JB/T 9736-1999 This standard is a revision of ZB J94 019-90 "Magnetic Particle Inspection Method for Injection Nozzle Components, Plunger Components, and Delivery Valve Components". During the revision, only editorial changes were made according to relevant regulations, and the main technical content remained unchanged. This standard specifies the requirements for magnetic particle inspection equipment, magnetic particles, magnetic suspensions, magnetization methods, magnetization specifications, and nuclear tests for detection sensitivity. This standard is applicable to magnetic particle inspection of injection nozzle components, plunger components, and delivery valve components made of ferromagnetic materials. This standard was first issued in 1982 as NJ 284-82 and was first revised to ZB J94 019-90 on June 20, 1990. JB/T 9736-1999 Magnetic particle inspection method for nozzle assembly, plunger assembly and oil delivery valve assembly JB/T9736-1999 Standard download decompression password: www.bzxz.net

This standard is a revision of JB/T9736--1999
Magnetic Particle Inspection Method. During the revision, this standard made editorial changes to the original standard ZBJ94019---90 "Injection Nozzle Pairs, Plunger Pairs, and Delivery Valve Pairs". The main technical content has not changed. This standard replaces ZBJ94019--90 from the date of implementation. This standard is proposed and managed by the Oil Pump and Nozzle Standardization Technical Committee. The drafting unit of this standard: Wuxi Oil Pump and Nozzle Research Institute. The main drafters of this standard: Song Xifen and Zhang Limin. This standard was first issued in 1982 as NJ284--82 and revised for the first time in 1990 as ZBJ94019-90. 519
Standard of the Machinery Industry of the People's Republic of China
Magnaflux method for the inspection ofinjection nozzle, plunger and delivery valveJB/T 9736—1999
Replaces ZBJ94019:90
This standard specifies the requirements for magnetic particle inspection equipment, magnetic particles, magnetic suspension, magnetization method, magnetization specifications and inspection sensitivity calibration. This standard is applicable to magnetic particle inspection of injection nozzle, plunger and delivery valve made of ferromagnetic materials. 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 versions of the following standards. GB253--1989 Kerosene
GB/T15822-1995 Magnetic Particle Inspection Method
3 Requirements for Surface of Parts by Magnetic Particle Inspection
3.1 Surface roughness R of parts. The value is 3.2μm. 3.2 Grease, rust, sticky sand, fiber and other substances that can stick to magnetic powder on the surface of parts should be removed. 3.3 For parts that need surface treatment, magnetic particle inspection should be carried out before surface treatment. If it must be carried out after surface treatment, the covering layer should not affect the inspection effect.
4 Inspection Equipment
4.1 Inspection equipment should have the functions of safely and reliably completing magnetization of parts, applying magnetic suspension, observing parts and demagnetizing. 4.2 The flaw detection equipment should be arranged reasonably. The installation direction of the demagnetizer should make the magnetic field generated by the demagnetizer perpendicular to the earth's magnetic field. The illumination of the equipment lighting device should not be less than 5001x.
4.3 The demagnetization device should reduce the residual magnetism of the parts to a magnetic induction intensity not greater than 2×101T (2Gs). 5 Magnetic powder
5.1 The material of the magnetic powder is ferroferric oxide, or as specified in the flaw detector manual. 5.2 The color of the magnetic powder should have a good contrast with the surface of the inspected part. 5.3 The magnetic powder should have certain magnetism, particle size, dispersibility and suspension. The magnetism measured by the magnetic weighing method should be no less than 7g; the particle size should be uniform, with an average diameter of 5~10μm and a maximum diameter of no more than 50μm. 6 Magnetic liquid
6.1 The magnetic suspension is prepared by magnetic powder and liquid medium oil. 6.2 Liquid medium oil has the characteristics of low volatility, high flash point, easy cleaning, no corrosion to parts and harmless to human body. Kerosene in accordance with the provisions of GB253 approved by the State Bureau of Machinery Industry on September 17, 1999 and implemented on January 1, 2000 is allowed.
