Title of Invention	AN IMPROVED PROCESS FOR THE PREPARATION OF A TUNGSTEN CARTIDE REINFORCED FERROUS COMPOSITE.
Abstract	The present invention provides a process for the preparation of tungsten carbide reinforced cast ferrous composite by melting a mild steel scrap and a tungsten scrap in a plasma furnace at a temperature of 1650 ° C, in the presence of a carbonaceous material for a time period ranging between 10-20 min, under inert atmosphere, tapping and casting of the above said melt to the required shape to get tungsten carbide reinforced ferrous composite.

Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF A TUNGSTEN CARTIDE REINFORCED FERROUS COMPOSITE.

Abstract

The present invention provides a process for the preparation of tungsten carbide reinforced cast ferrous composite by melting a mild steel scrap and a tungsten scrap in a plasma furnace at a temperature of 1650 ° C, in the presence of a carbonaceous material for a time period ranging between 10-20 min, under inert atmosphere, tapping and casting of the above said melt to the required shape to get tungsten carbide reinforced ferrous composite.

Full Text	The present invention relates to a process for the preparation of a east tungsten carbide reinforced ferrous composite. The tungsten carbide reinforced ferrous composites will have application as wear and erosion resistant components in mining and metallurgical industries. Further it is likely to have applications in fabrication of agricultural implements. Hither to known existing processes (Miyazaki, K; Ito, S; Kourva, N; Yoneda, Ni; Asaka, K; "J. of Japanese society of powder and powder metallurgy, 37(2), 1990, [219-224]" follows preparation of the same by the reaction of tungsten monocarbide powder and iron in an hot isostatic pressure chamber using the powder metallurgical route. Other related processes are vacuum mold cast in place hard facing [Wang, H; Jie, J; Chinese J. of Mech. Engg. 26(1), 1990 [1-6] and Zheng, Q; Fenxi Shiyanshi, 9(3), 1990 [27-30]. Laser melt particle injection processing [Memoires et etude scientifiques de la revue de metallurgie, 88(5), 1991, [279-282]; thermal spraying of powders ( alloy steels, 26[9], 1992, [237-247] etc. The hither to known powder metallurgical processes has got some disadvantages. The process requires raw materials in powder form. The development of composites require a process of compacting the powders to the required shape and size at high pressure followed by sintering to develop required strength properties. Thus the process involves number of unit operations. It is extremely difficult to develop large components for industrial applications using powder metallurgical techniques. In the invented process the above said disadvantages are overcome by applying liquid metallurgical technique wherein the said composite, made by in situ formation of carbide the ferrous matrix, are directly cast to shapes in either sand or permanent moulds depending on the requirements thus avoiding various unit operations as envisaged in the conventional powder metallurgical techniques. The main objective of the present invention is to develop a process for the preparation of cast tungsten carbide reinforced ferrous composite. Another objective of the invention is to utilize tungsten bearing scrap, iron and steel scrap materials. Still another objective of the invention is to produce tungsten carbide reinforced ferrous composites castings for various applications such as wear resistant applications. The principle underlying the present invention relates to in-situ formation of tungsten carbide in a ferrous matrix by dissolution of tungsten bearing scrap in either carbon rich molten ferrous matrix by melting tungsten scraps and steel scraps in presence of carbonaceous materials. Accordingly the present invention provides a process for the preparation of tungsten carbide reinforced ferrous composite characterized in that using melted scarp material as defined herein for in situ formation of ferrous carbide matrix , which comprises melting a mild steel scrap and a tungsten scrap in a plasma furnace at a temperature of 1650 ° C, in the presence of a carbonaceous material for a time period ranging between 10-20 min, under inert atmosphere, tapping and casting of the above said melt to the required shape to get tungsten carbide reinforced ferrous composite. In an embodiment of the present invention, the mild steel scrap used is selected from plain carbon scrap and alloy steel scrap. In another embodiment of the present invention, the tungsten scrap used is a heavy alloy scrap containing tungsten in the range of 90 - 97 wt% with balance as iron, and nickel. In still another embodiment of the present invention, the carbonaceous material used is selected from carbon rich ferrous matrix and carbon. In another ernbdiment of the present invention, the said composite prepared contains tungsten carbide in the range of 4-20 wl.%. The following typical example given below is to illustrate how the invention is carried out in actual practice and should not be construed to limit the scope of the invention. EXAMPLE -1 1.67 kg of mild steel scraps was melted in a plasma furnace (50 KW DC plasma reactor) at a temp of -1650 °C for 10 minules followed by addition of 72.2 gm of tungsten scraps containing 90 (wt %) tungsten such as heavy alloy scraps. The total duration of melting was 17 minutes. After completion of the reaction the melt was tapped and cast to shapes. The characteri-sattion of the product by X-ray diffraction analysis confirms formation of tungsten carbide in the iron phases. EXAMPLE -2 1.97 kg of mild steel scrap was melted in a plasma furnace ( 50 kW DC plasma reactor) at a temp of -1650 °C for 11 min followed by addition of 412 gm of tungsten scrap. Duration of the melting was 16 min. After the completion of the reaction the melt was tapped and cast to shapes. The characterization of this product also show the formation of tungsten carbide phase in the iron matrix. The novelty of this process is that it can he applied to prepare tungsten carbide reinforced ferrous composite with WC(4-20 wt% )using the scrap materials such as tungsten and mild steel scraps. XRD data of the said composite 'd' value h, k. 1 phases 2.83 001 WC 2.512 1 00 WC 2.026 i 1 0 a-Fe 1.873 101 WC 1.432 200 a-Fe 1.29 111 WC 1.22 102 WC 1.17 2 1 1 a-Fe The advantages of the inventions are of the followings a) The process involves use of scraps materials such as tungsten bearing scrap, iron and steel scraps as the raw materials. b) The invented process involves preparation of the said composite by melting the requisite raw materials and casting them to the required shapes in a single step. c) The process involves in casting the composite in required shape and size as well as control of grain size by casting in either sand or permanent mould. We Claim: 1. An improved process for the preparation of tungsten carbide reinforced ferrous composite characterized in that using melted scarp material as defined herein for in situ formation of ferrous carbide matrix , which comprises melting a mild steel scrap and a tungsten scrap in a plasma furnace at a temperature of 1650 ° C, in the presence of a carbonaceous material for a time period ranging between 10-20 min, under inert atmosphere, tapping and casting of the above said melt to the required shape to get tungsten carbide reinforced ferrous composite. 2. An improved process claimed in claim 1, wherein the mild steel scrap used is selected from plain carbon scrap and alloy steel scrap. 3. An improved process claimed in claims 1 & 2, wherein the tungsten scrap used is a heavy alloy scrap containing tungsten in the range of 90 - 97 wt% with balance as iron, and nickel. 4. An improved process as claimed in claims 1 - 3, wherein the carbonaceous material used is selected from carbon rich ferrous matrix and carbon. 5. An improved process as claimed in claims 1-4, wherein the said composite prepared contains tungsten carbide in the range of 4 - 20 wt%. 6. An improved process for the preparation of tungsten carbide reinforced ferrous composite substantially as herein described with reference to the examples.

