|Title of Invention||
"CAST WEAR PARTS WITH ENHANCED WEAR RESISTANCE AND ITS METHOD FOR MANUFACTURE"
|Abstract||The invention concerns a cast wear part with its structure reinforced by at least a type metal carbide, and/or metal nitride, and/or boride, and/or metal oxides, and/or intermetallic compounds, referred to below as constituents. The invention is characterized in that the raw materials used as reagents for said constituents have been introduced in a mould (1) before casting in the form of compacted powder inserts or preforms (3) or the form of slurries (4), and the reaction of said powders has been activated in situ by casting a metal, forming a porous conglomerate in situ, and said metal has infiltrated the porous conglomerate, thus forming a reinforced structure leading to inclusion of said constituents in the structure of the metal used for casting, thereby creating a reinforcing structure on the wear part (2).|
|Full Text||CAST PARTS WITH ENHANCED WEAR RESISTANCE
Field of the invention
 The present invention relates to the
production of cast parts with enhanced wear resistance by
an improvement in the resistance to abrasion whilst
retaining acceptable resistance to impact in the reinforced
Technological background at the basis of the invention
 Installations for extracting and breaking up
minerals, and in particular crushing and grinding material,
are subjected to numerous constraints of performance and
 As an example, one might cite in the area of
the treatment of aggregates, of cement and of minerals,
wear parts such as ejectors and anvils of grinding machines
with vertical shafts, hammers and breakers of grinding
machines with horizontal shafts, cones for crushers, tables
and rollers for vertical crushers, armoured plating and
elevators for ball mills or rod mills. With regard to
mining extraction installations, one might mention, among
others, pumps for bituminous sands or drilling machines,
pumps for mines and dredging teeth.
 The suppliers of wear parts for these
machines are faced with increased demands for wear parts
which meet the constraints of resistance to impact and
resistance to abrasion at the same time.
 Traditional materials generally meet one or
the other of these types of requirement but are very rarely
resistant to both impact and abrasion. Indeed, ductile
materials offer enhanced resistance to impact but have very
little resistance to abrasion. On the other hand, hard
abrasion-resistant materials have very little resistance to
 Historically, the first reflections on this
problem led to an exclusively metallurgical approach which
consisted in suggesting steels with manganese that are very
resistant to impacts and nevertheless achieve intermediate
hardness levels of the order of 650 to 700 Hv (Vickers
 Other alternatives such as castings with
chrome have also been suggested. These allow to achieve
hardness levels of the order of 700 to 850 Hv after
suitable thermal treatment. These values are achieved for
alloys containing a percentage of carbide up to 35%.
 Currently, bimetallic castings have also been
used, but these nevertheless have the disadvantage of being
limited to parts of simple shape, which drastically reduces
their opportunities for industrial application.
 Wear parts are generally considered as
consumables, which means that apart from purely technical
constraints, there is also a financial constraint which
limits the opportunities for solutions that have an average
cost of US$4/Kg. It is generally estimated that this price
level, which is twice as high as that of traditional wear
parts, is the threshold of financial acceptability for
Description of the solutions according to state of the art
 Achieving a wear part that is resistant to
abrasion and impact has already been the subject of studies
of various types.
 In this context, one has naturally turned to
composite parts based on ceramics and, in this area, the
Applicant already discloses in document WO 99/47264 an
alloy based on iron and ceramics which is very resistant to
wear and impact.
 In document WO 98/15373, the Applicant
proposes to insert into a mould, before casting, a wafer of
porous ceramic which is infiltrated by the metal during
casting. The opportunities for application of this
invention are nevertheless limited to parts of strong
cross-section and to alloys with high fluidity in casting.
Moreover, the positioning of these ceramic wafers is rather
conditioned by the requirements of infiltration by the cast
metal than by the actual requirements of the part's use.
 Without aiming at the same objectives,
Merzhanov discloses in document WO/9007013 a fireproof
porous material obtained by cold compression of the raw
material, of an exothermic mixture of powders under vacuum,
followed by starting the combustion of the mixture. Here,
we are dealing with a chain reaction. With this method, he
obtains extremely hard materials but without any resistance
to impact. This is essentially due to the high porosity of
 Moreover, in document WO/9011154, the same
inventor proposes a similar method where, in this case, the
mixture of powders, after having reacted, is subjected to
pressures as high as 1000 bars. This invention results in
the production of layers that are extremely resistant to
abrasion but with insufficient resistance to impact. The
aim here is above all to produce surfaces for abrasive
tools that are greatly solicited in this sense.
