GB/T 8320-2003 Copper tungsten and silver tungsten electrical contacts
Some standard content:
This standard replaces GB/T8320-1987 "Technical Requirements for Copper Tungsten and Silver Tungsten Electrical Contacts". Compared with GB/T8320-1987, the main changes of this standard are as follows: GB/T8320-2003
The standard structure is rearranged according to the requirements of GB/T1.1-2000 "Guidelines for Standardization Part 1: Structure and Writing Rules of Standards";
- The bending strength of copper-tungsten electrical contacts is appropriately improved (4.1 of the 1987 edition, 4.1.4 of this edition);- The chemical composition and physical and mechanical properties of copper and copper alloys at the conductive end no longer distinguish between contact fingers and contact rings, and the hardness is divided into hard and semi-hard states. The tensile strength is appropriately improved according to the yield strength of copper and copper alloys (4.1 of the 1987 edition, 4.3.2 of this edition); "The density of copper-tungsten and silver-tungsten electrical contact products should not be less than 96% of the theoretical density of their actual components." (4.2 of the 1987 edition) is removed;
The copper-tungsten alloy used for vacuum switches is added - The requirements for the gas content of silver-tungsten electrical contacts (see 4.2.2); - The provisions for the thickness of the welding layer are removed (4.9 of the 1987 edition, 4.1.9 of this edition); - The requirements for metallographic defects are appropriately adjusted (4.12 of the 1987 edition, 4.1.12 of this edition); - The tensile strength of the joint surface between copper tungsten and the conductive end of the copper-tungsten integral electrical contact is appropriately improved (4.3 of the 1987 edition, 4.3.3 of this edition); the original Appendix B and Appendix C are removed, and the determination of metallographic defects and the preparation of metallographic samples are carried out in accordance with the provisions of JB/T8985 (Appendix B and Appendix C of the 1987 edition, 6.8 of this edition); the original Appendix D is removed, and the tensile strength test method is carried out in accordance with the provisions of GB/T228 (Appendix D of the 1987 edition, 6.5 of this edition); - The marking and dimensioning of copper-tungsten integral electrical contacts are appropriately modified (Appendix F of the 1987 edition, Appendix C of this edition). Appendix A, Appendix B and Appendix C of this standard are normative appendices. This standard is proposed by the China Electrical Equipment Industry Association. This standard is under the jurisdiction of the National Technical Committee for Standardization of Electrical Alloys. The responsible drafting unit and main drafters of this standard: Guilin Electrical Science Research Institute: Xie Zhongguang, Xie Yongzhong, Yang Qing. Participating drafting units and drafters of this standard: People's Electrical Factory of Shanghai Electric Co., Ltd.: Fang Yaoxing; Shanghai Electrical Science Research Institute: Xiang Tui; Tianshui Great Wall Electrical Equipment Factory: Wang Haihong; Yueqing Electrical Alloy Co., Ltd.: Zheng Yuanlong; Shenyang Jinchangpu New Materials Co., Ltd.: Xiao Chunlin; Chongqing Chuanyi No. 1 Factory: Jiang Yuan; Zhejiang Chint Electric Co., Ltd.: Wang Jingkai; Zhejiang Fuda Alloy Materials Co., Ltd.: Xie Pingyun; Changshu Switch Factory: Yu Zuhong. This standard was first issued in 1987 and this is the first revision. 1 Scope
Copper tungsten and silver tungsten electrical contacts
This standard specifies the requirements, sampling, test methods, marking, labeling and packaging of copper tungsten and silver tungsten electrical contacts. GB/T8320—2003
This standard applies to copper tungsten and silver tungsten electrical contacts produced by powder pressing sintering and infiltration processes. These products are mainly used in high and low voltage electrical products.
