Title of Invention	A METHOD OF MANUFACTURE OF A METALIC MEMBER OF IMPROVED FATIGUE STRENGTH AND A DEVICE FOR CARRYING OUT THE SAID METHOD
Abstract	A method of manufacture of a metallic member of improved fatigue strength comprising the steps of submerging the specimen of the said material in the container of liquid- Ultrasonic vibrations are generated within the liquid close to the surface of the said specimen. Thereby innumerable gas/ vapour filled bubbles are created in the liquid, imploding on the surface of the said specimen. PRICE; THIRTY RUPEES

Title of Invention

A METHOD OF MANUFACTURE OF A METALIC MEMBER OF IMPROVED FATIGUE STRENGTH AND A DEVICE FOR CARRYING OUT THE SAID METHOD

Abstract

A method of manufacture of a metallic member of improved fatigue strength comprising the steps of submerging the specimen of the said material in the container of liquid- Ultrasonic vibrations are generated within the liquid close to the surface of the said specimen. Thereby innumerable gas/ vapour filled bubbles are created in the liquid, imploding on the surface of the said specimen. PRICE; THIRTY RUPEES

Full Text	This invention relates to a method of manufacture of a metallic member of improved fatigue strength and a device for carrying out the said method. Fatigue of metallic members constitutes an important aspect of engineering design, because a very large majority of industrial components are subjected to some form of repeated (cyclic), rather than monotonic, loading. Failure has been known to occur, generally, more due to fatigue than a single (intolerable) overload. The method and the device proposed herein are intended to improve the fatigue strength of metallic members, having regard to the fact that it is always desirable to have compressive residual stresses at the surface of a component if its fatigue life is to be improved. The usual means by which this is done is through impinging steel or cast iron shots at high velocities on to the component. This is commonly referred to as shot peening, an operation which is popular and is practised even today in industries. We 'have proposed a method and a device employing ultrasonic vibrations which, when set up in a liquid, create severe cavitational effects giving rise to innumerable gas/vapour filled bubbles in the liquid, imploding on the surface of a metallic member submerged therein, simulating a shot peening situation. One of the salient advantages of this invention is that it is applicable to objects of complex shapes which are commonly encountered in industrial components. Submerging the member in a liquid does not necessarily mean that the whole member should be submerged. It would suffice to have the surface to be treated alone below the level of liquid. Various other features of this invention will be apparent from the following further description thereof. The method of manufacture of a metallic member of improved fatigue strength, according to this invention, comprises the steps of submerging the specimen of the said material in a container of liquid; generating) ultrasonic vibrations within the liquid close to the surface of the said specimen, thereby creating innumerable gas/vapour filled bubbles, in the liquid, imploding on the surface of the said specimen. The device for the manufacture of a metallic member of improved fatigue strength, according to this invention, comprises a control unit incorporating means for generating an electrical output of ultrasonic frequency , a frequency meter and timer; a magnetostrictive transducer for receiving the said output and thereby generating ultrasonic vibrations; at least one concentrator coupled to the transducer, whereby whenever the tip of the concentrator is introduced into a liquid in a container in which the said member is submerged, ultrasonic vibrations set up by the concentrator in the liquid, close to the surface of the said member, create innumerable gas/ vapour filled bubbles, in the liquid, imploding on the surface of the said specimen, the timer indicating the duration of the implosion and the frequency meter indicating the frequency of the vibrations. This invention will now be described with reference to the accompanying drawings, which illustrate, by way of example, in Fig.l a layout of the said device in Fig.2 the concentrator introduced into a liquid in a container wherein the member whose fatigue life is to be improved is submerged. The control unit has an ultrasonic frequency power output. This is made possible by the dc power supply P, power inverter I, oscillator O and matching circuit M with dc bias D. The time T and frequency meter F included in the power control unit indicate, respectively, the duration of operation of the device and the frequency of the ultrasonic wave generated. The ultrasonic frequency output is fed to the magnetostrictive transducer E to generate vibrations. At least one concentrator C is coupled to the transducer E. Two or more concentrators may be used depending upon the requirements of a particular application. The tip of the concentrator C is introduced into the liquid L in a container Q. wherein the member J is submerged. The ultrasonic vibrations set up by the concentrator, in the liquid, give rise to innumerable gas/vapour filled bubbles in the liquid which implode on the surface of the member J simulating a shot peening effect responsible for production of high compressive stresses on the said surface, thereby improving the fatigue strength of the said member. It will be observed that this invention can treat selected surface portions of the member , leaving the rest untouched. The terms and expressions in this specification are of description and not of limitation, there being no intention in the use of such terms and expressions of excluding any equivalents of the features illustrated and described, having regard to the scope and ambit of this invention. We Claim: 1.A method of manufacture of a metallic member of improved fatigue strength comprising the steps of submerging the specimen of the said material in a container of liquid; generating ultrasonic vibrations within the liquid close to the surface of the said specimen, thereby creating innumerable gas/ vapour filled bubbles, in the liquid, imploding on the surface of the said specimen. 2.A method of manufacture of a metallic member of improved fatigue strength substantially as herein described with reference to, and as illustrated in, the accompanying drawings. 3. A device for member of improved control unit incorporating means for generating an electrical output of ultrasonic frequency , a frequency meter and timer; a magnetostrictive transducer for receiving the said output and thereby generating ultrasonic vibrations; at least one concentrator coupled to the transducer, whereby whenever the tip of the concentrator is the said member is submerged, ultrasonic vibrations set up by the concentrator in the liquid, close to the surface of the said member, create innumerable gas/ vapour filled bubbles, in the liquid, imploding on the surface of the said specimen, the timer indicating the duration of ther implosion and the frequency meter indicating the frequency of the vibrations. 4.A device for member of improved as herein described with reference to, and as illustrated in, the accompanying drawings.

