1.Rockwell hardness: It is an important performance index of metal materials, which is a physical quantity that characterizes the ability of the material to resist the local pressure of hard objects into its surface, the same test force, the deeper the indentation, the softer the material, the shallower the indentation, and the harder the material.
2.Adopt standards.
gb 3849-1983；astm b294-2010；q/62071126-8 f0501-2014。
3.Classification of Rockwell hardness.
Tungsten carbide is often characterized by HRA due to its high hardness.
4.Principle of Rockwell hardness testing.
The indenter (diamond cone or steel ball) is pressed into the surface of the specimen under the initial and total loads, respectively, and the main load is removed, and the Rockwell hardness is calculated from the measured residual indentation depth at the initial load.
5.Specimen requirements.
The roughness of the test surface is Ra 2 m and the thickness is 16mm, the test surface is parallel to the support surface, and its parallelism does not exceed 0 per 10mm length1mm。
6.Rockwell hardness tester.
7.Influencing factors of Rockwell hardness testing.
7.1 Human error.
The loading is too fast, the holding time is short, the initial test force holding time should not exceed 3s, and the total test force holding time is 2 6s.
The indenter is not installed properly, the correct installation method: the middle finger of the hand is against the diamond part, gently push towards the indenter rod hole, adhere to the support surface, and tighten the indenter fastening screw slightly.
7.2. Specimen bevel.
When the indenter is pressed into the surface of this sample, the resistance around the indentation is smaller than that of the plane, and even there is the phenomenon of high and slip, the pressure depth increases, and the hardness decreases.
7.3 Effect of the indenter.
The working part of the diamond indenter shall not have defects such as cracks, sand holes, chipping angles, etc.
7.4 Durometer.
The hardness tester is not in a horizontal position, and when testing hardness, its value is on the low side. Measure the levelness with a spirit level and then flatten the hardness tester. Installed in a place where there is no vibration or is far away from the hypocenter. Tungsten carbide