Wear characteristics of normal compressive crushing rings
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis examines the wear characteristics of a promising new rock-crushing technology.
This novel method employs a normal compressive force to comminute rocks
between two rotating rings. To further understand the wear mechanism of these
rings and the ring materials response to this type of wear, a variety of ring materials,
including Hardox600, two types of sintered Tungsten Carbide (WC)/Cobalt
(Co) matrix, identified as X1 and X2 - where X1 has less WC compared to X2 was
used. This range of materials enabled a comparative study of wear patterns under
the same operating conditions.
The thesis was carried out through a set of surface studies using Scanning Electron
Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Backscatter
Electron (BE) imaging. These tools were used to closely examine the worn features
on the surfaces of the tested materials. These detailed methods provided a clear
view of wear patterns, enabling a better understanding of how the ring materials
behave during rock crushing.
After a comprehensive analysis of the crushing principle and surface wear, the high
stress three-body abrasive wear was identified as the primary wear mode for this
application.
In response to this type of wear, the tested materials displayed contrasting material
removal mechanisms. Hardox600, being the softest of the materials, primarily experienced
cutting (Ploughing) and repeated plastic deformations, evidenced by slivers
on the worn surface.
Conversely, the sintered WC materials exhibited completely different post-wear surface
topography. For these materials, most material removal was due to WC particle
breakage and subsequent dislodging from the matrix. Of the two sintered materials
tested, the one with a higher WC content percentage demonstrated superior wear
resistance, underscoring the significance of hardness in relation to the hardness of
the abrasives. The superior wear can also be explained by the smaller and more
uniform WC used in the Sintered X2 compared to X1.
Based on the wear resistance and hardness of the evaluated materials, we conclude
that for optimal wear resistance in this wear application, materials should resist
plastic deformation, as it leads to severe wear. To control wear, materials should
have a hardness that is on par with that of the abrasives to minimize the severity
of wear.
Beskrivning
Ämne/nyckelord
Crushing, Wear mechanisms, three body abrasive wear, Hardox600, Sintered WC/Co, Surface analysis