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 HRB |
140 |
75 HRB |
78 |
- |
| 6B |
269 |
26 HRC |
247 |
22 HRC |
225 |
98 HRB |
153 |
81 HRB |
91 |
- |
| 25 |
171 |
87 HRB |
160 |
83 HRB |
150 |
80 HRB |
134 |
74 HRB |
93 |
- |
| 188 |
170 |
86 HRB |
159 |
83 HRB |
147 |
77 HRB |
129 |
72 HRB |
89 |
- |
| 230® |
142 |
77 HRB |
139 |
76 HRB |
132 |
73 HRB |
125 |
70 HRB |
75 |
- |
| 556® |
132 |
73 HRB |
129 |
72 HRB |
118 |
67 HRB |
100 |
56 HRB |
67 |
- |
HRB = Hardness Rockwell “B”.
HRC = Hardness Rockwell “C”.