FIELD OF THE INVENTION
The present invention relates to developing metal carbide-metal composite materials based
hammer system as impact crushers adapted to ensure high hardness and impact strength
as well as wear resistant properties. More particularly, the invention is directed to
developing a composite material for manufacturing said hammer head used to crush the
coke, lime stone, slag etc. by impact hammer wherein said composite comprising either
single metal carbide selected from CrC, WC, TiC, MoC, SiC, ZrC , preferably CrC or a
mixture of two or more of them, are mixed thoroughly with metals selected from Fe, Cr, Ni,
Ti, Mo, Zr, Al, Si, B either single or in combination. Such metal carbides and metals are
mixed thoroughly and in selective proportions so as to obtain a low melting point semisolid
melt when heated to a temperature of and cast them in mould of desired size and shape to
obtain hammer head tip to suit assembly with base head. The precast hammer head tip
made of metal carbide-metal composite is further fused to top of precast hammer head and
bolted with high strength bolts to retain the tip in position during operation. The hard metal
carbide in soft metal matrix form desired wear/impact resistant hammer head with high
hardness ranging between RC60-65 capable of crushing 1.5 to 3 times more flux/coke
without repair/replacement, as compared to conventional hammer head, ensuring longer
operating life and reliable performance of the hammer head and tip as well as the hammer
arm in the crusher system. The metal carbide-metal based composite and its use in the
hammer head tip as of the present invention is thus having prospects of wide scale
application in steel industry with significant cost advantage and improving productivity.
BACKGROUND OF THE INVENTION
It is known in the related art that coke/flux or slag needs to be crushed to suitable smaller
sizes for processing in steel plants. Conventionally, beater head attached to beater arm is
used to crush the coke /lime stone/ slag by impact in power hammering machines. During
this crushing operation, the beater heads are subjected to impact wear which results in
development of gap between head and jig plate. Thus big size of input coke/flux is put
through in the process. In conventional configuration these heads are made of high-Mn
grade III steel, used in solutionised and hardened condition and arm is usually made of
44CrMo steel. Attempts have been made in the past to improve the life of hammer head
subjected to impact wear, by modifying the material and design of hammer/beater arm with

head in a number of ways. It has been observed that high alloy steel having different
amount of carbide forming alloying elements when subjected to selective heat treatment
could enhance the hardness so that wear properties and life can be improved.
US 5,470,807 is a prior patent titled 'Chromium carbide based ceramics composite block
gauge' that disclosed a composite ceramic block gauge and its method of preparation
comprising a composite of tungsten carbide and reinforced chromium carbide matrix. It
further claimed a block gauge comprising a ceramic composite material comprising a
chromium carbide as the main ingredient and 5 to 35 vol. % Tungsten carbide which are
sintered in a controlled low-oxygen environment and under pressure and elevated
temperature. The ceramic block gauge comprises a tungsten carbide (WC) reinforced phase
and a chromium carbide(Cr3C2)matrix. The finished block gauge possesses excellent
properties such as hardness and corrosion resistance and high reflectivity. The block gauges
made from Cr3C2/WC composites as of the invention can be calibrated using the traditional
optical interferometry techniques. This invention helped overcoming the limitation of both
the ceramic and the metal materials used for similar applications but does not address the
requirement of impact wear in metal carbide based composite.
EP0482831 disclosed an invention titled 'Production of Chromium carbide Nickel base alloy'
wherein a process is described for improved erosion resistant coating of gas path
components of turbo machines comprising thermal spray depositing of a chromium carbide
and an age hardenable nickel base alloy such as Inconel 718, on the surface of gas path
components and then heat treating the gas path components. It also provides for a heat
treated thermal spray deposited Cr3C2 + Inconel 718 coating for a gas path component of
turbomachine.
JP 61296976 (A) disclosed in its abstract uniformly dispersed ceramic particles used to
reduce cost by disposing a powder mixture composed of metallic element powder on the
surface of a metallic material then heating and melting the powder mixture with a high-
energy source. It states about Cr powder having 50mu average grain size and carbon
powder having 20mu average grain size are uniformly mixed and the paste thereof is
formed with a binder. The paste is coated on a billet and is dried to form a powder mixture
layer. The powder layer is then locally heated and melted by a laser irradiated thereto while
Ar is released as a shielding gas from the top end of a laser gun. The Cr powder is
carbonized and the composite chromium alloy layer uniformly dispersed with the ceramic

