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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 17791-2007 Seamless copper tube for air conditioner and refrigeration equipment.
The following main technical changes have been made with respect to GB/T 17791-2007:
——The specification range has been expanded: the external diameter was expanded from 3mm~30mm to 3mm~54mm, the wall thickness was expanded from 0.25mm~2.0mm to 0.25mm~2.5mm, and the size of the increased specification and its tolerance were specified;
——The TU0(T10130) and QSn0.5-0.025(T50300) alloy designations have been added, and the mechanical property requirements of these designations have been specified;
——The cleanliness requirements for copper tubes used in refrigerators have been added, including: requirements for residue (total amount), chloride ion (Cl-), oil content, paraffin and moisture;
——Annexes B, C, D and E have been added.
This standard was proposed by China Nonferrous Metals Industry Association.
This standard is under the jurisdiction of National Technical Committee on Nonferrous Metals of Standardization Administration of China (SAC/TC 243).
The previous editions of this standard are as follows:
——GB/T 17791-1999 and GB/T 17791-2007.
Seamless copper and copper alloys tube for air conditioner and refrigeration equipment
1 Scope
This standard specifies the requirements, test methods, inspection rules, packaging, marking, transportation, storage and quality certificate, and order (or contract) contents of seamless copper and copper alloys tube for air conditioner and refrigeration equipment.
This standard is applicable to seamless copper and copper alloys tubes (hereinafter referred to as “the tube(s)”) for household air conditioners, refrigerators (freezers), small and medium-sized central air conditioners and refrigeration equipment.
2 Normative references
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 228.1-2010 Metallic materials — Tensile testing — Part 1: Method of test at room temperature
GB/T 242 Metallic materials — Tube — Drift expanding test
GB/T 246 Metallic materials — Tube — Flattening test
GB/T 2828.1 Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 5121 (all parts) Methods for chemical analysis of copper and copper alloys
GB/T 5231 Designation and chemical composition of wrought copper and copper alloys
GB/T 5248-2016 Electromagnetic (eddy-current) examination of copper and copper alloy seamless tube
GB/T 8888 Wrought heavy non-ferrous metal products-packing, marking, transportation, storing and certificate of quality
GB/T 23606 Copper-hydrogen embrittlement test method
GB/T 26303.1 Measuring method for dimensions and shapes of wrought copper and copper alloy — Part 1: Tube
YS/T 347 Copper and copper alloys — Estimation of average grain size
YS/T 482 Methods for analysis of copper and copper alloys — The atomic emission spectrometry
YS/T 668 Sampling method of physical and chemical testing for copper and copper alloys
YS/T 815 Preparation method of test pieces for mechanical and technological properties of copper and copper alloys
3 Requirements
3.1 Product classification
3.1.1 Designation, state and specification
The designation, state and specification of the tube shall meet those specified in Table 1. The internal and external diameters of tube coils shall meet those specified in Table 2.
Table 1 Designation, state and specification
Designation Code State Type Specification/mm
Outer diameter Wall thickness Length
TU0
TU1
TU2
TP1
TP2
T2
QSn0.5-0.025 T10130
T10150
T10180
C12000
C12200
T11050
T50300 Hard drawn (H80)
Drawn lightly (H55)
Surface hardened (O60-H) a
Slightly annealed (O50)
Softened annealed (O60) Straight tube 3.0~54 0.25~2.5 400~10,000
Coil tube 3.0~32 0.25~2.0 —
a Surface hardening (O60-H) refers to the state in which the softening annealing state (O60) is hardened by cold-working with a work rate of 1%~5%.
Table 2 Dimensions of internal and external diameters of coils
Type Minimum internal diameter / mm Maximum external diameter / mm Coil width / mm
Laminated coil 610; 560 1,230 75~450
3.1.2 Examples of marking
A product shall be marked in the order of product name, standard number, designation (or code), state and specification.
