HG/T 3691-2001 Industrial steel skeleton polyethylene plastic composite pipe fittings
Some standard content:
Registration No.: 10169-2002
HG/T3691-2001
This standard is formulated in combination with my country's national conditions. Foreword
Appendix A and Appendix B of this standard are the appendices of the standard. Foreword
This standard is proposed by the Policy and Regulations Department of the former State Administration of Petroleum and Chemical Industry. This standard is under the jurisdiction of the National Technical Committee for Standardization of Non-metallic Chemical Equipment. The drafting units of this standard are: Standardization Research Institute of the Ministry of Chemical Industry, Huachuang Tianyuan Industrial Development Co., Ltd., and Xinghe Industrial Co., Ltd. The main drafters of this standard are: Li Peng, Niu Mingchang, Wang Xiaobing, Wang Junliang, Mei Jian, Ma Xiaoming, Sun Lihua, and Zhou Wei. 13
Chemical Industry Standard of the People's Republic of China
Fittings of steel framed polyethylene plastic pipes for industry1Scope
HG/T3691—2001
This standard specifies the basic performance, product classification, requirements, test methods, inspection rules, marking, packaging, transportation and storage of steel framed polyethylene plastic composite pipes for industry (hereinafter referred to as pipes). This standard is applicable to steel framed plastic composite pipes made of thin steel plates uniformly punched and rolled and welded to form a reinforced frame and then injected with polyethylene. It can be used in the petroleum, chemical, pharmaceutical, metallurgy, mining, shipbuilding, municipal construction, food and other industries. The temperature range of the medium conveyed by the pipe fittings is 0~70℃.
2Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T709—1988 Dimensions, shapes, weights and tolerances of hot-rolled steel sheets and strips GB/T1033—1986 Test methods for density and relative density of plastics GB/T2828—1987
Batch-by-batch inspection counting sampling procedures and sampling tables (applicable to inspection of continuous batches) GB2918—1998 Standard environment for state adjustment and testing of plastic specimens GB/T6111—1985
GB/T6283—1986
GB/T8806--1988
GB/T 13021—1991
GB15558.1—1995
HG/T3690—2001
3 Definitions
Method for determination of the damage resistance time of thermoplastic plastic pipes under long-term constant internal pressure Determination of moisture content in chemical products Karl Fischer method (general method) Plastic pipe size measurement method
Determination of carbon black content of polyethylene pipes and fittings (thermal gravimetric method) Buried polyethylene pipes for gas
Industrial steel skeleton polyethylene plastic composite pipes This standard adopts the following definitions:
Nominal pressure
The maximum pressure allowed for the pipe to convey water at 20℃. 4 Raw materials and requirements
4.1 Polyethylene
4.1.1 Polyethylene special materials
The polyethylene used to make pipe fittings should be the same as the raw materials used in HG/T3690, and its basic properties should meet the requirements of Table 1. Approved by the State Economic and Trade Commission on January 24, 2002, and implemented on July 1, 2002
Density, kg/m
Moisture content, mg/kg
Volatile matter content, mg/kg
Carbon black content, %
Thermal stability, (200℃) min
Resistance to environmental stress cracking, h (100℃, 100%, F.) HG/T3691—2001
Basic properties of special materials for ethylene
Resistance to gas components, h (80℃, 2MPa)
Long-term static hydraulic strength, MPa (20℃, 50 years, 95%) Note: Carbon black content is only applicable to black pipes. 4.1.2 Polyethylene recycled materials
Performance requirements
The clean residue, debugging and process cutting scraps generated when producing pipe fittings according to this standard can produce pipe fittings that meet the requirements of this standard and can be recycled by mixing with new materials at a rate of no more than 5% after crushing or re-granulation. 4.2 Steel skeleton
4.2.1 Low carbon steel plate
The low carbon steel plate used to make the steel skeleton should meet the requirements of ordinary low carbon thin steel plate in GB/T709. 4.2.2 Surface coating
The surface of the steel skeleton needs to be coated with an anti-rust layer, and the coating surface is flat and smooth, does not fall off, has no leakage, and must not have oil, dust and other dirt. 5 Product classification
5.1 Pipe fittings series
Pipe fittings are divided into two series: ordinary and thin-walled, and their connection methods are divided into flange connection and electric fusion connection. The types of pipe fittings include 45° elbows, 90° elbows, tees and reducers. When the electric fusion connection method is used, it is equipped with an electric fusion connection sleeve. 5.2 Ordinary pipe fittings
5.2.1 Ordinary pipe flange connection type pipe fittings are divided into two types: Type I and Type I. Their basic parameters are shown in Table A1 and Table A2 in Appendix A (Appendix to the standard).
