WHAT KIND OF FACTORS WILL HAVE IMPACT ON UCI FINAL TESTING RESULT?

1.Surface roughness of specimen

The roughness of measured surface directly affects the accuracy of hardness measurement. With the increase of roughness, the smaller the resistance of the measured surface to indenter, the larger the plastic deformation, the bigger the circular indentation, the lower the corresponding hardness, so that the measured value is lower than the true value. So when using a hardness tester to measure the hardness of a workpiece, try to treat the surface of the workpiece as much as possible, The roughness of the measured surface can be made to meet the testing conditions of the durometer by hand grinding wheel or other methods so as to obtain accurate hardness values.

2.Depth of the coating material

 If surface hardness is to be measured, it is necessary to measure the depth of the coating material. For example, if the coating layer thickness is 0.125 micron or 0.25 micron, it measures about HV950 - 1,100 using measuring load of 300 gf/HV0.3. The testing data is not correct, because 300gf is too large for thickness: 0. 0.125 micron or 0.25 micron, the coating thickness must be penetrated in such force, because it is about 3um(micron) for the press-in depth.

3.Weight of the specimen

For lightweight specimens, specimens with suspension and thin wall，the impact force is easy to cause distortion, deformation and movement of the specimen in the process of test,