

The steel balls produced by Zhongrui comply with a number of international standards (ISO 3290, DIN 5401, JIS B1501). In addition to manufacturing according to international standards, we can also develop and manufacture products that are most suitable for customers according to customers' special requirements.
series | The precision of the steel ball is represented by numbers, the smaller the number, the more precise |
Basic diameter | A number used to distinguish the size of a steel ball. The basic diameter is obtained by measuring the distance between two planes in parallel contact with the steel ball |
The average diameter | The arithmetic average of the maximum diameter and minimum diameter of a steel ball |
Average batch diameter | The arithmetic average of the average diameter of the largest steel ball and the average diameter of the smallest steel ball in the same production batch |
Batch diameter tolerance | The difference between the average diameter of the largest steel ball and the average diameter of the smallest steel ball in the same production batch |
Diameter tolerance | The difference between the maximum and minimum diameters of a single ball |
Roundness | The maximum value of the difference between the radius of the smallest spherical surface on the surface of the steel ball and the radius of each point on the surface of the steel ball is the roundness of the steel ball |
Surface roughness | Different grades of steel balls have different surface roughness ranges, please refer to the attached table of grades and tolerances |
hardness | It can be divided into two testing methods, spherical hardness and flat hardness, please refer to the attached table of hardness and crushing value |
carburization | The distance from the surface of the steel ball to the point where the hardness of the center is RC 50 is the carburizing depth, which is only suitable for heat-treatable steel |
unit | VDS | W | VDL | Ra |
3 | 0.08 | 0.08 | 0.16 | 0.010 |
5 | 0.13 | 0.13 | 0.25 | 0.014 |
10 | 0.25 | 0.25 | 0.50 | 0.020 |
20 | 0.5 | 0.5 | 1.0 | 0.032 |
40 | 1.0 | 1.0 | 2.0 | 0.06 |
60 | 1.5 | 1.5 | 3.0 | 0.08 |
80 | 2.0 | 2.0 | 4.0 | 0.1 |
100 | 2.5 | 2.5 | 5.0 | 0.1 |
200 | 5.0 | 5.0 | 10 | 0.15 |
300 | 7.5 | 7.5 | 15 | × |
500 | 12.5 | 12.5 | 25 | × |
800 | 20 | 20 | 40 | × |
1000 | 25 | 25 | 50 | × |
2000 | 50 | 50 | 100 | × |
Unit: micron(μm) VDL : Batch diameter tolerance standard VDS: Single diameter tolerance standard
Ra: surface roughness single(μm) W: Roundness standard Standard basis: ISO 3290-2008
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Address: West End of Zhengfang Road, Maozhuang Industrial Park, Ningyang, Shandong, China
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