Abstrict A wear part (5) for detachable mounting on a supporting part in
an impact-type multi-action crusher is at least partly manufactured
by hot isostatic pressing. The wear part (5) has a body (19) for
mounting of the wear part (5) on the supporting part and a crushing
layer (20) which is attached to the body (19) and which is adapted
to be brought, during operation of the crusher, into repeated contact
with a raw material that is to be crushed. The body (19) is made
of a substance which is easy to machine to narrow tolerances, and
the crushing layer (20) is made of a material (27 28) of high abrasive
resistance. In a method of manufacturing the above wear part (5),
the following steps are carried out: introducing at least one powder
material (27 28) into a capsule, degassing and sealing the capsule,
subjecting the material (27 28) in the capsule to hot isostatic
pressing to form a crushing layer (20), and then after treatment
of the wear part (5).
Claims 24. A wear part configured for detachable mounting on a supporting
part in an impact-type multi-action crusher, the wear part being
at least partly manufactured by hot isostatic pressing, and including
a body for mounting of the wear part on a supporting part, and a
crushing layer attached to the body and adapted to be brought into
repeated contact with a raw material which is to be crushed; the
body comprising a substance easily machinable to narrow tolerances
than the crushing layer; and the crushing layer comprising a material
of higher abrasive resistance than the body.
25. A wear part as claimed in claim 24 wherein the crushing layer
comprises at least one powder material subjected to hot isostatic
pressing; and the substance of which the body is comprised has good
weldability properties.
26. A wear part as claimed in claim 24 wherein the crushing layer
comprises at least two powder materials subjected to hot isostatic
pressing without first being completely mixed with each other, said
powder materials, following the pressing and subsequent after-treatment,
having different respective abrasive resistances.
27. A wear part as claimed in claim 26 wherein the powder material
having a highest abrasive resistance is arranged at a highest-wear
region of the crushing layer.
28. A wear part as claimed in claim 24 wherein the crushing layer
and the body are joined together at a bonding zone.
29. A wear part as claimed in claim 24 wherein the body at least
partly comprises one of carbon steels or low alloy steels.
30. A wear part as claimed in claim 24 wherein a first portion
of the crushing layer comprises at least one first powder material;
a second portion of the crushing layer located downstream of said
first portion in a direction of flow of raw material to be crushed
comprising at least one second powder material; the second powder
material, following hot isostatic pressing and subsequent after-treatment
of the first and second powder materials, having higher abrasive
resistance than the first material.
31. A wear part as claimed in claim 30 wherein the first material
gradually merges into the second material in such a manner such
that abrasive resistance of the crushing layer increases gradually
in a direction of raw material flow, the abrasive resistance properties
arranged in corresponding relationship to the wear load in operation,
wherein the crushing layer is kept essentially intact during wearing
of the wear part.
32. A wear part as claimed in claim 24 wherein the crushing layer
comprises first and second powder materials, and at least one protrusion
formed of the second powder material; the second powder material,
following hot isostatic pressing and subsequent after-treatment
of the first and second powder materials, having higher abrasive
resistance than the first powder material.
33. A wear part as claimed in claim 26 wherein the crushing layer
has at least one protrusion formed by one of casting, sintering
or forging, the protrusion having higher abrasive resistance than
a material of the crushing layer disposed adjacent the protrusion.
34. A wear part as claimed in claim 33 wherein the protrusion
is configured as a rotationally symmetric step structure.
35. A wear part as claimed in claim 24 comprising a shell configured
for use in a gyratory crusher.
36. A wear part as claimed in claim 24 wherein the crushing layer
comprises at least two powder materials, which, after the materials
being subjected to hot isostatic pressing, have different respective
hardnesses; a softest of the powder materials being located in a
first layer closest to the body, and a hardest of the powder materials
being located in a second layer disposed outside of the first layer.
37. A method of manufacturing a wear part configured for detachable
mounting on a supporting part of an impact-type multi-action crusher,
comprising the steps of: A) introducing at least one abrasive-resistant
powder material into a capsule, B) degassing and sealing the capsule,
C) subjecting the degassed and sealed capsule to hot isostatic pressing
to form a crushing layer, and D) causing the crushing layer to be
attached to a body formed of a substance which is less abrasive
resistant and more easily machinable to narrow tolerances than the
crushing layer.
