1 Scope
This document specifies the rolling bearing parts (hereinafter referred to as "parts") wet magnetic particle inspection procedures.
This document applies to the magnetic particle inspection of the surface and near-surface defects of bearing parts made of ferromagnetic materials (including raw materials, blanks, semi-finished products, finished products, in-service maintenance parts).
2 Normative reference documents
The content of the following documents through the normative references in the text and constitute the essential provisions of this document. Among them, note the date of the reference documents, only the date of the corresponding version applies to this document; do not note the date of the reference documents, the latest version (including all the revision of the list) applies to this document.
GB/T 261-2008 Determination of flash point Binsky-Martin closed cup method
GB/T 265-1988 Determination of kinematic viscosity of petroleum products and kinetic viscometer algorithm
GB/T 9445-2015 Qualification and certification of non-destructive testing personnel
GB/T 12604.5-2020 Nondestructive testing terminology magnetic particle testing
3 Terminology and definitions
GB/T 12604.5-2020 defined and the following terms and definitions apply to this document.
4 Symbols
The following symbols apply to this document.
5 Magnetic particle inspection personnel
5.1 Magnetic particle inspection personnel should have expertise related to bearing materials and manufacturing, and obtain a qualification certificate in accordance with GB/T 9445-2015 or the relevant state department documents. Magnetic particle inspection personnel qualification level is divided into 1, 2, 3, 1 level of certified personnel should be under the supervision and guidance of the peal level or 3 level personnel before engaging in testing work.
5.2 magnetic particle inspection personnel whether or not after correction, at a distance of not less than 30 cm, the near vision of one or both eyes should be able to read Jaeger 1 Times New Roman4.5 or the equivalent size of the characters (1.6 mm high). Magnetic particle inspection personnel shall not be colour blind or colour impaired. The eyesight of magnetic particle inspection personnel should be checked and verified once a year.
5.3 Other requirements for staff engaged in magnetic particle testing are in accordance with the provisions of GB/T 9445-2015.
6 Magnetic particle inspection equipment and devices
6.1 Magnetic particle inspection machine
6.1.1 Magnetic particle testing with remanent magnetism, AC magnetic particle testing machine should have a power-off phase control function to ensure that the parts have sufficient and stable remanent magnetism after magnetization. DC and three-phase full-wave rectifier flaw detectors shall be equipped with an energizing time control relay.
6.1.2 Magnetic particle flaw detectors shall be installed in a well ventilated area away from heat and fire sources and with a dedicated power supply.
6.1.3 For non-fluorescent magnetic particle testing, the visible illumination of the inspected part surface shall not be less than 1 000 lx.
6.1.4 fluorescent magnetic particle inspection, the flaw detector should be equipped with a central wavelength of 365 nm, wavelength of 320 nm ~ 400 nm ultraviolet light source, 400 mm from the centre of the light source of ultraviolet radiation illumination should not be less than 1 000 pW/cm, the observation environment should not be greater than 20 lx visible illumination.
6.1.5 Other technical requirements of the magnetic particle flaw detector shall conform to the provisions of JB/T 8290-201l.
6.2 Auxiliary equipment
6.3 Magnetic Suspension
6.3.1 Magnetic powder
6.3.1.1 The maximum particle size of the magnetic powder shall be not more than 45 um (sieve mesh of about 320 mesh). Fluorescent magnetic powder or non-fluorescent magnetic powder shall be calibrated on a test piece (block) with natural defects (or artificial defects) approved for use by the competent department of the manufacturer, and only when the magnetic traces of defects are clearly shown.
6.3.1.2 Other technical requirements of the magnetic particle should be in accordance with the provisions of GB/T 15822.2-2005.
6.3.2 Carrier fluid
6.3.2.1 Oil-based carrier fluid
Oil-based carrier fluid should be in accordance with the provisions of Table 1.
6.4 Standard test pieces and test blocks
Depending on the shape of the part, a standard test piece of medium sensitivity not less than A1-15/50, A1-30/100 and D-15/50 or other standard test pieces or test blocks approved by the customer can be selected according to GB/T 23907-2009.
7 Magnetisation methods
7.1 When magnetising parts, at least the same inspected part shall be magnetised in two directions perpendicular or nearly perpendicular to each other.
7.2 continuous method of detection, can be used circumferential magnetization or longitudinal magnetization, but also the use of composite magnetization of parts for testing.