 In general, the use of very pure powders such
as titanium, boron, tungsten, aluminium, nickel,
molybdenum, silicon, carbon, etc. powders results in
extremely porous pieces after the reaction with porosity
rates close to 50%. These therefore require compression
after the reaction involving compaction and thus an
increase in density, which is indispensable for industrial
 The implementation complexity of such a
method, the control of the reactions and the cost of the
raw materials nevertheless considerably limit the
introduction of these technologies into industry.
 German patent application 1979777 - Lehmann
discloses a production method for cast parts that are
highly wear resistant. In this method, carbide powders are
combined with combustible binding agents and/or metallic
powders with a low melting point. During casting, the
binding agent gives up its place to the casting metal which
then surrounds the carbide particles. In this method, there
is no chemical chain reaction and all the particles highly
wear resistant are present in the mould from the start.
 Numerous documents disclose such a method for
surrounding hard particles, and in particular US-P-
5,052,464 and US-P-6,033,791 - Smith, which are based on
the presence of hard particles before casting which is to
infiltrate the pores between the ceramic particles.
 The invention avoids the pitfalls of the
state of the art by producing wear parts of original
structure and produced by an original and simple method,
which is thus inexpensive.
Aims of the invention
 The present invention aims to provide wear
parts resistant both to abrasion and to impact at a
financially acceptable price as well as a method for their
production. It aims in particular to solve the problems
associated with the solutions according to the state of the
Summary of the invention
The present invention relates to a cast wear part, with a structure reinforced by at least one component selected from the group consisting of metallic carbide, metallic nitrides, metallic oxides, metallic borides, as well as intermetallic compounds, characterised in that the raw materials acting as reagents for said components have been put into a mould, before casting, in the form of inserts or pre-shaped compacted powders or in the form of slurries, in that the reaction of said powders is triggered in situ by the casting of a metal forming a porous conglomerate in situ, and in that said metal infiltrates the porous conglomerate, thus forming a reinforced structure, so as to achieve the inclusion of said conglomerate in the structure of the metal used for the casting of the part, and thereby to create a reinforcing structure in the wear part.
One of the key aspects of the present invention shows that the porous conglomerate, created in situ and later infiltrated by the molten metal has a Vickers hardness of over 1000 Hv2o, the wear part thus obtained providing an impact resistance higher than that of the considered pure ceramics and at least equal to
According to one of the features of the invention, the reaction in situ between the raw materials, i.e. the reagents for said components, is a chain reaction and it is triggered by the heat of the molten metal by forming a very porous conglomerate capable of being simultaneously infiltrated by the molten metal without significant alteration of the reinforcing structure. According to one particularly advantageous embodiment of the invention, the reaction between the raw
materials takes place at atmospheric pressure and without any particular protective gaseous atmosphere and without the need for compression after the reaction. The raw materials intended to produce the component belong to the group of ferrous alloys, preferably of FerroTi, FerroCr, FerroNb, FerroW, FerroMo, FerroB, FerroSi, FerroZr or FerroV, or belong to the group of oxides, preferably TiO2, FeO, Fe2O3, SiO2, ZrO2/ CrO3, Cr2O3, B2O3, MoO3, V2O5, CuO, MgO and NiO or even to the group of metals or their alloys, preferably iron, nickel, titanium or aluminium and also carbon, boron or nitride compounds.
Brief description of the figures
Figure 1 shows a slurry 1 spread over the areas where the cast part 2 in the mould 1 is to be reinforced.
Figure 2 shows the invention in the form of reinforcing inserts 3 in the part to be cast 2 in the mould 1. Figures 3, 4 and 5 show hardness impressions for a casting with chrome (Fig. 3), a pure ceramic (Fig. 4) and an alloy (Fig. 5) reinforced with ceramic as in the present invention.
Figure 6 shows particles of TiC in an iron alloy, resulting from a reaction in situ of FeTi with carbon to produce TiC in an iron-based matrix. The size of the TiC particles is of the order of a few microns.
Detailed description of the invention
- The present invention proposes cast parts whose wear surfaces are reinforced by putting in the mould, before casting, materials comprising powders that are able to react in situ and under the sole action of the heat of the casting.
