DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A SYSTEM FOR INDUCTION HARDENING OF CONVEX PROFILE COMPONENTS

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru - 560 027,
Karnataka, India

The following specification particularly describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

[001] The present invention claims priority from Indian patent Provisional Application 202041003634 filed on 27 January 2020.

TECHNICAL FIELD
[002] The present subject matter described herein, in general, relates to a system for induction hardening of convex profile components.
BACKGROUND
[003] When the going gets huge, heavy and hard … very large bearings and rings are required to carry high loads and their resulting torques. Typical applications include general machinery, mining, marine, military-aerospace and construction equipment, as well as onshore and offshore energy technologies. These components are highly stressed and are, therefore, induction hardened to increase their dynamic strength and wear resistance.
[004] Generally, a quenching process is performed for rapid cooling of a workpiece in water, polymer, oil or air to obtain certain material properties. Spray quenching is one of the quenching processes that involves heat removal facilitated by the impingement of a quenchant medium on a hot metal surface.
[005] Conventionally, in a process of spray quenching, one or more components are heated all over and quenched in water spray with a quench pressure of 2.5Kg/cm² along with a rotation of the components of 10rpm. Typically, one or more convex profile components are processed using two half-convex profile shape coil, which may lead to an arc if the contact between the two coils are not properly tightened. Generally, stainless steel bolt is used for tightening. Coil cooling process is complicated and the cooling water leaks if the coil is not properly tightened or cleaned. Further, removing and fixing the two halves of the coil leads to wear and insufficient cooling of the coil. The insufficient cooling causes damage to the coil. In addition, loading and unloading time in the conventional process is higher and requires skilled operators to prevent damage to the coil and the components. The conventional process is complicated and causes blockage in the quench jacket. Further, frequent cleaning of the components is required to avoid wobbling during rotation of the component. In addition, the conventional process may lead to decreased productivity, and overheating of the components The above problems can be overcome by adopting a system for induction hardening of convex profile components.