particles is obtained in this stage; Part of the billet melts as well and the ceramic particle
dispersed layer is united to the billet. The production cost is thus reduced by the
instantaneous formation of the composite layer.
In some other methods, metallic carbides as hard particles in soft metallic matrix have been
attempted to improve wear resistance. Composites comprising these components in
selective proportion favor enhancing the wear properties in application.
There has thus been a need in the art to developing a material preferably a composite
comprising hard metal carbides in soft metal matrix adapted to ensure high hardness as
well as high impact strength and wear resistive properties favoring application in hammer
heads for crusher used to crush coke or lime stone flux/slag etc, wherein the head surface is
subjected to high amount of impact in repeating succession and resultant wear. Whole or
part of component made of this composite leads to improved wear properties. The material
and the method of fabrication of hammer head would on one hand favor achieving the high
hardness and impact wear resisting properties and on the other hand provide a cost
effective solution to the need for installation/replacement of hammer head of crusher in a
simple manner without causing interruption in operations in close succession, adversely
affecting the productivity.
OBJECTS OF THE INVENTION
The basic object of the present invention is thus directed to developing a metal-carbide-
metal based composite and a hammer head tip made thereof used in a hammer system for
crushers wherein said composite having a composition comprising chromium carbide and Fe
and other metals/carbides in selective proportion ensuring high hardness and high impact
wear resistant properties to ensure longer operating life.
Another object of the present invention is directed to developing a system comprising a
hammer arm, hammer head with hammer tip adapted to providing the facility of quick
installation and dismantling or replacement of the impact surface of the hammer head
assembly.

A further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher wherein the size, shape and weight of
hammer is maintained as per requirement of the system.
A still further object of the present invention is directed to developing said hammer arm
with base hammer head and tip assembly for impact crushers wherein the system is
configured to accommodate certain size of the hard tip to the base hammer to crush certain
size of coke, flux etc.
A still further object of the present invention is directed to developing said crusher hammer
comprising hammer arm with base hammer head and tip assembly for impact crushers for
crushing coke, flux or slag .
A still further object of the present invention is directed to developing said crusher hammer
wherein the hammer tip would be cast in mould from said composite material of desired size
and shape to suit end application and facilitate mounting on hammer head with arm.
A still further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher wherein the hammer arm in the crusher
system would be selectively prepared from existing EN 19 grade steel hardened and
tempered to provide desired hardness and strength favorable for supporting the base
hammer head having selective alloy composition and properties.
A still further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher wherein one or more metal carbide is
selected from WC, TiC, MoC, SiC, ZrC, preferably CrC, to develop the desired composite
material for tip.
A still further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher hammer wherein the soft metal matrix is
composed of metals comprising one or more of Fe,Cr, Ni, Ti, Mo, Zr, Al, Si, B in said
composite.
A still further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher wherein a fixed composition of metal carbides

with metals adapted to result in a low melting point compound favoring a semisolid melt for
casting into desired mould.
A still further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher wherein precast tip is fused and bolted to the
top of head to enhance hardness, strength and resist the impact wear during operation.
A still further object of the present invention is directed to developing a metal-carbide-metal
composite based hammer head tip for crusher wherein the hardness of the metal carbide-
metal composite tip is in the range of RC 60-65 adapted to crush about 1.5 times more of
flux and about 3 times more of coke as compared to conventional high alloy steel hammer
head.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to a hammer having high hardness
comprising:
metal carbide and metal mixed composites adapted to provide
hammer arm hardness in the range of 29-30Rc;
base hammer head hardness in the range of 28-32Rc; and
tip hardness in the range of 60-65 Rc.
Another aspect of the present invention is directed to developing a hammer wherein the
metal carbide comprises anyone or more of CrC, WC, TiC, MoC, SiC, ZrC preferably CrC.
A further aspect of the present invention is directed to said hammer wherein the metal
comprises anyone or more of Fe, Cr, Ni, Ti, Mo, Zr, Al, Si, B.
A still further aspect of the present invention is directed to said hammer comprising of

