Title of Invention | HIGH DIMENSIONAL CORED WIRES CONTAINING OXYGEN REMOVERS AND PROCESS FOR MAKING THE SAME |
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Abstract | Conventionally de-oxidation of steel was carried out by the addition of ferro-alloys or aluminium ingots, bars or solid aluminium wire. For bars and ingots the recovery (i.e. ratio of actual quantity and theoretical amount of aluminium) was poor, resulting in greater aluminium consumption. In case of aluminium wire, the recovery was better, but feeding time was more and often the wire could not reach the depth of molten steel bath. The present invention attempts to overcome the above drawbacks and provides high dimensional cored wires containing oxygen removers formed from cold-rolled steel sheet, said oxygen remover or de-oxidant material being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of the said cored wires varying between 13 and 4 0 mm, preferably between 19 and 34 mm, and the coated de-oxidant material filled in the core is held in place in compacted form by the seaming locks provided during formation of the said cored wires after filling. This invention also describes a process for producing the above cored wires containing the de-oxidant coated with a protective coat in a compacted form ensuring better recovery and rapid feeding of the de-oxidant in predetermined amounts. |
Full Text | The present invention relates to high dimensional cored wires containing oxygen removers and process for making the same. More particularly this invention pertains to high dimensional cored wires filled with an oxygen removing material selected from the group of aluminium, -titanium, zirconium and calcium silicide, preferably fine granules of reactive aluminium powder, having a coat of inorganic or/and organic material, or even without a coating and simple granules, and a process for preparing such high dimensional cored wires. De-oxidation plays an important role in the process of steel making, for which a number of deoxidants have been conventionally used. The term de-oxidant means a chemical compound, alloy or element which will remove the active oxygen present in the liquid metal and form an oxide as its final product, usually as a distinct phase and easily separable from the liquid metal Oxygen, if present in steel in the active/elemental form will result in pinholes and blowholes in the cast product as well as obstruct the process of continuously casting the steel in the modern continuous casting machines. Steel makers are in regular searen of a better and more economical method for removing the oxygen in the steel, which will ultimately reduce the consumption of deoxidants. For doing the primary de-oxidation or the bulk removal of oxygen, (primary killing) in the steel from a higher level of, say, 800-2000 ppm and above, to a lower level of to around 100-200 ppm, alloys such as "Ferro-Silicon", "Ferro-Manganese", "Silico-Manganese" and "Coke" are used, though in bulk, and these materials have served the purpose fairly well. These ferro- alloys or compounds have limitation on the extent to which they can be used in steel making and are limited to the extent of the specification that is allowed in the steel. In almost all grades of steel, silicon and manganese elements are used in various forms for the primary deoxidation along with aluminium in various forms such as bars, ingots, cubes or solid wires, etc. For secondary treatment of steel for the purpose of removing the remnant of oxygen, a number of de-oxidants selected from the group of aluminum, titanium and calcium silicide has been used. However, aluminium has been found to be the most suitable de-oxidant for two reasons, e.g. (i) affinity of aluminium for active oxygen, and (ii) the requirement of presence of aluminium in predetermined amounts in some grades of steel in the cast product. Aluminium is capable of removing oxygen present in molten steel at very low levels of around 4 p.p.m. or even less. It is also the most economical de-oxidiser element, alloy or compound known at present. Previously, primary deoxidation was carried out by the addition of aluminium ingots or bar3 and solid wires of dimension of 13 mm, and secondary or final deoxidation by adding ingots, notch bars and sometimes even solid aluminium wire. Addition through solid aluminium represents a higher percentage of recovery of aluminium compared to bars and ingots. In this specification, unless otherwise specified, the term 'recovery' defines the ratio of the acual quantify of aluminium to be added to remove the active oxygen to the theoretical amount of aluminium required. For bars and ingots, the recovery was very poor and accordingly consumption of aluminium increased. In case of solid aluminium wire, though the recovery was better than bars and ingots, but feeding time was more. The normal size of the aluminium wire that can be injected into the molten steel is around 3, 6, 9, 13 16 mm. For the