Note: Descriptions are shown in the official language in which they were submitted.
1
Crushing tool and method for producing a crushing tool
The invention relates to a crushing tool for attachment to a crushing roll of
a roll crusher, and to
a roll crusher having such a crushing tool. The invention also relates to a
method for producing
such a crushing tool.
For comminuting materials such as limestone, oil shale, marl, clay, oil sand
or similar mineral
materials, crushers, in particular roll crushers, are usually used. Known roll
crushers have two
crushing rolls, which rotate oppositely to one another and form a crushing gap
between the
crushing rolls. The crushing rolls have crushing tools, such as impact bars,
hammers, chisels or
crushing teeth, which are uniformly spaced apart from one another. The
crushing tools of a roll
crusher are exposed to a high degree of wear and must therefore be exchanged
regularly. DE
4123967 Al discloses such a crushing tool, for example.
In order to counteract the wear of the crushing tools, it is known to solder
or weld a wear layer
of a relatively hard material onto the crushing tool, which is formed for
example from relatively
soft steel. However, such a wear layer has only proven to provide sufficient
wear protection to a
limited extent and, in particular in the case of very abrasive material, does
not offer permanent
wear protection. WO 2015165934 Al discloses the application of wear protection
to a crushing
tool by means of hot isostatic pressing (HIP). This method is particularly
cost-intensive and very
complex to perform.
Against this background, an object of the present invention is to provide a
crushing tool which
has low wear and can be produced easily and cost-effectively.
According to a first aspect, a crushing tool for attachment to a crushing roll
of a roll crusher
comprises a main body, which can be attached to the crushing roll, and at
least one wear-
Date Recue/Date Received 2021-05-03
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protection element fastened to the main body, wherein the wear-protection
element is formed
from a hard metal. The main body is formed from a metal-matrix composite
material which
comprises a wear-protection insert of a hard metal. For example, the main body
comprises a
connecting surface, which can be connected to the surface of the crushing
roll, for example in a
material-bonding or form-fitting manner. The connecting surface of the main
body is preferably
formed in a complementary manner to a connecting surface of the crushing roll.
The crushing tool is in particular a crushing tooth, which is preferably
attached to a secondary
crusher or tertiary crusher. The crushing tooth has a substantially chisel-
shaped, in particular
tooth-shaped, contour with a tip pointing in the direction of rotation of the
crushing roll.
The metal-matrix composite material of the main body comprises a metal-matrix
material and
the wear-protection insert of a hard metal. The metal-matrix material is, for
example, high-
temperature-resistant steel and/or a ductile steel with a Brinell hardness of
approximately 90-
500 HB, in particular 120 ¨ 350 HB, preferably 150 HB, and for example an
elongation at break of
greater than or equal to 18-26%, in particular 14%.
A main body of a metal-matrix composite material can be produced particularly
easily and cost-
effectively. The wear-protection insert of a hard metal offers reliable wear
protection that can
be easily introduced on the surface of the crushing tool. The wear-protection
insert is preferably
produced from a powdered and/or granular mixture of particles (grains)
comprising ceramic,
aluminum and/or carbide such as boron carbide, tungsten carbide, silicon
carbide, wherein the
mixture, is mixed, for example with a binder, heated, in particular gassed,
and baked. In
particular, the mixture is heated in a for example flexible mold that
corresponds to the negative
form of the wear-protection insert. The mixture then cools and hardens to give
a very wear-
resistant body with a porous structure.
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According to a first embodiment, the main body is produced by a casting
process. The metal-
matrix composite material of the main body is preferably produced by a casting
process, in which
the wear-protection insert has been cast into the metal-matrix material. A
casting process offers
the advantage that the main body can be produced particularly easily in a
plurality of forms.
According to a further embodiment, the wear-protection insert is arranged on
the surface of the
main body. At least one part of the surface of the crushing tool is formed by
the wear-protection
insert. The wear-protection insert is preferably arranged on the upper surface
of the crushing
tool, facing outward in the radial direction of the crushing roll.
The wear-protection insert preferably comprises, and is preferably formed
completely from, a
hard metal such as tungsten carbide, ceramic, titanium carbide, boron carbide
or chromium
carbide. Hard metal offers the advantage of a particularly wear-resistant
surface.
According to a further embodiment, the wear-protection insert is cast at least
partially into the
main body. In particular, the metal-matrix material and the wear-protection
insert are bonded
by casting to give the metal-matrix composite material. The wear-protection
insert is preferably
cast completely into the metal-matrix material.
The wear-protection insert preferably has a thickness of approximately 5mm to
25mm,
preferably 10mm to 15mm, and is formed in one piece.