38. The method according to claim 37 wherein step A comprises
introducing, without being mixed together, first and second powder
materials, the second material having higher abrasive resistance
than the first material following step C; wherein step A further
comprises arranging the second powder material at a position of
greatest wearing of the crushing surface.
39. The method according to claim 37 wherein step D comprises
positioning the body to form a wall of the capsule during step A.
40. The method according to claim 37 wherein step A comprises
introducing first and second powder materials into first and second
parts, respectively, of the capsule, wherein the second material
is located downstream of the first material in a rock flow direction,
the second material exhibiting a higher abrasive resistance than
the first material following step C.
41. The method according to claim 40 wherein the first material
merges into the second material during step C, and the crushing
layer exhibits an abrasive resistance that progressively increases
from the first material to the second material.
42. The method according to claim 37 wherein step A includes arranging
a first powder material with a protrusion in the capsule, and arranging
a second powder material in the capsule adjacent the first material;
wherein following step C, the first material has a higher abrasive
resistance than the second material.
43. The method according to claim 37 wherein step A includes arranging
a first powder material with a protrusion in the capsule, and subsequent
to step C, affixing to the first material a second material of less
abrasive resistance than the first material.
44. A method of manufacturing a wear part configured for detachable
mounting on a supporting surface of an impact-type multi-action
crusher, comprising the steps of: A) forming a first crushing layer
portion in the form of a protrusion by one of sintering, casting,
or forging, B) inserting the protrusion into a capsule, C) introducing
into the capsule at least one powder material adjacent to the protrusion,
D) degassing and sealing the capsule, E) subjecting the degassed
and sealed capsule to hot isostatic pressing, whereafter the projection
exhibits higher abrasive resistance than the adjacent material.
45. The method according to claim 44 wherein the protrusion comprises
at least one step-shaped structure.
46. The method according to claim 37 wherein the body comprises
one of carbon steel or low alloy steel.
Description FIELD OF THE INVENTION
[0001] The present invention relates to a wear part for detachable
mounting on a supporting part in an impact-type multi-action crusher.
The invention also relates to a method of manufacturing such a wear
part.
BACKGROUND OF THE ART
[0002] Impact-type multi-action crushers, such as gyratory crushers
and jaw crushers, crush a raw material, such as a stone block, ore
block, concrete or brick block or the like, by a wear part being
repeatedly moved towards the raw material to crush it against a
counterbody. The wear part is supported by a supporting part which
transmits the necessary force from a motor, moment arm, shaft or
the like to the wear part. The crushing operation causes wear on
the wear part, which therefore now and then must be detached from
the supporting part and replaced.
[0003] For maximum life, the wear part is made of a material which
has maximum abrasive resistance. The wear part is usually cast from
what is referred to as Hadfield steels. These steels, which are
described, for instance, in U.S. Pat. No. 5069871 and EP 0 692
548 are austenitic manganese steels. A Hadfield steel has the property
that the surface of the steel is hardened (deformation hardening)
when the steel is acted upon by the raw material in the crusher,
which results in good abrasive resistance.
[0004] For the supporting part to give sufficient support to the
wear part, which is necessary to prevent the wear part from being
deformed or cracking or from deforming the supporting part, the
abutment surface of the wear part on the supporting surface of the
supporting part must be machined to narrow tolerances. The problem
is that the Hadfield steels also in such machining will be deformation-hardened,
which makes machining difficult and time consuming.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is to provide a wear
part for an impact-type multi-action crusher, said wear part having
good abrasive resistance and being easy to machine to narrow tolerances.
[0006] This object is achieved by a wear part for detachable mounting
on a supporting part in an impact-type multi-action crusher, said
wear part being characterized in that the wear part is at least
partly manufactured by hot isostatic pressing, and that the wear
part has a body for mounting of the wear part on the supporting
part and a crushing layer which is attached to the body and adapted
to be brought, during operation of the crusher, into repeated contact
with a raw material which is to be crushed, the body being made
of a substance which is easy to machine to narrow tolerances, and
the crushing layer being made of a material of high abrasive resistance.
By the wear part being divided into a body and a crushing layer,
each part can be given the properties that are the most important
ones for the part in question. Thus, the crushing layer is optimized
for good abrasive resistance and the body for good machinability.
By hot isostatic pressing, parts with complicated geometric structures
can be produced also of materials that could otherwise not be used.
