GOST 16971-71
GOST 16971−71 Seams weld joints of vinyl plastic, PVC plastic and polyethylene. Methods of quality control. General requirements
GOST 16971−71
Group B09
STATE STANDARD OF THE USSR
THE SEAMS OF WELDED CONNECTIONS OF VINYL PLASTIC
OF PVC AND POLYETHYLENE
Methods of quality control.
General requirements
Welded joints of Plasticized PVC, unplasticized PVC and polyethulene.
Qualitu control methods. Total requirements
Date of introduction 1972−01−01
DEVELOPED by the research Institute of plastic masses (of NIIPM)
Director of the Institute, doctor of engineering. Sciences Popov V. A.
Performers: Tatevosjan G. A., Vysotsky M. M.
INTRODUCED by the Ministry of chemical industry
Member Of The Board Sirakov M. G.
READY FOR ADOPTION
Department of chemistry and petroleum products the State Committee of standards of the Council of Ministers of the USSR
Acting head of Department L. I. povolotskii
GL. specialist Morozova E. N.
St. engineer T. F. Litvin
Department of welding of all-Union scientific-research Institute for normalization in mechanical engineering (VNIINMASH)
Head of Department L. X. Luchansky
Head. sector Rodin I. 3.
St. engineer Kalmykov V. A.
APPROVED by the State standards Committee of the Council of Ministers of the USSR on 25 December 1970 (Protocol No. 233)
The Chairman of the branch scientific-technical Commission Milovanov A. P.
Members: Kovalenko, F. F., Ushakov P. V., Tikhonov V. T., Belova E. M., Medvedeva T. V., Povolotsky, L. I.
Promulgated by Decree of the State Committee of standards of the USSR Council of Ministers of 14 may 1971, N 931
REPRINTING. February 1973
This standard establishes methods of quality control of welds of welded joints of rigid PVC, plastic and polythene made by all welding methods.
The standard establishes methods of quality control of welds of welded joints of pipes.
1. GENERAL REQUIREMENTS
1.1. Provides the following methods of control of the joints welded joints:
external examination and measurement;
mechanical testing tensile, heavy bending and impact bending;
the tightness test.
1.2. These methods should be applied in the quality control of the seams of finished products by testing samples made from products or from the control welded joints (samples). Leak tests are conducted only on finished products.
Allowed to use other control methods, not stipulated by this standard, a special technical documentation approved in the established order.
1.3. If the products made by welding shall be operated in corrosive environments, the joints welded joints must withstand in these environments, and then tested in tension, tense, or impact strength (depending on working conditions). The duration of exposure of samples of welded joints in the medium and the choice of test method established special technical documentation, duly approved.
1.4. Work with chemicals (solvents) and gas indicators should be performed in a fume hood or outdoors. If the gas lights were introduced into the vessel at the end of the work necessary to purge the container.
1.5. Weldability the alloy must be of the same material as the finished product. The material of the sample (composition, type, brand, thickness), technological welding conditions, and the conditions should be the same as in the manufacture of the product.
1.6. Before the test, the seam weld and heat affected zone shall be cleaned or washed from impurities hindering the inspection, the width of at least 10 mm on both sides of the seam.
1.7. Conditional images and symbols types and designs of joints welded joints — according to GOST 16310−70*.
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* On the territory of the Russian Federation GOST 16310−80. — Note the CODE.
1.8. Type and construction the weld of a welded connection sample must be the same as the test part.
1.9. When testing, always observe the valid safety regulations, industrial sanitation and fire safety.
2. SAMPLING
2.1. In the manufacture of trial joints welded joints shall be placed as shown on the devil.1−5.
Damn.1. Sample type 1
Sample type 1
Damn.1
Damn.2. Sample type 2
Sample type 2
Damn.2
Damn.3. Sample type 3
Sample type 3
Damn.3
Damn.4. Sample type 4
Sample type 4
Damn.4
Damn.5. Sample type 5
Sample type 5
Damn.5
2.2. For testing butt (hell.1), lap (damn.2−4) and T-shaped (Fig.5) connections must be used:
sample type 1 (Fig.1) for tensile tests, busy or impact strength of joints welded joints of sheet materials;
samples of types 2−5 (Fig.2−5) for tensile testing of welds for welded joints of plastic materials.
2.3. Test joints welded joints by method of a busy bend with the application of long-acting the efforts carried out on samples of sheet materials (polyethylene and vinyl plastic). Sample sizes should be:
made of polyethylene with a thickness of 2 to 7 mm;
length — 150 mm;
width — 30 mm;
of vinyl plastic with a thickness of 2 to 5 mm;
length — 150 mm;
width — 20 mm.