2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated referenced documents, the latest versions shall apply to this standard. GB/T228 Tensile test method for metallic materials at room temperature (GB/T228-2002, eqvISO6892:1998) GB/T2828.1 Sampling inspection procedure for attributes Part 1: Sampling plan for batch inspection based on acceptance quality limit (AQI) (GB/T2828.1-2003, ISO2859-1:1999, IDT) GB/T2900.4 Electrical terminology Electrical alloys (GB/T2900.4-1994, neqIEC51) GB/T5586 Basic performance test for electrical contact materials Methods GB/T5587
Basic shape, size, symbol and marking of silver-based electric contacts 7 Chemical analysis methods of electric contact materials
JB/T4107
Basic performance test methods of vacuum switch contact materials JB/T5351
JB/T8753 Metallographic spectrum of electric contact materials
5 Metallographic inspection methods of electric contact materials
JB/T8985
3 Terms and definitions
The terms and definitions established in GB/T2900.1 and the following terms and definitions apply to this standard. 3.1
Infiltration
The process of filling the pores of the unsintered or sintered porous body skeleton with a metal or alloy with a lower melting point than the skeleton material at a temperature higher than the melting point of the metal or alloy through the capillary action of the pores to obtain a dense product. 3.1.1
Infiltration by dipping Infiltration by dipping is the process of immersing the pre-sintered or unsintered porous body skeleton after metal powder pressing into liquid metal with a lower melting point than the porous body skeleton material.
Overlay Infiltration by overlay is the process of placing a metal or alloy with a lower melting point than the skeleton on or below the pre-sintered or unsintered porous body skeleton after metal powder pressing.
Solid contact solid contact
Electrical contact element for high-voltage electrical appliances in which the contact and the conductive end are integrated. 1
GB/T8320—2003
Included layer
The electrical contact is not fully sintered or the copper or silver molten metal is not fully penetrated, resulting in dark or uneven parts inside. 3.4
Thermal stability
The electrical contact can maintain the same size under the specified temperature and insulation time, and has no cracks, bubbles and low melting point metal seepage on the surface.
4 Requirements
4.1 Copper tungsten and silver tungsten electrical contacts
4.1.1 The surface of copper tungsten and silver tungsten electrical contacts must be free of cracks and obvious defects such as dents, bubbles, missing edges, corners, burrs, corrosion and rust.
4.1.2 The working surface of copper tungsten and silver tungsten electrical contacts should be smooth and flat, and its surface roughness R shall be determined by negotiation between the supply and demand parties. 4.1.3 The dimensional tolerance of silver tungsten electrical contact products shall comply with the requirements of GB/T5587; the dimensional tolerance of copper tungsten electrical contact products shall refer to the provisions of GB/T5587: the dimensional tolerance of copper tungsten and silver tungsten electrical contact products can also be determined by negotiation between the supply and demand parties. 4.1.4 The representative symbols, chemical composition and physical and mechanical properties of copper tungsten and silver tungsten electrical contacts are shown in Table 1. Table 1
Representative symbols, chemical composition and physical and mechanical properties of copper tungsten and silver tungsten electrical contacts Chemical composition/%
Electrical contact
Representative symbol
Product name
Copper tungsten (50)
Copper tungsten (55)
Copper tungsten (60)
Copper tungsten (65)
Copper tungsten (70)
Copper tungsten (75)
Copper tungsten (80)
Copper tungsten (85)
Copper tungsten (90)
CuW(50)
CuW(55)||tt ||CuW(60)
Cuw(65)
CuW(70)
CuW(75)
Cuw(80)
Cuw(85）
CuW(90)
Density/
(g/cm2）
Physical and mechanical properties
Resistivity/
(μa·cm)
Conductivity
IACS/%
Strength/
Electrical contact
Product name
Silver tungsten(30)| |tt||Silver tungsten (40)
Silver tungsten (50)
Silver tungsten (55)
Representative symbol
AgW(30)
AgW(40)
AgW(50)
AgW(55)
Silver tungsten (60)
AgW(60)
Silver tungsten (65)
AgW(65)
AgW(70)
Silver tungsten (70)
Silver tungsten (75)
Silver tungsten (80)
AgW( 75)
AgW(80)
Chemical composition/%
Table 1 (continued)
Density/
(g/cm*)
GB/T8320—2003
Physical and mechanical properties
Resistivity/
(μQcm)
Conductivity
IACS/%
Strength/
Note 1: Names and representative symbols of electrical contacts The order of the conductive metal copper, silver and the refractory metal tungsten can also be interchanged, such as: the representative symbol of tungsten copper (20) is WCu(20).