hammer arm obtained of En-19 grade steel having composition C-1.1% , Cr-1.1% Mo-
0.3% and Mn-0.6% hardened and tempered at 1050°C-1100°C such as to provide final
hardness was 29-30Rc ;
the base hammer head obtained of C-1.3% Cr-2.3% and Mn-13% to provide hardness of
28-32Rc;
the tip of the hammer head obtained of mixing metallic carbide CrC and metal preferably
selected from Fe, Al, Si, Mo to provide a final hardness of Rc 60-65.
A still further aspect of the present invention is directed to said hammer wherein at least a
portion of the hard top is accommodated to the base hammer adapted to crush certain size
of coke, flux and the like and thereby of high wear resistant properties.
According to yet another aspect of the present invention is directed to a process for the
manufacture of a hammer having desired hardness and resistance to impact wear
comprising:
step of obtaining the hammer arm adapted to support the hammer head preferably made
of En-19 grade steel having composition C-1.1% , Cr-1.1% Mo-0.3% and Mn-0.6%,
hardening and tempering at 1050°C-1100°C such as to obtain said final hardness was 29-
30Rc ;
step of obtaining the base hammer head with the composition preferably comprising C-
1.3% Cr-2.3% and Mn-13% such as to achieve the hardness of 28-32Rc;
step of obtaining the tip of the hammer head comprising mixing metallic carbide CrC and
metal preferably selected from Fe, Al, Si, Mo and mixing thoroughly, melting the powder in
a vacuum induction furnace to get the semi solid stage and thereafter casting in required
mould followed by pressing; and
finally, the tip was further fused to the base head and it was bolted to attain more strength
with desired final hardness of the tip of Rc 60-65.

A still further aspect of the present invention is directed to said process for the manufacture
of a hammer wherein the size, shape and weight of the hammer was set as per the end
requirement.
A still further aspect of the present invention is directed to said process for the manufacture
of a hammer wherein the precast tip was fused and bolted to the top of head to enhance
strength and to avoid impact wear during operation.
The present invention and its objects and advantages are described in greater details with
reference to the following non limiting accompanying illustrative figures.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1: is the photograph of the conventional hammer head illustrating the shape and size
of hammer used in existing art to crush the coke, flux etc.
Figure 2: is the schematic illustration in plan, elevation and side view of the metal carbide-
metal composite cast hammer attached to base hammer according to the configuration of
the present invention.
Figure 3: is the schematic illustration of the impact face configuration of the cast composite
hammer head tip made of metal carbide-metal composite material according to the present
invention.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING FIGURES
The present invention is directed to developing a metal carbide-metal composite material
and a hammer head tip of crusher produced using said composite to crush coke or flux or
slag by impact hammer so that the hammer head is capable of providing required hardness
and impact wear resisting properties in the resulting hammer head tip. Advantageously, the
invention is directed to developing a selective composite composition comprising said metal

carbide in soft metals matrix having specified ranges of any one or more of metal carbides
comprising CrC 30 to 50%, WC 60 to70%, TiC 10 to 20% , MoC 10 to 20%, SiC 50 to
60%,and any one or more of metals comprising Fe- 90 to 95%,Cr- 10 to30%, Ni- 10 to
20%,Ti- 10 to 20%, Mo- 2 to 10%, Zr- 2 to 20%, Al- 2 to20% , Si- 2 tol0%, B- 0 to 5% ,
favor achieving low melting point semisolid melt suitable to be cast into mould of desired
shape and size of tip, the desired end properties of high hardness in the range of Rc 60-65
associated with high impact wear resistance in said composite used to produce said hammer
head tip, ensuring longer operating life. These hammer tip is further fused to the base of
hammer and strengthened by fixing high strength bolting favoring simple and faster
installation/ replacement of said hammer head tip as and when required.
The advantageous aspect of the invention of producing said metal carbide-metal based
composite for application in hammer head of crushers for crushing coke, lime stone, slag
and like materials will be apparent from the following description with reference to
accompanying figures and example.
Reference is first invited to the accompanying Figure 1, that illustrate a photographic
image of the hammer head with arm previously used in the existing crusher. It is shown
that the prior art hammerheads or the beater head attached with beater arm are used to
crush the coke/lime stone/slag by impact. During this crushing, the beater heads are
subjected to impact wear which results the development of gap between head and jig plate.
This in turn allow big size of particles to move through in the process. In the existing
hammer, these heads have been made of high Mn steel grade III and used in solutionised
and hardened condition and arms have been made of 44CrMo steel.
Reference is now invited to the accompanying Figure 2, that schematically illustrate the
hammer head with tip and the hammer arm assembly according to the present invention in
three different views e.g. the plan, elevation and the side view wherein the head tip is
prepared from a metal carbide-metal composite produced following the process of the
invention. The said Figure 2 also show the high strength bolt and the locking pin used in the
assembly of hammer arm, head and tip assembly in a crusher system. Advantageously, the
hammer head tip is made from a composite prepared according to the present invention
using metal carbide-metal mix in selective particle size and selective proportions so that the
tip is made by casting a low melting point compound semisolid melt obtained of said

