JB/T 8118.3-1999 JB/T 8118.3-1999 Technical requirements for magnetic particle inspection of piston pins of internal combustion engines JB/T8118.3-1999 Standard download decompression password: www.bzxz.net

JB/T8118.3—1999
This standard is a revision of NJ32784 "Technical Conditions for Magnetic Particle Inspection of Internal Combustion Engine Piston Pins". The main technical content has not changed. This standard replaces NJ327-84 from the date of implementation. The original standard was edited during the revision. This standard was proposed and managed by the National Technical Committee for Standardization of Internal Combustion Engines. The drafting unit of this standard: Shanghai Internal Combustion Engine Research Institute. The main drafter of this standard: Li Guoen.
This standard was first issued in 1984.
Standard of the Machinery Industry of the People's Republic of China
Piston pins
Internal combustion engines
Technical conditions for magnetic particle inspection
Internal combustion engines-Piston pins-Specifications of magnetic particle inspectionJB/T8118.3-1999
Replaces NJ327-84
This standard specifies the specifications, technical requirements and defect judgment of magnetic particle inspection of piston pins of internal combustion engines. This standard is applicable to magnetic particle inspection of piston pins of reciprocating internal combustion engines with a cylinder diameter less than or equal to 200mm. 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 will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. JB/T9744--1999 Internal Combustion Engine Parts and Components Magnetic Particle Inspection Method 3 Inspection Specifications
3.1 Inspection Method www.bzxz.net
The inspection of piston pins adopts the alternating current, circumferential, continuous magnetization method, that is, when the alternating current magnetization is passed along the longitudinal direction of the piston pin, the magnetic suspension is sprinkled on the outer surface and both end faces of the piston pin to show the defects of the outer surface, both end faces and chamfers. If necessary, the longitudinal magnetization method should also be used for inspection.
3.2 Inspection Current
The inspection current should be 10~15 times the outer diameter of the piston pin (unit: mm). The inspection current of piston pins with different outer diameters is shown in Table 1.
Outer diameter
$10~±15
≥20～25
≥25～30
>30 ~35
4 Technical requirements
Outer diameter
>5~$40
≥40～45
>45~50
>50～55
>55～0
4.1 There shall be no cracks on the outer surface, both end faces and chamfers of the piston pin. 4.2 Regulations on the cracks on the outer surface of the piston pin
4.2.1 The maximum length of the cracks shall not exceed 20mm. Approved by the State Bureau of Machinery Industry on September 17, 1999 454
Implemented on January 1, 2000
JB/T8118.3—1999
4.2.2 The total length of the grooves on the same generatrix shall not exceed 1/4 of the piston pin length. If two grooves are on the same generatrix and the spacing between them is less than 2mm, they shall be counted as one groove including the spacing. 4.2.3 The total length of the grooves on the same piston pin shall not exceed 40% of the piston pin length. 4.2.4 The distance between two grooves on the circumference of the same cross section shall not be less than 10mm. 4.2.5 The groove length is less than 2mm and is not counted. 4.2.6 Transverse grooves are not allowed. When the angle between the groove and the piston pin generatrix is ​​greater than 30°, it shall be treated as transverse grooves. 5 Defect judgment
5.1 Defect judgment shall be in accordance with the provisions of JB/T9744. 5.2 After the magnetic traces are wiped off, the hairline is difficult to detect with the naked eye. If necessary, a 5x magnifying glass can be used for identification.
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