According to a further embodiment, the main body has a plurality of wear-
protection inserts,
which are cast at least partially into the main body. For example, at least
one wear-protection
insert is arranged on a side surface facing in the axial direction of the
crushing roll. It may likewise
be provided that a plurality of wear-protection inserts are fitted on the
surface of the crushing
tool that is facing outward in the radial direction of the crushing roll. The
relatively easy
production process of casting the main body makes it possible to arrange a
plurality of wear
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inserts such that those regions of the crushing tool that are exposed to a
high degree of wear
comprise a wear-protection insert. For example, the plurality of wear-
protection inserts
comprises a plurality of particles, in particular hard metal or ceramic
particles or diamonds.
Preferably, each wear-protection insert consists of precisely one particle,
the wear-protection
inserts being in a disordered arrangement in the metal-matrix material.
According to a further embodiment, the wear-protection element is connected in
a material-
bonding manner, in particular welded, adhesively attached or soldered, to the
main body. A form-
fitting and/or force-fitting connection, such as a screw connection, is also
conceivable. The wear-
protection element is preferably fitted on the surface of the main body that
is facing in the
direction of rotation of the crushing rolls and is thus exposed to the
greatest degree of wear,
since this surface is first to come into contact with the material to be
crushed. The wear-
protection element is preferably fitted in a cutout in the main body. The
cutout is preferably
formed on the front side, in particular the side surface of the crushing tool
that is facing in the
direction of rotation of the crushing roll.
According to a further embodiment, the wear-protection insert has a porous
structure. In
particular, the wear-protection insert is in the form of a sponge or formed
such that infiltration
of the metal-matrix material into the wear-protection insert is made possible.
It is likewise
conceivable that the wear-protection insert has a smooth, planar structure and
the wear-
protection insert is bonded to the metal-matrix material by casting only on
the surface. The wear-
protection insert preferably has the form of a plate and is formed in one
piece.
The invention furthermore comprises a roll crusher having two crushing rolls
arranged next to
one another rotatably oppositely to one another and wherein a crushing gap is
formed between
the crushing rolls and wherein a crushing tool is attached to at least one of
the crushing rolls. The
crushing tool is preferably attached to a shoulder on the surface of the
crushing roll. In particular,
the main body of the crushing tool is mounted on the surface of the crushing
roll, preferably on
Date Recue/Date Received 2021-05-03
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the shoulder of the crushing roll, and is connected thereto in a material-
bonding and/or form-
fitting manner.
The invention also comprises a method for producing a crushing tool for
attachment to a crushing
roll of a roll crusher, comprising the steps of:
- positioning a wear-protection insert of a hard metal in a casting mold
for casting a main
body of the crushing tool,
- casting the main body so that the wear-protection insert is enclosed at
least partially by
the casting material of the main body and
- fitting a wear-protection element of a hard metal on the cast main body.
The wear-protection insert is preferably enclosed completely by the casting
material so that the
casting material infiltrates into the wear-protection insert. The casting
material comprises the
metal-matrix material described with reference to the crushing tool.
The advantages and explanations described with reference to the crushing tool
likewise apply,
correspondingly in method terms, to a method for producing a crushing tool.
According to a first embodiment, the wear-protection element is connected in a
material-
bonding manner, in particular welded or soldered, to the main body.
Description of the drawings
The invention is explained in more detail below on the basis of a number of
exemplary
embodiments with reference to the accompanying figures.
Fig. 1 shows a schematic illustration of a roll crusher having a plurality of
crushing tools in a
sectional view according to one exemplary embodiment.
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Fig. 2 shows a schematic illustration of a crushing tool in a sectional view
according to a further
exemplary embodiment.
.. Fig. 3 shows a schematic illustration of a crushing tool in a plan view
according to the exemplary
embodiment of figure. 2.
Figure 1 shows a roll crusher 10 having two crushing rolls 12, which are
arranged next to one
another and wherein a crushing gap, in which the material is comminuted, is
formed between
the crushing rolls 12. Such roll crushers 10 are used, for example, in the oil
sand industry in
surface mining. The crushing rolls 12 each comprise on their surface a
plurality of crushing tools
14, which are arranged circumferentially on the respective crushing roll 12
and, by way of
example, are uniformly spaced apart from one another. A plurality of shoulders
18 for fastening
in each case a crushing tool 14 are formed on the surface of the crushing
rolls 12. Each shoulder
18 comprises a substantially planar connecting surface on which the crushing
tool 14 is fastened.
The crushing tools 14 are each connected in a material-bonding manner, in
particular welded, to
the surface of the crushing roll 12. It is likewise conceivable that the
crushing tools 14 are
additionally or exclusively connected in a form-fitting manner to the crushing
roll 12. During
operation of the roll crusher 11, the crushing rolls 12 rotate oppositely to
one another in the
direction of the arrows. The material to be comminuted is loaded from above
into the crushing
gap 16 and comminuted in the crushing gap 16.
Figures 2 and 3 show a crushing tool 14 for attachment to a crushing roll 12
of a roll crusher 10
according to figure 1. The crushing tool 14 substantially comprises the form
of a chisel with, for
example, four or more side surfaces. Furthermore, the crushing tool comprises
a main body 20
and at least one wear-protection element 24. The wear-protection element 24 is
formed from a
hard metal, such as for example sintered carbide hard metals, such as tungsten
carbide, that have
a high hardness, wear resistance and heat resistance and corrosion resistance.
