1, applicable scope
1.1 this standard applies to the outside diameter of 28 to the ordinary bearing all types within the range of 430mm.
1.2 bearing residual magnetism is not uniform magnetic field is nonlinear, the measured values and the measuring principle, sensing element and its distance measurement etc.. Residual magnetic so that the value of the standard refers to the measurement in the provisions of the 5.1 conditions, the residual magnetic other parameters measured value does not apply to this standard.
2, reference standards
GB 3102.5-82 "electrical and magnetic quantities and units"
JB 3371-83 "rolling bearings and commercial parts inspection rules"
Unit 3, the definition and content
3.1 residual magnetic refers to the bearing is magnetized in the production process, the maximum residual magnetism by demagnetization has not been eliminated.
3.2 residual magnetism is represented by the magnetic induction intensity of this physical quantity, the unit using it (mT).
4, measurement method
The principle of Holzer effect using 4.1 residual magnetic measurement, measuring instrument must have 1mT range and accuracy of plus or minus 3%. Instrument equipped with the Holzer component specifications for 4*2*0.2 cubic meters, Holzer element plane and measured surface distance is positive and negative 0.05mm.
4.2 for radial ball bearing, measurement sites for the two end face and chamfer. When measuring with maximum reading income for the value of the residual magnetic bearing.
4.3 for cylindrical roller bearings, needle roller bearings, spiral roller bearing, tapered roller bearing and thrust roller bearings, which can be separated parts should be separated different measurement. In addition, the outer ring within the measurement site (or seat, shaft ring) face and chamfer, also should measure the rolling body exposed parts, such as found in the rolling body residual magnetic part is at the junction with the holder, may be appropriate to turn the rolling body, the exposed parts of measurements. Measurement methods for separating type can not be this kind of bearing, in accordance with the provisions of article 5.2.
4.4 for spherical roller bearings, measuring two face and chamfer, with reference to the provisions of article 5.2. Measurement of rolling body should be carried out within the outer ring of the radial plane, each 90 degrees. Measurement method of rolling body in accordance with the provisions of the rolling body measuring about 5.3.
4.5 for the thrust ball bearing, separable washers shall be separated measurement, measurement sites for the face and chamfer of seat, shaft ring. Measurement methods for separating type can not be this kind of bearing, in accordance with the provisions of article 5.2.
4.6 measurement of bearing surface residual magnetism, probe perpendicular to the bearing end position, measurement of bearing chamfer and rolling residual magnetism, probes can be used on tilt, but not greater than 45 degrees inclination.
4.7 when the bearing ring or rolling residual magnetic body close to the specified value, should be the first end face of the bearing in the flat position, then the disposal in the east-west direction were measured, in order to reduce the influence of geomagnetic field.
4.8 does not allow the measurement in the magnetic worktable and greater environmental magnetic field in magnetic field strength.
4.9 distribution of residual magnetism on the bearing is random, measurement, measuring position of probe on the bearing can not be set in advance. Motion of probe should make it can reach the bearing on any measured position measurement, fixed probe is not applicable to this standard.
5, inspection rules
Residual magnetic inspection method using acceptance sampling, the sampling number according to the provisions of JB3371, the acceptable quality level 4 for AQL, sampling general inspection level.
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