This standard applies to ordinary carbon steel welded steel pipes for wire casings. GB/T 3640-1988 Ordinary carbon steel wire casings GB/T3640-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Plain carbon steel wire casing
Plain carbon steel pipes for electric wire This standard applies to plain carbon steel welded steel pipes for electric wire casing: 1 Dimensions, shape and shape
1.1 Dimensions
1. 1. 1 The dimensions of the steel pipe shall comply with the provisions of Table 1. Table 1
Permissible deviation in nominal size
Note: ① With the cooperation of both the supplier and the buyer, the dimensions other than those specified in Table 1 can be produced. Wall thickness
UDC 669.14-462
621. 315. 67
GB3640—88
Generation #GB3610-83
Theoretical weight
(excluding arm joint)
@When delivering, each arm should be accompanied by an arm joint: when calculating the theoretical weight of the steel pipe, the weight of the pipe joint should be added. 1.1.2 Length of steel pipe
1. 1. 2. 1 Normal length: 3~9 m.
1.1.2.2 With the agreement between the supply and demand parties, the pipe can be supplied in fixed length and multiple lengths, with the maximum length not exceeding 8m, and the full length allowable deviation is +15mm+. For steel pipes delivered in multiple lengths, each single length should have a cutting allowance of 5~10mm. 1.1.3 Both ends of the steel pipe shall be provided with cylindrical threads. The standard thread profile and size of the steel pipe and the pipe joint shall comply with the provisions of Appendix A of this standard.
1.2 Appearance
1.2.1 The curvature of the steel pipe shall not exceed 3mm per meter. 1.2.2 Both ends of the steel pipe shall be cut straight, with a shear slope of not more than 2°, and burrs shall be removed. 1.3 Weight
1.3.1 The steel pipe shall be delivered according to the actual weight.
Approved by the Ministry of Metallurgical Industry of the People's Republic of China on February 2, 1988 and implemented on March 1, 1989
GB 3640 88
1.3.2 Delivery may also be based on theoretical weight upon agreement between the supplier and the buyer. At the time of delivery, the weight tolerance of each batch of steel pipes shall be ±10% of the theoretical weight. The weight tolerance of a single steel pipe shall be 17.5% of the theoretical weight. 1.3.3 When delivered according to theoretical weight, galvanized or other coated steel pipes are allowed to be 1% to 6% heavier than steel pipes without zinc coating (coating) according to the type and thickness of the coating (coating).
1, 4 Marking example:
The marking of the wire casing with a nominal size of 25mm made of B2 steel is: Wire casing B225-GB3640-88
2 Technical requirements
2.1 The steel pipe is manufactured in accordance with GB8164-87 "Steel Strip for Welded Steel Pipes". 2.2 The steel pipe is subjected to a 90° bending test at room temperature. There shall be no cracks and cracks at the bends, and no cracks at the welds. 2.3 The outer surface of the steel pipe shall be free of cracks and scars. Slight jade marks, straight lines, scratches, pits and burr marks after grinding or removal that are not greater than the allowable deviation of the thickness of the steel strip used to manufacture the steel pipe are allowed to exist (pits with a diameter of less than 2mm are not subject to assessment). 2.4 The inner surface of the steel pipe should be smooth, and burrs with a height of no more than 1mm are allowed at the weld. 2.5 The outer surface of the galvanized or other coated steel pipe should have a complete coating (coating) and the surface should not have peeling or bubbles; a slightly rough surface and local scars are allowed.
2.6 The galvanized steel pipe should be tested for uniformity of the galvanized layer. It should not turn red (copper color) after being immersed in a sulfuric acid solution for 5 consecutive times. 2.7 The galvanized steel pipe should be tested for corrosion resistance. During the salt water spray test, the surface of the electro-galvanized steel pipe treated with chromate gloss should not produce white corrosion products.
2.8 Upon agreement between the supply and demand parties, the galvanized steel pipe can be measured by weight of the galvanized layer. The average value should not be less than 500g/m, but any sample should not be less than 480g/m.
2.9 The coated steel pipe should be tested for film scraping or bending. During the test, the surface shall not be cracked. 2.10 The threads of the steel pipe shall be even, smooth and free of cracks, and slight burrs are allowed. Black skin is allowed on the threads at the weld of the steel pipe. The reduction in the height of the low thread section shall not exceed 15% of the specified height. The broken or incomplete thread is allowed to exist when the total length does not exceed 10% of the specified length. The same part of two adjacent buckles shall not be broken at the same time. 3 Test method
3.1 The surface of the steel pipe shall be inspected one by one with the naked eye or other methods. The depth of the outer surface defects shall be checked at one or several places by chain cutting or other methods.
3.2 The bending test of the pipe shall comply with the provisions of GB244-82 "Jinzhan Pipe Bending Test Method". The bending radius is 4 times the diameter of the steel pipe, and the weld should be placed on the measuring surface in the bending direction. 3.3 The zinc coating uniformity test and zinc coating weight measurement test of galvanized steel pipes shall comply with the provisions of Appendix A and Appendix B of GB3091-82 "Galvanized welded steel pipes for low pressure fluid transportation". 3.4 The corrosion resistance test of galvanized steel pipes shall be carried out in accordance with Appendix B of this standard. 3.5 The coating steel pipe shall be subjected to the film scraping test using pencil hardness. 3.5.1 Use an H pencil that meets the standard of CB149-75 "Pencil" of ordinary grade or above. The lead should be sharpened into a plane perpendicular to the length direction (see Figure 1).
