NewSonic SonoDur2 - Formulas and Terms

NewSonic SonoDur2 Issue 04 09/2016 Page 68
11.4 Formulas and Terms
Section 7.5 “Information Menu“, contains calculation results that are described in detail below (see
also EN ISO 18265).
Average value in Figure 11.1 is represented by the letter X with a bar over it, here referred to as
“Overline X”.
Overline X =


 󰇛󰇜


(1)
With X(i) = Individual Hardness Measurement Value, N = Total Quantity of Measurements
If hardness gradient measurements are not performed, the average value is usually the characteristic
degree of hardness for a material or for a particular test position on the test object. Impacts caused
by the operator and/or material inhomogeneity effects can be reduced by averaging. (Highly
heterogeneous materials such as GG or GGG-cast iron are an exception).
R = Range/spread or maximum error in a series of measurements (absolute value):
R = X(Max) – X(Min) (2)
Please note:
Relative range is defined dependent on the used scale according EN ISO 18265:
R [%] =
___ R___
Overline X
* 100
(for HV, HB, HK, MPa)
(3)
R [%] =
______ R ____
100 - Overline X
* 100
(for HRC, HRA, HRD, HRN)
(4)
R [%] =
______ R_____
130 - Overline X
* 100
(for HRB and HRF)
(5)
Figure 11.1
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