Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T7361-94
Hardness test method for rolling bearing parts
Published on July 26, 1994
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1995
Mechanical Industry Standard of the People's Republic of China
Hardness test method for rolling bearing parts
1 Subject content and scope of application
This standard specifies the hardness test method, test instrument and test result processing of steel rolling bearing parts. This standard is applicable to the hardness inspection of steel rolling bearing parts, after tempering and finished bearings. 2 Reference standards
GB/T 230
GB1184
GB1818
GB4340
GB/T4342
GB5030
JB1255
3 Symbols
Methods for testing Rockwell hardness of metals
Form and position tolerances Provisions for tolerances not specifiedMethods for testing Rockwell hardness of metal surfaces
Methods for testing Vickers hardness of metals
Methods for testing micro-Vickers hardness of metals
Methods for testing small-load Vickers hardness of metals
High carbon chromium bearing steel rolling bearing parts heat treatment Processing technical conditions HRA: A scale Rockwell hardness
HRC: C scale Rockwell hardness
HV: Vickers hardness
HLD: Leeb hardness when using D-type impact device D: nominal outer diameter of the sleeve, mm
Dw: nominal diameter of rolling element, mm
b: effective width of the end face of the ring (the wall thickness minus the size of the inner and outer chamfers), mm4 Basic requirements for hardness test
4.1 Test room
JB/T736194
The hardness test room must be dry and clean, without strong vibration and corrosive gas sources around. The indoor temperature is generally 1035℃, the standard hardness tester requires 23±5℃, and it is equipped with a workbench, standard parts cabinet and dust cover, etc. 4.2 Test instruments
All kinds of hardness testers and standard parts used for hardness test should be calibrated regularly by the national metrology department. 5 Test samples
Bearing parts must be demagnetized before hardness test. 5.1
5.2 Surface roughness R of hardness inspection surface and positioning surface of bearing parts. Values shall be in accordance with the requirements of Table 1. Approved by the Ministry of Machinery Industry on July 26, 1994
Implemented on July 1, 1995
Test methods
German Civil Law
JB/T7361-94
Vickers method
The hardness test surface of bearing parts shall not have defects such as burns, decarburization, cracks, etc. The positioning surface of bearing parts hardness test shall not have defects such as scale, rough scratches, burrs, bumps, etc. 5.4
Leeb method
5.5 When measuring Rockwell and Vickers hardness of bearing rings, spherical rollers and crowned rollers, the parallelism of the two end surfaces shall comply with the provisions of tolerance grade 8 in Appendix 3 of GB1184.
Hardness test method
Hardness test method shall be selected according to Table 2;
Part specification
Dw4.7625~60
Dw<4.7625
D≥200;
b,≥10;
Egg measurement method
Determination by A,C scale of Rockwell method
Determination by Vickers method
Determination by Leeb method
Note: If the user has special requirements for hardness inspection, other methods may be used to check the hardness. 6.2 Hardness test rules
Preferentially use the Rockwell C scale
Can be measured directly or after spectrum embedding
All rolling bearing parts that cannot be measured on a benchtop hardness tester can be measured using the Leeb method
6.2.1 Before the test, all types of hardness testers should be calibrated at more than 3 points using a standard hardness block with a hardness value close to that of the bearing parts. All parts of the hardness tester should work normally and the indication error should meet the requirements. 6.2.2 The test surface, support surface, test table and indenter surface of the bearing parts should be clean, free of oil and dust, and the sample should be placed stably to ensure that no displacement or deformation occurs during the test.
6.2.3 The hardness test surface of bearing parts is generally on the end face of the ring. For rings with D>500mm, when the end face hardness cannot represent the working face hardness, the working face roughness (raceway) can be directly measured with a Leeb hardness tester. Rolling elements are generally on curved surfaces (surface grinding is allowed between processes). Rolling elements with Dw<4.7625mm can be embedded in a close plane and the Vickers hardness can be measured. Spherical rollers and crowned rollers can be measured on the end face. 6.2.4
The test force should be determined based on the shape, size, effective width of the end face, etc. of the bearing parts. The test force selection is based on Table 3. Table 3
Test method
Grillet method C scale
Rockwell method A scale
Vincent method
Vickers method
Parts specification
b,>1.5~2.0
b,>1.2~1.5
Dw>2.0~4.7625
6,>0.8~1.2
Test force N
Test method
Vickers method
Vickers method
Leegle method
JB/T 736194
Continued Table 3
Parts specification mm
b,>0.6~0. 8
D≥0.6~0.8
Dw≥60
Previous,①For bearing parts with surface hardening treatment, select appropriate test force and test method according to the depth of the hardened layer,③Test force holding time, according to the relevant hardness test method standards,6.2.5 Hardness measurement point position
Test force N
0.011J (Joule)
6.2.5.1 Rockwell method: The distance from the center of the hardness indentation to the edge of the specimen shall not be less than 1.5 times the diameter of the indentation, but shall not be less than 1mm, and the distance between the centers of the two indentations shall not be less than 2mm.