high dimensional wires proposed in the present invention, feeding of solid aluminium wire as available new becomes very difficult to feed with the conventional wire feeders. The other problem encountered with solid aluminium wire is that due to the high temperatures encountered in steel making, aluminium becomes very soft due to the high temperatures and is not able to penetrate deeply into the molten steel bath which consequently results in lower recovery. The present invention aims at overcoming the foregoing shortcomings of the prior art and carry out production of steel more effectively maintaining an optimum level of aluminium in steel. This invention also has the objective to further enhance the recovery of aluminium, simultaneously reducing the quantum of consumption and time of feeding of aluminium to liquid metal. A further object of the present invention is to provide a technique to use aluminium scraps as de-oxidant after converting them into granules followed by coating with a protective material like graphite, low density polythene, polyamide, low molecular weight vinyl acetate paolymer, talc, steatite, calcium silicide, powdered lime, and the like to prevent fusion or adhesion of the granular particles into a single mass while being pressed and drawn in the wire. It is also possible to use the aluminium granules without coating. A still further object of this invention is to provide high dimensional cored wires containing aluminium granules coated with graphite which while being drawn, the contents become tightly packed, thereby imparting dimensional rigidity and stiffness to the wire. Another object of the present invention is to provide a process for preparing high dimensional cored wires containing de-oxidants in granular form and coated with a protective coating to prevent sticking and fusing into a single mass while being pressed and drawn into wire. The foregoing objectives are fulfilled by the present invention which relates to high dimensional cored wires containing oxygen removers formed from cold-rolled steel sheet, said oxygen removers or deoxidant material being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of said cored wires varying between 13 and 40 mm, preferably between 19 and 34 mm, and the coated de-oxidant material filled in the core is held in place in compacted form by the seaming locks provided during the formation of the said wire after filling. The wire can also be made by totally welding the sheath so that there is no seam. The subject invention also relates to a process for preparing high dimensional cored wires containing oxygen removers as defined above, comprising the steps of - (a) slitting cold-rolled steel sheet of thickness varying between 0.2 and upto 1 mm and required width of 90-110 mm, providing for the double seaming locks; (b) feeding the slit coils into forming rolls which gives the slits the desired near round shape with diamten of 13 to 40 mm, preferably between 19 and 34 mm; (c) filling reactive aluminium powder/granules or other de-oxidants from bunkers or feeders into the blank spaces of the wire; (d) sealing the powder/granule filled wire, either singly or doubly, by the time it conies out of the last forming roll; (e) coiling the thus formed wire over a mandrel with inner diameter varying from 200 ram to 2.5 metres in diameter, generally of around 1 metre in diameter, depending on customer requirement; (f) applying a thin film of oil or anti-rust solution to the exposed surface or outer layer of the coil to prevent rust formation, and (g) strapping and/or wrapping the coils with plastic/stretch film for preventing moisture ingress and then placing over wooden or steel pallets. As pointed out earlier, de-oxidants may be selected from metallic, aluminium, titanium, zirconium and calcicum silicade, but aluminium has been found to give best results as the oxide f— formed may be removed easily due to phase separation and ite refractoriness. Aluminium is used in granular or powdery form, coated with graphite. Scrap aluminium obtained from discarded used beverage cans, sheets/foils/strips/old electrical cable and the like are smelted or shredded and converted into granular form followed by application of a protective coating material like graphite, talc, lime stone dust, calcite, steatite, LDP (low density polyethylene) and the like to prevent fusion or adhesion of granules at the time of being pressed and drawn in the wire. The lacquer coating on the used be verage cans also serve the purpose of protective coating. Size of aluminium granules should be optimally be around 40 mesh, but finer or coarser size granules may just as well be used; however, care should be taken to prevent handling loss. While drawing the aluminium granule- filled wire, the contents become tightly packed, thereby imparting dimensional rigidity and stiffness to the wire, ensuring ease of handling the coil. Deoxidation with aluminium by changing the form of aluminum