Full Text

The present invention relates to a process for the preparation of a east tungsten carbide reinforced ferrous composite.
The tungsten carbide reinforced ferrous composites will have application as wear and erosion resistant components in mining and metallurgical industries. Further it is likely to have applications in fabrication of agricultural implements.
Hither to known existing processes (Miyazaki, K; Ito, S; Kourva, N; Yoneda, Ni; Asaka, K; "J. of Japanese society of powder and powder metallurgy, 37(2), 1990, [219-224]" follows preparation of the same by the reaction of tungsten monocarbide powder and iron in an hot isostatic pressure chamber using the powder metallurgical route. Other related processes are vacuum mold cast in place hard facing [Wang, H; Jie, J; Chinese J. of Mech. Engg. 26(1), 1990 [1-6] and Zheng, Q; Fenxi Shiyanshi, 9(3), 1990 [27-30]. Laser melt particle injection processing [Memoires et etude scientifiques de la revue de metallurgie, 88(5), 1991, [279-282]; thermal spraying of powders ( alloy steels, 26[9], 1992, [237-247] etc.
The hither to known powder metallurgical processes has got some disadvantages. The process requires raw materials in powder form. The development of composites require a process of compacting the powders to the required shape and size at high pressure followed by sintering to develop required strength properties. Thus the process involves number of unit operations. It is extremely difficult to develop large components for industrial applications using powder metallurgical techniques.
In the invented process the above said disadvantages are overcome by applying liquid metallurgical technique wherein the said composite, made by in situ formation of carbide the ferrous matrix, are directly cast to shapes in either sand or permanent moulds

depending on the requirements thus avoiding various unit operations as envisaged in the conventional powder metallurgical techniques.
The main objective of the present invention is to develop a process for the preparation of cast tungsten carbide reinforced ferrous composite.
Another objective of the invention is to utilize tungsten bearing scrap, iron and steel scrap materials.
Still another objective of the invention is to produce tungsten carbide reinforced ferrous composites castings for various applications such as wear resistant applications.
The principle underlying the present invention relates to in-situ formation of tungsten carbide in a ferrous matrix by dissolution of tungsten bearing scrap in either carbon rich molten ferrous matrix by melting tungsten scraps and steel scraps in presence of carbonaceous materials.
Accordingly the present invention provides a process for the preparation of tungsten carbide reinforced ferrous composite characterized in that using melted scarp material as defined herein for in situ formation of ferrous carbide matrix , which comprises melting a mild steel scrap and a tungsten scrap in a plasma furnace at a temperature of 1650 ° C, in the presence of a carbonaceous material for a time period ranging between 10-20 min, under inert atmosphere, tapping and casting of the above said melt to the required shape to get tungsten carbide reinforced ferrous composite.
In an embodiment of the present invention, the mild steel scrap used is selected from plain carbon scrap and alloy steel scrap.
In another embodiment of the present invention, the tungsten scrap used is a heavy alloy scrap containing tungsten in the range of 90 - 97 wt% with balance as iron, and nickel.

