Ball Quality

- Apr 09, 2019 -

Ball quality is defined as follows:


Surface Hardness  is measured on the Rockwell Scale. Minimum hardness is RC 60 for carbon, chrome and 440 stainless balls and varies for other products according to the material and desired toughness.
Case Depth is the radial distance from the ball surface to the point where hardness falls to Rockwell C 50. The core is the remaining soft inner area (avalible in carbon steel ball).
Surface Integrity is defined as the surface smoothness and freedom from defects such as flats, pits, soft spots and cuts. Balls must be free of such defects when inspected without magnification.
Size is the mean diameter, measured between two parallel planes on the ball surface.
Sphericity is defined as the deviation from a true spherical form (out-of-round condition).

Standard

Grade

Ball diameter variable

Spherical error

Batch diameter variation

Surface roughness

G5

0.13

0.13

0.25

0.014

G10

0.25

0.25

0.5

0.020

G16

0.4

0.4

0.8

0.025

G20

0.5

0.5

1

0.032

G24

0.6

0.6

1.2

0.040

G28

0.7

0.7

1.4

0.050

G40

1

1

2

0.060

G60

1.5

1.5

3

0.080

G100

2.5

2.5

5

0.100

G200

5

5

10

0.150

G500

12.5

12.5

25


G1000

25

25

50