Hardness Scale |
Hardness Range of The Standard Testing Blocks |
The Max. Tolerance of Hardness Display Value |
HRA | 20~≤75HRA | ±2HRA |
>75~≤88HRA | ±1.5HRA | |
HRB |
20~≤45HRB | ±4HRB |
>45~≤80HRB | ±3HRB | |
>80~≤100HRB | ±2HRB | |
HRC | 20~≤70HRC | ±1.5HRC |
Hardness Value of Standard Testing Blocks (HBW) |
Tolerance of Displayed Value (%) |
Repetition of Displayed Value (%) |
≤125 | ±3 | ≤3 |
125<HBW≤125 | ±2.5 | ≤2.5 |
>225 | ±2 | ≤2 |
Tolerance of Displayed Value | Repetition of Displayed Value | |||
Hardness Scale |
Displayed Value of Hardness Test Block |
Tolerance of Displayed Value |
Displayed Value of Hardness Test Block |
Repetition of Displayed Value |
HV30 HV100 |
≤250HV | ±3% | ≤225HV | 6% |
300~1000HV | ±2% | >225HV | 4% |