HV Hardness is the vickers hardness, and HRC is the representation of rockwell hardness.Their differences are mainly in the hardness test, the indentation shape is different.
The conversion between HV and Mpa
Load 49~980 N,The conical diamond with the Angle of 136 degrees is pressed into the surface of the material,After keeping time,Measure the diagonal length of the indentation,Then we calculate the hardness by the formula.It is suitable for the determination of the hardness of larger workpiece and deep layer.
vickers hardness has a small load testing, testing load 1.961~<49.03N.It is applicable to thinner workpiece, tool surface or coating hardness measurement.
Microscopy Vickers hardness,testing load n<1.961N,Applicable to metal foil, extremely thin surface layer hardness measurement.
HV is suitable for microscopic analysis,Vickers hardness (HV),press diamond square cone with 136 degree top angle into the surface of material within 120kg load.The surface area of the indentation pit is divided by the load value,it’s the vickers hardness value .
Pascal (Pa),1Pa=1N/m2,since Pa is too small,it is often represented by its multiple unit MPa (MPa) in engineering.1MPa=106Pa,Our country commonly USES unlegal pressure unit bar, millibar, standard atmosphere pressure, engineering atmosphere, millimeter mercury column and so on.
Atmospheric pressure we usually says,
the engineering unit: Kgf/CM 2,
1 MPa is equivalent to 10.2 pressure (Kgf/cm2)
HV measuring
Diamond coating is very thin surface, HV can be measured, HRC and HRA are not applicable.The head shape of HRC and HRA is a round cone of 120 degrees, and the top is a sphere.The head of HV is a sharp four pyramid with four spheres intersecting.The measurement methods of two kinds of hardness are judged by the depth of the material pressed into the material. The more shallow the pressure is, the greater the hardness of the material。However, because of the shape of the head, HRC and HRA can apply a relatively large force to press the head into the material, (the pre-pressure of both methods is 10KG and the total pressure is 60KG and 150KG respectively). For very hard material,HRC and HRA exists on the spherical surface of the front end,The depth is too shallow to be accurately resolved.For the material of large differences in surface and internal hardness,the depth is too deep,also not applicable.
Because of the sharp pyramid, HV can not be confined to the force, and can be selected according to the depth of the surface of the material as small force.It is also possible to obtain accurate hardness values for extremely hard materials and thin layers.
Please below link to download