[0007] According to a preferred embodiment, the crushing layer
is made of at least one powder material which has been subjected
to hot isostatic pressing, the substance of which the body is made
also having good weldability. There are a plurality of powder materials
which are suitable as crushing layer and which can be subjected
to hot isostatic pressing to form such a layer. A body which has
good weldability is advantageous since the wear part is often fixed
by welding.
[0008] Preferably, the crushing layer comprises at least two powder
materials, which, without first being completely mixed with each
other, have been subjected to hot isostatic pressing and which,
after said pressing and subsequent aftertreatment, have different
abrasive resistances, the crushing layer having portions of different
abrasive resistances. The use of at least two materials makes it
possible to vary the abrasive resistance of the crushing layer to
obtain specific properties, such as improved abrasive resistance
in some portions and lower abrasive resistance in other portions.
Since the two materials are not mixed with each other, or at least
not completely mixed with each other, there will, after the hot
isostatic pressing, be portions with different abrasive resistances.
If a highly abrasive resistant material, which is expensive, is
used, this can be located in the portions of the crushing layer
where the highest abrasive resistance is required, while a less
expensive material can be used in the remaining portions. The material
which after pressing and after-treatment has the highest abrasive
resistance is therefore conveniently arranged in the portions of
the crushing layer where the greatest wear is to be expected. In
this way, a more even wear is obtained over the surface of the wear
part, which ensures a longer life of the wear part.
[0009] Preferably, the crushing layer and the body are joined by
a bonding zone. The bonding zone, which may be formed, for instance,
when a powder material in contact with a compact material is subjected
to hot isostatic pressing, results in a safe connection between
the body and crushing layer over the entire contact surface and
renders it possible to do without a screw joint, weld joint and
the like.
[0010] The body is suitably at least partly made of a substance
selected from a group consisting of carbon steels and low alloy
steels. These substances are easy to machine, have good weldability
and are available at a low price. A body made of one of these substances
can, for instance, be cast, machined or forged to the desired basic
shape and then be finished to narrow tolerances. The body can also
be made of a powder of one of the above substances, which is then
subjected to hot isostatic pressing.
[0011] Preferably, a first portion of the crushing layer is made
of at least one first powder material and, located downstream of
said first portion in the direction of flow of the raw material,
a second portion of the crushing layer is made of at least one second
powder material, which, after subjecting the materials to hot isostatic
pressing and subsequent aftertreatment, has higher abrasive resistance
than the first material, whereby the second portion has higher abrasive
resistance than the first portion. Wear is usually greatest in the
portions located downstream in the direction of flow of the raw
material since a larger number of objects are to be crushed in these
portions. By locating the material having the highest abrasive resistance
in these portions, it is thus possible to extend the life of the
wear part. According to a still more preferred embodiment, the first
material gradually merges into the second material in such a manner
that the crushing layer obtains an abrasive resistance which increases
gradually in the direction of flow of the raw material and which
corresponds to the wear load in operation so that the profile of
the wearing layer is kept essentially intact during the life of
the wear part. This has the advantage that the crusher will have
essentially the same and, thus, predictable capacity during the
entire life of the wear part.
[0012] According to a preferred embodiment, the crushing layer
has at least one protrusion protruding from the crushing layer and
being made of at least one powder material which, after subjecting
the powder materials to hot isostatic pressing and subsequent aftertreatment,
has higher abrasive resistance than the powder material or materials
of which the parts of the crushing layer which surround the protrusion
are made. The protrusion will be exposed to particularly great wear
load. At the same time the protrusion is, in the cases when it is
being used, critical to the function of the wear part. By locating
the most wear resistant material in the protrusion, the life of
the wear part can thus be extended significantly.
[0013] According to another preferred embodiment, the crushing
layer has at least one protrusion protruding from the crushing layer
and being made by casting, sintering or forging and having higher
abrasive resistance than the powder material or materials of which
the parts of the crushing layer which surround the protrusion are
made. Thus the protrusion can be made of materials, such as sintered
tungsten carbide, which have excellent abrasion resistance but are
better suited for other manufacturing methods than hot isostatic
pressing. The protrusion can also be made of cast materials, such
as Hadfield steels. Then it is possible to deformation-harden the
protrusion in advance, before attaching it to the crushing layer.
