Appendix
NewSonic SonoDur-R
Issue 105 06/2020
Page 80
11.4
Conversion Limits
The Vickers Scale is the basis for all conversions. Currently, the conversion tables for all material
tables have been entered in accordance with EN ISO 18265. Depending on requirements,
enhancements of the conversion ranges and new material tables can be generated.
Measuring range in HV (UCI): 10 - 2000 (1 - 9999)
Minimal conversion: 80 HV = 76 HB, Maximum conversion: 940 HV = 68 HRC (for steel, Table A1 EN
ISO 18265).
Conversion rules according to EN ISO 18265 for low alloy steel:
Scale
HB
HRB
HRF
HRC
HRA
HRD
HR45N
Rm [MPa]
HK
Min
76
41
82,6
20,3
60,7
40,4
19,9
255
-
Max
618
105
115,1
68,0
85,6
76,9
75,4
2180
-
Table 11-6
Conversion rules according to ASTM 140-07 for low alloy steel:
Scale
HB
HRB
HRF
HRC
HRA
HRD
HR45N
Rm [MPa]
HK
Min
100
55
88,2
20,0
37,2
40,1
19,6
-
112
Max
739
100
99,6
68,0
85,6
76,9
75,4
-
920
Table 11-7
WARNING
The conversion tables according to EN ISO 18265 and ASTM E140 have different ranges for the
different materials. For SonoDur devices, the load-bearing Vickers Hardness scale applies which
always has a measurement value. If no value pairs in HRC, HB, etc. are available for certain scales,
an extrapolation is initially attempted. If this results in no result, the operator must choose a
different hardness scale for the existing measurement series or return only to the Vickers
presentation. The extrapolated values are in any case not covered by standard values and are
subject to a high degree of uncertainty. Therefore, they will be represented in RED and offered to
the operator for use.