Note 2: The conductivity IACS is based on the resistivity of the international standard soft copper (i.e. annealed copper) of 1.7241μn·cm as 100% conductivity. 4.1.5
The impurities of copper tungsten and silver tungsten electrical contacts are mainly analyzed as Cu, Fe, C, SiOz and alkali metals Na and K, and their contents are shown in Table 2. Table 2 Impurity Content of Copper Tungsten and Silver Tungsten Electrical Contacts
Contact Material
Copper Tungsten Series
Silver Tungsten Series
Impurity Content/% (≤)
4.1.6Additives added to improve performance are not considered impurities. If nickel or other additives are added to copper tungsten electrical contacts, the amount shall not exceed 1%; the amount of nickel or other additives in silver tungsten electrical contacts shall not exceed 2%; the resistivity of copper tungsten and silver tungsten electrical contacts containing additives shall be determined by negotiation between the supply and demand parties.
4.1.7For copper tungsten and silver tungsten electrical contact products with special uses, their composition and performance requirements can be determined by negotiation between the supply and demand parties according to the special use requirements of the user.
4.1.8 The hardness of copper tungsten and silver tungsten electrical contact products shall be determined by Brinell hardness. When Brinell hardness cannot be used, it shall be determined by negotiation between the supply and demand parties.
When necessary, the welding surface of copper tungsten and silver tungsten electrical contacts may have a copper or silver welding layer. Copper tungsten and silver tungsten electrical contact products should not have interlayers. 4.1.10
The metallographic structures of copper tungsten and silver tungsten electrical contact products are evenly distributed. The metallographic structure diagram is shown in Appendix A. The metallographic defects of copper tungsten and silver tungsten electrical contact products (see JB/T8753 for the diagram) are not allowed to have cracks or interlayers on the entire observation surface of the sample grinding disc, and aggregates greater than or equal to 200μm, or pores and inclusions with a length of 80μm or longer are not allowed. In any observation field (100×), a maximum of three aggregates greater than or equal to 100μm and less than 200μm, pores greater than or equal to 50μm and less than 80μm or inclusions are allowed. When aggregates, pores, and inclusions within the above allowable value range exist at the same time, the total number should not exceed three.
3 Silver-tungsten electrical contact products sintered by mixed powder should have considerable thermal stability. After heating in air at 970℃±10℃ for 1min, the electrical contact should not melt, deform, crack, bubble, and there should be no silver precipitation greater than 2mm on the surface. 4.2 Copper tungsten and silver tungsten electrical contacts for vacuum switches 4.2.1 Copper tungsten and silver electrical contacts for vacuum switches must comply with the provisions of 4.1. 4.2.2 Copper tungsten and silver tungsten electrical contacts for vacuum switches shall have an oxygen content of less than or equal to 0.008% and a nitrogen content of less than or equal to 0.002%.
4.3 Copper-tungsten integral electrical contact
The copper-tungsten contact of the copper-tungsten integral electrical contact must comply with the relevant provisions of 4.1. 4.3.1
4.3.2 The chemical composition and physical and mechanical properties of the copper or copper alloy at the conductive end of the copper-tungsten integral electrical contact are shown in Table 3. Table 3 Chemical composition and physical and mechanical properties of the copper and copper alloy at the conductive end of the copper-tungsten integral electrical contact Chemical composition/%
Material name
Chemical symbol
Copper alloy
Total impurities
Additives
Note 1: The copper alloy additives in the table are mainly Cr, Zr, Cd, etc. Density/
(g/cm2）
Physical and mechanical properties
Hardness HB
Semi-hard
Note 2: The hardness value "hard" means that the electrical contact product has not been annealed or strengthened after pressure processing. Note 3: The hardness and tensile strength of the soft product are determined by negotiation between the supply and demand parties. 4.3.3 The tensile strength of the copper-tungsten integral electrical contact and the conductive end joint surface of the copper-tungsten contact shall not be less than 185MPa. Resistivity/
Tensile strength
4.3.4 The copper or copper alloy at the conductive end of the copper-tungsten integral electrical contact shall have a uniform metallographic structure, the maximum length of pores or inclusions shall not exceed 0.5mm, and the total defect area shall not exceed 5% of the grinding surface. 4.3.5 No cracks are allowed on the joint surface of the copper-tungsten integral electrical contact and in the 40μm width area on both sides of the joint surface; the total length of the pores or inclusions on the grinding surface shall not exceed 5% of the joint surface length on the entire grinding surface. 5 Sampling
5.1 The quality inspection of copper-tungsten and silver-tungsten electrical contact products shall be carried out in batches by the inspection department of the production unit, and each batch shall be the same raw materials, the same ingredients and the same process.
