Uncertainty Evaluation on Rockwell Hardness Results of X70 Pipeline Steel

In terms of the method processes of GB/T 230.1-2009, Rockwell hardness test (scale HRB) was carried on the sample of X70 pipeline steel by Wilson 2001T Rockwell apparatus. The source of measurement uncertainty was explained, e.g. the test repeatability and reproducibility of hardness tester, every uncertainty component was evaluated, and finally the expanded uncertainty and measurement uncertainty report was offered. The results showed that the average hardness of the X70 steel sample was (78.5±2.4) HRB, k=2. It would be useful to evaluate other measurement uncertainty in Rockwell hardness testing.