Note: Composite magnetisation is the simultaneous circumferential magnetisation and longitudinal magnetisation of the part, producing a composite magnetic field on the part that varies with time and can detect defects in all directions.
defects in all directions. Compound magnetisation is only applicable to the continuous method.
7.3 For remanent magnetisation, circumferential and longitudinal magnetisation should be used in sequence, and the part should be demagnetised after observation of the magnetic traces before changing magnetisation. The order of circumferential and longitudinal magnetisation can be determined by the user.
7.4 Other magnetisation methods may be used after consultation between the user and the manufacturer.
8 Magnetisation specifications
8.1 General rules
After magnetization parts surface tangential flux density should be ≥ 1 T. Usually bearing parts surface magnetic field of 2 kA / m ~ 6 kA / m, can obtain more than 1T tangential flux density. The magnetisation current is determined by using a Tesla meter to measure the magnetic field strength on the surface of the part, or it can be determined by using a standard specimen with a fully and clearly marked manual groove. Bearing parts are magnetised using the energising method, the conductor method. Inductive current method. When magnetising toroidal parts by cable winding or coil method, the magnetisation specifications are selected in accordance with 9.2 to 9.6.
8.3 Conductor method
8.3.1 Central conductor method
When using the central conductor method, the axis of the central conductor should be nearly reunited with the central axis of the part and should use the magnetization specifications specified in Table 2.
8.3.2 Eccentric conductor method
8.3.2.1 When using the eccentric conductor method, the central conductor should be close to the inner wall of the part and the magnetisation specification should be used as specified in table peal, where D = central conductor diameter + 2 times the wall thickness of the part.
8.3.2.2 ﹑ eccentric conductor magnetisation, along the circumference of the part of the effective magnetisation zone for the centre of the conductor diameter of four times, around the centre of the conductor to test the full circumference of the part, each time there should be about 10% of the effective magnetisation overlap zone.
8.4 Induced current method
The magnetisation specifications for the induction current method are:
Continuous method: NI=(8~15) Deif;
The remanence method: NI=(25~40)Delf.
8.5 Ring around cable method
When magnetizing the ring around the cable method, the magnetization specification specified in Table 2 should be used and NI should be used instead of Ⅰ.
8.6 Coil method
8.6.1 Magnetisation by the continuous method
8.7 Magnetic readout method
When using the magnetic readout, the magnetic pole and part surface clearance should be no more than 0.5 mm; AC electromagnetic readout should have a minimum lifting force of 45 N; DC (including rectifier) or permanent magnetic readout should have a minimum lifting force of 177 N; cross magnetic readout should have a minimum lifting force of 118 N.
9 Demagnetisation
9.1 Parts that have passed the test should be demagnetised. Parts that have been heat treated to 700 °C or more after testing may not be demagnetised.
9.2 When demagnetising multiple parts at the same time, the parts should be spaced apart and placed in non-metallic trays or baskets for demagnetisation.
9.3 The current used for demagnetisation should not be less than the current used for magnetisation. Generally, AC magnetisation is used for AC demagnetisation and DC demagnetisation is used for DC demagnetisation.
9.4 After demagnetisation of the part, the residual magnetisation shall be determined and the requirements and methods shall conform to the provisions of JB/T6641-2017.
9.5 Demagnetised parts should be kept 1.5 m away from the magnetisation equipment and demagnetisation equipment.
10 Magnetic particle testing procedures and operational precautions
10.1 Magnetic particle testing procedures
11 Magnetic particle inspection report
A test report must be completed for all magnetic particle tested bearing parts. The magnetic particle inspection report should include at least the following:
a) the specification or type of the part.
b) the inspected part of the part.
c) the name of the magnetic particle testing equipment, and
d) magnetisation method and magnetisation specification.
e) the number of tests, and
f) the results of the magnetic particle inspection.
g) Record of defects (optional).
h) date of inspection.
i) Signature of the person carrying out the test and auditing.
contents
1 Scope
2 Normative reference documents
3 Terminology and definitions
4 Symbols
5 Magnetic particle inspection personnel
6 Magnetic particle inspection equipment and devices
7 Magnetisation methods
8 Magnetisation specifications
9 Demagnetisation
10 Magnetic particle testing procedures and operational precautions
11 Magnetic particle inspection report