The parts of the crushing layer which surround and fix the protrusion
are also in these cases made of at least one powder material which
has been subjected to hot isostatic pressing.
[0014] The wear part can be an inner shell or an outer shell for
use in a gyratory crusher. In gyratory crushers, the requirements
for narrow tolerances in the abutment of the wear part on the supporting
surface are strict, which makes the invention particularly suitable
for this type of crushers.
[0015] According to a particularly preferred embodiment, the protrusion
has the form of a rotationally symmetric step extending round the
crushing layer. The step improves the crushing of the raw material
and improves the grain shape of the crushed raw material. According
to a preferred embodiment, the crushing layer comprises at least
two powder materials, which, after subjecting the materials to hot
isostatic pressing, have different hardnesses, the softer of the
two materials being located in a first layer closest to the body
and the harder of the two materials being located in a second layer
on the outside of the first layer. As a result, a very hard, but
brittle, material can be used in the outer layer of the crushing
layer and be supported by a softer material placed under the outer
layer.
[0016] The object of the present invention is also to provide a
method of manufacturing a wear part for an impact-type multi-action
crusher, said wear part having great abrasive resistance and being
easy to machine to narrow tolerances.
[0017] According to the invention, this object is achieved by a
method of manufacturing a wear part for detachable mounting on a
supporting part in an impact-type multi-action crusher, said method
being characterized in that the wear part is manufactured as a body
for mounting of the wear part on the supporting part and a crushing
layer which is attached to the body and adapted to be brought, during
operation of the crusher, into repeated contact with a raw material
which is to be crushed, the body being made of a substance which
is easy to machine to narrow tolerances, and the crushing layer
being made of a material of high abrasive resistance by at least
one powder material being introduced into a capsule, the capsule
being degassed and sealed and the material in the capsule being
subjected to hot isostatic pressing, after which the wear part is
subjected to aftertreatment. By the wear part being divided into
a body and a crushing layer, each part can be given the properties
that are the most important ones for the part in question. Thus,
the crushing layer is optimized for good abrasive resistance and
the body for good machinability. By hot isostatic pressing, parts
with complicated geometric structures can be manufactured. The abrasive
resistant materials that are normally of interest for use in the
crushing layer are often very difficult to machine to complicated
geometric structures.
[0018] According to a preferred method, at least two powder materials,
which after hot isostatic pressing and subsequent aftertreatment
have different abrasive resistances, are introduced into the capsule
without being completely mixed with each other, in such a manner
that the material of the highest abrasive resistance is arranged
in the parts of the capsule which correspond to the portions of
the crushing layer where the greatest wear is to be expected. If
a highly abrasive resistant material, which is expensive, is used,
this can be located in the portions of the crushing layer where
the highest abrasive resistance is required, while a less expensive
material can be used in the remaining portions. A further advantage
is that the wear on the wear part will be more even than if the
same material is used in the entire crushing layer. Unevenly worn
crushing layers constitute a common source of functional troubles
and shortened life of wear parts.
[0019] Preferably, the body of the wear part is used as a wall
in the capsule to be joined with the crushing layer. This saves
a wall in the capsule that is used. Moreover, the advantage is achieved
that the body and crushing layer are joined by a bonding zone which
will be very strong since it covers the entire surface where the
body and the crushing layer are in contact with each other. Nor
is a weld joint, bolt joint or the like required to hold the body
and the crushing layer together.
[0020] According to a preferred method, at least one first powder
material is introduced into a first part of the capsule which corresponds
to a first portion of the crushing layer and at least one second
powder material is introduced into a second part of the capsule
which corresponds to a second portion of the crushing layer, which
second portion is located downstream of the first portion in the
direction of flow of the raw material, the second material in the
second portion, after subjecting the materials to hot isostatic
pressing and subsequent after-treatment, having higher abrasive
resistance than the first material. Uneven wear is a great problem
in many crushers, especially in gyratory crushers. Owing to the
wear which usually is greatest in the portions positioned downstream
in the direction of flow of the raw material, the crusher capacity
of crushing a raw material is reduced and, after a certain period
of operation of the wear part, the crusher cannot crush the raw
material to the same small sizes, and therefore the wear part must
be replaced. By a more abrasive resistant material being used in
the portion of the crushing layer which is close to the end point
of the flow of raw material, the life of the wear part can be increased
significantly. According to a particularly preferred-method, the
first material and the second material are introduced into the capsule
in such a manner that the first material gradually merges into the
second material, the crushing layer obtaining an abrasive resistance
that increases gradually in the direction of flow of the raw material
and corresponds to the wear load in operation, so that the profile
of the crushing layer is kept essentially intact during the life
of the wear part. As mentioned above, this has the advantage that
the performance of the crusher will be constant and thus predictable
for the entire life of the crusher.