composite in mould of desired shape and size. The hammer arm with base hammer and
hammer head and tip assembly constitute a total crusher hammer system.
The process of preparing the metal-carbide-metal composite as well as the fabrication of the
hammer head tip and its assembly with the base head and arm is described with reference
to following example I.
Example I:
(i) In the present invention, the hammer arm is made of En-19 grade steel having
composition C-l.1%, Cr-1.1% Mo-0.3% and Mn-0.6%. It is hardened and
tempered at a temperature range of 1050°C-1100°C. The final hardness achieved
is 29-30Rc. The purpose of this arm is to support the hammerhead.
(ii) The base hammer head is developed from a steel composition comprising C-
1.3%, Cr-2.3% and Mn-13% favoring attaining hardness of 28-32Rc.
(iii) According to an embodiment of the present invention, the tip of the hammer
head is prepared by mixing metallic carbide CrC and metal i.e. Fe, Al, Si, Mo and
it is mixed thoroughly. Said mix having the carbide and metal in a selective
proportion comprising :
A) CrC: 30 to 50 wt %, of particle size 0.2 tol2um;
Bl)Fe: 90 to 95wt %, of particle size 0.2 tol2um;
B2)AI:2 to 3 wt %, of particle size 0.2 tol2um;
B3 ) Si:2 to 3 wt %, of particle size 0.2 tol2um;
B4 ) Mo:2 to 3 wt %, of particle size 0.2 tol2um;
The powder of CrC 35%(A) and metal powder 65% of above said composition Fe , Al, Si, Mo
(B1+B2+B3+B4) is melt in a vacuum induction furnace at a temperature of 1200-1250C °C
to get the semi solid stage and then it is cast in required mould and pressed. Final hardness
of the tip achieved following this process is Rc 60-65. Accompanying Figure 3 shows a
photographic image of the impact face of the metal carbide-metal composite tip mounted
hammer head produced following the process of the present invention.

(iv) According to an embodiment of the present invention, following steps have been
followed to introduce desired metal carbide-metal based hammer head tip in a crusher
system:
a. System is designed to accommodate a certain size of the hard tip to the base
hammer to crush a certain size of coke, flux etc.
b. The size, shape and weight of hammer is kept as per requirement of the system;
c. Precast tip made of metal carbide-metal composite as in step (i), fused and bolted to
the top of head to enhance strength and to overcome the impact wear during
operation wherein the hard tip is a mixture of metal carbide and metal which is
melted and cast in desired shape as detailed in preceding step (i). The tip is
prepared from composite comprising metal carbide which includes CrC: 30 to50wt
%, and it can also include one or more of other metal carbides e.g. WC,TiC,MoC,SiC
or ZrC; and wherein metals include Fe 90 to 95%,Si 2 to 3%, Al 2 to 3%, Mol.5 to
3% and can also include one or more of Cr, Ti ,Zr,Si,B etc.
d. This tip is further fused to the base head and it is additionally bolted to attain more
strength.
e. A fixed composition of metal carbide in soft metal matrix comprising CrC35% and
balance of C 3.1%, Crl6.5%, Mol.8%, Fe78.6%, providing a low melting point
compound to prepare a semisolid melt favoring casting into desired mould of
required shape and size.
f. The hammerhead with the composite head tip fused on base and bolted on head is
detachably assembled with the hammer arm by a pin and circle ring.
g. The average hardness of the invented hammer head tip is found to be Rc-60-65 .
h. The hammer assembly with the hammer head tip made of said metal carbide-metal
composite so obtained is observed to ensure 1.5 times more crushing of
limestone/flux and 3 times more crushing of coke during continuous operation, as
compared to conventional high alloy steel based hammer.
It is thus possible by way of the present invention to developing a composite composition
comprising metal carbide-metal for application as the hammer head tip for crusher for
crushing of coke, limestone, slag etc by impact hammer. The tip of the hammer head in the
system comprising the hammer arm and base head, is adapted to ensure on one hand
longer operation with reliable performance because of its high hardness and favorably high
impact wear resistance improving productivity and on the other hand favor uniform crushing

free of wear on tipped hammer head surface and thus avoiding through put of larger sized
crushed fragments of coke or flux in the processes. Advantageously, the fused and bolted
connection of composite head tip on hammer head as of the invention further providing
means for easy and faster mounting/servicing of the impact hammer as well as economize
the use of expensive materials reducing cost and longer operating life for such composite tip
based hammer/crusher system making such hammer head capable of wide industrial
application in iron and steel industry.