In still another embodiment of the present invention, the carbonaceous material used is selected from carbon rich ferrous matrix and carbon.
In another ernbdiment of the present invention, the said composite prepared contains tungsten carbide in the range of 4-20 wl.%.
The following typical example given below is to illustrate how the invention is carried out in actual practice and should not be construed to limit the scope of the invention. EXAMPLE -1
1.67 kg of mild steel scraps was melted in a plasma furnace (50 KW DC plasma reactor) at a temp of -1650 °C for 10 minules followed by addition of 72.2 gm of tungsten scraps containing 90 (wt %) tungsten such as heavy alloy scraps. The total duration of melting was 17 minutes. After completion of the reaction the melt was tapped and cast to shapes. The characteri-sattion of the product by X-ray diffraction analysis confirms formation of tungsten carbide in the iron phases. EXAMPLE -2
1.97 kg of mild steel scrap was melted in a plasma furnace ( 50 kW DC plasma reactor) at a temp of -1650 °C for 11 min followed by addition of 412 gm of tungsten scrap. Duration of the melting was 16 min. After the completion of the reaction the melt was tapped and cast to shapes. The characterization of this product also show the formation of tungsten carbide phase in the iron matrix.
The novelty of this process is that it can he applied to prepare tungsten carbide reinforced ferrous composite with WC(4-20 wt% )using the scrap materials such as tungsten and mild steel scraps.

XRD data of the said composite
'd' value h, k. 1 phases
2.83 001 WC
2.512 1 00 WC
2.026 i 1 0 a-Fe
1.873 101 WC
1.432 200 a-Fe
1.29 111 WC
1.22 102 WC
1.17 2 1 1 a-Fe
The advantages of the inventions are of the followings
a) The process involves use of scraps materials such as tungsten bearing scrap, iron
and steel scraps as the raw materials.
b) The invented process involves preparation of the said composite by melting the
requisite raw materials and casting them to the required shapes in a single step.
c) The process involves in casting the composite in required shape and size as well
as control of grain size by casting in either sand or permanent mould.

We Claim:
1. An improved process for the preparation of tungsten carbide reinforced
ferrous composite characterized in that using melted scarp material as
defined herein for in situ formation of ferrous carbide matrix , which
comprises melting a mild steel scrap and a tungsten scrap in a plasma
furnace at a temperature of 1650 ° C, in the presence of a carbonaceous
material for a time period ranging between 10-20 min, under inert
atmosphere, tapping and casting of the above said melt to the required shape
to get tungsten carbide reinforced ferrous composite.
2. An improved process claimed in claim 1, wherein the mild steel scrap used is
selected from plain carbon scrap and alloy steel scrap.
3. An improved process claimed in claims 1 & 2, wherein the tungsten scrap
used is a heavy alloy scrap containing tungsten in the range of 90 - 97 wt%
with balance as iron, and nickel.
4. An improved process as claimed in claims 1 - 3, wherein the carbonaceous
material used is selected from carbon rich ferrous matrix and carbon.
5. An improved process as claimed in claims 1-4, wherein the said composite
prepared contains tungsten carbide in the range of 4 - 20 wt%.
6. An improved process for the preparation of tungsten carbide reinforced
ferrous composite substantially as herein described with reference to the
examples.

Documents:

1217-del-2000-abstract.pdf

1217-del-2000-claims.pdf

1217-del-2000-correspondence-others.pdf

1217-del-2000-correspondence-po.pdf

1217-del-2000-description (complete).pdf

1217-del-2000-form-1.pdf

1217-del-2000-form-19.pdf

1217-del-2000-form-2.pdf

1217-del-2000-form-3.pdf

« Previous Patent

Next Patent »

Patent Number

242186

Indian Patent Application Number

1217/DEL/2000

PG Journal Number

34/2010

Publication Date

20-Aug-2010

Grant Date

18-Aug-2010

Date of Filing

26-Dec-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH,

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	PRATIMA KUMARI MISHRA	SCIENTIST-C, RRL, BHUBANESHWDER PIN-751013, ORISSA (INDIA)
2	RAMACHANDRA KRISNARAO GALGALI	SCIENTIST-F, RRL, BHUBANESHWER PIN-751013, ORISA.(INDIA.)

PCT International Classification Number

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA