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GB/T 20928-2020

Chinese Standard: 'GB/T 20928-2020'
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GB/T 20928-2020English339 Add to Cart Days<=4 Seamless inner grooved copper tube Valid GB/T 20928-2020
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BASIC DATA
Standard ID GB/T 20928-2020 (GB/T20928-2020)
Description (Translated English) Seamless inner grooved copper tube
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard H62
Classification of International Standard 77.150.30
Word Count Estimation 19,193
Date of Issue 2020-09-29
Date of Implementation 2021-08-01
Older Standard (superseded by this standard) GB/T 20928-2007
Drafting Organization Jinlong Precision Copper Tube Group Co., Ltd., Zhejiang Hailiang Co., Ltd., Zhejiang Naile Copper Industry Co., Ltd., Jiangsu Cuilong Precision Copper Tube Co., Ltd., CNMC Obote Copper and Aluminum Co., Ltd., Shandong Xinglu Nonferrous Metals Group Co., Ltd., Qingdao Hongtai Copper Co., Ltd., Ningbo Jintian Copper (Group) Co., Ltd., Foshan Huahong Copper Tube Co., Ltd., Jiangxi Jiangtong Longchang Precision Copper Tube Co., Ltd., Jiangxi Naile Copper Co., Ltd., Qingdao Hongtai Metal Products Co., Ltd., Shandong Zhongjia Electronic Technology Co., Ltd., Changshu Zhongjia New Material Co., Ltd., Tsinghua University
Administrative Organization National Nonferrous Metal Standardization Technical Committee (SAC/TC 243)
Regulation (derived from) National Standard Announcement No. 20 of 2020
Proposing organization China Nonferrous Metals Industry Association
Issuing agency(ies) State Administration for Market Regulation, National Standardization Administration

GB/T 20928-2020
Seamless inner grooved copper tube
ICS 77.150.30
H62
National Standards of People's Republic of China
Replace GB/T 20928-2007
Seamless internal thread copper tube
2020-09-29 released
2021-08-01 implementation
State Administration for Market Regulation
Issued by the National Standardization Management Committee
Preface
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 20928-2007 ``Seamless Internally Threaded Copper Tubes''. Compared with GB/T 20928-2007, the main technical changes are as follows.
---Modified the representation method of grade and status (see Table 1, Table 1 of.2007 edition);
--- Two grades of TU1 and TU2 have been added, and their mechanical properties and grain size requirements have been specified (see Table 1, Table 8, Table 9);
---Modified the cut slope index of straight pipe, from "not greater than 2mm" to "not greater than 0.40mm" (see 5.2.3,.2007 version 4.3.3);
--- Change the original "specified non-proportional extension strength RP0.2" in the mechanical properties to "specified plastic extension strength RP0.2" (see Table 8,.2007 version of Table 6);
--- Deleted the original standard table 7 and table 8, revised to "standard sample tube artificial defects shall comply with the provisions of GB/T 5248" (see 5.6,.2007 edition 4.6);
---Modified the test method of mechanical properties, from "in accordance with GB/T 228" to "in accordance with GB/T 34505" (see 6.3,.2007 edition 5.2);
---Modified the grain size, the grain size of the soft annealed (O60) state is changed from "0.020mm~0.060mm" to "0.015mm~
0.060mm", the grain size of light annealed (O50) state is changed from "0.015mm~0.035mm" to "0.010mm~0.035mm"
(See Table 9, Table 6 of the.2007 edition);
--- Added "Sampling method according to YS/T 668 regulations, in which the preparation of flared test specimens is according to YS/T 815 regulations." (see 7.4);
--- The normative appendix "Measurement method of tooth profile parameters of seamless internally threaded copper pipes" has been deleted (see Appendix A of the.2007 edition).
This standard was proposed by China Nonferrous Metals Industry Association.
This standard is under the jurisdiction of the National Nonferrous Metals Standardization Technical Committee (SAC/TC243).
Drafting organizations of this standard. Jinlong Precision Copper Tube Group Co., Ltd., Zhejiang Hailiang Co., Ltd., Zhejiang Naile Copper Co., Ltd.
