The following are results from standard vacuum furnace hot hardness tests. Values are given in originally measured DPH (Vickers) units and conversions to Rockwell C/B scale.
| Alloy |
800°F (425°C) |
1000°F (540°C) |
1200°F (650°C) |
1400°F (760°C) |
1600°F (870°C) |
| Vickers |
Rockwell |
Vickers |
Rockwell |
Vickers |
Rockwell |
Vickers |
Rockwell |
Vickers |
Rockwell |
| 242® |
271 |
26 HRC |
263 |
24 HRC |
218 |
95 HRBW |
140 |
75 HRBW |
78 |
- |
| 6B |
269 |
26 HRC |
247 |
22 HRC |
225 |
98 HRBW |
153 |
81 HRBW |
91 |
- |
| 25 |
171 |
87 HRBW |
160 |
83 HRBW |
150 |
80 HRBW |
134 |
74 HRBW |
93 |
- |
| 188 |
170 |
86 HRBW |
159 |
83 HRBW
|
147 |
77 HRBW |
129 |
72 HRBW |
89 |
- |
| 230® |
142 |
77 HRBW |
139 |
76 HRBW |
132 |
73 HRBW |
125 |
70 HRBW |
75 |
- |
| 556® |
132 |
73 HRBW |
129 |
72 HRBW |
118 |
67 HRBW |
100 |
56 HRBW |
67 |
- |
HRBW = Hardness Rockwell “B”, Tungsten Indentor.
HRC = Hardness Rockwell “C”.