 To this end, reagents in compacted powders
are used and placed in the mould in the form of wafers or
inserts 3 in the required shape, or alternatively in the
form of a coating 4 covering the mould 1 where the part 2
is to be reinforced.
 The materials that can react in situ produce
hard compounds of carbides, borides, oxides, nitrides or
intermetallic compounds. These, once formed, combine with
any possible carbides already present in the casting alloy
so as to further increase the proportion of hard particles
with a hardness of Hv>1300 that contribute to the wear
resistance. The latter are "infiltrated" at about 1500°C by
the molten metal and form an addition of particles
resistant to abrasion incorporated into the structure of
the metal used for the casting (Fig. 6).
 Moreover, in contrast to the methods of the
state of the art, it is not necessary to use pure metallic
powders to obtain this reaction in situ. The method
proposed advantageously allows to use inexpensive ferrous
alloys or oxides in order to obtain extremely hard
particles embedded in the matrix formed by the casting
metal where reinforcement of the wear resistance is
 Not only does the invention require no
subsequent compaction, that is compression, of the areas
with reinforced structure, but it benefits from the
porosity thus created in said areas to allow the
infiltration of the molten metal into the gaps at high
temperature (Fig. 6).
 This requires no particular protective
atmosphere and takes place at atmospheric pressure with the
heat provided by casting, which clearly has a particularly
positive consequence on the cost of the method. A structure
with very favourable features in terms of the simultaneous
resistance to impact and abrasion is thus obtained.
 The hardness values achieved by the particles
thus embedded into the reinforced surfaces are in the range
of 1300 to 3000 Hv. Following the infiltration by the
casting metal, the compound obtained has a hardness higher
than 1000 Hv2o whilst retaining an impact resistance higher
than lOMPavw . The impact resistance is measured by
indentation, which means that a dent is made by means of a
diamond piercing tool of pyramidal shape at a calibrated
As a result of the load, the material is bent and may
develop cracks at the corners of the dent. The length
measurement of the cracks allows the impact resistance to
be calculated (Figures 1, 2 and 3) .
 The raw materials intended to produce the
component belong to the group of ferrous alloys, preferably
of FerroTi, FerroCr, FerroNb, FerroW, FerroJMo, FerroB,
FerroSi, FerroZr or FerroV, or they belong to the group of
oxides, preferably Ti02, FeO, Fe203, Si02, Zr02, Cr03 Cr203,
B203, Mo03, V205, CuO, MgO and NiO or to the group of metals
or their alloys, preferably iron, nickel, titanium or
aluminium and also carbon, boron or nitride compounds.
 By way of an example, the reactions used in
the present invention are generally of the type:
FeTi + C -> TiC + Fe
Ti02 + Al + C -> TiC + A1203
Fe203 + Al -> A1203 + Fe
Ti + C -> TiC
Al 4- C + B203 -> B4C + A1203
Mo03 + Al + Si -> MoSi2 + A1203
These reactions may also be combined.
 The reaction speed may also be controlled by
the addition of different metals, alloys or particles which
do not take part in the reaction. These additions may
moreover advantageously be used in order to modifythe
impact resistance or other properties of the composite
created in situ according to requirements. This is shown by
the following illustrative reactions:
Fe203 + 2A1 + xA!203 -> (1+x) A1203 + 2Fe
Ti + C + Ni -> TiC + Ni
Description of a preferred embodiment of the invention
 The first preferred embodiment of the
invention consists in compacting the chosen reactive
powders by simple cold pressure. This takes place in a
compression mould bearing the desired shape of the insert
or the preformed shape 3, possibly in the presence of a
binding" agent, for the reinforcement of the cast part 2.
This insert or preformed shape will then be placed into the
casting mould 1 in the desired place.
 For the powders, a particle size distribution
is chosen with a D50 between 1 and 1000 microns, preferably
lower than lOOu. Practical experience has shown that this
particle size was the ideal compromise between the handling
of the raw materials, the ability of the porous product to
be infiltrated and the control of the reaction.
 During casting, the hot metal triggers the
reaction of the preformed shape or of the insert which
transforms into a conglomerate with a porous structure of
hard particles. This conglomerate, still at high
temperature, is itself infiltrated and embedded in the
casting metal making up the part. This step is carried out
between 1400 and 1700°C depending on the casting
temperature of the alloy chosen to make the part.
