Technical Specification of Tungsten Contact of Breaker

The following is the technical specifications of tungsten contact for breaker, including range, standard, technical specification, testing method, transportation, packing, etc.

1.0 Range

This standard JB/T 9860.1-1999 specifies the technical requirements, test methods, inspection rules and markings, packaging, transportation and storage of lamp-type tungsten contacts products for magnetic circuit breakers.

2.0 Standard Applied

Standards applied in this standard:

GB/T 230-1991 Rockwell Hardness Test

GB/T 2828-1987 Sampling Process and Quantity of Each Lot

GB/T 4197-1984 Tungsten and Molybdenum and Alloys Crystal Grain Size Testing Method

GB/T 4324.1-4324.30-1984 Tungsten Chemicals Testing Method

GB/T 4340/1984 Vickers Hardness Testing Method

JB/T 9860.2-1999 Technical Specifications of Tungsten Rod for Contacts of Breaker

JB/T 9864.2-1999 Testing Method of Breaker of Megnato

3.0 Technical Specifications

3.1 Tungsten contact should comply with this standard, and be produced with the approved drawing, samples and technical data.

3.2 The contact should be welded with tungsten sheet, copper/iron sheet and welding materials under H2, N2 protection.

3.3 The raw material should pass the testing under JB/T 9860.2 and the contact should follow the attached data.

Purity of tungsten, %	Hardness, HRA	Crystals Number, pcs/mm2
W≥99.95	≥70	7,500~25,000

3.4 The leg material of contact should be 0.15%~0.2% low carbon iron, or other material suitable for welding and with similar properties.

3.5 The welding material of copper should be with purity higher than 99.9%.

3.6 Welding area strength should be higher than 78.45MPa.

3.7 Dimensions and Appearance

3.7.1 Dimensions and the tolerances should produce according to the drawing agreed by users and producers.

3.7.2 The appearance of contact is smooth, and without breaks, sharp edges, rusts, color change and cold joint. Coating layer is with no peeling, no leakage plating, and deplating.

3.7.3 The welding seam is uniform and there is no obvious copper flow phenomenon. The apparent thickness of the weld is not more than one-fourth of the thickness of the tungsten sheet.

3.7.4 The maximum allowable value of Ra specified for the roughness of the contact surface of the tungsten contacts is 0.4um. The contact surface of the contacts must not have dents or residual processing traces.

4.0 Test method

4.1 The chemical purity analysis of the tungsten sheet can be replaced by the analysis result of the tungsten rod made of this sheet, and the method shall be carried out in accordance with the provisions of GB/T 4324.1~4324.30.

4.2 The hardness test method is carried out in accordance with the provisions of GB/T 230: it is measured with a Vickers hardness tester, with a load of 4.904N, and carried out in accordance with the method specified in GB/T 4340. The measured value is converted according to the comparison table and should meet the HRA regulations.

4.3 The method for determining the number of cross-sectional grains shall be carried out in accordance with GB/T4197.

4.4 The weld strength is measured according to 5.14 in JB/T 9864.2-1999.

4.5 According to the requirements of 3.7.1, the size of the tungsten point is measured and checked with a general measuring tool.

4.6 According to the requirements of 3.7.2 and 3.7.3, the appearance and welds of the contacts should be inspected visually or with a magnifying glass.

4.7 According to the requirements of 3.7.4, the roughness of the contact surface of the contacts should be tested with a surface roughness sample block or a surface roughness measuring instrument.

5.0 Inspection Rules

5.1 Tungsten contacts must be inspected by the manufacturer's quality inspection department to ensure that the product meets the requirements of the standard and fill in the quality certificate.

5.2 The user can inspect the received product. If the inspection result does not conform to the specifications and technical indicators marked on the mark, it shall be submitted to the manufacturer within three months from the date of receipt of the product, and both parties shall identify it together and if it still does not conform Is unqualified.

5.3 The sampling of each batch shall be as follows:

To check the chemical purity, hardness and grain number of tungsten, take any sample from the tungsten rods of the same batch of products produced above, take a sample at a quarter, and crush it to the required requirements. Users can also use tungsten contacts to directly prepare samples for measurement.

5.4 Random inspections can be performed on 3.3. If the sampling result is unqualified, double the sampling and re-inspection. If there is still one unqualified item, the batch of products is unqualified.

5.5 The welding seam strength and size of the contacts, the roughness and appearance of the contact surface of the contacts should be inspected according to the methods specified in GB/T 2828.

The specific acceptance plan is negotiated between the manufacturer and the user.

6.0 Marking, packaging, transportation and storage

6.1 After the contacts are packaged in plastic bags, they are packaged in metal or plastic boxes. Tungsten contacts of the same type, specification and batch number are placed in the same packing box.

6.2 Each batch should be accompanied by a mark and indicate the contact type, mark and standard number, production batch number, specifications, quality, production date, and the manufacturer and inspection department's mark.

6.3 The contacts should be packed in a small wooden box padded with moisture-proof paper and reinforced during transportation. The words or symbols such as "Don't Throw" and "Moisture Prevention" should be marked on the box.

6.4 Severe impact should be prevented during transportation to prevent acid-base erosion and rain and snow.

6.5 Tungsten contact should be stored in a dry room without corrosive gases such as acids and alkalis.

 

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