OBJECT OF THE INVENTION
[006] Main object of the present invention to provide an induction hardening coil for convex profile components.
[007] Another object of the present invention to provide a single turn closed rectangular hollow copper coil for induction hardening.
[008] Yet another object of the present invention to reduce blockage in the coil quench box for easy cleaning, thereby reducing fatigue of operator.
[009] Yet another object of the present invention to reduce damage to the coil in a quenching process, thereby increasing productivity.
[0010] Yet another object of the present invention is to develop a simple and easy to mount design of induction hardening coil for convex profile components
SUMMARY
[0011] Before the present system and method are described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to a system for induction hardening of convex profile components, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[0012] The present invention discloses a system for induction hardening of convex profile components. The system for induction hardening of convex profile components may comprise of a single piece of copper coil configured with a single turn and a straight part with an inbuilt cooling provision. The system may lead to a higher productivity than spray quenching. For induction hardening, the component may be locally heated in the required area with a rotation of 10 rpm and quenched in water or a polymer. The coil design may be simple and without any joints. The system may eliminate arc in the coil during processing. Further, the system of present invention may eliminate overheating, development of soft patches, cracks and uneven hardening pattern of the components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawing:
[0014] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
[0015] Figure 1 illustrates a single turn closed rectangular hollow copper coil for induction heating, in accordance with one embodiment of the present subject matter.
[0016] Figure 2 illustrates a quenching jacket configured to quench the convex components after induction heating, in accordance with one embodiment of the present subject matter.
[0017] Figure 3 illustrates a convex component after induction hardening process, in accordance with one embodiment of the present subject matter.
[0018] Figure 4 illustrates a single turn closed rectangular hollow copper coil for induction heating with inlets and outlets for water cooling, in accordance with one embodiment of the present subject matter.
[0019] Figure 5 illustrates the complete induction hardening system with induction coil and quenching jacket and the component, in accordance with one embodiment of the present subject matter.
[0020] Figure 6 illustrates the top view of induction heating coil, in accordance with one embodiment of the present subject matter.
[0021] Figure 7 illustrates the top view of quenching jacket, in accordance with one embodiment of the present subject matter.
[0022] Figure 8 illustrates the front view of induction heating coil, in accordance with one embodiment of the present subject matter.
[0023] Figure 9 illustrates the side view of induction heating coil, in accordance with one embodiment of the present subject matter.
[0024] Figure 10 illustrates the front view of quenching jacket, in accordance with one embodiment of the present subject matter.
[0025] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0026] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, systems and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0027] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0028] Induction hardening is comprised of two process steps: heating followed by rapid cooling (quenching) with a quenching fluid. The heating is caused by alternating current flowing through a coil (sometimes called an inductor) that is sized and shaped according to the workpiece. The alternating coil current creates a corresponding alternating magnetic field that, in turn, induces eddy currents inside the workpiece. These eddy currents produce heat inside the workpiece. The heating depth is inversely proportional to coil current frequency. Higher frequencies produce shallower heating in the workpiece. This very useful phenomenon is known as the “skin effect.” Heat originates inside the workpiece and does not have to be transferred into the workpiece via radiation or convection at the surface. The heating period is therefore short (e.g., a few seconds), and unwanted core heating is avoided. In the next process step – quenching – the austenitized steel is rapidly cooled at a controlled rate. This rapid cooling prevents the diffusion of carbon atoms and the reformation of original ferrite and cementite mixture. Dissolved carbon atoms are trapped in the ferrite, causing the ferrite body-centered cubic (BCC) crystal structure to deform into a body-centered tetragonal (BCT) structure called martensite. The temperature difference and the cooling rate, which can be controlled by selecting the right quenching medium (such as oil, or water with polymer additives), determine the level of martensite formation. Faster cooling below the transformation temperature produces more martensite. The fresh martensite is hard and brittle. Tempering (controlled heating to prescribed moderate temperatures for defined time periods) reduces this brittleness and gives the steel the desired combination of hardness, strength and toughness.
[0029] With single-shot hardening, either the workpiece rotates past one or more stationary inductors or a complete 360-degree ring inductor interfaces with the entire workpiece. The entire bearing surface (race) is heated to the appropriate austenitizing temperature followed by a quench of the entire surface. Quenching may be done by submerging the workpiece in a bath or by using spray nozzles that are integrated into the inductors and tailored for the process requirements. The single-shot process is best suited for workpieces with a diameter less than 2 meters. The induction heating electrical-power requirement grows quadratically with increasing workpiece diameter. Compared to scan hardening, the single-shot process with its high power is very fast, typically measured in seconds. With single-shot hardening, either the workpiece rotates past one or more stationary inductors or a complete 360-degree ring inductor interfaces with the entire workpiece. The entire bearing surface (race) is heated to the appropriate austenitizing temperature followed by a quench of the entire surface. Quenching may be done by submerging the workpiece in a bath or by using spray nozzles that are integrated into the inductors and tailored for the process requirements. The single-shot process is best suited for workpieces with a diameter less than 2 meters. The induction heating electrical-power requirement grows quadratically with increasing workpiece diameter. Compared to scan hardening, the single-shot process with its high power is very fast, typically measured in seconds.
[0030] For induction hardening, the component may be locally heated in a required area with a rotation of 10 rpm and quenched in water or a polymer. The system may be simple, without any joints and easy to mount. The system may be easy to repair and may eliminate arc in the coil during processing. The operator may operate without a fear of shot circuit or arc. Further, the system may eliminate an overheating, soft patches, and cracks and uneven hardening pattern of the component. The system may reduce a setting time and increase productivity. The system may prevent a blockage in a coil quench box. Further, a pressure in the quench box may be uniform. The system may be easy to clean, thereby reducing a fatigue of the operator. Further, the system may reduce damage to the coil. Furthermore, the temperature and the water jet in the quench box may be easily monitored. In addition the power consumption by the system may be less as compared to the conventional technology. Further, the system may be easy to load and unload. The metallurgical properties of the components may be improved by local heating and a distortion during the process may be reduced. Further, the size of the coil and quenching jacket may vary according to the size of the component to be hardened.
[0031] Further, referring to figures 1 to 4. In one embodiment, the system may be used for induction hardening of convex profile components. The system may comprise an induction hardening coil. The induction hardening coil may be a single turn closed loop rectangular hallow copper coil. The induction hardening coil may have 99% purity and a thickness of 2mm. The induction hardening coil may comprise of at least one inlet (7) and at least one outlet (5). The at least one inlet (7) and at least one outlet (5) may be used for water-cooling of the induction hardening coil. Further, the coil is operated with an operating power of 80KW, a frequency of 10 KHz with a vertical movement of 2mm/sec and a quench pressure of 2.5Kg/cm².
[0032] Further, the system may comprise a mounting attachment and a quenching jacket. The quenching jacket may comprise a closed loop rectangular hallow copper coil with a thickness of 2mm and a hole size of 1.8 mm on the inner diameter. The coil may comprise of any other cross section. The quenching jacket may comprise four inlets (1) for quenching. Further, the induction hardening coil and a quench box may be insulated to avoid arc in the induction hardening coil.
[0033] Accordingly the present invention discloses a system for induction hardening of convex profile components comprising at least one hollow induction coil of conducting material with a predetermined profile configured to match the convex profile of the component for localized heating, wherein the hollow portion of the said coil is configured with cooling provision and at least one quenching jacket configured with plurality of quenching holes for quenching of component after induction heating, wherein said quenching jacket is provided with plurality of water inlet holes.
[0034] The induction hardening coil is configured with at least one inlet hole and at least one outlet hole for water cooling of the coil. The induction hardening coil is provided to be operated at a power of 80 KW, at frequency of 10 KHz, wherein the power and frequency of operation is configured to vary based on the size of the induction coil and component. The induction hardening coil adapted for vertical movement of 2 mm/sec, is configured to vary the speed of movement based on the size of the induction coil and component. The quenching jacket adapted to quench at pressure of 2.5Kg/cm² is configured to vary the pressure of quenching based on the size of the induction coil and component. The quenching jacket with a hollow copper coil of 2mm thickness and hole size of 1.8 mm on inner diameter is configured to vary the thickness and hole size based on the size of the induction coil and component. The quenching jacket is configured with 4 inlets for quenching after the induction heating, wherein the number of inlets are configured to vary based on the size of the induction coil and component. The size and profile of the induction coil and quenching jacket is configured to vary based on the size of the component. The induction hardening coil and quenching jacket are configured to be insulated to avoid arc in the induction hardening coil.
[0035] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0036] Some objects of the present invention enable to develop a simple and easy to mount design of induction hardening coil for convex profile components.
[0037] Some objects of the present invention reduce blockage in the coil quench box for easy cleaning, thereby reducing fatigue of operator.
[0038] Some objects of the present invention reduce damage to the coil in a quenching process, thereby increasing productivity.
[0039] Some objects of the present invention reduce overheating of the components integrated in the system.
[0040] REFERRAL NUMERALS:
Element Description Reference Numeral
Quenching inlet 1
Quenching outlet 3
Coil cooling outlet 5
Coil cooling inlet 7
Induction coil holder 9
Quenching jacket holder 11
Convex profile component 13
Induction coil 15
Quenching Jacket 17
Hardened part of convex component 19
Mounting holes for induction coil 21
Pipes for inlet of quenching jacket 23