5.2.2 Ordinary pipe electric fusion connection type pipe fittings are divided into two types: flat end and tapered end. Their basic parameters are shown in Table A5 and Table A6 in Appendix A (Appendix to the standard).
5.2.3 For the basic parameters of the electric fusion sleeve matching ordinary pipes (flat mouth), please refer to Table B1 in Appendix B (Appendix to the standard). 5.2.4 For the basic parameters of the electric fusion sleeve matching ordinary pipes (tapered mouth), please refer to Table B2 in Appendix B (Appendix to the standard). 5.2.5 For the specifications and dimensions of reducers, please refer to Table A3 in Appendix A (Appendix to the standard). 5.3 Thin-walled pipe fittings
5.3.1 For the basic parameters of thin-walled pipe flange connection fittings, please refer to Table A4.5.3.2 The basic parameters of thin-walled pipe electric fusion connection fittings are shown in Table A7 in Appendix A (Appendix to the standard), and the basic parameters of electric fusion sleeves matching thin-walled pipes are shown in Table B3 in Appendix B (Appendix to the standard).5.4 Nominal pressure correction factor
5.4.1 When pipe fittings are used to transport liquid media above 20°C, their nominal pressure should be corrected. The correction method is to multiply the nominal pressure shown in Appendix A (Appendix to the standard) or Appendix B (Appendix to the standard) by the correction factor shown in Table 2. Table 2 Nominal pressure correction factor
Temperature t
Nominal pressure correction factor
HG/T3691—2001
5.4.2 When pipe fittings are used to transport special media, the corrected nominal pressure should be multiplied by a safety factor of 0.8 for correction, or it can be agreed upon by both the supplier and the buyer.
5.5 Electric fusion sleeve
Electrofusion sleeves should be equipped with a reinforced skeleton. The wall thickness of the sleeve should not be less than the wall thickness of the pipe, and the strength of the skeleton should not be less than the strength of the pipe skeleton. When conveying normal temperature and low pressure media, pure plastic or thickened pure plastic electric fusion sleeves can be used, or PE100 grade resin can be selected, provided that the corresponding design specifications are met.
6 Requirements
6.1 Color
Pipe fittings are generally black, and other colors can also be determined by negotiation between the supply and demand parties according to the purpose of the pipe fittings. 6.2 Appearance
6.2, 1 The inner surface of the pipe fitting should be smooth and flat, and the outer surface should be in a naturally contracted state. There should be no bubbles, cracks, decomposition discoloration lines and obvious scratches on the inner and outer surfaces. The pipe fitting port should be flat, the sealing groove should be smooth and free of burrs, and the edges and corners should be clear and intact. 6.2.2 The heating wires in the electric fusion sleeve should be evenly arranged without looseness, and the terminal should be firm. 6.3 Specifications and Dimensional Deviations
6.3.1 Specifications and dimensional deviations of flanged and fusion-connected pipe fittings are listed in Appendix A (Standard Appendix). 6.3.2 Specifications and dimensional deviations of fusion-connected sleeves shall comply with Appendix B (Standard Appendix). 6.4 Out-of-roundness
Out-of-roundness of pipe fittings shall not exceed 5%.
