This standard proposes the technical requirements for zinc spraying on the outer surface of ductile iron pipes. It is applicable to the prefabrication method of providing a protective coating system for the outer surface of centrifugal ductile iron pipes defined in GB 13294, GB 13295 and Appendix A. The system consists of a zinc spray coating and a final coating. GB/T 17456-1998 Zinc spray coating on the outer surface of ductile iron pipes GB/T17456-1998 Standard download decompression password: www.bzxz.net
This standard proposes the technical requirements for zinc spraying on the outer surface of ductile iron pipes. It is applicable to the prefabrication method of providing a protective coating system for the outer surface of centrifugal ductile iron pipes defined in GB 13294, GB 13295 and Appendix A. The system consists of a zinc spray coating and a final coating.

GE/T17456-1998
ISOForeword
ISO (International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing international standards is generally carried out through ISO technical committees. Each member body interested in the relevant topics determined by the technical committee has the right to make representations to the committee. International organizations, both governmental and non-governmental, that have relations with TS may also participate in this work. In all aspects of electrotechnical standardization, ISU maintains close cooperation with the International Electrotechnical Commission (IEC). The draft international standards adopted by the technical committee are sent to the member bodies for voting before being approved as formal international standards by the ISO Council. At least 75 member bodies participating in the voting must be recognized before it can be published as an international standard. International Standard ISO8179-1 was developed by SC2 Cast Pipes, Fittings and Connectors Subcommittee under ISO/TC5 Technical Committee on Ferrous Metal Pipes and Fittings.
I50 8179-1, the first edition, and 150 8179-2, the first edition, replace and cancel IS08179:1985, making technical modifications to the latter in terms of content. IS08179 is divided into the following two parts under the general title "Zinc coating on the outer surface of ductile iron pipes": Part 1: Sprayed zinc coating with decorative layer; Part 2: Zinc-rich coating with final decorative layer. wmGB/T17456-1998
This standard is equivalent to IS8179-1: 1995 & Zinc coating on the outer surface of ductile iron pipes Part 1: Sprayed zinc coating with final decorative layer
The main differences between this standard and 1SO8179-1 are: I The referenced standards have been increased. These referenced standards are formulated with reference to the versions of advanced foreign standards, thereby ensuring the integrity and matching of this standard system, facilitating users and enhancing the operability of this standard. Appendix A is added to clarify the definition of ductile iron pipes in 1S02531: 1991 and ISO7186: 1996. Appendix A of this standard This standard is the appendix of the standard.
This standard is proposed by the State Machinery Industry Bureau. This standard is under the jurisdiction of the National Technical Committee for Standardization of Metallic and Non-metallic Coatings. The responsible drafting units of this standard are: Wuhan Institute of Material Protection, Xuzhou Everbright Xinxing Casting Pipe Co., Ltd. The main drafters of this standard are: Li Jianzhong, Qian Hongben, Huang Guangjing, Hu Youquan, Zhang Haicheng. 1Fan
National Standard of the People's Republic of China
Ductile iron pipes -External zinc-spray coatingGB/T 17456-1998
eqv 1so 8179-1.1995
This standard proposes the technical requirements for zinc spraying on the outer surface of ductile iron pipes. It is applicable to the prefabrication method of providing a protective coating system for the outer surface of centrifugal ductile iron pipes defined in GB13294.GB13295 and Appendix A. The system consists of a zinc spray coating and a final coating. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards: GB/T18294-1991 Spherical cast iron pipe fittings (neqIS) 2531: 1986) GB/T13295-19 91 Centrifugal casting ball cast iron pipe (negISO2531:1986) CB/T17459-1998 Ductile iron arm asphalt coating 3 Materials
The purity of the zinc coating material shall not be less than 99% (machine/m), and the final coating material shall be asphalt paint or synthetic resin compatible with the zinc coating. 4 Spray zinc coating
4.1 Surface condition of cast pipe
The surface of the cast pipe shall be dry and free of dust, especially any loosely attached particles or foreign matter such as oil or grease. The surface of the cast pipe that has been oxidized or cleaned by sandblasting or ground can be zinc-coated. It is up to the manufacturer to decide. 4.2 Coating method
The zinc coating is prepared by thermal spraying, that is, the zinc is heated to a molten state by spraying and sprayed onto the pipe wall in droplets. The design and structure of the spraying equipment are not included in the scope of this standard. 4.3 Requirements for coating
The zinc coating shall cover the entire outer wall of the pipe without exposed spots and other defects. As long as the quality of the zinc coating meets the requirements of 4.4, a spiral appearance is allowed. The damage to the zinc coating caused by operation can be considered to be of qualified quality as long as the cumulative damaged area per square meter does not exceed 5cm and the size of a single damaged area does not exceed 5nm. Larger area damage should be repaired according to 4.6. 4.4 Quality of zinc coating
The average value of the zinc coating mass measured according to 4.5 should not be less than 130g/m. The local minimum should not be less than 110g/m. The manufacturer shall visually check the condition and uniformity of the coating of each pipe, and shall regularly measure the quality of the zinc coating according to the method described in 4.5. 4.5 Measurement of zinc coating quality Before zinc spraying on the pipe, a short test piece shall be attached to the outer wall of the pipe along the axial direction. After spraying and trimming, the minimum size of the test piece shall be any of the following: Approved by the State Administration of Quality and Technical Supervision on August 12, 1998, and implemented from July 1, 1999: a) 250 mmX1 (Hl mm) b) 500 mm×50 mm.
