THE INFLUENCE OF THICKNESS ON THE NON UNIFORMITY VALUES OF ROCKWELL B HARDNESS STANDARD BLOCKS

Abstract: In the present work, the influence of thickness variation and of the microstructural aspects on the hardness uniformity of Rockwell B standard blocks is discussed. In order to correlate the results, two different heat treatments were performed on the steel employed to manufacture the standard blocks. Three different thickness ranges were studied for each of the two heat treatments conditions applied to the standard blocks material. The microstructural characteristics were studied by means of optical microscopy. The hardness measurements were carried out in hardness testing machines belonging to the three Brazilian Institutes involved in the present study. The results indicate that the non-uniformity hardness values are directly affected by the resulting microstructural changes due to the applied heat treatments. However, a relationship between thickness variation and hardness values has not yet been entirely understood.