A second preferred embodiment is the use of a slurry (paste) 4 containing the various reagents so as to coat certain areas of the mould 1 or of the cores. The application of one or more layers is possible depending on the thickness desired. These different layers are then allowed to dry before the metal is poured into the mould 1. This molten metal also serves to trigger the reaction in order to create a porous layer which is infiltrated immediately after its reaction to form a structure that is particularly resistant both to impact and wear.
1. Wear part produced in a foundry
comprising a reinforced structure, said reinforced
structure comprising at least one component selected from
the group consisting of metallic carbides, metallic
nitrides, metallic borides, metallic oxides and
intermetallic compounds, characterised in that:
- said components are formed by a reaction in situ from raw materials acting as reagents for said components, said reagents being first put into a mould (1) before casting, in the form of inserts or preformed shapes of compacted powders (3) or in the form of slurries (4),
- the reaction in situ of said powders is triggered by the casting of a metal,
- said reaction in situ forms a porous conglomerate,
- said casting metal infiltrates said porous conglomerate, resulting in an inclusion of said conglomerate in the structure of the metal used for the casting, thus creating a wear part (2) comprising a reinforced structure.
2. Wear part as claimed in Claim 1,
wherein said porous conglomerate is created in situ and is
infiltrated by the cast metal, in that said conglomerate
has a Vickers hardness between 1300 and 3000 Hv, and in
that said reinforced structure on the wear part has an
impact resistance of over l0MP m .
3. Method for the production of wear part
as claimed in claim 1 or 2, wherein wear part is with a
structure reinforced by at least one component selected
from the group consisting of metallic carbides, metallic
nitrides, metallic borides, metallic oxides, and
intermetallic compounds, and characterised in that:
- said components are formed by a reaction in situ from raw materials acting as reagents for said components, said reagents being first put into a mould (1), before casting, in the form of inserts or preformed shapes of compacted powders (3) or in the form of slurries (4),
- the reaction in situ of said powders is triggered by the casting of a metal,
- said reaction in situ forms a porous conglomerate,
- said casting metal infiltrates said porous conglomerate resulting in an inclusion of said conglomerate in the structure of the metal used for the casting, thus creating a wear part (2) comprising a reinforced structure,
- said reaction in situ between the raw materials intended to form said components after said reaction is triggered and sustained by the heat of the molten metal.
4. Method for the production of the wear
part as claimed in Claim 3, wherein the reaction between
the raw materials forms a very porous conglomerate capable
of being simultaneously infiltrated by the cast metal
without any particular alteration of the reinforced
5. Method for the production of wear part as
claimed in Claim 3 or 4, wherein the reaction between the
raw materials takes place at atmospheric pressure without
the method requiring any compression after reaction of the
6. Method for the production of wear part
as claimed in any one of Claims 3 to 5, wherein the
reaction between the raw materials does not require any
specific gaseous protective atmosphere.
7. Method for the production of wear part as claimed in any one of Claims 3 to 6, wherein said raw materials belong to the group of ferrous alloys of the kind such as herein described, preferably FerroTi, FerroCr, FerroNb, FerroW, FerroMo, FerroB, FerroSi, FerroZr and FerroV.
8. Method for the production of wear part as claimed in any one of Claims 3 to 6, wherein said raw materials belong to the group of oxides of the kind such as herein described, preferably Ti02, FeO, Fe203, Si02, Zr02, Cr03, Cr203, B203, Mo03, V205, CuO, MgO and NiO.
9. Method for the production of wear part as claimed in any one of Claims 3 to 6, wherein said raw materials belong to the group of metals or their alloys of the kind such as herein described, preferably iron, titanium, nickel or aluminium.
10. Method for the production of wear part as claimed in any one of Claims 3 to 6, wherein said raw materials include carbon, boron, or nitride compounds.
11. Wear part as produced in any one of the preceding claims 3 to 10 as and when used for appliances requiring resistance to both wear and impact.
|Indian Patent Application Number||1466/DELNP/2004|
|PG Journal Number||41/2009|
|Date of Filing||28-May-2004|
|Name of Patentee||MAGOTTEAUX INTERNATIONAL S.A.,|
|Applicant Address||RUE ADOLPHE DUMONT,B-4051 VAUX-SOUS-CHEVREMON,BELGIUM|
|PCT International Classification Number||B22D 19/02|
|PCT International Application Number||PCT/BE02/00150|
|PCT International Filing date||2002-09-30|