6.2.5.2 Vickers method: The distance from the center of the hardness indentation to the edge of the specimen shall not be less than 1.5 times the length of the diagonal of the indentation, and the distance between the centers of the two indentations shall not be less than 2.5 times the average length of the diagonal.
6.2.5.3 Single method: The distance between the hardness test point and the edge level shall not be less than 4mm. The distance between the test points shall not be less than 5mm. 6.2.6 Number of hardness test points
6.2.6.1 Set of medical
D>430mm, measure one point every 150~400mm, and each part shall not be less than 8 points. D≥200~430mm, measure one point every 100mm or so, and each part shall not be less than 5 points. D<200mm, measure one point every 120° or so, and each part shall be measured at 3 points. 6.2.6.2 Rolling element
D>40mm, measure one point every 60°~120° or so, and each part shall be measured at 3 to 6 points. Dw≤40mm, measure one point every 120° or so, and each part shall be measured at 3 points. b.
For spherical rollers and crowned rollers, measure 3 points on one end face. 6.2.6.36, <1.2mm, Dw <4.7625mm miniature bearing parts, after plating and embedding (not embedding when positioning is good), grind into a flat surface for measurement, evenly measure 3 points for each ring and needle roller, and measure one point for the steel ball at the center. 6.2.7 Test result processing
6.2.7.1 If the hardness of a certain point (or area) of the bearing part exceeds the tolerance, two points can be re-checked at 3~5mm on the left and right. If the hardness of the re-checked point is qualified, the original excess data will be included: If there is still a little flare difference between the left and right points, the original excess data cannot be included, and the initial inspection and re-inspection data should be recorded in the hardness test report
6.2.7.2 The hardness average of several points is not allowed to represent the hardness value of the bearing part for the same part. If there are many measuring points, it can be abbreviated as the hardness value range. 6.2.7.3 After the test, re-calibrate the hardness tester. If it is found that the indication error exceeds the hardness tester requirement, all the test data of this batch will be invalid. 6.2.7.4 The Rockwell hardness HRC value (or HRA, HV, HLD conversion value) in the test report shall be accurate to 0.5 Rockwell hardness unit.5 The hardness values measured on the curved surface of the equal parts shall be corrected according to Table 2 and Table 3 of JB1255. The tapered roller shall be corrected according to the diameter of the measuring point.
7 Test report
The test report must be filled in by the inspector and include: product specifications, models, material grades, heat treatment status, product production date and batch number, inspection and test dates, and all test data for determining whether the product is qualified or not. It shall be signed by the inspector and proofreader. 3
JB/T7361-94
Appendix A
Conversion table of Leeb hardness and Rockwell hardness
(reference part)
The conversion of Leeb hardness and Rockwell hardness is shown in Table A1. Table A1
JB/T736194
Appendix B
Dimensions of steel ball hardness test bench
(reference)
B1 Dimensions of steel ball hardness test bench see Figure B1 and Table B1. oo
Nominal diameter of steel ball
>10~20
>20~30
>30~50
Angle 1×45*
Surface bluing
90° or 120°
JB/T7361-94
Appendix C
Dimensions of cylindrical roller hardness test bench
(reference part)
C1 Dimensions of cylindrical roller hardness test bench are shown in Figure C1 and Table C1. 20.A
Nominal diameter of cylindrical roller
>10~20
Note: To measure the hardness of the chain, the corresponding √-type bench can be processed according to the taper of the roller. 6bzxz.net
90° or 120*
Acute angle example Blunt surface
>20~30
>30～50
Additional instructions:
JB/T7361-94
This standard was proposed by the National Technical Committee for Standardization of Rolling Bearings. This standard was drafted by the Luoyang Bearing Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Wang Zhongyu and Zhang Zongliang.
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