gas leakage in the steel tube.
Appendix B
(Informative)
Requirements for the inner surface of high-cleanliness steel tubes for
refrigeration
B.1 Moisture content
B.1.1 Requirements
The moisture content of the inner surface of the steel tube shall not exceed 30
mg/m2.
B.1.2 Test methods
The test of the moisture content of the inner surface of the steel tube shall
comply with the provisions of the electrolysis method of GB/T 11605. Through
negotiation between the supplier and the purchaser, it may also use the
moisture analyzer of the electrolysis method. The uncertainty of the instrument
measurement shall be no more than 5%. The preparation of specimen and test
methods shall be as specified in the instrument manual.
B.2 Residue content
B.2.1 Requirements
The residue on the inner surface of the steel tube shall be not more than 30
mg/m2.
B.2.2 Test methods
See Appendix D for the test method for the residues on the inner surface of
steel tubes. Through negotiation between the supplier and the purchaser, it may
also use other methods.
B.3 Oil content
B.3.1 Requirements
The oil content of the inner surface of the steel tube shall not exceed 10 mg/m2.
B.3.2 Test methods
The test of the oil content on the inner surface of the steel tube shall comply
with the provisions of GB/T 16488. Through negotiation between the supplier
and the purchaser, it may also use the oil analyzer of infrared spectroscopy.
GB/T 24187-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.75
H 48
Cold-drawn precision single welded steel tubes
ISSUED ON. JUNE 25, 2009
IMPLEMENTED ON. APRIL 01, 2010
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Classification and code ... 6 
4 Ordering content ... 7 
5 Dimensions, shape, weight and tolerance ... 7 
6 Technical requirements ... 10 
7 Test methods ... 14 
8 Inspection rules ... 15 
9 Packaging, marking and quality certificate ... 16 
Appendix A (Normative) Bell-mouth test of steel tubes for automotive ... 17 
Appendix B (Informative) Requirements for the inner surface of high-cleanliness
steel tubes for refrigeration ... 19 
Appendix C (Informative) Steel tube’s outer plating requirements ... 21 
Appendi...