Company, Jiangsu Cuilong Precision Copper Tube Co., Ltd., CNFC Obote Copper and Aluminum Co., Ltd., Shandong Xinglu Nonferrous Metals Group Co., Ltd., Qinghai
Dao Hongtai Copper Co., Ltd., Ningbo Jintian Copper (Group) Co., Ltd., Foshan Huahong Copper Tube Co., Ltd., Jiangxi Jiangtong Longchang Jing
Mi Copper Tube Co., Ltd., Jiangxi Naile Copper Co., Ltd., Qingdao Hongtai Metal Products Co., Ltd., Shandong Zhongjia Electronic Technology Co., Ltd., Chang
Shuzhongjia New Materials Co., Ltd., Tsinghua University.
The main drafters of this standard. Huang Ming, Hang Jing, Sun Xinchun, Wang Xiangdong, Liu Jinlong, Wang Zhengtang, Lang Yanping, Lu Minghua, Tian Yuanchen, Meng Wenguang,
Li Fupeng, Chao Guohui, Jiang Wensheng, Luo Xin, Liang Zihao, Sun Tao, Zhao Qinhai, Li Baojin, Shi Lin, Wei Lianyun, Wu Xinyu, Luo Qiliang, Zhang Chunming,
Feng Chenggui, Sui Changfen, Yang Shuhu, Xiang Yanlong, Chen Jinfang, Wang Xiguang, Li Hui.
The previous versions of the standard replaced by this standard are as follows.
---GB/T 20928-2007.
Seamless internal thread copper tube
1 Scope
This standard specifies the classification and marking, technical requirements, test methods, inspection rules and markings, packaging, transportation, and storage of seamless internally threaded copper pipes.
The contents of the deposit, quality certificate and purchase order (or contract).
This standard applies to seamless internally threaded copper pipes for air conditioning and refrigeration equipment (hereinafter referred to as "pipes").
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document.
For undated references, the latest version (including all amendments) applies to this document.
GB/T 242 Metal pipe flaring test method
GB/T 2828.1 Sampling inspection procedure by attributes Part 1.Batch inspection sampling plan retrieved by acceptance quality limit (AQL)
GB/T 5121 (all parts) Methods for chemical analysis of copper and copper alloys
GB/T 5231 Processed copper and copper alloy grades and chemical composition
GB/T 5248 Copper and copper alloy seamless pipe eddy current testing method
GB/T 8170 Numerical rounding rules and the expression and determination of limit values
GB/T 8888 Packaging, marking, transportation, storage and quality certificate of heavy non-ferrous metal processing products
GB/T 26303.1 Copper and copper alloy processed material outline dimension test method Part 1.Pipe
GB/T 34505 Room temperature tensile test method for copper and copper alloy materials
YS/T 347 Copper and copper alloy average grain size determination method
YS/T 482 Copper and copper alloy analysis method photoelectric emission spectrometry
YS/T 483 Copper and copper alloy analysis method X-ray fluorescence spectrometry (wavelength dispersion type)
YS/T 668 Copper and copper alloy physical and chemical testing sampling method
Preparation method of YS/T 815 copper and copper alloy mechanical properties and process performance samples
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
The outer surface is smooth, the inner surface has a certain number of regular threads, and a copper pipe with a continuous section and circumference.
3.2
Mick Heavy
The mass of the internally threaded copper pipe per 1m length, in grams per meter (g/m).
4 Classification and marking
4.1 Product Classification
The grade, code, status and supply shape of the pipe shall meet the requirements of Table 1.The tooth profile of the pipe is shown in Figure 1, and the size range should be
5.4 Grain size
The grain size of the pipe should meet the requirements of Table 9.
Table 9 Grain size of pipe
5.5 Flaring test
The pipe shall be subjected to a flaring test, using a 60° top core with a flaring rate of 40%. After the test, the sample should not produce visible cracks or cracks.
5.6 Eddy current flaw detection
The pipe should be subjected to eddy current testing. The artificial defects of the standard sample tube should meet the requirements of GB/T 5248.Eddy current flaw detection should be through
Head and rotating probe combined flaw detection. Straight pipes are not allowed to have flaw detection defects, the number of defects of the coiled pipe is negotiated by the supplier and the buyer, and the flaw detection defect of the coiled pipe is deep
The length of the color mark is not less than 300mm.