5.2 Appearance inspection 100%.
5.3 Dimension inspection:
a) Dimension inspection of copper-tungsten integral electrical contacts 100%. b) The dimension inspection of copper-tungsten and silver-tungsten electrical contact products used for other types of electrical appliances shall be carried out in accordance with GB/T2828.1 with a normal inspection secondary sampling plan, and sampling at the level of general inspection of level II (see Appendix B), with a qualified quality level of 4.0. c) For copper-tungsten and silver-tungsten electrical contact products with complex and special shapes, the dimension inspection shall be determined by negotiation between the supply and demand parties. 5.4 For the inspection of density and hardness, the sampling shall be carried out according to the normal inspection secondary sampling plan of GB/T2828.1 and the special inspection level of S-2 (see Appendix B), and the qualified quality level is 2.5.
5.5 For the inspection of chemical composition, resistivity, flexural strength, tensile strength, gas content, surface roughness, cross-section interlayer, metallographic and thermal stability, the sampling shall be carried out according to the normal inspection secondary sampling plan of GB/T2828.1 and the special inspection level of S-3 (see Appendix B), and the qualified quality level is 10.
5.6 For the inspection of density, hardness, chemical composition and metallographic, the inspection shall be carried out on the same sample. 5.7 For the chemical composition analysis, the sample quantity shall not be less than 10g. If the single mass of the extracted electric contact product does not meet the requirement of the sample quantity of 10g, the number of extracted electric contact products shall be increased. 5.8 In the first spot check, if only one of the performance items does not meet the standard requirements, then only the unqualified performance can be rechecked in the second spot check. If several performance items do not meet the standard requirements in the same or several products in the spot check, these performance items should be rechecked at the same time in the second spot check. 5.9 Users shall conduct re-inspection and acceptance in accordance with the provisions of this standard within one month after receiving the goods. 6 Test method
6.1 The appearance quality and cross-section interlayer of the electrical contact product shall be inspected visually or with the help of a 10x magnifying glass (or tool microscope). 6.2 The size of the electrical contact product shall be divided into a scale value of 0.6.3 The inspection of surface roughness shall be determined by negotiation between the supplier and the buyer. 6.4 The measurement of density, hardness, resistivity and bending strength shall be carried out in accordance with the provisions of GB/T5586. 6.5 The measurement of tensile strength shall be carried out in accordance with the provisions of GB/T228. 6.6 The chemical composition analysis shall be carried out in accordance with the provisions of JB/T4107. 6.7 The gas content analysis shall be carried out in accordance with the provisions of JB/T5351. 6.8 The metallographic inspection shall be carried out in accordance with the provisions of JB/T8985. 6.9 The thermal stability test of silver tungsten electric contact is carried out in a square muffle furnace with a maximum inner furnace size of 170mm×150mm×100mm and automatic temperature control by resistance wire heating. A small refractory brick is placed in the center of the furnace bottom, so that the sample is in the center of the furnace, and the temperature measuring thermocouple is immediately above the sample; the test is carried out in air, and the temperature in the furnace is raised to 970℃±10℃ during the test. After the temperature stabilizes, the furnace door is quickly opened to put the sample in. The sample is placed on a 50mm×20mm×15mm refractory porcelain boat or porcelain plate. The sample is placed on a small refractory brick in the center of the furnace together with the refractory porcelain boat or porcelain plate, and the furnace door is closed. At this time, the temperature in the furnace drops. The temperature must be raised to 970℃±10℃ within 5 minutes, and the sample must be taken out after being kept warm for 1 minute, and its surface is observed. 7 Marking, labeling and packaging
7.1 The product marking and size marking of silver tungsten electric contact shall be carried out in accordance with the provisions of GB/T5587. 7.2 For product marking and dimension marking of copper tungsten electrical contacts, please refer to Appendix C. 7.3 Each batch of products shall be accompanied by a product certificate and an inspection form. 7.4 The product certificate shall indicate:
a) the name (or representative symbol) of the electrical contact product, the size specification and batch number, and the number of this standard;
the number of electrical contacts (number or net mass); the date of manufacture;
d) the name of the manufacturer;
the seal of the inspector and the seal of the inspection department.
