HT-RHT-45MA Manual Rockwell Hardness Tester, based on the mechanical principle of conical diamond or hard alloy indenter pressing into the sample surface to produce indentation, realizing the material hardness measurement by measuring the depth of the indentation. Capable of inspecting the finished or semi-finished parts of the machined sample, it is suitable for high accuracy hardness testing for batches parts with various metal or non-metallic materials. According to statistics, Rockwell hardness testing is the most widely used hardness testing method in metal processing industry, which utilization ratio is more than 70°/o. With novel appearance, stable performance and convenient visual reading of the classical dial, It is widely used in metal processing and manufacturing, various metal material' s failure analysis and other fields like colleges and research institutions. It is the new type Brinell hardness testing instrument for testing the hardness of the materials like cast iron, steel, soft alloy and so on.
The Rockwell hardness test is taking the diamond cone with 120° apex angle or the hardened steel ball with specified diameter as the indenter to press into sample surface with specific test force, then get the Rockwell hardness of the measured metallic materials according to the sample surface indentation depth. The Rockwell hardness measurement principle is shown as below figure. 0-0 is the position that the diamond indenter is not yet in contact with the sample. 1-1 figure is the indenter position under the affect of the preliminary test force, the indentation depth is h,. The preliminary test is to eliminate the influence to the testing result accuracy caused by the roughness of the sample surface 2-2 in the figure is the indenter position under the influence of the testing force (the preliminary test force and the main test force). The depth is h2. 3-3 in the figure is the indenter position after dismounting the main test force. As the metal elasticity will recovery some degree after deformation, the really indentation depth of the indenter is h3. The plastic deformation caused by the main test force make the indenter pressing into the depth is h = h3 - h, Rockwell hardness value is determined by the size of h, the greater the depth h, the lower the hardness, otherwise, the higher the hardness. In the traditional concept, usually use a constant C minus h to represent the level of hardness, while the depth of indentation per 0.002mm as a unit of hardness. The hardness value obtained is called the Rockwell hardness value, denoted by the symbol HR. It should be noted that the hardness values measured with different indenter and test force are different Therefore, the Rockwell hardness test specifies 15 different hardness test scales according to the different indenter specifications and test force sizes. HRB, HRC, HRA is the most widely used.
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