Example 1: Lightly annealed (O50) coil with designation QSn0.5-0.25(T50300), external diameter of 6.0mm and wall thickness of 0.4mm, which is marked as follows:
Coil GB/T 17791-QSn0.5-0.025O50-φ6.0×0.4
Or coil GB/T 17791-T50300O50-φ6.0×0.4
Example 2: Drawn lightly (H55) straight tube with designation TP2(C12200), external diameter of 6.35mm,wall thickness of 0.65mm and length of 5,000, which is marked as follows:
Straight tube GB/T 17791-TP2H55-φ6.35×0.65×5000
Or straight tube GB/T 17791-C12200 H55-φ6.35×0.65×5000
3.2 Chemical composition
The chemical composition of tubes shall meet the requirements of corresponding designation in GB/T 5231.
3.3 Overall dimension and its tolerance
3.3.1 The overall dimension and tolerance of tubes shall comply with the provisions in Table 3 and Table 4.
Table 3 Outer diameter and its tolerance of tubes In mm
Range of dimensions Tolerance
3.0~15 ±0.05
>15~20 ±0.06
>20~30 ±0.07
>30~54 ±0.08
Note: When the tolerance of external diameter is required to be all (+) or all (-) unilateral tolerance, its value is twice the corresponding value in the table.
Table 4 Wall thickness and its tolerance of tubes In mm
Mean external diameter Wall thickness
Range of dimensions 0.25~0.4 >0.4~0.6 >0.6~0.8 >0.8~1.5 >1.5~2.5
Tolerance (±)
3.0~15 ±0.03 ±0.04 ±0.05 ±0.06 ±0.07
>15~20 ±0.04 ±0.05 ±0.06 ±0.07 ±0.09
>20~30 — ±0.05 ±0.07 ±0.09 ±0.10
>30~54 — — ±0.09 ±0.10 ±0.12
Note: When the tolerance of wall thickness is required to be all (+) or all (-) unilateral tolerance, its value is twice the corresponding value in the table.
3.3.2 The unspecified length of straight tube is 400mm~10,000mm. The specified length or multiple length of tube shall be within the unspecified length range. The multiple length shall be added to the cutting quantity during cutting sections. Each cutting quantity is 5mm. The specified tolerance of straight tube shall comply with the provisions of Table 5.
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Table 5 Specified length tolerance of straight tubes In mm
Length Tolerance
400~600 +2
0
>600~1,800 +3
0
>1,800~4,000 +5
0
>4,000~10,000 +8
0
3.3.3 The roundness of straight tubes in hard drawn (H80), drawn lightly (H55) and surface hardened (O60-H) states and with a wall thickness of not less than 0.4mm shall comply with the provisions in Table 6.
Table 6 Roundness of straight tube
(Wall thickness/external diameter) Ratio Roundness / mm
Not greater than
0.01~0.03 1.5% of nominal external diameter
>0.03~0.05 1.0% of nominal external diameter
>0.05~0.10 0.8% of nominal external diameter (minimum value: 0.05)
>0.10 0.7% of nominal external diameter (minimum value: 0.05)
3.3.4 Straightness of straight tubes in hard drawn (H80), drawn lightly (H55) and surface hardened (O60-H) states shall comply with the provisions in Table 7.
Table 7 Straightness of straight tube In mm
Length Maximum arc depth
400~1,000 3
>1,000~2,000 5
>2,000~2,500 8
>2,500~3,000 12
≥3,000 The maximum arc depth per 3,000 at any part of the total length is 12.
3.3.5 The ends of tubes shall be cutting neatly, slight burrs are allowed, and the cutting incline of straight tubes shall not be more than 2mm.
3.4 Mechanical property
The mechanical property of tubes at ambient temperature shall meet those specified in Table 8.
Table 8 Mechanical property of tubes at room temperature
Designation State Tensile strength, Rm/MPa Proof strength, plastic extension RP0.2/ MPa Elongation A/%
TU00
TU0
TU1
TU2
TP1
TP2
T2 Hard drawn (H80) ≥315 ≥250 —
Drawn lightly (H55) 245~325 ≥120 —
Surface hardened (O60-H) 220~280 ≥80 ≥40
Slightly annealed (O50) ≥215 40~90 ≥40
Softened annealed (O60) ≥205 35~85 ≥43
QSn0.5-0.025 Softened annealed (O60) ≥255 50~100 ≥40
3.5 Processing property
3.5.1 Flaring test
Flaring test shall be conducted for tubes in slightly annealed (O50) state and softened annealed (O60) state. A proper length shall be cut from the end of the tube as a sample, and a 60° impact cone is used, and the flaring rate is in accordance with the requirements of Table 9. After flaring, the sample shall not produce cracks or cracks visible to the naked eye.
