NewSonic SonoDur2 Issue 04 09/2016 Page 7
2 Introduction
This instruction manual describes the hardness tester SonoDur2 with motorized and hand-held
measuring probes for UCI hardness testing (Ultrasonic Contact Impedance).
2.1 Measuring Method
The hardness measurement by means of ultrasonic indirectly evaluates the indentation testing of the
Vickers diamond and digitally displays the result immediately. The application of force can be
implemented either motor-driven or manually against a spring. A hardness value is calculated at a
defined force (penetration force), which correlates to the area of impression after indentation,
although the measurement was carried out under load.
The UCI hardness testing is standardized according to ASTM A 1038, DIN 50159-1 and -2 and
described in VDI / VDE Standards 2616, Sheet 1.
Thereby, it must be noted that the measurement result depends, among others, on the elastic
properties of the test material and therefore, the measurement device must be calibrated onto the
test material. Hence, the UCI hardness testing is representing a comparative method attributed to
reference standards (calibrated or adjusted by the operator). The reference scale for the hardness
testing is the Vickers unit (HV). Adjustment can be indirectly performed on hardness reference blocks
or directly via comparative measurement, for instance, by means of a Vickers machine (identical test
force) on a specimen of the test material.
If a different test method is being used (Rockwell, Brinell, etc.), shape and material of the indenter,
indentation size and hence, the measuring range varies. Therefore, depending on the material,
treatment and surface condition, adjustment or conversion of hardness values can be incorrect or
inadmissible with one another as well as with tensile strength values.
Conversions from the calculated Vickers hardness values are therefore permitted with restrictions
and only in accordance with relevant standards. All conversion tables in accordance with EN ISO
18265, ASTM E 140 are defined in the SonoDur2 tester. However, it’s up to the responsible individual
to decide about the admissibility of a conversion based on the calculated Vickers hardness on the
basis of his specific requirements and experiences.
Motorized measuring probes: Based on the very low test forces between 1 N (HV0, 1) and 8.6 N
(HV1), the measurements are virtually non-destructive at almost constantly low dispersion of
measured values, even at high hardness levels. Thus, the main applications for motorized probes,
production control and maintenance checks of smooth (polished, lapped) and thereby also coated
surfaces (hard chrome, copper), such as rollers, rotogravure cylinders, automotive components and
other components, are associated with high-level requirements pertaining to a clean and undamaged
material surface. It is also very well possible to measure small spring components or other precious
components, if a possible component vibration can be suppressed by holding or fastening the device
properly.
Hand-held measuring probes with, for instance, test forces of 10N (HV1), 50N (HV 5) and 100N
(HV10), have fewer roughness requirements. Therefore, the area of application is wider, also rather
tends to very large and heavy components in hardening plants, for example, after induction
hardening, on welding seams of boilers and pressure pipes. For the cutting edge assessment on
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