[0021] According to a preferred method, the crushing layer is manufactured
with at least one protrusion protruding from the crushing layer,
at least one powder material being introduced into the capsule in
the parts of the capsule which correspond to the protrusion and
at least one other powder material being introduced into the parts
of the capsule which correspond to the parts of the crushing layer
which surround the protrusion, the material of the protrusion, after
subjecting the materials to hot isostatic pressing and subsequent
after-treatment, having higher abrasive resistance than the material
of the parts of the crushing layer which surround the protrusion.
As mentioned above, the life of the protrusion will thus be increased,
which ensures the above advantages of longer life for the entire
wear part.
[0022] According to another preferred method, the protrusion is
manufactured in a first step by hot isostatic pressing, after which
the parts of the crushing layer which surround the protrusion are
manufactured in a second step. This method results in improved control
of the conditions under which the protrusion is manufactured. The
extent and connection surfaces of the protrusion to the surrounding
material can also be formed with greater accuracy. It is also possible
to make the protrusion of a material that requires hot isostatic
pressing in conditions, as regards, for instance, temperature and
pressure, that are unsuitable for the surrounding material.
[0023] According to another preferred method, the crushing layer
has at least one protrusion protruding from the crushing layer and
being made in a first step by sintering, casting or forging, the
protrusion in a second step being arranged in the capsule and at
least one powder material being introduced into the parts of the
capsule which correspond to the parts of the crushing layer which
surround the protrusion, the protrusion, after subjecting the materials
to hot isostatic pressing and subsequent aftertreatment, having
higher abrasive resistance than the parts of the crushing layer
which surround the protrusion. As mentioned above, this makes it
possible to select for the protrusion also such abrasive resistant
materials as are not best suited for hot isostatic pressing.
[0024] According to a preferred method, the protrusion is formed
as a step. The step ensures, as mentioned above, advantages in crushing.
Preferably, the body is at least partly made of a substance selected
from a group consisting of carbon steels and low alloy steels. Owing
to these substances, the abutment surface of the body is easy to
machine to narrow tolerances, as mentioned above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The invention will now be described in more detail by way
of embodiments and with reference to the accompanying drawings.
[0026] FIG. 1 shows a gyratory crusher.
[0027] FIG. 2 is a cross-sectional view of a portion of the crusher
in FIG. 1 and shows an inner shell and an outer shell according
to prior art.
[0028] FIG. 3 is a cross-sectional view and shows a wear part according
to the invention in a first embodiment, formed as an inner shell.
[0029] FIG. 4 is a cross-sectional view and shows a wear part according
to the invention in a second embodiment, formed as an inner shell.
[0030] FIG. 5 is a cross-sectional view and shows a wear part of
the invention in a third embodiment, formed as an inner shell.
[0031] FIG. 6 is a cross-sectional view and shows a wear part according
to the invention in a fourth embodiment, formed as an inner shell.
[0032] FIG. 7 is a cross-sectional view and shows wear parts according
to the invention formed as an inner shell and an outer shell, intended
for a crusher that is normally used in coarse crushing.
[0033] FIG. 8 is a cross-sectional view and shows a capsule for
manufacturing wear parts according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] FIG. 1 shows a gyratory crusher 1. The crusher 1 has a crusher
shaft 2 which at its lower end 3 is eccentrically mounted. In its
upper portion, the crusher shaft 2 has a crushing head 4. The crushing
head 4 has an inner shell 5 which in the simultaneous rotary and
oscillating motions of the crusher shaft 2 crushes raw materials,
that are supplied to the upper portion 6 of the crusher 1 against
an outer shell 7. A crushing chamber 8 is formed between the inner
shell 5 and the outer shell 7. As a rule, the function of the crusher
1 is determined by the gap S which is the smallest distance between
the inner shell 5 and the outer shell 7 of the crusher 1. The crusher
shaft 2 can by means of an adjusting device 9 be moved in the vertical
direction. Thus, the gap S of the crushing chamber 8 can be adjusted,
thus allowing setting in a desirable manner the relation between
the amount of material that is crushed by the crusher 1 and the
size of the crushed material.
