1. A process for manufacturing of steel cops/bobbins/pirns for synthetic yarn comprising following steps: a) sealing of two edges of base strips by electric resistance welding (ERW) to form primary tube; b) cold drawing the primary steel tubes, obtained in step (a), at a room temperature to reduce the cross section area and thickness of said welded steel tubes; c) straightening the cold drawn steel bobbin at a room temperature to remove stress generated during step b); d) carrying out hardening to further improve the mechanical strength and percentage elongation (ductility) in the straightened steel tubes obtained in step (c); and e) quenching of the steel tubes, obtained in step (d), to render final products.

2. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein steel grade is selected from SAE 1020, SAE 1026, ST-52, ST-52.3, SAE 1541, MC-11 and IS 7226 C40.

3. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein the step (c) is carried out by hyperbolic 6 roll machine.

4. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein the hardening process is carried out by perspective hardening, salt hardening and induction hardening.

5. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein the step (d) is carried out at in furnace at 900 °C.

6. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein solution treatment is carried out by fog or water quenching after straightening the cold drawn steel tubes.

7. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in as claimed in claim 1 wherein weight reduction in product is 30%.

8. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn in as claimed in claim 1, wherein the mechanical properties includes improvement in tensile strength and percentage elongation, reduction in cross section area, reduction in weight and achievement of the precise dimensional tolerance includes tolerance on internal diameter and uniform thickness of the steel tubes. Dated this 3rd Day of February, 2016 , Description:FORM 2 THE PATENT ACT 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10 and rule 13) TITLE OF THE INVENTION: PROCESS FOR MANUFACTURING OF STEEL COPS/BOBBINS/PIRNS FOR SYNTHETIC YARN

2. APPLICANT: (a) NAME : Siddhi Engineers (b) NATIONALITY : Indian (c) ADDRESS : “SIDDHI HOUSE” 6, Virkunj Society, Nr. Vidyanagar School, Usmanpura, Ahmedabad-380014

