A Study on the Evaluation of Long Term Stability of Brinell Standard Hardness Tester and Automatic Indentation Measurement System and Optimum Test Condition

브리넬 경도 표준 시험기 및 압입자국 자동 측정 장치의 장기 안정도 평가와 최적 시험조건에 관한 연구

Evaluation of long term stability of the Brinell standard hardness tester was carried out to secure its application as a national standard in Brinell hardness. Accuracy and repeatability in load application were tested through evaluating errors in hardness measurement of certified reference blocks. All of those requirements in KS as well as ISO specifications were satisfied by this standard hardness tester. In addition to this, long term stability test of automatic indentation measurement system was carried out. The scattering range was almost the same with its error range. To figure out an optimum test condition for better repeatability and long term stability, the effect of load variation, load application speed and time have been studied using orthogonal array experimental plan. It was found that the best combination is $30{\mu}m/s$ of load application speed and 25 seconds of load application time.