JB/T 8724-1998 This standard specifies the representation method, type and size, technical requirements, test methods and inspection rules of reaction sintered silicon nitride sealing rings for mechanical seals. This standard is applicable to water, oil, solvents and other fluid media except strong alkali and hydrofluoric acid with a sealing chamber pressure of less than 2MPa and a temperature of -30℃ to 200℃; the inner diameter of reaction sintered silicon nitride sealing rings for mechanical seals is 16 to 120mm. JB/T 8724-1998 Reaction sintered silicon nitride sealing rings for mechanical seals JB/T8724-1998 Standard download decompression password: www.bzxz.net

ICS21.140
Machinery Industry Standard of the People's Republic of China
JB/T8724—1998
Reactively sintered silicon nitride seal ring for mechanical seal
Published on March 19, 1998
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1998
JB/T8724—1998
Appendix A of this standard is a prompt appendix.
This standard is proposed and managed by the Mechanical Seal Standardization Technical Committee of the Ministry of Machinery Industry. The responsible drafting units of this standard: Fenghua Mechanical Seal Factory, Hefei General Machinery Research Institute of the Ministry of Machinery Industry The main drafters of this standard: Wang Yadi, Yao Liming, Chen Deqiang, Wu Zhaoshan, Lv Kang. 1 Scope
Mechanical Industry Standard of the People's Republic of China
Reaction sintered silicon nitride sealing ring for mechanical sealReacdtively sintered silicon nitride sealing ring for mechanical sealJB/T8724-1998
This standard specifies the representation method, type and size, technical requirements, test methods and inspection rules of reaction sintered silicon nitride sealing ring for mechanical seal.
This standard is applicable to water, oil, solvent and other fluid media except strong alkali and hydrofluoric acid with a sealing chamber pressure of less than 2MPa and a temperature of -30 to 200℃; the inner diameter of reaction sintered silicon nitride sealing ring for mechanical seal is 16~120mm2Reference 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 will be revised, and the parties using this standard should explore the possibility of using the latest version of the following standards. GB/T 1184—1996
GB/T 1818—94
GB2828-87
GB 2997—82
GB 300182
3 Representation method
Shape and position tolerances Provisions for tolerances not indicated Test methods for Rockwell hardness of metal surfaces
Batch inspection Count sampling procedures and sampling tables (applicable to inspection of continuous batches) Test methods for apparent porosity, water absorption, bulk density and true porosity of dense shaped refractory products Test methods for flexural strength of refractory products at room temperature Representation method of silicon nitride sealing rings for mechanical seals shall comply with the following provisions. 1-xx
Inner diameter of ring × maximum outer diameter × thickness (mm) For details of the ring type, see Table 1.
For details of the ring forming method, see Table 1.
The material code of the ring is Q.
Forming method and type code
Forming method
Molding
Isostatic pressing
Approved by the Ministry of Machinery Industry on March 19, 1998
Forming method and type code for silicon nitride sealing ring for mechanical seal
Seal ring type
Stationary ring
Rotating ring
Implemented on July 1, 1998
Example
QGI-25X40×9
JB/T8724-1998
Indicates silicon nitride sealing ring for mechanical seal (Q), dry pressing (G), stationary ring (U), inner diameter of 25mm, maximum outer diameter of 40mm, thickness of 9mm.
Type and main dimensions
For the types and main dimensions of reaction sintered silicon nitride sealing rings for mechanical seals, see Appendix A (suggestive appendix) 5 Technical requirements
Physical and mechanical propertieswww.bzxz.net
The main physical and mechanical properties of isostatically pressed and dry pressed rings shall comply with the provisions of Table 2. Appearance and manufacturing quality
The appearance and manufacturing quality of isostatically pressed or dry pressed rings shall comply with the provisions of Table 3 Table 2 Main physical and mechanical properties of reaction sintered silicon nitride rings Performance items
Free silicon content
Volume density
Apparent porosity
Flexural strength
Thermal shock stability
Isostatic pressing
≥196.10
Technical requirements||t t||Compression molding
≥166.70
Table 3 Technical requirements for the appearance and manufacturing quality of reaction sintered silicon nitride rings Performance items
Surface quality
Flatness of sealing surface
Surface roughness R of sealing surface
Marking on sealing surface
Bright spot ≤±0.2mm on sealing surface
Maximum size of pores on sealing surface
≤Φ02mm
≤04mm
Surface roughness R of contact surface with auxiliary sealing ring Parallelism of sealing end face and contact end face of auxiliary sealing ring Perpendicularity of sealing end face to outer circle in contact with sealing ring Dimension tolerance
Concave and convex defects not greater than 2mm on non-working surface 2
Sagging and blackening are not allowed, cracks are not allowed, and scratches on sealing surface are not allowed ≤00009
Marking that does not affect use is allowed||tt| |According to the requirements of level 7 in GBT1184-1996
According to the requirements of level 7 in GBT1184-1996
According to the requirements of the drawings
6 Test methods and inspection rules
JB/T8724-1998
Test method for free silicon content in sealing rings Determined by the analysis of inorganic non-metallic materials using the silicon-molybdenum colorimetric method 6.2 The test methods for bulk density and apparent porosity shall be carried out in accordance with the provisions of GB2997. 6.3 The test method for hardness shall be carried out in accordance with the provisions of GB/T1818. 6.4 The test method for flexural strength shall be carried out in accordance with the provisions of GB3001, with the test strip size of 3mmX4mm×30mm, the span of 20mm and the loading speed of 0.05mm/s.
6.5 The test method for thermal shock stability is to heat the sample with the specification of Φ25×Φ40×9 to 800℃, then cool it in water (normal temperature), and record the number of repetitions when cracks are generated. 6.6 The flatness test method of the sealing surface is measured by using a level-precision flat crystal and a monochromatic light source spectrum. 6.7 The appearance is visually inspected, and the roughness is measured by a roughness measuring instrument. It can also be checked by the sample block comparison method. 6.8 The sealing ring is inspected by the quality inspection department of the manufacturer for hardness, dimensional tolerance, form and position tolerance, appearance and other items. It can only be shipped after passing the inspection.
6.9 Products are sampled according to the normal sampling plan of GB2828, special inspection level S4, and AQL is 4.0. For unqualified products, the manufacturer should replace them.
6.10 The same product should be inspected according to the requirements of Chapter 5 when it is produced for half a year and new products are trial-produced, or raw materials are replaced, or the process is changed. 7 Packaging
The packaging should ensure that it will not be knocked, bumped, scratched, etc. during transportation. 7.2 The product certificate should be attached when leaving the factory, and the certificate should be signed and dated by the quality inspection department and the inspection personnel. The manufacturer should provide users with product instructions. 7.3
Sealing ring type
JB/T8724-1998
Appendix A
(Suggestive appendix)
Sealing ring type and main dimensions
For sealing ring types, see Figure A1, Figure A2, Figure A3 and Figure A4A2
Main dimensions of sealing ring
For main dimensions of sealing ring, see Table A1, Table A2, Table A3 and Table A4Figure Al
JB/T8724-1998
JB/T8724-1998
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JB/T8724-1998
Republic
Mechanical Industry Standard
Reaction Sintered Silicon Nitride Sealing Ring for Mechanical Seals JB/T8724-1998
Published and distributed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry Printed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry (No. 2 Shouti South Road, Beijing: Postal Code 100044)*
Format 880X12301/16 Printing Sheet 3/4
4 Number of Words 16.000
First Edition in June 1998 First Printing in June 1998 Number of Prints 00,001-500 Cost 1000 Yuan
No. 98-007
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