3. PREMABLE TO THE DESCRIPTION PROVISIONAL The following specification describes the invention. ? COMPLETE The following specification particularly describes the invention and the manner in which it is to be performed. Field of the invention The present invention relates to a process for manufacturing of metal cops/bobbins/pirns for synthetic yarn more particularly it relates to manufacturing of metal cops or bobbin made-up of steel and other components for winding of nylon and polyester yarns. Back ground and prior art of the invention Synthetic yarns have become popular on account of their ideal characteristics for clothes which mainly includes more compact molecular structure, creases can be heat-set at higher temperatures, better weathering properties; better sunlight resistance, superior colourfastness, excellent abrasion resistance, greater elasticity and elastic recovery. Nylon and polyester are generic designations for a family of synthetic polymers, more specifically aliphatic or semi-aromatic polyamides. Nylon polymers have found significant commercial applications in fibers (apparel, flooring and rubber reinforcement), in heavy industries (molded parts for cars, electrical equipment, etc.) and in films (mostly for food packaging). Various grades (i.e. N6 and N66) are available in nylon as per the requirement of textile industries. Nylon has an inherent tendency to shrink once wound on any object that lead to create pressure of the nylon flat yarn on cops/bobbins/pirns which lead to bulge from the centre resulting into stoppage of the whole winding panel. It is also important to have excellent dimension control and high tensile strength for exact fitment on the spindle. For manufacturing end products from the yarn an extrusion plant is used which produces flat yarn of the nylon is used as the raw material. The flat yarn is continuously wound on cops/bobbins/pirns by draw twisting process on draw twisting machine & splitting machines. Large numbers of cops/bobbins/pirns (i.e. 144 or 156) are used simultaneously for the purpose of winding. Such yarn which is wound on the cops/bobbins is then taken to weaving process. The winding process which involves winding of nearly 144 or 156 cops/bobbins/pirns at a time with one forth number of electric motors makes the process very high energy consuming. The cops/bobbins/pirns is mounted on spindle where they rotate at high speed in the range of 10000-18000 RPM. If the cops/bobbins does not have accurate dimension then fitment of the cops/bobbins/pirns on spindle is not accurate which lead to poor winding and vibration in the system. If the cops/bobbins/pirns does not have enough strength then the same will bulge leading to loss of yarn and also blocking of such spindles leading to productivity issues. Steel tubes as well as aluminium tubes have been traditionally used for manufacturing cops/bobbins/pirns. Aluminium is more costly and pure aluminium doesn’t have high tensile strength compared to steel that diminish its use for cops/bobbins/pirns manufacturing. Conventionally, various methods for manufacturing of cold drawn steel products are available. For example, Chinese patent application CN102764958, discloses cold rolled/cold drawn precision welded steel pipe manufacturing process. The process provides improvement tensile strength, the surface hardness and the wear resistance of the steel pipe. The said improvement shows resultant tensile strength in range of 530-560 MPa compared to initial strength in the range of 450-480 MPa. Further said process doesn’t provide idea about induction hardening. The tensile strength and hardness of the product obtained is not sufficient to withstand pressure generated by synthetic yarn. Hence, to overcome above mentioned problems (i.e. bulging of the cops/bobbins/pirns non accurate fitting of the cops/ bobbins/pirns, very high electricity consumption and very high maintenance), it is desperately needed to invent a method of manufacturing steel cops/bobbins/pirns for textile industry which is not subjected to aforesaid problems so that the finally obtained steel cops/bobbins/pirns which has desired mechanical properties, consistent, lower maintenance and high level tolerance that is suitable for using in textile industry. Object of the invention The main object of present invention is to provide a method of manufacturing cops/bobbins/pirns made up of steel for winding synthetic yarn. Another object of the present invention is to provide a method for manufacturing cops/bobbins/pirns made up of steel having excellent ductility, % elongation, high tensile strength and proof stress for winding nylon or polyester yarn. Another object of the present invention is to provide a method of manufacturing cops/bobbins/pirns made up of steel with a low maintenance, lesser electricity consumption due to light weight and precise fitting for end products. Another object of the present invention is to provide cops/bobbins/pirns, made-up of steel, with characteristics of multiple usage in winding yarn. Yet another object of the present invention is to provide a light weight though high tensile steel cops/bobbins/pirns for winding. Further object of present invention is to provide a method of manufacturing cops/bobbins/pirns from different steel grades (i.e. ST- 52.3 or SAE-1541 etc.). Summary of the Invention The present invention relates to a process for manufacturing of steel cops/bobbins/pirns for winding synthetic textiles fibres. The present invention provides light weight, strong and precise product made-up of specific steel grade (i.e. ST- 52.3 or SAE-1541 etc.) duly cold drawn and induction harden to achieve consistency, very high strength to weight ratio and improved % elongation. The present invention utilizes strip of one steel grade as a feed stock which undergoes electric welding to obtain primary tube. The primary tubes of steel are subjected to a cold drawn