addition, which is carried out by injecting high diemnsional cored wire filled with highly reactive aluminium in fine gran form and coated with an organic material like graphite for better recovery and achieving the optimum level of oxygen and aluminium with lesser consumption of aluminium are a unique feature of this invention. The coating is not limited to organic materials but can also include inorganic coating materials like calcium oxide, talc, chalk powder, and the like. De-oxidation in accordance with the present invention can be carried out both in the primary and the secondary levels, as per requirement of the steel maker. As pointed out earlier, aluminium powder is converted into fine granules and then coated with an inert organic coating material like graphite flakes or any organic or inorganic coatina material to prevent the aluminium powder from sticking and fusing into a single mass while being pressed and drawn in the wire. While drawing the aluminium powder filled wire, the contents become tightly packed, thereby imparting dimensional rigidity and stiffness to the wire. This also ensures ease of handling the coil. A notable feature of this invention is to use scrap aluminium of any grade in granular or powdered form as the de-oxidant, suitably coated with organic or inorganic coating material as described hereinbefore. Use of scrap/waste aluminium bodies effectively adds to the economy of the overall process. As an additional feature of this invention, winding of the powder filled coil is subjected to 'coreless coiling' so that the coil can be uncoiled from inner diameter of the stationary coil, generally called a "flipping coil", either vertical or horizontal. The coil can also be made into a spool with a core made of either wooden, synthetic, metal any such material. The novel product of this invention, namely, high dimensional cored wire filled with fine granules of aluminium powder coated with graphite and securely held inside, is provided with seaming locks. By 'high dimensional' it is implied that dimensions of the cored wire ranges between 13 and 40 mm, optimally between 19 mm and 34 mm, and the internal diameter of the wound wire over the mandrel may vary between 200 mm to 2.5 meters and the weight of each coil may range between 1 MT to around 20 BT, depending on customer requirement. The present invention will be further illustrated by the experimental data included in the following Example, but it is to be understood that the invention is not restricted to the results given therein. Various advantages of the products of the present invention may be briefly outlined as under : 1. An increasing amount of de-oxidant like aluminium can be filled per unit length of wire, and as more material is compacted per meter of wire of larger dimension, the cost of the steel sheathing becomes less. 2. There is substantial rise in the feeding rate, thereby saving feeding time and resulting in an enhanced time available for steel making. 3. Due to larger dimension, better rigidity and stiffness, the high dimensional wire allows for deeper penetration into steel, thereby resulting in better recovery and homogenization of aluminium. 4. Graphite coated fine granules of aluminium is used as filler material for making high dimensional cored wire (known as "REACTIVE ALUMINIUM"), which results in an estimated 15-25% higher recovery than the conventional solid aluminium wire. 5. Since the aluminium cored wire is of "flipping type", there is a saving on the conversion cost in converting the solid aluminium wire into "flipping type". 6. Lesser consumption of aluminium in-turn will reduce the production cost of steel, particularly in view of the use or scrap aluminium of any grade and coated with protective coating material. 7. Less consumption of packing material brings down production cost. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described experimental data are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and ambit as defined in the claims appended hereinafter, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds, are therefore intended to be embraced by the appended claims. I claim : 1. High dimensional cored wires containing oxygen removers formed from cold-rolled steel sheet, said oxygen remover or de-oxidant material being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of the said cored wires varying between 13 and 40 mm, preferably between 19 and 34 mm, and the coated de-oxidant material filled in the core is held in place in compacted form by the seaming locks provided during formation of the said cored wires after filling. 2. High dimensional cored wires as claimed in Claim 1, wherein finely divided granules of aluminium powder coated with graphite is used as the de-oxidant. 