| Grade |
Rockwell B Scale (Rb) |
| Imperial (psi) |
Metric (Mpa) |
Typical Spec |
Typical Range |
68 |
69 |
70 |
71 |
72 |
73 |
74 |
75 |
76 |
77 |
78 |
79 |
80 |
81 |
82 |
83 |
84 |
85 |
86 |
87 |
88 |
89 |
90 |
91 |
92 |
93 |
94 |
95 |
96 |
97 |
98 |
99 |
100 |
101 |
| 45000 |
300 |
SAE J2340 300XP |
72-80 |
← |
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→ |
| 50000 |
34 |
SAE J2340 340XP |
78-85 |
← |
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→ |
| 60000 |
420 |
SAE J2340 420XP |
82-90 |
← |
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→ |
| 70000 |
490 |
SAE J2340 490XP |
88-95 |
← |
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→ |
| 80000 |
550 |
SAE J2340 550XP |
93-100 |
← |
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→ |
Green Zone: High Level of Confidence that part will be successful.
Yellow Zone: Borderline.
Red Zone: Low Level of Confidence.