to obtained ultimate dimension control then sequentially it is subjected to induction hardening to achieve high tensile strength up to 1600-1700 MPa. After induction hardening, tubes are further subjected to solution treatment by special quenching of fog or water. The present process provides advantages in steel cops/bobbins/pirns like light weight, consistency, high tensile strength, economically significant and multiple usage capability compared to conventional processes. Detail description of the Invention Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompany drawings. The invention is capable of other embodiments, as depicted in figure as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation. Dimension and weight of steel cops/bobbins/pirns used conventionally are varies as per the ultimate applications. Conventionally the outer diameter ranges from 44.45 mm to 51 mm. The length of cops/bobbins/pirns ranges from 305 mm to 450mm. The inner diameter depends on the ultimate thickness and uniformity of the cops/bobbins/pirns. The thickness of cops/bobbins/pirns is normally ranges from 0.70 - 1.30 mm. Based on the varying dimension weight of the cops/bobbins/pirns are in the range of 300 to 750 gm. The method for manufacturing steel cops/bobbins/pirns for synthetic yarn primarily uses strips of the basic steel as feed stock. This strip is further subjected to Electric resistance welding (ERW). This welding process provides seam welding to flange of strips by producing coalescence of surfaces where heat to form the weld is generated by the electrical resistance (10000 A). The principal behind this welding is based on material deformation with the time and the force used to hold the materials together during welding. This welding process ultimately gives tube with basic characteristic of basic steel. Different grades of steels have different tensile strength, hardness and % elongation. The requirement of further processing is needed as basic raw material doesn’t have requisite characteristics for cops/bobbins/pirns manufacturing. The present process is investigated on various steel grades (SAE 1020, SAE 1026, ST 52, ST 52.3, SAE 1541, MC 11 and IS 7226 C40. These steel grades are evaluated for improvement in tensile strength, hardness and % elongation. The basic strips of steel are selected as feed stock or raw material. The said strips are subjected to splitting in predefined length which will undergo sealing the ends to form tube. The said steel grades have tensile strength in range of 400 – 700 MPa depending on the grades of steel. Composition and tensile strength of various steel grades is given in table 1. Table - A Steel grade# Carbon (%) Manganese (%) Ultimate tensile strength SAE 1020 0.18 – 0.23 0.3-0.6 420 SAE 1026 0.22 – 0.28 0.6-0.9 490 ST 52 0.2 0.9-1.7 490-630 ST 52.3 0.22 1.6 Max 510-680 SAE 1541 0.36-0.44 1.35-1.65 706 MC 11 0.38 – 0.44 0.65 – 0.75 685 - 880 IS 7226 C40 0.35-0.45 0.6-0.9 680 - 870 #Grades are denoted as per the standards of SAE societies. These mechanical properties are not sufficient for making steel tubes deserve to achieve desired eventual product with high tensile strength for textile industry. Further, during welding, the level of dimensional tolerance achieved is very fluctuating. Hence to counter these issues, the welded steel tubes are subsequently cold drawn at room temperature. This cold drawing process serves to reduce cross section area of the steel tubes without damage to the surface finish and also to achieve close dimensional tolerance on internal diameter. Close dimension or even surface is particularly requisite in textile industry as the additives are attached at the either or both ends which mainly include spindle guides, top adaptors, bottom adaptors and ABS antistatic sleeve. Further, close dimension control is requisite quality for vibration free and silent operation. In drawing process tensile strength of the steel tubes can be elevated to a level of 550-850 MPa while percentage elongation is reduced to about 6 to 10 % with reference to primary tubes. During the cold drawn step, an undesirable stress is developed in the steel tubes. Hence, to relieve supposed stress, the cold drawn steel tubes are then straightened on hyperbolic 6 rolls machine. This process is done with tubes inputs from one end and if required the tubes direction is reversed to again pass through the straightening machine with a view to make sure that straightness is achieved. Then after, for achieving desirable mechanical properties in resultant steel tubes, final hardening is carried out by induction hardening process to generate fine grains in the re-crystallization thereby enduring strength of steel tubes. In hardening process, the steel tubes are heated for induction hardening at about 900 °C. The time generally depends upon the dimension and thickness of the tubes, after which tensile strength shall go beyond 1600-1700 MPa and percentage elongation is limited to a level of 8 to 15 % with reference to cold drawn steel tubes. This hardening process is done by various methods which include perspective hardening, salt hardening and induction hardening. The resultant steel tubes obtained by the foregoing method of the invention from various steel grades having higher ductility, consistent and less breakable than conven¬tional steel tubes are substantially suitable for textile industry. The present method provides tensile strength and consistant product by following steps: (a) The strip of basic steel grade is selected as a feed stock; (b) The said strip is welded through electric welding resistance (ERW) to form the primary tube; (c) The primary tube is cold drawn to achieve specific diameter in the tube; (d) The said tube is further straightened on hyperbolic straightening machine and transversally split in to desired length; (e) The said tube is hardened by induction hardening at 900 °C to achieve high tensile strength; (f) The tube is quenched by water to obtain final product. The invention is illustrated more in details in the following example. The example describes and demonstrates embodiments within the scope of the present invention. This example is given solely for the purpose of illustration and is not to be construed as limitations of the present invention, as many variations thereof are possible without departing from spirit and scope. Example 1: a) The suitable steel stripe of SAE 1020 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of SAE 1020. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – I Segment of Process Tensile strength (MPa) % Elongation Hardness HV- 10 scale Yield 0.2% Proof Stress MPa After rolling (ERW) 420 20 190-220 350 After Cold Drawing 550 6-10 230-270 450 After Age hardening 1000 11 370-420 800 Example 2: a) The suitable steel stripe of SAE 1026 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of SAE 1026. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – II SAE 1026 Segment of Process Tensile strength (MPa) % Elongation Hardness HV-10 Scale Yield 0.2% Proof Stress MPa After rolling (ERW) 490 15 200-225 415 After Cold Drawing 610 6-8 250-300 425 After Age hardening 1100 10 375-425 900 Example 3 a) The suitable steel stripe of ST 52 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of ST 52. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – III Segment of Process Tensile strength (MPa) % Elongation Hardness HV – 10 Scale Yield 0.2% Proof Stress MPa After rolling (ERW) 490-630 20 200-270 350 After Cold Drawing 630-720 6-12 325-400 540-630 After Age hardening 1400-1600 8-14 450-550 1200-1300 Example 4 a) The suitable steel stripe of ST 52.3 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of ST 52.3. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – IV Segment of Process Tensile strength (MPa) % Elongation Hardness HV - 10 Scale Yield 0.2% Proof Stress Mpa After rolling (ERW) 510-680 22 225-275 HVIO Scale 350 After Cold Drawing 650-750 6-12 350-400 550-640 After Age hardening 1400-1600 8-14 450-550 HVIO Scale 1200-1350 Example 5: a) The suitable steel stripe of SAE 1541 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of SAE 1541. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – V Segment of Process Tensile strength (MPa) % Elongation Hardness HV – 10 Scale Yield 0.2% Proof Stress After rolling (ERW) 700-720 20 350 600 After Cold Drawing 820-850 6-12 450 700-750 After Age hardening 1600-1800 10-14 500-575 1200-1400 Example 6: a) The suitable steel stripe of MC 11 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of MC 11. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – VI Segment of Process Tensile strength (MPa) % Elongation Hardness HV – 10 Scale Yield 0.2% Proof Stress MPa After rolling (ERW) 700-730 20 350 600-620 After Cold Drawing 820-860 6-10 440-475 700-760 After Age hardening 1600-1800 10-15 510-580 1250-1450 Example 7: a) The suitable steel stripe of IS 7226 C40 was taken as feed stock. b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of IS 7226 C40. c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm. d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length. e) The said tube was subjected to induction hardening at temperature 900 °C in furnace. d) The said tube was subjected to water quenching to have final product. Table – VII Segment of Process Tensile strength (MPa) % Elongation Hardness HV- 10 Scale Yield 0.2% Proof Stress Mpa After rolling (ERW) 670-700 20 350 550-590 After Cold Drawing 780-820 6-12 450 680-720 After Age hardening 1400-1600 10-14 480-550 1100-1250 Result and Discussion: The result shown in table (I-VII) provides the clear indication about the improvement in the requisite characteristics for textile industry. Tensile strength of each steel grade is improved marginally with respect to primary tubes or ERW treated tubes. The cold drawn tubes show improvement in the strength and elongation in the range of 550-850 and 6-10% respectively. Cold drawn tubes were induction hardening provides improvement in the strength and elongation in the range of 1000-1800 and 10-14% respectively. It is to be noted that hardness is proportionally increases with the tensile strength of the steel tube. % Elongation is important criteria for ductility and close dimension. The said tensile strength is achieved by using combination of cold drawn and hardening process. Advantages of the process: Steel cops/bobbins/pirns produced by this process provides close tolerance, exceptional tensile strength with percentage elongation which provides ductility and lesser weight product. Reduction in weight by this process is 30% with respect to conventional methods. Close dimension in cops/bobbins/pirns provides precise fittings with spindles and components (adaptors etc.) Further this property leads to provide noise free operations in factory. If the improvement is calculated on practical basis then 140 to 240 gm weight reduction for each cops/bobbins/pirns will reflect in making process economical in terms of lower maintenance, electricity consumption and lower handling efforts. The high tensile strength provides durability and long life to the cops/bobbins/pirns which also provides multiple usage capability. Therefore this process provides economical significance with respect to current state of art. The steel cops/bobbins/pirns according to present invention have excellent ductility, reduced weight, suitable tensile strength and proof stress in resultant product for textile industry application. While various embodiments of the present invention have been described in details, it is apparent that modification and adaptation of those embodiments will occur to those skilled in the art. It is expressly understood, however, that such modifications and adaptations are within the spirit and scope of the present invention as set forth in the following claims.