3. High dimensional cored wires as claimed in Claims 1 and 2, wherein there is used scrap aluminium sheets, foils, strips and the like as the de-oxidant, shredded and converted into granular/powdery form, followed by application of a protective coating material like graphite, talc, steadite, lime stone dust, calcite, LDP and the like to prevent fusion or adhesion of granules at the time of being pressed and drawn in the wire. 4. High dimensional cored wires as claimed in Claim 3, wherein while drawing aluminium powder/granule filled wire, the contents become tightly packed, thereby imparting dimensional rigidity and stiffness to the wire, ensuring ease of handling the coil. 5. A process for preparing high dimensional cored wires containing oxygen removers as claimed in the preceeding claims, comprising the steps of- (a) slitting cold-rolled steel sheet of thickness varying between 0.2 and upto 1 mm and required width of 90-110 mm, providing for the double seaming locks; (b) feeding the slit coils into forming rolls which gives the slits the desired near round shape with diameter of 13 to 40 mm, preferably between 19 and 34 mm; (c) filling reactive aluminium powder/ granules or other de-oxidants from bunkers or feeders into the blank spaces of the wire; (d) sealing the powder/granule filled wire, either singly or doubly, by the time it comes out of the last forming roll; generally of around 1 metre in diameter; (f) applying a thin film of oil or anti-rust solution to the exposed surface or outer layer of the coil to prevent rust formation, and (g) strapping and/or wrapping the coils with plastic/streteh film for preventing moisture ingress and then placing over wooden or steel pellets. 6. A process as claimed in Claim 5, wherein the thickness cold-rolled steel sheet (DD and soft grade) varies between and 1 mm, and weight of each coil varies between 1MT and 20MT 7. A process as claimed in Claims 5 and 6, wherein the diameter of the formed wire varies between 13 and 40 mm, preferably between 19 and 34 mm. 8. A process as claimed in Claims 5 to 7, wherein winding of the de-oxidant filled coil is subjected to coreless winding thereby allowing the said coil to be unwinded or uncoiled from the inner diameter of the stationary coil. 9. A process for preparing high dimensional cored wires containing oxygen removers, substantially as hereinbefore described. 10. High dimensional cored wires containing oxygen removers, substantially as hereinbefore described with particular reference to the illustrative example. Conventionally de-oxidation of steel was carried out by the addition of ferro-alloys or aluminium ingots, bars or solid aluminium wire. For bars and ingots the recovery (i.e. ratio of actual quantity and theoretical amount of aluminium) was poor, resulting in greater aluminium consumption. In case of aluminium wire, the recovery was better, but feeding time was more and often the wire could not reach the depth of molten steel bath. The present invention attempts to overcome the above drawbacks and provides high dimensional cored wires containing oxygen removers formed from cold-rolled steel sheet, said oxygen remover or de-oxidant material being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of the said cored wires varying between 13 and 4 0 mm, preferably between 19 and 34 mm, and the coated de-oxidant material filled in the core is held in place in compacted form by the seaming locks provided during formation of the said cored wires after filling. This invention also describes a process for producing the above cored wires containing the de-oxidant coated with a protective coat in a compacted form ensuring better recovery and rapid feeding of the de-oxidant in predetermined amounts. |
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00725-kol-2006-correspondence-1.1.pdf
00725-kol-2006-description(complete).pdf
0725-KOL-2006-CORRESPONDENCE OTHERS 1.2.pdf
0725-kol-2006-correspondence others.pdf
0725-kol-2006-description (provisional).pdf
0725-KOL-2007-CORRESPONDENCE OTHERS 1.2.pdf
725-KOL-2006-(18-07-2012)-CORRESPONDENCE.pdf
725-KOL-2006-(18-07-2012)-OTHERS.pdf
725-KOL-2006-CORRESPONDENCE.pdf
725-KOL-2006-DESCRIPTION (PROVISIONAL).pdf
725-KOL-2006-EXAMINATION REPORT.pdf
725-KOL-2006-GRANTED CLAIMS.pdf
725-kol-2006-GRANTED SPECIFICATION.pdf
725-KOL-2006-GRANTED-ABSTRACT.pdf
725-KOL-2006-GRANTED-DESCRIPTION (COMPLETE).pdf
725-KOL-2006-GRANTED-FORM 1.pdf
725-KOL-2006-GRANTED-FORM 2.pdf
725-KOL-2006-REPLY TO EXAMINATION REPORT.pdf
Patent Number | 249245 | ||||||||
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Indian Patent Application Number | 725/KOL/2006 | ||||||||
PG Journal Number | 41/2011 | ||||||||
Publication Date | 14-Oct-2011 | ||||||||
Grant Date | 12-Oct-2011 | ||||||||
Date of Filing | 20-Jul-2006 | ||||||||
Name of Patentee | GODA SURYA NARAYAN | ||||||||
Applicant Address | BB-8, 7&8 AREA, CIVIL TOWNSHIP, ROURKELA, 769004, ORISSA | ||||||||
Inventors:
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PCT International Classification Number | C23C8/12 | ||||||||
PCT International Application Number | N/A | ||||||||
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