Table 9 Flaring rate
Outer diameter ≤20mm Outer diameter > 20mm
40% 30%
3.5.2 Flattening test
The tubes in slightly annealed (O50) and soften annealed (O60) state shall be subjected to flattening test. Press the tubes until the distance between the two walls is equal to the wall thickness, and the sample shall not produce cracks or cracks visible to the naked eye.
3.6 Eddy current inspection
When carrying out eddy current inspection on tubes, straight tubes that do not trigger alarm signals on the signal device of eddy current inspection equipment shall be considered as tubes conforming to this standard. The coil shall be printed with a dark mark not less than 300mm at the defective position, and the allowable number of defects shall be determined through negotiation between the supplier and the purchaser. The standard artificial defect shall be a through hole, and the drilling diameter shall comply with Table 4 of 6.4 in GB/T 5248-2016.
3.7 Grain size
The average grain size of the tube shall comply with the provisions in Table 10.
Table 10 Average grain size
Designation State Average grain size / mm
TU0
TU1
TU2
TP1
TP2
T2 Softened annealed (O60) 0.015~0.060
Slightly annealed (O50) ≤0.040
QSn0.5-0.025 Softened annealed (O60) 0.010~0.035
3.8 Hydrogen embrittlement test
Copper tubes of designation TU0(T10130), TU1(T10150) and TU2(T10180) shall be subjected to hydrogen embrittlement test. Closed bending method is adopted in the test, and cracks shall not appear on the external side of the sample after bending.
3.9 Cleanliness
3.9.1 The residue (total amount) on the internal surface of the tube of softened annealed (O60) and slightly annealed (O50) shall comply with the provisions in Table 11. The residues (total amount) on the internal surface of the tube of hard drawn (H80), drawn lightly (H55) and surface hardened (O60-H) shall be determined by the supplier and the purchaser through negotiation.
Table 11 Internal surface residue (total amount)
Outer diameter/ mm Residue (total amount) / (mg/m2)
≤15 ≤25
>15 ≤38
3.9.2 The residues on the internal surface of copper tubes for refrigerators shall comply with the provisions in Table 12.
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Table 12 Residues on the internal surface of copper tubes for refrigerators
Item Maximum allowable amount / (mg/m2)
Residues (total amount) 25
Oil content 7
Water content 25
Chloride ion (Cl-) 0.2
Paraffin 0.5
Note 1: Residues (total amount) include soluble and insoluble impurities, excluding water.
Note 2: Oil includes mineral oil and non-mineral oil.
3.10 Surface quality
The internal and external surfaces of the tube shall be clean and bright, and free from hazardous defects affecting the use.
4 Test method
4.1 Chemical composition
The chemical composition of tubes shall be analyzed according to the provisions of GB/T 5121 (all parts) or YS/T 482, and the arbitration shall be conducted according to the provisions of GB/T 5121 (all parts).
4.2 Dimension and tolerance
The overall dimension and tolerance of the tube shall be measured in accordance with the provisions of GB/T 26303.1.
4.3 Mechanical property
The tensile test of tubes shall be carried out according to the provisions of GB/T 228.1-2010, and the tensile sample shall be carried out according to the provisions of S7 sample in GB/T 228.1-2010. The tensile sample of tubes with external diameter >30mm~50mm may be carried out according to the provisions of S1 sample in GB/T 228.1-2010, and the tube sample with external diameter >50mm may be carried out according to the provisions of S2 sample in GB/T 228.1-2010.
Foreword i
1 Scope
2 Normative references
3 Requirements
4 Test method
5 Inspection rules
6 Marking, packaging, transportation, storage and quality certificate
7 Order form (or contract) contents
Annex A (Normative) Determination method for residues (total amount) on the internal surface of copper tubes
Annex B (Informative) Determination method for oil content on internal surface of copper tube
Annex C (Informative) Determination method for moisture on internal surface of copper tube
Annex D (Informative) Determination method of chloride ion (Cl-) on internal surface of copper tube
Annex E (Informative) Analysis method of paraffin on internal surface of copper tube