Claims:We Claim,
1. A process for manufacturing of steel cops/bobbins/pirns for synthetic yarn comprising following steps:

a) sealing of two edges of base strips by electric resistance welding (ERW) to form primary tube;
b) cold drawing the primary steel tubes, obtained in step (a), at a room temperature to reduce the cross section area and thickness of said welded steel tubes;
c) straightening the cold drawn steel bobbin at a room temperature to remove stress generated during step b);
d) carrying out hardening to further improve the mechanical strength and percentage elongation (ductility) in the straightened steel tubes obtained in step (c); and
e) quenching of the steel tubes, obtained in step (d), to render final products.
2. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein steel grade is selected from SAE 1020, SAE 1026, ST-52, ST-52.3, SAE 1541, MC-11 and IS 7226 C40.

3. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein the step (c) is carried out by hyperbolic 6 roll machine.

4. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein the hardening process is carried out by perspective hardening, salt hardening and induction hardening.

5. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein the step (d) is carried out at in furnace at 900 °C.

6. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in claim 1 wherein solution treatment is carried out by fog or water quenching after straightening the cold drawn steel tubes.

7. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn as claimed in as claimed in claim 1 wherein weight reduction in product is 30%.

8. The process for manufacturing of steel cops/bobbins/pirns for synthetic yarn in as claimed in claim 1, wherein the mechanical properties includes improvement in tensile strength and percentage elongation, reduction in cross section area, reduction in weight and achievement of the precise dimensional tolerance includes tolerance on internal diameter and uniform thickness of the steel tubes.

Dated this 3rd Day of February, 2016
, Description:FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION: PROCESS FOR MANUFACTURING OF STEEL COPS/BOBBINS/PIRNS FOR SYNTHETIC YARN

2. APPLICANT:
(a) NAME : Siddhi Engineers
(b) NATIONALITY : Indian
(c) ADDRESS : “SIDDHI HOUSE”
6, Virkunj Society,
Nr. Vidyanagar School,
Usmanpura, Ahmedabad-380014
3. PREMABLE TO THE DESCRIPTION
PROVISIONAL

The following specification describes the invention. ? COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention
The present invention relates to a process for manufacturing of metal cops/bobbins/pirns for synthetic yarn more particularly it relates to manufacturing of metal cops or bobbin made-up of steel and other components for winding of nylon and polyester yarns.

Back ground and prior art of the invention
Synthetic yarns have become popular on account of their ideal characteristics for clothes which mainly includes more compact molecular structure, creases can be heat-set at higher temperatures, better weathering properties; better sunlight resistance, superior colourfastness, excellent abrasion resistance, greater elasticity and elastic recovery.
Nylon and polyester are generic designations for a family of synthetic polymers, more specifically aliphatic or semi-aromatic polyamides. Nylon polymers have found significant commercial applications in fibers (apparel, flooring and rubber reinforcement), in heavy industries (molded parts for cars, electrical equipment, etc.) and in films (mostly for food packaging). Various grades (i.e. N6 and N66) are available in nylon as per the requirement of textile industries.
Nylon has an inherent tendency to shrink once wound on any object that lead to create pressure of the nylon flat yarn on cops/bobbins/pirns which lead to bulge from the centre resulting into stoppage of the whole winding panel. It is also important to have excellent dimension control and high tensile strength for exact fitment on the spindle.
For manufacturing end products from the yarn an extrusion plant is used which produces flat yarn of the nylon is used as the raw material. The flat yarn is continuously wound on cops/bobbins/pirns by draw twisting process on draw twisting machine & splitting machines. Large numbers of cops/bobbins/pirns (i.e. 144 or 156) are used simultaneously for the purpose of winding. Such yarn which is wound on the cops/bobbins is then taken to weaving process.
The winding process which involves winding of nearly 144 or 156 cops/bobbins/pirns at a time with one forth number of electric motors makes the process very high energy consuming. The cops/bobbins/pirns is mounted on spindle where they rotate at high speed in the range of 10000-18000 RPM. If the cops/bobbins does not have accurate dimension then fitment of the cops/bobbins/pirns on spindle is not accurate which lead to poor winding and vibration in the system. If the cops/bobbins/pirns does not have enough strength then the same will bulge leading to loss of yarn and also blocking of such spindles leading to productivity issues.
Steel tubes as well as aluminium tubes have been traditionally used for manufacturing cops/bobbins/pirns. Aluminium is more costly and pure aluminium doesn’t have high tensile strength compared to steel that diminish its use for cops/bobbins/pirns manufacturing.
Conventionally, various methods for manufacturing of cold drawn steel products are available. For example, Chinese patent application CN102764958, discloses cold rolled/cold drawn precision welded steel pipe manufacturing process. The process provides improvement tensile strength, the surface hardness and the wear resistance of the steel pipe. The said improvement shows resultant tensile strength in range of 530-560 MPa compared to initial strength in the range of 450-480 MPa. Further said process doesn’t provide idea about induction hardening. The tensile strength and hardness of the product obtained is not sufficient to withstand pressure generated by synthetic yarn.
Hence, to overcome above mentioned problems (i.e. bulging of the cops/bobbins/pirns non accurate fitting of the cops/ bobbins/pirns, very high electricity consumption and very high maintenance), it is desperately needed to invent a method of manufacturing steel cops/bobbins/pirns for textile industry which is not subjected to aforesaid problems so that the finally obtained steel cops/bobbins/pirns which has desired mechanical properties, consistent, lower maintenance and high level tolerance that is suitable for using in textile industry.

