This standard specifies the residual magnetism limits, measurement methods and inspection rules for rolling bearings. This standard is applicable to the inspection and acceptance of residual magnetism of various types of general-purpose bearings with an outer diameter less than 430mm by manufacturers and users. JB/T 6641-1993 Residual magnetism of rolling bearings and its evaluation method JB/T6641-1993 Standard download and decompression password: www.bzxz.net

J11 | | tt | | JB | |Residual magnetism and its evaluation method
Implemented on 1994-01-01
Ministry of Machinery Industry of the People's Republic of China
Published
Machinery Industry Standard of the People's Republic of China||tt| |Residual magnetism and its evaluation method
Rolling bearings
1 Subject content and scope of application
This standard specifies the residual magnetization limits, measurement methods and inspection rules for rolling bearings (hereinafter referred to as bearings) . JB/T664193
This standard is applicable to the inspection and acceptance of residual formaldehyde in various types of general-purpose bearings with an outer diameter less than 430mm by manufacturers and users. Reference standards
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GB3102.5
ZBJ11020
3 Definitions and units of quantities
Quantities and units of electricity and magnetism||tt| | Inspection rules for rolling bearings and their commercial parts 3.1 Residual magnetism refers to the residual magnetism after the bearing has been magnetized and demagnetized. 3.2 Residual magnetism is expressed by magnetic induction intensity, and its unit is Punta (mT). 4 Residual magnetism value
The residual magnetism value should not exceed the following table:
Bearing outer diameter
mm
exceeds
to
Maximum residual magnetism mT
5Measurement method
30
0. 4
30
50
0. 5||tt ||50
120
0. 6bzxz.net
120
250
0.8
250
430||tt ||1. 0
5.1 The residual magnetism measurement adopts the Frost effect principle. The measuring instrument must have a range of 1mT and an accuracy of ±3%. The specifications of the Zhaier element equipped with the instrument are: 4mm×2mm×0.2mm, and the distance between the plane of the Hall element and the measured surface is 1±0.05mm (see Figure 1). Probe
Jidong components
Non-introduction workbench
Figure 1
Approved by the Ministry of Machinery Industry 1993-05-07
Measurement diagram||tt ||Implemented on 1994-01-01
1
JB/T6641-93
5.2 When measuring residual magnetism, the measured maximum value shall be the residual magnetism value of the bearing. 5.3 It is not allowed to measure on a magnetic workbench or in an environmental magnetic field that is greater than the geomagnetic field. 5.4 For ball bearings, roller bearings and needle roller bearings, the measurement parts are the end faces and chamfers of the inner and outer rings (or shafts or seat rings). Separable bearings, spherical roller bearings and spherical ball bearings should also be measured. base rolling element. Separable bearings should be measured after separation; spherical roller bearings and self-aligning ball bearings should be measured with the inner and outer diagrams at 90° to each other. If the residual magnetism of the rolling elements is found to be at the junction with the cage, the rolling elements can be rotated. Measure after cooling
5.5 When measuring the residual magnetism on the bearing end face, the probe should be perpendicular to the position of the bearing end face. When measuring the bearing chamfer and rolling element residual magnetism, the probe can be tilted appropriately, but the inclination angle should not be greater than 45°. .
5.6 When the residual magnetism on the bearing sleeve or rolling element is close to the specified value, the bearing end surface should be placed in a flat position first, and then measured in the east-west direction to reduce the influence of the geomagnetic field (see figure 2), North
Detect the amount of residual magnetism
Figure 2 How to avoid the geomagnetic field
5.7 The distribution of residual magnetism on the bearing is random. When measuring, the probe is on the bearing The measurement position cannot be preset, and the movement of the probe should be such that it can reach any measured part on the bearing. The measurement method of the circumferential probe is not applicable to this standard. 6 Inspection Rules
Bearing residual magnetism shall be subject to sampling inspection in accordance with the provisions of ZBJ11020. The sample size shall be selected according to the general inspection level 1, and the qualified quality level AQL value shall be selected according to 4.
Additional notes:
This standard is proposed by the National Rolling Bearing Standardization Technical Committee. This standard is under the jurisdiction of the Luoyang Bearing Research Institute of the Ministry of Machinery Industry. This standard is drafted by Shanghai Bearing Technology Research Institute. The drafters of this standard are Wang Jun and Yan Xiali.
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