3.5.2 The prepared pencil is 45° to the test surface. Draw at least 3 lines as shown in Figure 2. The load when drawing is 9.8N (Newton), and the length of the line is not less than 20mm
1nm 1
GB3640.88
3.6 The corrosion resistance test of coated steel pipes shall be carried out in accordance with Appendix C of this standard Figure 2
3.7 Check the appearance quality of the thread with the naked eye. Use a common disc to check the thread length and outer diameter, and use a standard ring gauge to check the quality of the thread
4 Acceptance rules
4.1 Steel pipes should be submitted for inspection and acceptance in batches. Each batch of steel pipes should be steel with the same diameter and the same steel grade. 4.2 When conducting each test on galvanized or other coated steel pipes, randomly select 2 pipes from each batch of pipes that have passed the size and appearance inspection, and cut a longitudinal specimen from each pipe.
4.3 For the corrosion resistance test of zinc-plated steel pipes, the scraping test and bending test of other coated steel pipes, if the supplier can guarantee the qualified finished products, the test may not be conducted during the regular acceptance of the products. 4.4 The acceptance, re-inspection and judgment rules of steel pipes shall comply with the provisions of GB2102-88 "Steel Pipe Acceptance, Packaging, Marking and Quality Certificate".
5 Packaging, Marking and Quality Certificate
5.1 Steel pipes are bundled in small bundles and then bundled into large bundles for delivery. The small bundles are bundled in two places, and one end of the unsealed pipe joint is screwed with a wire ring or wrapped with linen. The maximum weight of each small bundle is 150kg. 5.2 Other requirements for steel pipe packaging shall be carried out in accordance with the provisions of GB2102-B8. 5.3 The marking and quality certificate of steel pipes shall comply with the provisions of Gn2102-88. GB3640-88
Appendix A
Standard thread shape and size of steel pipes and pipe joints (supplement)
A.1 Standard thread shape of steel pipes and pipe joints A.1.1 The standard thread shape of steel pipes and pipe joints shall comply with the provisions of Figure AI.
D is the outer diameter of the pipe thread;
D is the average diameter of the pipe thread; wwW.bzxz.Net
D is the inner diameter of the pipe thread +
D is the inner diameter of the steel pipe thread; ... 1
（6）
Number of threads per 25.4 mm
GB3640-88
Thread diameter.mm
31,464
Average diameter4:
62.021 1 61.7$4
75.85574.72174.434
The thread size of steel pipe fittings shall comply with the provisions of Table^2. Table A2
With connector
Number of threads in mm
Outer diameter D
14. 06813. 709
23. 366 1 22. 985
Thread diameter, m
Average diameter D
30,833
Effective length of thread + mm
B.1 Preparation of test specimens
GB 3640 —88
Appendix B
Corrosion test of galvanized steel pipes—water spray method (supplement)
Take any two galvanized steel pipes from each batch of qualified tests, and cut a pipe section of about 150mm in length at one end of each steel bar as test specimens. The surface oil stains of the test specimens shall be removed first, and then wiped clean with a clean soft cloth, and a 50mm wide coating and wax shall be applied from the cut surface to the test surface to seal the end surface of the test specimen.
B.2 Preparation of test solution
Use 5% sodium chloride (chemically pure) and distilled water after boiling and deoxygenation to prepare a (5±1)% concentration of salt water. The pH value of the salt water shall be adjusted with a dilute acid solution with a specific gravity of 1.19 or a dilute sodium hydroxide solution with a concentration of 10%, and controlled between 6.5 and 7.2. The volume of the salt water shall be determined by the size of the salt spray chamber.
B.3 Test operation method
.3.1 Place the prepared sample on the bracket in the box vertically or at an angle of 30°. 8.3.2 Heat the salt water and air in the box to make the temperature reach 35±1℃. 8.3.3 When the salt water is sprayed, the air pressure delivered by the nozzle is 60~100kPa; the spray volume is collected in the sampler with a diameter of 80mm, and the amount is [,2-2. 0 mL/h.
B.3.4 The sample is sprayed continuously for 8h, stopped for 16h, repeated twice and then sprayed for 8h. B.3.5 During the salt water spray test, the sample conditions must be kept constant. B. 4 Test result judgment
After 72h of salt water spray test, the sample should meet the following requirements: No white corrosion products should appear on the surface of the electro-galvanized steel pipe treated with chromate gloss. C.1 Preparation of samples
GB364088
Corrosion resistance test of coated copper pipes
(Supplement)
Bending test method
Take any 2 pieces of coated copper pipes from each batch of qualified ones, and cut a section of pipe of appropriate length at one end of each steel pipe as the sample. The length of the sample should ensure the bending test. C.2 Test operation method
C.2.1 Put the sample on a smooth cylindrical cylinder and slowly bend it into an arc. When bending, a cardboard or other similar items about 3mm thick should be inserted between the sample and the cylinder. C.2.2 The bending radius should comply with the provisions of Table C1. Table cl
Nominal size of steel
32~-76
c.2.3 Others should comply with the relevant provisions of Gn244-82. C.3 Test result judgment
After the specimen is bent, the surface shall not be cracked. Additional remarks:
This standard is proposed by the Information Standard Research Institute of the Ministry of Metallurgy. This standard is drafted by the Shanghai Tenth Iron and Steel Plant. This standard is marked with GB 3640-881 "
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