Object of the invention
The main object of present invention is to provide a method of manufacturing cops/bobbins/pirns made up of steel for winding synthetic yarn.
Another object of the present invention is to provide a method for manufacturing cops/bobbins/pirns made up of steel having excellent ductility, % elongation, high tensile strength and proof stress for winding nylon or polyester yarn.
Another object of the present invention is to provide a method of manufacturing cops/bobbins/pirns made up of steel with a low maintenance, lesser electricity consumption due to light weight and precise fitting for end products.
Another object of the present invention is to provide cops/bobbins/pirns, made-up of steel, with characteristics of multiple usage in winding yarn.
Yet another object of the present invention is to provide a light weight though high tensile steel cops/bobbins/pirns for winding.
Further object of present invention is to provide a method of manufacturing cops/bobbins/pirns from different steel grades (i.e. ST- 52.3 or SAE-1541 etc.).

Summary of the Invention
The present invention relates to a process for manufacturing of steel cops/bobbins/pirns for winding synthetic textiles fibres. The present invention provides light weight, strong and precise product made-up of specific steel grade (i.e. ST- 52.3 or SAE-1541 etc.) duly cold drawn and induction harden to achieve consistency, very high strength to weight ratio and improved % elongation. The present invention utilizes strip of one steel grade as a feed stock which undergoes electric welding to obtain primary tube. The primary tubes of steel are subjected to a cold drawn to obtained ultimate dimension control then sequentially it is subjected to induction hardening to achieve high tensile strength up to 1600-1700 MPa. After induction hardening, tubes are further subjected to solution treatment by special quenching of fog or water. The present process provides advantages in steel cops/bobbins/pirns like light weight, consistency, high tensile strength, economically significant and multiple usage capability compared to conventional processes.