[0035] FIG. 2 shows an inner shell 5' and an outer shell 7' of
prior-art type. As illustrated, the inner shell 5' is supported
by a supporting part in the form of a support cone 10 included in
the crushing head 4 and the outer shell 7' on a supporting part
11 in the form of an intermediate ring. The inner shell 5' is held
on the support cone 10 by a nut 12 which by means of a ring 13
that is welded to the inner shell 5' and the nut 12 holds the inner
shell 5' on the support cone 10. The outer shell 7' is attached
to a base 11' by means of a bolt joint. When operating the crusher,
raw materials are supplied to the inlet 14 of the crusher and conveyed
in the direction of flow P of the raw material, (in FIG. 2 indicated
by an arrow) downwards through the crusher 1. According to prior-art
technique, both the inner shell 5' and the outer shell 7' are made
of cast manganese steel. The abutment surface 15 of the inner shell
5' on the support cone 10 is machined to narrow tolerances in complicated
turning operations. In the same way, the abutment surfaces 16 of
the outer shell 7' on the supporting part 11 are machined to narrow
tolerances. To ensure a correct gap 5 usually also the crushing
surface 17 of the inner shell 5' and the crushing surface 18 of
the outer shell 7' are machined by means of complicated turning
operations.
[0036] The dashed lines in FIG. 2 indicate the extent of the inner
shell 5' and the outer shell 7' after a period of wear. The wear
makes it necessary to move the crusher shaft 2 upwards to maintain
a constant gap S. When the crusher shaft 2 has reached its uppermost
position, the inner shell 5' must be replaced without its upper
portion being worn out.
[0037] FIG. 3 shows a first embodiment of a wear part according
to the invention in the form of an inner shell 5a for the gyratory
crusher 1. The inner shell 5a has a body 19 made of a carbon steel
which is easy to machine. The abutment surface 15 of the body 19
for abutment on the support cone 10 has been turned to narrow tolerances
for a good fit to the support cone 10. The inner shell 5a has a
crushing layer 20. The crushing layer 20 is made of two different
powder materials 21 and 22 for instance Elmax and Vanadis 10 made
by Uddeholm AB, SE, which have been subjected to hot isostatic pressing.
[0038] In hot isostatic pressing the body 19 and the crushing layer
20 will be partly joined by diffusion and form a bonding zone 20'
which extends along the entire contact surface between the body
19 and the crushing layer 20.
[0039] In the embodiment shown in FIG. 3 two powder materials
21 22 are used in the crushing layer 20 as mentioned above. The
first material 21 is placed at the end, located at the inlet 14
of the inner shell 5a in a first portion 21' of the crushing layer
20 and the second material 22 is placed in a second portion 22'
of the crushing layer 20 which is positioned downstream of the
first portion 21' in the direction of flow P of the raw material.
The materials 21 22 are selected so that the second material 22
has higher abrasive resistance than the first material 21 after
both materials being subjected to hot isostatic pressing. In a portion
23 of the crushing layer 20 the first material 21 gradually merges
into the second material 22 in the direction of flow P of the raw
material. In the embodiment in FIG. 3 uneven wear that arises in
prior-art technique (FIG. 2) is thus avoided owing to the fact that
the abrasive resistance of the crushing layer 20 along the direction
of flow P of the raw material has been adjusted to the actual wear.
As is evident from FIG. 3 the crushing layer 20 has on its outside
a special curvature. This curvature, which is described, for instance,
in GB2123314 is intended to maintain a constant inlet 14 as the
crusher shaft 2 moves upwards subsequent to wear. Thus the inner
shell 5a will have an almost constant profile during its entire
life, which ensures that the correct gap S can be set without the
capacity of the crusher 1 decreasing.
