Converting HV to MPa
Converting HV to MPa
(OP)
I am trying to find the reference and validity of converting the hardness value into MPa by multiplying the HV value by 9.807 as stated from the surface engineering forum, does anyone know of any references or experiences with this.
http://www.gordonengland.co.uk/hardness/hvconv.htm
Many Thanks
http://www.gordonengland.co.uk/hardness/hvconv.htm
Many Thanks





RE: Converting HV to MPa
Does what above tell you anything?
RE: Converting HV to MPa
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Converting HV to MPa
There are two different things to consider here. The first is what exactly is HV? The following is the definition from ASTM E 384 Standard Test Method for Knoop and Vickers Hardness of Materials
Vickers hardness number, HV, n — an expression of
hardness obtained by dividing the force applied to a Vickers
indenter by the surface area of the permanent impression made
by the indenter.
So, this means that the value of HV can be a "pressure" with units of MPa or GPa.
The second issue is how does this relate to the strength of a material. The answer is that increasing HV corresponds to increasing tensile strength. It does not have a meaningful correlation to yield strength. However, you cannot divide HV by 9.907 or any other number and obtain a tensile strength. This can only be approximated, with values given in either ISO/TR 10108 or ISO 18265.
RE: Converting HV to MPa
if you are trying to model it remember it is an "impact" test. applyinf a pressure to an area (ie using a static representation of the impact) is pretty much doomed to failure.
you need to use NL FEA to model the impact.
RE: Converting HV to MPa
The article discusses converting results in kgf/mm2 into N/m2 (Pa). This is straightforward units conversion. It should be dead easy.
RE: Converting HV to MPa
Regards,
Cockroach