COMPARATIVE MEASUREMENTS OF SLOVENIAN AND USA ROCKWELLC HARDNESS SCALES

摘要

A national scale is set up for each hardness scale representing the reference hardness values in each country. From metrological and international trade aspects agreement between the national scales is very important. Good agreement makes possible good industrial cooperation. Therefore comparison between national scales is necessary. Comparison between national hardness scales and hardness scales set up by the producers of the reference blocks is necessary as well. The Rockwell measurement method is the most widely used hardness measurement method throughout the world. The measurement is practical, relatively easy to carry out and the measurement result is quickly and simply indicated on the indicator. Among the different Rockwell scales, the C scale is very useful. It satisfies demands for accurate hardness measurement especially during hardening process of steel, which is often applied in industry. In this paper comparative measurements between the Rockwell C national scales of Slovenia as measured by Zavod za gradbenistvo Slovenije (ZAG) and USA as measured by the National Institute of Standards and Technology (NIST) and the scale set up by a producer of reference blocks, David L. Ellis Co., Inc., are presented.