[0040] FIG. 4 shows a second embodiment of a wear part according
to the invention in the form of an inner shell 5b. Like in the embodiment
shown in FIG. 3 this inner shell 5b has a body 19 having an abutment
surface 15 and being made in the manner as described above, and
a crushing layer 20. The crushing layer 20 has, in its portion positioned
at the inlet 14 a number of shoulders or steps 24 25. The steps
24 25 which can be analogized to rotationally symmetric stairs
extending round the crushing layer 20 and which are positioned upstream
of a portion 26 improve the possibility of crushing the raw material
to smaller pieces and also improve the grain shape of the crushed
raw material. The steps 24 25 which in operation are exposed to
heavy wear, are made of a powder material 27 having a higher abrasive
resistance than the material 28 of which the remainder of the crushing
layer 20 is made, after the materials being exposed to hot isostatic
pressing. The steps 24 25 will thus last longer than in the case
if they had also been made of the material 28 thereby increasing
the operating time in which the shell S exhibits the desired function.
[0041] The steps 24 25 can be made at the same time as the remainder
of the crushing layer 20 in the above isostatic pressing. However,
it is also possible to make the steps 24 25 in a first step, i.e.
a first processing step, by hot isostatic pressing and then in a
second step, i.e. a second processing step, make the remainder of
the crushing layer. It is also possible to make the steps 24 25
by casting, sintering, for instance of tungsten carbide, or forging,
after which the parts of the crushing layer 20 which surround the
steps 24 25 are made of a powder material that is subjected to
hot isostatic pressing.
[0042] FIG. 5 illustrates a third embodiment of a wear part according
to the invention in the form of an inner shell 5c. This embodiment
differs from the embodiment shown in FIG. 4 essentially only by
its inner shell 5 having larger shoulders or steps 29. The steps
29 which may be analogized to rotationally symmetric stairs extending
round the crushing layer 20 give the advantage that a smaller crushing
surface 30 is obtained, thus allowing the raw material to be crushed
with greater force against this surface 30. The steps 29 thus prevent
large objects from reaching the crushing surface 30. A certain degree
of wear by the raw material also takes place in the area of the
steps 29.
[0043] FIG. 6 illustrates a fourth embodiment of a wear part according
to the invention in the form of an inner shell 5d. In this embodiment,
the crushing layer 20 has at least two different layers 31 32
viz, a lower layer 31 closest to the body 19 and an upper layer
32 which is harder than the lower layer 31. The hard, but brittle,
layer 32 is supported by the softer lower layer 31. The outer surface
of the harder layer 32 thus constitutes the crushing surface 17
of the crushing layer 20.
[0044] Both the softer layer 31 and the harder layer 32 are made
by hot isostatic pressing of powder materials. The layers 31 32
can be made simultaneously. Alternatively, the softer layer 31 can
be made in a first step and the harder layer 32 can be made in a
subsequent second step. It is also possible to make the lower layer
31 of a cast manganese steel, for instance a Hadfield steel. The
manganese steel has relatively high abrasive resistance, which is
advantageous if the upper layer 32 should be damaged at any point.
[0045] FIG. 7 illustrates a primary gyratory crusher 33. The primary
gyratory crusher 33 is a type of gyratory crusher which is used
for crushing large objects. Thus, the inlet 14 is very wide. The
outer shell 34 of the primary gyratory crusher 33 is divided into
a number of segments 35 36 which are attached to a supporting part
11. The segment 35 has a crushing layer 37 which is made of a powder
material that has been subjected to hot isostatic pressing and that
is attached to a body 38. The body 38 is made of a carbon steel.
The segment 36 positioned downstream of the segment 35 in the direction
of flow P of the raw material has a crushing layer 39 which is made
by hot isostatic pressing and is attached to a body 38. The crushing
layer 39 has higher abrasive resistance than the crushing layer
37. Since the wear is smaller in the portions of the crusher 33
which are positioned close to the inlet 14 the segments 35 36
will be worn at approximately the same rate in operation of the
crusher, which ensures an even profile of the outer shell 34. The
crusher 33 also has an inner shell 5e which is replaceably attached
to a support cone 10. This shell 5e can be formed in the manner
as described above with reference to FIGS. 3-6.
[0046] The hot isostatic pressing, which is described, for instance,
in U.S. Pat. No. 3695597 is carried out by means of a capsule
40 (see FIG. 8). In the capsule 40 the body 19 is used as a wall.
