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TECHNOLOGY 37
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has been illustrated respectively. A thorough examination of mean free path and an increase in hardness, leading to an
the SEM micrographs indicated that the deterioration of the increase in wear resistance.
cutting edge predominantly occurred on the working surface, However, the utilisation of 0.7 µm grains diminished the
a consequence of the friction between the working surface resistance of this material to strong impacts and heavy cutting.

and the workpiece. The absence of impact resistance renders such materials
SEM images obtained at higher magnifications reveal the unsuitable for utilisation under particularly exacting cutting
presence of tungsten carbide grains that protrude convexly conditions.
from the wear surface. Consequently, the authors proposed the utilisation of an
In addition, the images show depressions that were once enhanced cutting insert design, entailing modifications to the
occupied by carbide grains but had since been removed. geometry and the refinement of the quality of the cutting edge
It is hypothesised that, for blades with grain sizes of 0.4 through the employment of modified grinding techniques.
and 0.8 µm, wear occurs through the removal of the cobalt Blades with nanometre-sized WC grains can fracture or
bond between the WC grains, which then leads to the removal break off fragments due to mechanical action, resulting in a

of the WC grains themselves. deterioration in machining quality. Mechanical stresses are
The observation that the wear surfaces of submicron WC caused by forces during the cutting process, such as pressure,
grain sizes are similar in appearance suggests that analogous impact, or vibration.
wear mechanisms. These forces can weaken the blade’s structure, particularly
Numerous scientific studies confirm that the preferential in weak or damaged areas. To minimise this risk, it is necessary
removal of tungsten carbide grains during the wear process to regularly monitor blade condition, use appropriate machining
is a complex, multifaceted phenomenon occurring through parameters, and use durable, stress-resistant materials.

various physicochemical mechanisms. The EDS analysis of all the tested blade variants revealed
The most important of these are chemical corrosion, the presence of elements such as calcium, silicon, and oxygen,
oxidation, extrusion, and abrasion. In practice, it is highly in addition to tungsten, carbon, and cobalt.
likely that multiple mechanisms are at work simultaneously These elements are not part of the tool material itself,
during the wear process. but rather constitute impurities within the chipboard, such as
These mechanisms overlap and interact, creating a complex silicon or calcium from calcium hydroxide.
picture of material degradation. For instance, oxidation can
form protective layers or weak layers that accelerate the
wear process. Dotun55

In the case of blades made of cemented carbides with
nanometric WC grain sizes, the presence of distinct microcracks
was observed, which ultimately led to catastrophic blade wear.
A salient disadvantage of this material is its low resistance
to the milling parameters employed.
The experiment encompassed the testing of WC-Co
composites, incorporating WC grain sizes ranging from 0.7

to 1.7 µm. The reduction in grain size and bonding phase
content has been demonstrated to result in a reduction in