6.5 Physical and Mechanical Properties
The physical and mechanical properties of pipe fittings shall comply with the provisions of Table 3. Table 3 Physical and mechanical properties of pipe fittings
Short-term hydraulic
Strength test
Burst strength test
Sealing performance test
(water)
Test method
Temperature, 20℃Time: 1h; Test pressure: nominal pressure × 1.5Temperature: 70℃, Time 165h; Test pressure: nominal pressure × 1.5 × 0.76Temperature: 20℃, pressurize to the pipe bursting temperature within 60~70s: 20℃; Time, >1h; Test pressure: nominal pressure × 1.5 Temperature: 70℃; Time, >1h: Test pressure: nominal pressure × 1.5 × 0.76 7.1 Standard environmental performance requirements for specimen state adjustment and test
No rupture,
No leakage
Burst pressure ≥
Nominal pressure × 3
No rupture,
No seepage
Test method
See 7.11.1
See 7.11.1
See 7.11.2
The standard environment for sample conditioning and testing shall comply with the provisions of GB2918, the temperature shall be (23 ± 2)°C, and the sample conditioning time shall be not less than 24h.
7.2 Appearance inspection
Visual inspection, the inner wall can be observed with the help of a light source.
7.3 Geometric dimension determination
7.3.1 The length of the pipe
Measured with a measuring tool with an accuracy of not less than 1mm. Www.bzxZ.net
7.3.2 The inner and outer diameters
Measured in accordance with the provisions of GB/T8806.
7.3.3 Other dimensions
HG/T3691—2001
Measured with a measuring tool with an accuracy of not less than 0.02mm. 7.4 Determination of out-of-roundness
Perform according to 5.4 of GB15558.1-1995. 7.5 Determination of density
Perform according to GB/T1033.
7.6 Determination of moisture content
Perform according to GB/T6283, and the sample is not conditioned. 7.7 Determination of volatile matter
Perform according to 5.7 of GB15558.1-1995. 7.8 Determination of carbon black content
Perform according to GB/T13021.
7.9 Thermal stability test
Perform according to 5.9 of GB15558.1--1995. 7.10 Resistance to gas component test
Perform according to 5.11 of GB15558.1-1995. 7.11 Determination of physical and mechanical properties of pipe fittings
7.11.1 Short-term hydrostatic test and burst strength test shall be carried out in accordance with the provisions of GB/T6111, and the test shall be carried out on the assembly. The performance of the pipe fittings is expressed by the performance of the assembly. Taking the 45° elbow as an example, the connection method of its assembly is shown in Figure 1.7.11.2 Sealing performance test
The test shall be carried out in accordance with the provisions of GB/T6111, and the test shall be carried out on the assembly. The performance of the pipe fittings is expressed by the performance of the assembly. Taking the 90° elbow as an example, the connection method of its assembly is shown in Figure 2. Figure 2
8 Inspection rules
Pipe fittings must be inspected and qualified by the quality inspection department of the manufacturer and accompanied by a certificate of conformity before they can leave the factory. 18
8.1 Inspection classification
Inspection is divided into factory inspection and type inspection. 8.2 Factory inspection
HG/T3691—2001
8.2.1 The factory inspection items for pipe fittings are short- and medium-term hydrostatic strength tests in 6.1, 6.2, 6.3, 6.4 and 6.5. 8.2.2 The products are made of pipe fittings of the same specification produced with the same raw materials, formula and process as a batch, and the sampling is carried out in accordance with the provisions of GB/T2828. The normal inspection one-time sampling plan is adopted, with the general inspection level IL=I and the qualified quality level AQL=6.5. The sampling plan is shown in Table 4. Table 4 Sampling plan
Batch range N
151~280
281~500
501~1200
1201~3200
3201~10000
Sample size n
Number of qualified judgments Ac
Number of unqualified judgments Re
8.2.3 Randomly select sufficient samples from the qualified products of counting sampling to carry out the 20℃ short-term static hydraulic strength test in 6.5. When unqualified products appear, double samples should be re-drawn for a second test. If they still fail, the batch is judged to be unqualified. 8.3 Type inspection
8.3.1 The type inspection items are all the items required by this standard. 8.3.2 Type inspection should be conducted in any of the following situations: a. When there are major changes in raw materials or processes that may affect product performance; b. During normal production, at least once a year; c. When production is resumed after a stoppage of more than six months; d. When there is a major difference between the factory inspection result and the last type inspection; e. When the national quality supervision agency proposes to conduct type inspection. 8.3.36.2, 6.3.6.4 and 6.5 shall be determined according to Table 5. If one of 6.5 does not meet the requirements, double samples may be randomly selected for re-inspection of the item. If one item is still unqualified, the batch shall be determined to be unqualified. 9 Marking, packaging, transportation, storage
9.1 Marking
Pipe fittings should have the following obvious markings:
a. Pipe fitting type, specification, nominal pressure; b. Connection method (F is flange connection, D is electric fusion connection) c. Production date or production batch number;
d. This standard number:
e. Manufacturer name or trademark.
