This standard specifies the dimensions, tolerance grades and technical requirements of carbon steel balls. This standard applies to the manufacture, inspection and user acceptance of carbon steel balls for carbon steel ball bearings and other purposes. JB/T 5301-1991 Carbon Steel Ball JB/T5301-1991 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB5301-91
Carbon Steel Ball
Published on 1991-06-25
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Implementation on 1992-07-01
Mechanical Industry Standard of the People's Republic of China
Carbon Steel Ball
Subject Content and Scope of Application
This standard specifies the dimensions, tolerance grades and technical requirements of carbon steel balls (hereinafter referred to as steel balls). This standard applies to the manufacture, inspection and user acceptance of carbon steel balls for carbon steel ball bearings and other purposes. 2
Cited standards
GB6930
ZBJ11020
JB3034
Rolling bearings
Rolling bearings
Inspection rules for rolling bearings and their commodity parts Bearing oil seal anti-rust packaging
3 Terms, symbols and definitions
Nominal diameter D of the ball
Single diameter Dw of the ball
Average diameter Dm of the ball
Variation of ball diameter Vpws
Deformation error 4sph
Batch average diameter DwmL
Batch diameter variation VpL
3.9 Ball tolerance grade
Note: The definitions of the above terms are in accordance with GB6930. 3.10 Batch average diameter deviation 4Dvml
The difference between the batch average diameter and the nominal diameter of the same batch of balls. 3.11 Crushing load
JB5301-91
On the material testing machine, apply a compressive load to the steel ball according to the prescribed method until the instantaneous load value when the steel ball is damaged. 4 Size
The nominal size of the steel ball is specified in Table 1.
Approved by the Ministry of Machinery and Electronics Industry on June 25, 1991 and implemented on July 1, 1992
(5/32)
(7/32)
(13/64)
(5/16)
Note: The imperial steel balls in brackets are non-preferred steel ball sizes. 5 Technical requirements
5.1 Tolerance grade
JB:530191
(29/64)
(15/32)
(19/32)
(29/32)
Steel balls are divided into four grades of 100, 200, 500 and 1000 according to the size and shape tolerance of the manufacturing, and the accuracy is from high to low. 5.2 Tolerance
The size, shape tolerance and surface roughness of steel balls of each tolerance grade shall be in accordance with the provisions of Table 2. 2
Tolerance grade
5.3 Appearance
Upper deviation
Lower deviation
JB5301-91
The surface of the steel ball must be smooth, and there shall be no visible cracks, rust and other defects on the surface. 5.4 Material
The steel balls specified in this standard are made of No. 10, 15 high-quality carbon steel and other carbon steels with carbon content and mechanical properties close to them. 5.5 Carburized layer depth
The carburized layer depth on the surface of the steel ball shall be as specified in Table 3. Table 3
5.6 Hardness
Minimum depth of carburized layer
The surface hardness of the steel ball shall generally not be less than 60HRC. If the user has special requirements, it can be implemented according to the agreement between the two parties. 5.7 Crushing load
The crushing load of the steel ball is generally not tested. For steel balls for carbon steel ball bearings and steel balls with crushing load requirements by users, after consultation with the manufacturer, the crushing load value specified by the manufacturer's competent department shall be tested. 6 Inspection method
6.1 Appearance
The appearance of the steel ball is generally visually inspected under a diffuse light. 6.2 Tolerance
The dimensional tolerance of steel balls shall be tested in accordance with the provisions of Article 6.2.1 of GB308. 6.2.2 The measurement of spherical error of steel balls shall generally be measured by the V-block (three-point) method in accordance with the provisions of Appendix B of GB308. In case of dispute, the measurement of roundness instrument shall prevail.
6.3 Surface roughness
The measurement of surface roughness of steel balls can generally be determined by comparing with standard parts under a magnifying glass. In case of dispute, the measurement of instrument shall prevail. 6.4 Minimum depth, hardness and crushing load of carburized layer The measurement of minimum depth, hardness and crushing load of carburized layer of steel balls shall be in accordance with the provisions of the competent department of the manufacturer. 3
7 Inspection rules
JB5301—91
General rules for steel ball inspection shall be in accordance with Article 7.1 of GB308, 7.1
7.2 The procedures for user acceptance of steel balls and the sampling inspection plan shall be in accordance with the provisions of ZBJ11020. The inspection level and qualified quality level (AQL) of each inspection item of steel balls shall comply with the provisions of Table 4. Table 4
Steel balls for carbon steel bearings
Inspection items
Surface roughness
Crushing load
Carburized layer depth
Inspection level
Qualified quality level
Inspection level
According to the provisions of ZBJ11020
General steel balls
Qualified quality level AQL
Dw<4mm
Inspect 3 balls, qualified judgment number is 0
Note: ①The inspection items of 500 and 1000 levels can be negotiated with the user and can be reduced as appropriate. ②The crushing load is generally not inspected.
Marking, packaging and storage
8.1 Marking
Out),
Marking content and sequence,
Material code of steel balls. The symbol "c" is used to represent carbon steel; the nominal diameter of the steel ball. The unit is "mm\ (not marked); the tolerance grade of the steel ball. It is represented by the symbol "G" plus a number; 2.5
Dw≥4mm
batch average diameter deviation or the symbol "b\ (not grouped by batch diameter variation). The unit of batch average diameter deviation is um" (not marked with this standard number or this standard number plus the supplementary technical condition number. Marking method
In places where steel ball quality certificates and packaging materials need to be marked, they should be marked according to the content and sequence of Article 8.1.1, and a space should be left between each item.
Marking example
The material is carbon steel, the nominal diameter of the steel ball is 5.000mm, the tolerance grade is 100, and the batch average diameter deviation is 5um: C5.000G100+5JB5301—91
The material is carbon steel, the nominal diameter of the steel ball is 6.350mm, tolerance grade 200, steel balls not grouped by batch diameter variation: C6.350G200bJB5301—91
8.2 Packaging
8.2.1 Finished steel balls that have passed the inspection shall be rust-proofed and packaged in accordance with the provisions of JB3034. When packaging, steel balls of different sizes, tolerance grades, materials, and batch average diameter deviations shall be packed into different containers (boxes) and shall not be mixed.
JB5301—91
8.2.2 The outside of the packaging container (box) shall be marked with Carbon steel balls, steel balls, quantity, mark, manufacturer name (trademark), batch number and packaging date. 8.3 Storage
After the steel balls are packed with anti-rust packaging, they should be guaranteed not to rust within 12 months from the date of leaving the factory under the reasonable transportation and normal warehouse storage conditions specified in JB3034.
Additional instructions:
This standard is proposed by the National Technical Committee for Rolling Bearing Standardization. This standard is under the jurisdiction and drafting of Luoyang Bearing Research Institute. The main drafter of this standard is Xu Wenbao.
Republic of China
Mechanical Industry Standard
JB530 1—91
Published by the Machinery Standardization Research Institute of the Ministry of Machinery and Electronics Industry (P.O. Box 8144, Beijing
Postal Code 100081)bzxz.net
Copyright reserved
No reproduction allowed
Printed by Qinghe County Printing Factory, Hebei Province
Format 880×12301/16 Printing sheet 5/8 Number of words 10000 First edition in September 1991
First printing in September 1991
Print run 00.001—2000
Price 1.60 yuan
Serial number 0014
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