2.4. Testing of welds for welded joints on impact bending is carried out on samples without notch.
2.5. For all kinds of testing of seam welds must be located in the middle of the sample and perpendicular to the plane of its cutting.
2.6. For all test samples cut from the monitored weld or from the sample milling for materials with a thickness more than 1 mm and a special device according to the GOST 14236−69* — film materials.
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* On the territory of the Russian Federation GOST 14236−81, here and hereafter. — Note the CODE.
2.7. The thickness of the sample material should match the material thickness of the test part. The length of the sample (see the devil.1) is determined by the number of samples cut out of it taking into account the allowances to the width of the cut and subsequent processing, and the width of the unused sections
of the seam weld. The width of the unused land at the beginning and at the end of the sample should be not less than:
20 mm — when the welding is heated by the gas welding rod or welding of the heated extruded additive;
15 mm when welding high-frequency and thermal contact method.
2.8. The deflection of the specimen welded from sheet material, measured on the basis of 200 mm should not exceed 5% of the thickness of the specimen or sample, but not more than 2 mm.
2.9. The mutual offset of the edges of the seam welded joint of the sample made from the controlled product or the sample of type 1 (see the devil.1) should not exceed 5% of the thickness of the sample.
2.10. Edit the sample before the test or sample before cutting from it of samples is not allowed.
2.11. The marking produced by the marking, or causing permanent paint:
sample — non-working portion;
a sample of unused land ().
The marking shall remain on the samples after testing.
3 TESTING
3.1. Exterior inspection and measurement
3.1.1. External examination reveals cracks, lack of penetration, displacement of edges, irregularity of the geometric shape of the weld, the size mismatch of the weld.
3.1.2. Joints welded joints inspect both sides for the entire length with the use of magnifying devices with a magnification of 10 times.
3.1.3. Weld sizes and defects (measuring) measure measurement tool with an accuracy of ±0,01 mm.
3.1.4. To detect internal defects in the seam weld (lack of fusion, cracks, pores, gas and solid inclusions) visually examine the fracture on one sample from each sample.
3.2. Mechanical tensile tests
3.2.1. Tensile tests of sheet materials of a thickness of > 1 mm is carried out on samples of type 2 or 3 according to GOST 11262−68, plastic materials — according to GOST 14236−69; for testing, you need to take at least five samples.
3.2.2. The strength of the weld of a welded joint is expressed as a ratio to maintain the properties of () in percent as the ratio of the strength of welded material (
) to the strength of the seam weld (
) and it is calculated according to the formula:
3.2.3. The test report shall indicate the design of the seam, the place of his selection (for the samples made from products), the place of destruction, test temperature, test data for all the samples, the test result and the retention of properties.
3.2.4. If necessary for the tensile testing of welds welded joints after exposure to aggressive environments select at least 20 samples according to GOST 11262−68. Half of the samples placed in an environment. While keeping the samples in an environment with the ambient temperature and the test procedure set by agreement of the parties on specific technical documentation approved in the established order. The remaining samples were subjected to the test without exposure to aggressive environment. After the test and nepodvizhnykh subjected to action of aggressive environment samples calculate the average arithmetic value of the tensile strength for the other group of samples and calculated the conditional retention properties () in percentage by the formula:
where:
— arithmetic mean value of the limit of the tensile strength of the samples exposed to corrosive environment;
— arithmetic mean value of the limit of the tensile strength of specimens not exposed to aggressive environment.
Seam weld quality is considered at 
3.3. Mechanical testing method busy bending
3.3.1. Samples (see p.2.3) is placed in a fixture (Fig.6) so that the weld is subjected to bending. For this sample load selection the load so that the distance
between the ends of the specimen was equal to 0.8
.
Damn.6. Device for mechanical testing method busy bending
1 — guide; 2 — cargo; 3 — upper plate; 4 — bottom plate; 5 — sample; 6 — emphasis
Damn.6
3.3.2. If necessary, testing is allowed by method of a busy bending samples after exposure to aggressive environments.
3.3.3. For testing select at least 20 samples. Half of the samples immersed in the environment. While keeping the samples in an environment with the ambient temperature and duration of subsequent aging of the samples as a busy bending set by agreement of the parties on specific technical documentation approved in the established order.
After aging in the environment, samples exposed to environment and not exposed to the environment set to test (see item 3.3.1).
Samples think has stood the test, if the surface tension of the seam is not formed cracks and tears. Otherwise, the test is performed repeatedly on the same number of samples.