6.3 The content of magnetic powder in magnetic suspension is 8~15g/l. JB/T9736-1999
6.4 The magnetic suspension should be stirred evenly when used, and should be replaced regularly according to the use and kept clean. 7 Magnetization method
7.1 Circumferential magnetization method
The parts are directly passed through an electric current or the current passes through the core rod (diamagnetic material) in the inner hole of the parts, so that circumferential magnetic lines of force are generated in the parts, which are used to check the axial and near-axial defects on the surface of the parts. 7.2 Longitudinal magnetization method
Place the part in the magnetic field generated by the energized coil or electromagnet to generate longitudinal magnetization on the surface of the part, which is used to check the defects on the surface of the part that are perpendicular to the axis and nearly perpendicular to the axis.
7.3 Composite magnetization methodbZxz.net
The part can be magnetized circumferentially and longitudinally at the same time, which is used to check the defects on the surface of the part in any direction. The selection of magnetization method is mainly determined by the direction of the defects generated by the part, so that the direction of the applied magnetic field is perpendicular to the direction of the defects to be found.
8 Flaw detection method
8.1 Continuous method
Pour magnetic suspension on the part to make the whole part evenly wet, and continue to energize several times while continuing to pour the magnetic suspension, each time 1-~35. After stopping pouring, energize several times, each time 0.5~15. Cut off the current and check the defects of the part. Alternating current is generally used for magnetization. 8.2 Residual magnetism method
Pass a certain current instantaneously (about 0.5s) through the parts, put them into the stirred magnetic suspension after power off for 20-40s and then slowly take them out, or sprinkle the magnetic suspension 2-3 times after power off, let it stand for 1-2min, and then inspect them. Direct current is generally used for magnetization. If alternating current is used, a power-off phase controller should be used.
When selecting the flaw detection method, it should be determined based on the residual magnetic induction intensity and coercive force of the material under different heat treatment conditions. When the residual magnetic induction intensity is above 0.8T and the coercive force is above 800A/m, the residual magnetic method can be used for inspection. 9 Magnetization specification
9.1 When using the continuous method, the magnetic field intensity should generally be greater than the magnetic field intensity at which the maximum magnetic permeability appears and less than the saturation magnetic field intensity. When using the residual magnetic method, the current intensity should be such that it reaches the saturation state. The current intensity should not be too large, and the parts and the lead plate of the flaw detector should be in good contact to avoid burning the parts and melting the lead plate.
9.2 When the continuous method is used for circumferential magnetization, the current intensity is generally specified as follows: when D>20 mm, I=(8~15)D;
when D≤20 mm, I=(10~25)D.
D. Maximum diameter of the inspected part of the part, mm; I—effective value of the current intensity, A.
9.3 Determination of magnetic field intensity when the solenoid coil is used for longitudinal magnetization 9.3.1 When the residual magnetism method is used, the central magnetic field intensity H of the solenoid coil with the inspected part is generally specified as follows: when L/D>10, H is 11940A/m
when L/D>2~10, H is 19900A/m;
when L/D≤2, H is 35810 A/m.
L./D-ratio of the length to the diameter of the inspected part. 9.3.2 When using the continuous method, select one third of the magnetization intensity of the residual magnetization method. 521
Verification of flaw detection sensitivity
JB/T 9736--1999
10.1 Before flaw detection, the concentration of magnetic suspension and the current intensity must be verified by the continuous method with the standard push test piece. During the verification, the notch must be clearly displayed on the standard test piece, otherwise it should be checked whether one of the above links is normal. 10.2 This standard uses the A-15/100 type standard test piece specified in GB/T15822--1995. 10.3 Since the A-type standard test piece is frequently used and easily damaged, the sample with natural defects can be used to verify the flaw detection sensitivity, but the correct reliability of the sample sensitivity must be regularly verified by the standard test piece. 10.4 The standard test piece should be checked and verified regularly to avoid failure. 11 Demagnetization
11.1 All parts after flaw detection must be demagnetized. 2 After the parts are demagnetized, their residual magnetism shall not exceed 5×10-4T, which can be measured by a magnetometer. 11.2
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