7.5 The content of the product inspection form should include:
a) the product name (or representative symbol), size specifications and batch number, and the number of this standard of the electric contact;
the number of electric contacts (number or net mass);
the chemical composition, physical and mechanical properties and metallographic photos of the product;
simple instructions for use and storage;
date of manufacture;
GB/T8320-2003
f) the name of the manufacturer;
g) the seal of the inspector and the seal of the inspection department. 6 Copper tungsten and silver tungsten electrical contact products should be packaged according to the same batch of the same model and size specifications. 7.6
7.7" Copper tungsten and silver tungsten electrical contact products can be double-wrapped in plastic bags or packed in plastic bags and then boxed. 7.8
3 Electrical contact products packed in plastic bags or boxes should be shipped in packaging boxes and filled with soft materials; the weight of each box shall not exceed 15kg.
9 A packing list should be attached to the packaging box, which should include 7.9
The total number of bags (boxes);
The number of bags (boxes) of electrical contacts of various models or sizes; the net weight of the electrical contacts;
The packaging date;
The seal of the packer.
The outside of the packaging box should be marked with:
Manufacturer name;
Electric contact product name or representative symbol;
Moisture-proof and handle with care signs
Electrical contact products should avoid severe vibration during transportation to avoid mechanical damage. 7.12
Electrical contact products should be stored in a warehouse without corrosive media to prevent moisture. Appendix A
(Normative Appendix)
Metallurgical Structure Legend
A.1 This metallographic structure legend can be used as a reference when checking the metallographic structure of copper tungsten and silver tungsten electrical contacts. A.2 Copper tungsten electrical The metallographic structure of the contact is shown in Figure A.1. a) CuW (50) ||tt ||) Cuw (70) ||tt || e) CuW (90) ||tt || Metallographic structure of copper tungsten electrical contact ||tt || b) Cuw (60) ||tt || d) CuW (80) ||tt || GB/T8320—2003 ||tt || GB/T8320-2003 ||tt || The metallographic structure of silver-tungsten electrical contacts is shown in Figure A.2a) AgW(30)
AgW(50)
AgW(70)
Figure A.2 Metallographic structure of silver-tungsten electrical contacts
b) Agw(40)
AgW(60)
f) AgW(80)
GB/T8320—2003
Appendix B
(Normative Appendix)
Product Inspection Sampling Table
The data quoted in this appendix are partially extracted from GB/T2828.1 for reference when using this standard. B.1
Secondary Normal Inspection Sampling Table (as shown in Table B.1). B.2
Sampling Table
Acceptable Quality Level (AQL)
Special Inspection Level
Batch Range Circumference/piece
151~280Www.bzxZ.net
281~500
501~1200
1201~3200
3201100 00
10001~35000
35001~150000
150001~500000
Above 500000|| tt||GB/T8320—2003
Symbols in the table:
V—Use the first sampling plan below the arrow. If the sample size is greater than or equal to the batch size, the entire batch shall be inspected 100%;
Use the first sampling plan above the arrow; *
Use the applicable sampling plan below;
-The number of qualified judgments;
The number of unqualified judgments.9
Total number of bags (boxes);
Number of bags (boxes) of various types or sizes of electric contacts; Net weight of electric contacts;
Packing date;
Seal of the packer.