,CLAIMS:
1. A system for induction hardening of convex profile components comprising:
at least one hollow induction coil of conducting material with a predetermined profile configured to match the convex profile of the component for localized heating, wherein the hollow portion of the said coil is configured with cooling provision; and
at least one quenching jacket configured with plurality of quenching holes for quenching of component after induction heating, wherein said quenching jacket is provided with plurality of water inlet holes.

2. The system for induction hardening of convex profile components as claimed in claim 1, wherein said induction hardening coil is configured with at least one inlet hole and at least one outlet hole for water cooling of the coil.

3. The system for induction hardening of convex profile components as claimed in claim 1, wherein said induction hardening coil is provided to be operated at a power of 80 KW, at frequency of 10 KHz, and wherein the power and frequency of operation is configured to vary based on the size of the induction coil and component.

4. The system for induction hardening of convex profile components as claimed in claim 1, wherein said induction hardening coil is adapted for vertical movement of 2 mm/sec, is configured to vary the speed of movement based on the size of the induction coil and component.

5. The system for induction hardening of convex profile components as claimed in claim 1, wherein said quenching jacket adapted to quench at pressure of 2.5Kg/cm² is configured to vary the pressure of quenching based on the size of the induction coil and component.

6. The system for induction hardening of convex profile components as claimed in claim 1, wherein said quenching jacket with a hollow copper coil of 2mm thickness and hole size of 1.8 mm on inner diameter is configured to vary the thickness and hole size based on the size of the induction coil and component.

7. The system for induction hardening of convex profile components as claimed in claim 1, wherein said quenching jacket is configured with 4 inlets for quenching after the induction heating, wherein the number of inlets are configured to vary based on the size of the induction coil and component.

8. The system for induction hardening of convex profile components as claimed in claim 1, wherein the size and profile of the induction coil and quenching jacket is configured to vary based on the size of the component.

9. The system for induction hardening of convex profile components as claimed in claim 1, wherein said induction hardening coil and quenching jacket are configured to be insulated to avoid arc in the induction hardening coil.