WE CLAIM:
1. A hammer having high hardness comprising:
metal carbide and metal mixed composites adapted to provide
hammer arm hardness in the range of 29-30Rc;
base hammer head hardness in the range of 28-32Rc; and
tip hardness in the range of 60-65 Rc.
2. A hammer as claimed in claim 1 wherein the metal carbide comprises anyone or more of
CrC, WC, TiC, MoC, SiC, ZrC preferably CrC.
3. A hammer as claimed in anyone of claims 1 or 2 wherein the metal comprises anyone or
more of Fe, Cr, Ni. Ti, Mo, Zr, Al. Si, B.
4. A hammer as claimed in anyone of claims 1 to 3 comprising of
hammer arm obtained of En-19 grade steel having composition C-1.1% , Cr-1.1% Mo-
0.3% and Mn-0.6% hardened and tempered at 1050°C-1100°C such as to provide final
hardness was 29-30Rc ;
the base hammer head obtained of C-l.3% Cr-2.3% and Mn-13% to provide hardness of
28-32Rc;
the tip of the hammer head obtained of mixing metallic carbide CrC and metal preferably
selected from Fe,AI,Si, Mo to provide a final hardness of Rc 60-65.
5. A hammer as claimed in anyone of claims 1 to 4 wherein atleast a portion of the hard top
is accommodated to the base hammer adapted to crush certain size of coke ,flux and the
like and thereby of high wear resistant properties.
6. A process for the manufacture of a hammer as claimed in anyone of claims 1 to 5
comprising:

step of obtaining the hammer arm adapted to support the hammer head preferably made
of En-19 grade steel having composition C-1.1% , Cr-1.1% Mo-0.3% and Mn-0.6%,
hardening and tempering at 1050C-1100C such as to obtain said final hardness was 29-
30Rc;
step of obtaining the base hammer head with the composition preferably comprising C-
1.3% Cr-2.3% and Mn-13% such as to achieve the hardness of 28-32Rc;
step of obtaining the tip of the hammer head comprising mixing metallic carbide CrC and
metal preferably selected from Fe,AI,Si, Mo and mixing thoroughly, melting the powder in
a vacuum induction furnace to get the semi solid stage and thereafter casting in required
mould followed by pressing; and
finally, the tip was further fused to the base head and it was bolted to attain more strength
with desired final hardness of the tip of Rc 60-65.
7. A process for the manufacture of a hammer as claimed in claim 6 wherein the size, shape
and weight of the hammer was set as per the end requirement.
8. A process for the manufacture of a hammer as claimed in anyone of claims 6 or 7
wherein the precast tip was fused and bolted to the top of head to enhance strength and to
avoid impact wear during operation.
9. A hammer having high hardness and its process of manufacture substantially as here in
described and illustrated with reference to the accompanying figures.

The present invention relates to developing a metal carbide-metal composite based
hammerhead tip to ensure high hardness, strength and wear resistant properties. More
particularly, the hammer head tip is adapted to crush coke, lime stone, slag etc. by impact
wherein said composite comprising one or more metal carbides selected from CrC, WC, TiC,
MoC,SiC,ZrC, preferably CrC, in metal matrix selected from one or more of Fe, Cr, Ni, Ti,
Mo,Zr,AI,Si,B. The composite is suitable to be cast in mould of desired size and shape. The
hammer arm is made of EN 19 grade steel, hardened and tempered to provide final
hardness of 29-30RC and the base hammer head obtained of steel having C-1.3% Cr-2.3%
and Mn-13% to provide hardness of 28-32Rc The precast hammer head tip is fused to top
of precast hammer head and bolted for high strength, crushing 1.5 to 3 times more
flux/coke. The metal carbide-metal based composite and its use in the hammer head tip is
thus having prospects of wide scale application in steel industry.