26
8.1.7
Surface preparation
More consistent results are obtained with better surface finishes, however, as a minimum, 600
grit finish is recommended.
Also, it is suggested that any surface scale, rust, contamination of other debris should be
removed from the surface before testing.
8.1.8 Minimum specimen thickness
In general, the specimen thickness should be >8-10 X the depth of the indent. (see following
table)
Average Dent
Diameter, d
Minimum
Specimen
Thickness
Ball Diameter
D=1
D=2.5
D=3
D=10
0.2
0.10
0.3
0.23
0.4
0.41
0.5
0.68
0.6
0.8
0.36
0.7
0.50
0.8
0.66
0.9
0.84
1
1.04
1.1
1.28
1.2
1.54
0.73
1.3
1.83
0.86
1.4
2.15
1.00
1.5
2.5
1.15
1.6
1.31
1.7
1.49
1.8
1.68
1.8
1.88
2
2.09
2.2
2.55
2.4
3.08
1.47
2.6
3.65
1.73
2.8
4.29
2.00
3
5.00
2.30
3.2
2.62
3.4
2.98
3.6
3.35
3.8
3.75
4
4.18
4.2
4.63
4.4
5.10