9.2 Packaging
Pipe fittings should be sealed and packed in plastic bags and placed in packaging boxes to prevent damage. The packaging box should be accompanied by a product quality certificate from the quality inspection department. 9.3 Transportation
Pipe fittings are strictly prohibited from being subjected to severe impact, scratching, throwing, exposure, rain and pollution during transportation. 9.4 Storage
Pipe fittings should be stored in a warehouse away from heat sources, with a temperature generally not exceeding 40°C, a flat floor and good ventilation. The storage period of pipe fittings shall not exceed two years.
HG/T3691—2001
Appendix A
(Appendix to the standard)
Basic parameters of pipe fittings
Basic parameters of flange-connected pipe fittings (connected with ordinary pipe I-type joints) Ai
Basic parameters of flange-connected pipe fittings (connected with ordinary pipe I-type joints) Table A1
Nominal inner diameter Dn
(d in the figure) mm
Nominal wall thickness e.mm
Basic size
Limit deviation
Nominal pressure||t t||HG/T3691-2001
Basic parameters of flange-connected pipe fittings (connected with ordinary pipe type II joints) A2
Table A2 Basic parameters of flange-connected pipe fittings (connected with ordinary pipe type II I joints) Name
Nominal inner diameter Dn
Nominal wall thickness e, mm
Basic size
Limit deviation
Nominal pressure
Basic parameters of reducing pipe fittings
HG/T3691—2001
Table A3 Basic parameters of reducing pipe fittings| | tt | 250
300200
250200
250150
200~150
200~125
150125
150100
125~100
125~80
100~65
100~50
≥200
≥180
≥150
≥120
Note: When flange connection or electric fusion connection is used, the reducer is respectively injection-molded with flange joints, tapered mouth, or turned into a flat mouth. For its specific dimensions, please refer to 5.2.1 and 5.2.2 of HG/T36902001.
HG/T3691—2001
A4 flange connection type pipe fittings (connected with thin-walled pipes) basic parameter table A4 flange connection type pipe fittings (connected with thin-walled pipes) basic parameters Nominal inner diameter Dn
Nominal wall thickness e, mm
Basic size
Limit deviation
Nominal pressure
HG/T3691-2001
Electrofusion connection type pipe fittings (connected with ordinary pipe flat end) basic parameters A5
5Electrofusion connection type pipe fittings (connected with ordinary pipe flat end) basic parameter table A5
Nominal inner diameter Dn
(d in the figure)
Nominal wall thickness e, mm
Basic size
Limit deviation
Nominal pressure
Outer diameter of hot melt zone D| | tt | t||273.8±0.40| | tt | .40
273.8±0.40
324.0±0.50
71.0±0.20
86.0±0.20
103.0±0.25
123.0±0.25
148.3±0.30| |tt||173.1±0.30
224.4±0.40
273.8±0.40
324.0±0. 50
HG/T3691—2001
Basic parameters of electric fusion fittings (connected with ordinary pipe tapered end) Table A6 Basic parameters of electric fusion fittings (connected with ordinary pipe tapered end) Each
D(small mouth)
nominal inner diameter Dn
(d in the figure)
nominal wall thickness e, mm
basic size||tt ||Limit deviation
Nominal pressure Melt zone outer diameter D
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.