Salutron HardyTest HARTIP 1800, Operation Manual

Page: 8 / 40

6
5. Preparation before Measuring
5.1. Requirements for the sample
5.1.1. The surface temperature of sample should be less than 120

C.
5.1.2. The samples must feature a metallic smooth, ground surface, in order to eliminate
erroneous measurements brought about by coarse grinding or lathe scoring. The
roughness of the finished surface should not exceed 2μm.
5.2. Requirements for the weight of the sample
For samples weighing over 5 kg and of compact shape, no support is needed.
Samples weighing between 2-5 kg, and also for heavier samples with protruding parts or
thin walls, should be placed on a solid support in such a manner that they do not bend or
move by the impact force.
Samples weighing less than 2 kg should be firmly coupled with a stable support weighing
over 5 kg.
For coupling purposes,

The coupling surface between the sample and base plate should be flat, plane parallel and
ground.

A thin proper layer of coupling paste is to be applied to the contact surface of the sample.

The sample should be firmly pressed against the surface of the base plate by moving it
with a circular motion.

The direction of impact should be perpendicular to the coupling surface.

For the coupling operation, the following prerequisites must be fulfilled:
 The contact surface of the sample and the surface of the base plate must be flat, plane
parallel and ground.

The direction of the test impact must be perpendicular to the coupled surface.

Minimum thickness of the sample for coupling (5mm).
Proper Coupling:
Proper coupling requires a little experience. Insufficiently coupled samples produce large
variations of individual measurements, L-values which are too low and the operation is
characterized by a rattling noise upon impact of the test tip.
Example for coupling a test piece with a base plate:
5.3. Requirement for the surface hardened layer of the sample
Surface -hardened steels and especially case-hardened steels produce L-values which are
too low when case-hardening depth is small because of their soft core. When measuring
Application of the coupling
paste (As thin as possible).
A particular advanced of coupling is
the possibility of obtaining a very
uniform, rigid connection between
the sample and the support, totally
eliminating stresses at the sample
surface. The resulting variation in
measured values is very low.
Mutual rubbing of both
parts while firmly press the
sample against the base
plate.