Detail description of the Invention
Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompany drawings. The invention is capable of other embodiments, as depicted in figure as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.
Dimension and weight of steel cops/bobbins/pirns used conventionally are varies as per the ultimate applications. Conventionally the outer diameter ranges from 44.45 mm to 51 mm. The length of cops/bobbins/pirns ranges from 305 mm to 450mm. The inner diameter depends on the ultimate thickness and uniformity of the cops/bobbins/pirns. The thickness of cops/bobbins/pirns is normally ranges from 0.70 - 1.30 mm. Based on the varying dimension weight of the cops/bobbins/pirns are in the range of 300 to 750 gm.
The method for manufacturing steel cops/bobbins/pirns for synthetic yarn primarily uses strips of the basic steel as feed stock. This strip is further subjected to Electric resistance welding (ERW). This welding process provides seam welding to flange of strips by producing coalescence of surfaces where heat to form the weld is generated by the electrical resistance (10000 A). The principal behind this welding is based on material deformation with the time and the force used to hold the materials together during welding. This welding process ultimately gives tube with basic characteristic of basic steel. Different grades of steels have different tensile strength, hardness and % elongation. The requirement of further processing is needed as basic raw material doesn’t have requisite characteristics for cops/bobbins/pirns manufacturing. The present process is investigated on various steel grades (SAE 1020, SAE 1026, ST 52, ST 52.3, SAE 1541, MC 11 and IS 7226 C40. These steel grades are evaluated for improvement in tensile strength, hardness and % elongation. The basic strips of steel are selected as feed stock or raw material. The said strips are subjected to splitting in predefined length which will undergo sealing the ends to form tube. The said steel grades have tensile strength in range of 400 – 700 MPa depending on the grades of steel. Composition and tensile strength of various steel grades is given in table 1.
Table - A
Steel grade# Carbon (%) Manganese (%) Ultimate tensile strength
SAE 1020 0.18 – 0.23 0.3-0.6 420
SAE 1026 0.22 – 0.28 0.6-0.9 490
ST 52 0.2 0.9-1.7 490-630
ST 52.3 0.22 1.6 Max 510-680
SAE 1541 0.36-0.44 1.35-1.65 706
MC 11 0.38 – 0.44 0.65 – 0.75 685 - 880
IS 7226 C40 0.35-0.45 0.6-0.9 680 - 870
#Grades are denoted as per the standards of SAE societies.
These mechanical properties are not sufficient for making steel tubes deserve to achieve desired eventual product with high tensile strength for textile industry. Further, during welding, the level of dimensional tolerance achieved is very fluctuating. Hence to counter these issues, the welded steel tubes are subsequently cold drawn at room temperature. This cold drawing process serves to reduce cross section area of the steel tubes without damage to the surface finish and also to achieve close dimensional tolerance on internal diameter. Close dimension or even surface is particularly requisite in textile industry as the additives are attached at the either or both ends which mainly include spindle guides, top adaptors, bottom adaptors and ABS antistatic sleeve. Further, close dimension control is requisite quality for vibration free and silent operation. In drawing process tensile strength of the steel tubes can be elevated to a level of 550-850 MPa while percentage elongation is reduced to about 6 to 10 % with reference to primary tubes.
During the cold drawn step, an undesirable stress is developed in the steel tubes. Hence, to relieve supposed stress, the cold drawn steel tubes are then straightened on hyperbolic 6 rolls machine. This process is done with tubes inputs from one end and if required the tubes direction is reversed to again pass through the straightening machine with a view to make sure that straightness is achieved.
Then after, for achieving desirable mechanical properties in resultant steel tubes, final hardening is carried out by induction hardening process to generate fine grains in the re-crystallization thereby enduring strength of steel tubes. In hardening process, the steel tubes are heated for induction hardening at about 900 °C. The time generally depends upon the dimension and thickness of the tubes, after which tensile strength shall go beyond 1600-1700 MPa and percentage elongation is limited to a level of 8 to 15 % with reference to cold drawn steel tubes. This hardening process is done by various methods which include perspective hardening, salt hardening and induction hardening. The resultant steel tubes obtained by the foregoing method of the invention from various steel grades having higher ductility, consistent and less breakable than conven¬tional steel tubes are substantially suitable for textile industry.
The present method provides tensile strength and consistant product by following steps:
(a) The strip of basic steel grade is selected as a feed stock;
(b) The said strip is welded through electric welding resistance (ERW) to form the primary tube;
(c) The primary tube is cold drawn to achieve specific diameter in the tube;
(d) The said tube is further straightened on hyperbolic straightening machine and transversally split in to desired length;
(e) The said tube is hardened by induction hardening at 900 °C to achieve high tensile strength;
(f) The tube is quenched by water to obtain final product.
The invention is illustrated more in details in the following example. The example describes and demonstrates embodiments within the scope of the present invention. This example is given solely for the purpose of illustration and is not to be construed as limitations of the present invention, as many variations thereof are possible without departing from spirit and scope.

Example 1:
a) The suitable steel stripe of SAE 1020 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of SAE 1020.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – I
Segment of Process Tensile strength (MPa) % Elongation Hardness
HV- 10 scale Yield 0.2%
Proof Stress MPa
After rolling
(ERW) 420 20 190-220 350
After Cold Drawing 550 6-10 230-270 450
After Age hardening 1000 11 370-420 800

Example 2:
a) The suitable steel stripe of SAE 1026 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of SAE 1026.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – II
SAE 1026
Segment of Process Tensile strength (MPa) % Elongation Hardness
HV-10 Scale Yield 0.2%
Proof Stress MPa
After rolling
(ERW) 490 15 200-225 415
After Cold Drawing 610 6-8 250-300 425
After Age hardening 1100 10 375-425 900