GB/T 17456-..1998
The average mass of zinc coating can be calculated according to the mass difference before and after spraying of the test piece by the following formula: C(ma-m))
Where: m—average mass of zinc coating, g/m; mi and mz—mass of test piece before and after zinc spraying-g (measured to the nearest 0.1 g); A—area of ​​test piece m\:
C—correction coefficient reflecting the difference between the surface roughness of the test piece and the surface roughness of the pipe, which depends on the material of the test piece. When a report is required, the C value shall be determined and stated by the manufacturer. Note: For sandblasted steel or polyester panels, the C value is between 1.0 and 1.2 (for reference). The uniformity of the zinc coating is determined by daily inspection of the test piece. If it is not uniform, a small piece of 50 mm × 50 mm should be cut from the thinner coating area of ​​the test piece, and then the minimum local mass of the zinc coating should be determined. 4.6 Repair of zinc coating
Areas not covered by the test piece and areas where the degree of coating damage exceeds the allowable range listed in 4.3 should be repaired. Choose one of the following methods:
a) Spray zinc to meet 4. 4t
b) Apply zinc-rich paint for repair, the zinc content (mass) of the dry film should be greater than 85%, and the average base of the paint should be not less than 150/nz\. 5 Final coating
After zinc spraying, the asphalt paint in accordance with GB/T17459 or synthetic resin compatible with zinc coating should be used as the final coating material. The coating process of the final coating can be selected by the manufacturer, such as spraying or brushing. The final coating should evenly cover the zinc coating without exposed spots or loose adhesion.
The average thickness of the final coating film should be not less than 70μm, and the local minimum thickness should be not less than 5>μ. The thickness of the dry film of the final coating can be measured by one of the following methods: a) Direct measurement, using an appropriate measuring instrument, such as a magnetic thickness gauge, or a "wet film" thickness gauge that can display the relationship between the dry and visible film thicknesses; b) Indirect measurement, the sample is attached to the wall before the process, and after coating, the dry film thickness of the sample is measured by an appropriate method such as microscopy, magnetic thickness measurement or weighing method similar to 4.5. The measurement method is selected by the manufacturer. A1 Ductile iron pipes for pressure pipes GB/T17456-1998 Appendix A (Standard Appendix) Nominal dimensions of ductile iron pipes and fittings A1.1 This Appendix A1 is equivalent to the corresponding part of ISO2531:1991. A1.2 Ductile Iron Pipe Manufacturing Process
Ductile iron pipes are manufactured using one of the following four processes: 1) Centrifugal casting using a metal mold on a production line or off-line; 2) Sand mold centrifugal casting;
3) Sand mold casting;Www.bzxZ.net
4) Metal mold casting.
A1. 3 Maximum working pressure and pressure test
For pipes with different nominal diameters (DV), the actual test pressure should not exceed the following values: -DN 100~DN 300: #=10 MPa:
-DN350~DN600: p=8MPa:
-DN700~DN1000: force=6MPa:
-DN 1200--DN 2000; p-4 MPu:
-DN 2200~DN 2600: p=2.5MFa.
A2 Ductile iron for non-pressure pipes, etc.
A2.1 This Appendix A2 is equivalent to the corresponding part of ISO 7186:1996. A2.2 Scope
The ductile iron pipe defined in this standard refers to the ductile iron pipe used for conveying sewage in a free state or under a pressure of less than 6 MPa.
If a higher working pressure is required, the supplier and the ordering party shall agree on the wall thickness of the pipe separately. A3 Nominal size of pipe fittings
A3.7 This Appendix A3 is equivalent to the corresponding part of IS0 6708:1995. A3.2 Nominal size series
The nominal size series of pipe fittings are as follows:
DN25DN 32 DN 40 DN 50DN G0 DN 65DN BCDN 1NO
LN 10DN15 DN 2
DN 125 DN 1G0 DN 200
DN 700
DN 1800
1N3600
DN 20G0
DN 3800
DN 250
DN 300
[N 1000
DN 2200
DN4000
DN 350
TN 1100
DN 400
DN 1200
DN 2400
DN 2800
DN 500
DN 1400
DN 1600
0
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