Otherwise, the capsule 40 has the geometric shape that is desired
for the completed inner shell 5e. Steps 29 if any, that have been
made in advance by, for instance, hot isostatic pressing, sintering,
casting or forging, are placed in the capsule 40 in the positions
as required in the completed crushing layer 20. In the capsule 40
at least one powder material is introduced in at least one opening
41. After vibrating, degassing and sealing, the capsule 40 is exposed
to heat and pressure, whereby the powder material is deformed and
joined by diffusion. The capsule 40 can then be removed. In some
cases, the capsule 40 is joined with the crushing layer 20 and becomes
part thereof. After subsequent treatment, comprising, for instance,
tempering, the inner shell 5e is ready for use. Owing to the conditions
in pressing, the crushing surface 17 of the shell 5e need not be
machined at all but satisfies the tolerances that are required for
the selected gap S. The abutment surface 15 of the body 19 can be
machined either before pressing or after the same.
[0047] It will appreciated that a number of modifications of the
embodiments described above are feasible within the scope of the
invention.
[0048] Thus, for instance an inner shell 5 or an outer shell 7
can be formed, in which the steps 24 25 29 shown in FIGS. 4 and
5 are combined with a crushing layer 20 containing the combinations
of powder materials 21 22 31 32 shown in FIG. 3 and/or FIG. 6
said materials being subjected to hot isostatic pressing with a
view to forming different portions and layers. Of course, a plurality
of, for instance 2-7 different powder materials can be used for
the different layers, portions and steps of the wear part. The materials
can either merge more or less gradually into each other or be separated
by distinct limits. Such limits may consist of, for instance, thin
metal foils that are inserted into the capsule 40.
[0049] Wear parts according to the invention can be manufactured,
inter alia, for the above-described gyratory crushers and jaw crushers.
Jaw crushers in general are described, for instance, in WO 00/25926
and U.S. Pat. No. 4927089. A jaw crusher has two jaws each having
the shape of a relatively flat surface, one jaw crushing the raw
material against the other jaw by a reciprocating motion. A raw
material is introduced into the upper portion of the jaw crusher
and passed downwards through the crusher in an essentially vertically
downward direction of flow of the raw material. When passing downwards
through the jaw crusher, the raw material will be crushed a plurality
of times to increasingly smaller dimensions. The jaws comprise supporting
parts to which wear parts according to the invention can be attached
by welding or bolting. A great deal of the wear will arise in the
lower parts of the jaw crusher where a very large number of objects
of the raw material are to be crushed. In many cases it will thus
be convenient to use wear parts in the jaw crusher that have been
manufactured, for instance, according to the principles as described
in connection with FIGS. 3 and 7. Gyratory crushers and jaw crushers
are impact-type multi-action crushers, i.e. crushers in which a
piece of the raw material is crushed several times while passing
through the crusher and by impact between two surfaces that are
accelerated towards each other and strike against the raw material.
[0050] The body 19 is made of a substance which is easy to machine
but which at the same time has the mechanical strength that is necessary
to support the crushing layer 20. The body can be cast, forged or
cold- and/or hot-worked to the correct shape. Since the body is
not in contact with the raw material, it can be made of a substance
of low abrasive resistance. Low abrasive resistance often makes
the substance easy to machine. The substances that are most convenient
for the body are carbon steels and low alloy steels. The abutment
surface 15 16 of the body on the supporting part 10 11 can be
machined to narrow tolerances, for instance by turning, milling
or grinding.
[0051] Substances that are easy to weld are particularly advantageous
as substance for the body. The wear part can be attached to the
supporting part by means of a weld that should resist high loads.
Particularly suitable substances are therefore carbon steels and
lower alloy steels.
[0052] The segments 35 36 illustrated in FIG. 7 can also each
be formed according to the principles described above in connection
with FIGS. 3-6. Thus, wear parts for gyratory crushers as well as
jaw crushers can be made in several segments. Each segment may either
comprise a single powder material or a plurality of materials. The
segments may also comprise steps.
[0053] When a plurality of steps 24 25 29 are used, they can
be made of the same material, but also of different materials and
by different methods. For instance, it is possible to make the steps
24 of a powder material that is subjected to hot isostatic pressing,
and the step 25 of a still harder material which has been made in
advance by sintering.
[0054] It is also possible to manufacture a body and a crushing
layer each separately, for instance by casting, machining, forging
or hot isostatic pressing, and then attach the body and the crushing
layer to each other by hot isostatic pressing, also referred to
as diffusion bonding. |