The outside of the packing box should be marked with:
Name of the manufacturer;
Name or representative symbol of the electric contact product;
Moisture-proof and handle with care signs.
Electrical contact products should avoid severe vibration during transportation to avoid mechanical damage. 7.12
Electrical contact products should be stored in a warehouse without corrosive media to prevent moisture. Appendix A
(Normative Appendix)
Metallurgical structure legend
A.1 This metallographic structure legend can be used as a reference for checking the metallographic structure of copper tungsten and silver tungsten electric contacts. A.2 The metallographic structure legend of copper tungsten electric contacts is shown in Figure A.1. a)CuW(50)
)Cuw(70)
e)CuW(90)
Metallurgical structure example of copper tungsten electrical contact
b)Cuw(60)
d)CuW(80)
GB/T8320—2003
GB/T8320-2003
Metallurgical structure example of silver tungsten electrical contact is shown in Figure A, 2a)AgW(30)
AgW(50)|| tt||AgW(70)
Figure A.2 Metallographic structure of silver-tungsten electrical contact
b) Agw(40)
AgW(60)
f) AgW(80)
GB/T8320—2003
Appendix B
(Normative Appendix)
Product inspection sampling table
The data quoted in this appendix are partially extracted from GB/T2828.1 for reference when using this standard. B.1
Second normal inspection sampling table (such as Table B.1). B.2
Sampling table
Acceptable quality level (AQL)
Special inspection level
Batch range/piece
151~280
281~500
501~1200
1201~3200
320110000
10001~35000
35001~150000
1500 01~500000
Above 500000
GB/T8320—2003
Symbols in the table:
V—Use the first sampling plan below the arrow. If the sample quantity is greater than or equal to the batch size, the entire batch shall be inspected 100%;
Use the first sampling plan above the arrow;*
Use the applicable sampling plan below;
-Qualified number;
Unqualified number.9
Total number of bags (boxes);
Number of bags (boxes) of various types or sizes of electric contacts; Net weight of electric contacts;
Packing date;
Seal of the packer.
The outside of the packing box should be marked with:
Name of the manufacturer;
Name or representative symbol of the electric contact product;
Moisture-proof and handle with care signs.
Electrical contact products should avoid severe vibration during transportation to avoid mechanical damage. 7.12
Electrical contact products should be stored in a warehouse without corrosive media to prevent moisture. Appendix A
(Normative Appendix)
Metallurgical structure legend
A.1 This metallographic structure legend can be used as a reference for checking the metallographic structure of copper tungsten and silver tungsten electric contacts. A.2 The metallographic structure legend of copper tungsten electric contacts is shown in Figure A.1. a)CuW(50)
)Cuw(70)
e)CuW(90)
Metallurgical structure example of copper tungsten electrical contact
b)Cuw(60)
d)CuW(80)
GB/T8320—2003
GB/T8320-2003
Metallurgical structure example of silver tungsten electrical contact is shown in Figure A, 2a)AgW(30)
AgW(50)|| tt||AgW(70)
Figure A.2 Metallographic structure of silver-tungsten electrical contact
b) Agw(40)
AgW(60)
f) AgW(80)
GB/T8320—2003
Appendix B
(Normative Appendix)
Product inspection sampling table
The data quoted in this appendix are partially extracted from GB/T2828.1 for reference when using this standard. B.1
Second normal inspection sampling table (such as Table B.1). B.2
Sampling table
Acceptable quality level (AQL)
Special inspection level
Batch range/piece
151~280
281~500
501~1200
1201~3200
320110000
10001~35000
35001~150000
1500 01~500000
Above 500000
GB/T8320—2003
Symbols in the table:
V—Use the first sampling plan below the arrow. If the sample quantity is greater than or equal to the batch size, the entire batch shall be inspected 100%;
Use the first sampling plan above the arrow;*
Use the applicable sampling plan below;
-Qualified number;
Unqualified number.
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