Hard metals
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comprise for example 90-94% tungsten carbide and 6-10% cobalt. The wear-
protection element
24 is arranged on the side surface of the crushing tool 14 that is facing in
the direction of rotation
of the crushing roll 12. The main body 20 has a cutout 26, in which the wear-
protection element
24 is fitted, on its side surface facing in the direction of rotation of the
crushing roll 12. The cutout
26 extends along the radially outer edge of the side surface of the crushing
tool 14. The wear-
protection element 24 is fitted completely within the cutout 26 of the main
body 20 and finishes
flush with the main body 20 on all of the side surfaces of the crushing tool
14. It is likewise
conceivable that the wear-protection element 24 protrudes beyond the main body
at the side
surfaces of the crushing tool 14. The wear-protection element 24 is for
example connected in a
material-bonding manner and/or connected in a form-fitting manner, in
particular welded,
sintered, adhesively attached, soldered or screwed to the main body 20.
The main body 20 is formed from a metal-matrix composite material and
comprises a wear-
protection insert 22. The wear-protection insert 22 is arranged on the side
surface of the crushing
.. tool 14 that is facing outward in the radial direction of the crushing roll
12 and said wear-
protection insert 22 finishes flush with the side surface of the main body 20.
A connecting surface
for connecting the main body 20 to the surface of the crushing rolls 12 is
formed on the bottom
surface, lying opposite the wear-protection insert 22, of the main body 20.
The main body 20 is
preferably connected in a material-bonding manner to the shoulder 18 of the
crushing roll 12.
The wear-protection insert 22 protrudes, by way of example, from the main body
20 on those
side surfaces of the crushing tool 14 that are facing in the axial direction
of the crushing roll 12.
The wear-protection insert 22 is formed, for example, from a hard metal, such
as tungsten
carbide, ceramic, titanium carbide, boron carbide or chromium carbide. In
particular, the wear-
protection insert 22, as shown in figure 2, comprises a honeycomb-shaped
structure. Further
porous structures of the wear-protection insert 22 are also conceivable, this
being formed in such
a way that infiltration of the metal-matrix material into the wear-protection
insert 22 is made
possible. The wear-protection insert 22 is formed in one piece and has for
example a thickness
of 5mm to 25mm, preferably 10mm to 15mm.
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The main body is formed from the metal-matrix material, the wear-protection
insert 22 at least
partially being enclosed by, in particular being cast into, a metal-matrix
material. The metal-
matrix material is for example high-temperature-resistant steel and/or a steel
with a Brinell
hardness of approximately 150 ¨ 400 HB. A high-temperature-resistant steel is
understood to
mean a heat-resistant steel with a high chromium-nickel content that has a
temperature
resistance of up to 650 C, in particular up to 1000 C. Such steels are for
example austenitic
chromium-nickel steels, such as for example GX25CrNiSi18-9, GX40CrNiSi25-12,
GX40NiCrSiNb35-26. High-temperature-resistant steels to 600 C are for example
steels in
accordance with DIN EN 10213. High-temperature-resistant steels to 1200 C are
for example
steels in accordance with DIN EN 10295.
In the exemplary embodiment of figures 2 and 3, the wear-protection insert 22
extends, by way
of example, over a part of the radially outwardly facing side surface of the
main body 20. It is
likewise conceivable that the wear-protection insert 22 extends over the
entire radially
outwardly facing side surface and/or further side surfaces of the main body
20. The wear-
protection insert forms at least one part of the surface of the main body 20.
In the production of the crushing tool 14, a the wear-protection insert 22 of
hard metal, such as
tungsten carbide, ceramic, titanium carbide, boron carbide or chromium
carbide, is positioned,
for example fastened, in a casting mold for casting a main body 20 of the
crushing tool 14. The
wear-protection insert 22 comprises for example the form of a plate and is
positioned on the
upper side, in particular the side surface of the crushing tool 14 that is
facing radially outward in
the direction of the crushing roll 12. The main body 20 is then cast from the
metal-matrix material
so that the wear-protection insert 22 is enclosed at least partially by the
casting material of the
main body 20, the casting material for example infiltrating into the porous
structure of the wear-
protection insert 22. In particular, the wear-protection insert 22 is enclosed
completely by the
casting material. The wear-protection element 22 is then fastened, in
particular soldered, to the
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main body 20. The main body 20 is preferably machined in advance on the
connecting surfaces
that are connected to the wear-protection element 24 so that the connecting
surfaces have a
low roughness of RZ= 1.6¨ 10 and/or RA=0.4-1, preferably RZ=6.
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List of reference signs
Roll crusher
12 crushing roll
14 Crushing tool
5 16 Crushing gap
18 Shoulder
Main body
22 Wear-protection insert
24 Wear-protection element
10 26 Cutout
Date Recue/Date Received 2021-05-03