5.7 Cleanliness
Residues on the inner surface of the pipe should be no more than 0.025g/m2.
5.8 Heat transfer performance
The pipe can be inspected for heat transfer performance, and the heat transfer performance index shall be determined through negotiation between the supply and demand parties.
5.9 Surface quality
The surface of the pipe should be clean and bright, and there should be no harmful defects that affect the use. Slight processing ring marks on the surface are allowed.
6 Test method
6.1 Chemical composition
The chemical composition analysis of the pipe shall be carried out in accordance with the regulations of GB/T 5121 (all parts) or YS/T 482 and YS/T 483.Press during arbitration
The provisions of GB/T 5121 (all parts) are carried out.
6.2 Dimensions and allowable deviation
The external dimensions and allowable deviation of the pipe shall be measured in accordance with GB/T 26303.1.
6.3 Mechanical properties
The tensile test of the pipe is carried out in accordance with the provisions of GB/T 34505, and the tensile test specimens are carried out in accordance with the provisions of the full-section specimen in GB/T 34505.
6.4 Grain size
The grain size of the pipe shall be carried out in accordance with YS/T 347.
6.5 Flaring test
The flaring test of the pipe shall be carried out in accordance with the provisions of GB/T 242.
6.6 Eddy current flaw detection
The eddy current flaw detection of the pipe shall be carried out in accordance with the provisions of GB/T 5248.
6.7 Cleanliness
The cleanliness of the pipe shall be determined in accordance with Appendix B.
6.8 Heat transfer performance
The heat transfer performance of the pipe can be carried out in accordance with the provisions of Appendix C, or carried out by a method approved by both the supplier and the buyer.
6.9 Surface quality
The quality of the outer surface of the pipe shall be inspected visually.
7 Inspection rules
7.1 Inspection and acceptance
7.1.1 The product should be inspected by the supplier to ensure that the quality of the product meets the requirements of this standard and the purchase order (or contract), and fill in the quality certificate
Ming book.
7.1.2 The purchaser shall inspect the received products in accordance with the provisions of this standard, such as the inspection results and the provisions of this standard and the purchase order (or contract).
In case of discrepancy, it shall be submitted to the supplier in written form, and the supplier and demander shall negotiate and resolve. Objections that belong to appearance quality or size should be received
Raised within months; objections to other properties should be raised within three months from the date of receipt of the product. If arbitration is required, it should be negotiated between the supplier and the buyer.
7.2 Batch
The pipes should be submitted for acceptance in batches, and each batch should be composed of pipes of the same brand, state, specification and processing technology, and the weight of each batch should not be greater than
10000kg.
7.3 Inspection items
The inspection items of the pipe shall be carried out in accordance with the provisions of Table 10.Before the pipes are packaged and put into storage, they shall be inspected at the factory according to the provisions of this standard. Have
In any of the following cases, type inspection shall be carried out in accordance with the provisions of this standard.
a) During trial production and appraisal of new products;
b) When the structure, material, and process of the product have been greatly changed, which may affect the performance of the product;
c) During normal production, type inspection is carried out once a year;
d) When production is resumed after the product is stopped;
e) When the factory inspection result is significantly different from the last type inspection;
f) When the national quality supervision agency requests for type testing.
C.4.2 Data collation
C.4.2.1 Draw the relationship curve between the heat transfer coefficient h on the inner surface of the seamless internally threaded copper tube and the refrigerant mass flow rate Gr.
C.4.2.2 Draw the relationship curve between the pressure drop per unit length of the refrigerant and the refrigerant mass flow rate Gr.
C.5 Conclusion and analysis
C.5.1 Determination of heat transfer performance.
C.5.2 Determination of fluid resistance characteristics.
C.5.3 Analyze the measurement results and make necessary explanations.
C.6 Test report
C.6.1 Task source.
C.6.2 Test purpose.
C.6.3 Test conditions.
C.6.4 Test time and participants.
C.6.5 The processing and calculation method of test data.
C.6.6 Conclusion and analysis.
Related standard: GB/T 13587-2020    GB/T 26017-2020
Related PDF sample: GB 20424-2006    GB/T 17791-2017