Example 3
a) The suitable steel stripe of ST 52 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of ST 52.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – III
Segment of Process Tensile strength (MPa) % Elongation Hardness
HV – 10 Scale Yield 0.2%
Proof Stress MPa
After rolling
(ERW) 490-630 20 200-270 350
After Cold Drawing 630-720 6-12 325-400 540-630
After Age hardening 1400-1600 8-14 450-550 1200-1300

Example 4
a) The suitable steel stripe of ST 52.3 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of ST 52.3.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – IV
Segment of Process Tensile strength (MPa) % Elongation Hardness
HV - 10 Scale Yield 0.2%
Proof Stress Mpa
After rolling
(ERW) 510-680 22 225-275
HVIO Scale 350
After Cold Drawing 650-750 6-12 350-400 550-640
After Age hardening 1400-1600 8-14 450-550
HVIO Scale 1200-1350

Example 5:
a) The suitable steel stripe of SAE 1541 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of SAE 1541.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – V
Segment of Process Tensile strength (MPa) % Elongation Hardness HV – 10 Scale Yield 0.2%
Proof Stress
After rolling
(ERW) 700-720 20 350 600
After Cold Drawing 820-850 6-12 450 700-750
After Age hardening 1600-1800 10-14 500-575 1200-1400

Example 6:
a) The suitable steel stripe of MC 11 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of MC 11.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – VI
Segment of Process Tensile strength (MPa) % Elongation Hardness
HV – 10 Scale Yield 0.2%
Proof Stress MPa
After rolling
(ERW) 700-730 20 350 600-620
After Cold Drawing 820-860 6-10 440-475 700-760
After Age hardening 1600-1800 10-15 510-580 1250-1450

Example 7:
a) The suitable steel stripe of IS 7226 C40 was taken as feed stock.
b) The said strip was welded through electronic resistance welding at flanges to form the primary tube of IS 7226 C40.
c) The said tube was cold drawn at room temperature to have thickness in dimension of 47.85mm × 0.8 mm.
d) The said tubes were straightened on hyperbolic straightening machine and then transversally split to 380mm length.
e) The said tube was subjected to induction hardening at temperature 900 °C in furnace.
d) The said tube was subjected to water quenching to have final product.
Table – VII
Segment of Process Tensile strength (MPa) % Elongation Hardness
HV- 10 Scale Yield 0.2%
Proof Stress Mpa
After rolling
(ERW) 670-700 20 350 550-590
After Cold Drawing 780-820 6-12 450 680-720
After Age hardening 1400-1600 10-14 480-550 1100-1250

Result and Discussion:
The result shown in table (I-VII) provides the clear indication about the improvement in the requisite characteristics for textile industry. Tensile strength of each steel grade is improved marginally with respect to primary tubes or ERW treated tubes. The cold drawn tubes show improvement in the strength and elongation in the range of 550-850 and 6-10% respectively. Cold drawn tubes were induction hardening provides improvement in the strength and elongation in the range of 1000-1800 and 10-14% respectively. It is to be noted that hardness is proportionally increases with the tensile strength of the steel tube. % Elongation is important criteria for ductility and close dimension. The said tensile strength is achieved by using combination of cold drawn and hardening process.

Advantages of the process:
Steel cops/bobbins/pirns produced by this process provides close tolerance, exceptional tensile strength with percentage elongation which provides ductility and lesser weight product. Reduction in weight by this process is 30% with respect to conventional methods. Close dimension in cops/bobbins/pirns provides precise fittings with spindles and components (adaptors etc.) Further this property leads to provide noise free operations in factory. If the improvement is calculated on practical basis then 140 to 240 gm weight reduction for each cops/bobbins/pirns will reflect in making process economical in terms of lower maintenance, electricity consumption and lower handling efforts. The high tensile strength provides durability and long life to the cops/bobbins/pirns which also provides multiple usage capability. Therefore this process provides economical significance with respect to current state of art.
The steel cops/bobbins/pirns according to present invention have excellent ductility, reduced weight, suitable tensile strength and proof stress in resultant product for textile industry application.
While various embodiments of the present invention have been described in details, it is apparent that modification and adaptation of those embodiments will occur to those skilled in the art. It is expressly understood, however, that such modifications and adaptations are within the spirit and scope of the present invention as set forth in the following claims.