3.4. Mechanical tests the impact strength
3.4.1. Testing the impact strength of joints welded joints of sheet materials of thickness greater than 1 to 5 mm is carried out on the sample of type 2 according to GOST 4647−69* thickness from 5 to 10 mm on the sample type 1 according to GOST 4647−69*.
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* On the territory of the Russian Federation GOST 4647−80. — Note the CODE.
3.5. If necessary it is possible to perform all types of mechanical testing at elevated and low temperatures.
3.6. Processing of results of mechanical tests are produced according to GOST 14359−69.
3.7. Leak tests
3.7.1. The tests are carried out to establish the seams of welded connections in the following ways:
air;
chemical indicators;
air pressure;
hydraulic pressure;
bulk of water.
It is allowed to conduct leak tests of joints welded joints pressure working environment, spark testing, helium leak detector and measuring the electrical resistance of the electrolyte on both sides of the seam.
The method of testing is chosen depending on the product structure, its dimensions and its operating conditions and set the special technical documentation, duly approved.
A. the Test of blowing
3.7.2. Air cooling of the seam weld with a compressed air jet is produced, as shown in hell.7. Compressed air under pressure of 2.5 kgf/cmserves through a flexible hose with a tip.
Damn.7. Air cooling of the seam weld with compressed air
Damn.7
The distance between the tip of the hose and seam welded joint should be not more than 50 mm.
3.7.3. Prior to blowing or simultaneously with the blowing of the seam weld air the opposite side of the seam moistened with a soap solution (0.1 kg of neutral soap per 1.0 liter of drinking water according to GOST 2874−54).
Leakage of the seam welded joint is determined by the appearance of bubbles on the moist side.
3.7.4. Testing at temperatures below 0 °C is performed with partial replacement of water by alcohol (60%) or with the use of antifreeze, solvent and soap do not react with the material of the controlled product.
After testing, the solution should be washed away with water.
B. Test chemical indicators
3.7.5. The test weldment with a closed volume. On weld applied paper tape, impregnated 5% aqueous solution of nitrate of mercury GOST 4521−68. Tape width shall be 20 mm greater than the width of the seam.
After packing and fastening of the tape on the seam inside of the test items administered ammonia in the amount of 1% of the volume of air in the product during the ambient pressure, and then compressed air to create pressure, set the appropriate technical documentation, duly approved.
The product is held under pressure for 3−5 min, after which a paper ribbon, folded and inspected. Places of leakage in the seam weld install black spots on the paper tape.
3.7.6. The tightness of the joints welded joints may also be checked by filling the volume of the weldment with a mixture of ammonia with air under a pressure of 10 mm of water.St. with subsequent irrigation or pulverization of the seam from the outside with a slurry of the following composition:
phenolphthalein (powder) according to GOST 5850−51 — 4 parts;
technical ethyl alcohol according to GOST hydrolysis 17299−71* — 40 pieces;
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* On the territory of the Russian Federation GOST 17299−78, here and hereafter. — Note the CODE.
distilled water GOST 6709−72 — 100 parts.
Places of leakage in a seam welded joint is determined by color change of slurry, forming a red-violet spots.
V. the Test air pressure
3.7.7. Before the test weldment sealed gas-tight plugs and immersed in water so that over the product was a layer of water between 20−40 mm. After immersion in the product supply compressed air. The pressure created in the product, and the dwell time of the product under pressure establish a special technical documentation, duly approved.
3.7.8. In products that may not be fully submerged in water, create a pressure, as specified in clause 3.7.7 (but dip them in the water), then the product is partially immersed in water so that the controlled joints were in the water. So alternately subjected to control all the seams of the product.
3.7.9. Allowed to test joints welded joints for leaks by creating a in the product pressure, as specified in clause 3.7.7, followed by wetting the joints with a soap solution as indicated in claim
3.7.10. Places of leakage in a seam welded joint is established by appearance of air bubbles in water (test on PP.3.7.7 and 3.7.8) or bubbles with soapy water the surface of the weld (when tested on PP.3.7.3 and 3.7.9).
G. Testing the hydraulic pressure
3.7.11. The hydraulic pressure test is carried out according to GOST 1999−60.
D. the Test of pouring water
3.7.12. Prior to testing, joints welded joints from the outside wipe with a cloth or blown air to obtain a dry surface. The product is filled with water having a temperature of 5−50 °C. the Test is carried out at a temperature below 5 °C.
3.7.13. Places of leakage in a seam welded joint is determined by appearance of a leak.
Replacement
GOST 6709−72 introduced to replace GOST 6709−53.
GOST 17299−71 introduced to replace GOST 8314−57, in addition to the test methods.
