ASTM Hardness
Minimum Thickness Requirements
Minimum allowable thickness for a corresponding hardness in the respective scales
| Minimum |
Minimum |
- |
Rockwell |
- |
- |
- |
Superficial |
Rockwell |
- |
- |
| thickness |
thickness |
C |
A |
B |
15N |
30N |
45N |
15T |
30T |
45T |
| in. |
mm. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 0.006 |
0.15 |
|
|
|
92 |
|
|
|
|
|
| 0.008 |
0.20 |
|
|
|
90 |
|
|
|
|
|
| 0.010 |
0.25 |
|
|
|
88 |
|
|
91 |
|
|
| 0.012 |
0.30 |
|
|
|
83 |
82 |
77 |
86 |
|
|
| 0.014 |
0.36 |
|
|
|
76 |
78.5 |
74 |
81 |
80 |
|
| 0.016 |
0.41 |
|
86 |
|
68 |
74 |
72 |
75 |
72 |
71 |
| 0.018 |
0.46 |
|
84 |
|
|
66 |
68 |
68 |
64 |
62 |
| 0.020 |
0.51 |
|
82 |
|
|
57 |
63 |
|
55 |
53 |
| 0.022 |
0.56 |
69 |
79 |
|
|
47 |
58 |
|
45 |
43 |
| 0.024 |
0.61 |
67 |
76 |
94 |
|
|
51 |
|
34 |
31 |
| 0.026 |
0.66 |
65 |
71 |
87 |
|
|
37 |
|
|
18 |
| 0.028 |
0.71 |
62 |
67 |
80 |
|
|
20 |
|
|
4 |
| 0.030 |
0.76 |
57 |
60 |
71 |
|
|
|
|
|
|
| 0.032 |
0.81 |
52 |
|
62 |
|
|
|
|
|
|
| 0.034 |
0.86 |
45 |
|
52 |
|
|
|
|
|
|
| 0.036 |
0.91 |
37 |
|
40 |
|
|
|
|
|
|
| 0.038 |
0.96 |
28 |
|
28 |
|
|
|
|
|
|
| 0.040 |
1.02 |
20 |
|
|
|
|
|
|
|
|
The above tables are from ASTM E 18.
Reprinted from the Annual Book of ASTM Standards, copyright American Society for Testing and Materials.
100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 |
|