Full Text

This invention relates to a method of manufacture of a metallic member of improved fatigue strength and a device for carrying out the said method.
Fatigue of metallic members constitutes an important aspect of engineering design, because a very large majority of industrial components are subjected to some form of repeated (cyclic), rather than monotonic, loading. Failure has been known to occur, generally, more due to fatigue than a single (intolerable) overload.
The method and the device proposed herein are intended to improve the fatigue strength of metallic members, having regard to the fact that it is always desirable to have compressive residual stresses at the surface of a component if its fatigue life is to be improved. The usual means by which this is done is through impinging steel or cast iron shots at high velocities on to the component. This is commonly referred to as shot peening, an operation which is popular and is practised even today in industries.
We 'have proposed a method and a device employing

ultrasonic vibrations which, when set up in a liquid, create severe cavitational effects giving rise to innumerable gas/vapour filled bubbles in the liquid, imploding on the surface of a metallic member submerged therein, simulating a shot peening situation.
One of the salient advantages of this invention is that it is applicable to objects of complex shapes which are commonly encountered in industrial components.
Submerging the member in a liquid does not necessarily mean that the whole member should be submerged. It would suffice to have the surface to be treated alone below the level of liquid.
Various other features of this invention will be apparent from the following further description thereof.
The method of manufacture of a metallic member of improved fatigue strength, according to this invention, comprises the steps of submerging the specimen of the said material in a container of

liquid; generating) ultrasonic vibrations within the liquid close to the surface of the said specimen, thereby creating innumerable gas/vapour filled bubbles, in the liquid, imploding on the surface of the said specimen.
The device for the manufacture of a metallic member of improved fatigue strength, according to this invention, comprises a control unit incorporating means for generating an electrical output of ultrasonic frequency , a frequency meter and timer; a magnetostrictive transducer for receiving the said output and thereby generating ultrasonic vibrations; at least one concentrator coupled to the transducer, whereby whenever the tip of the concentrator is introduced into a liquid in a container in which the said member is submerged, ultrasonic vibrations set up by the concentrator in the liquid, close to the surface of the said member, create innumerable gas/ vapour filled bubbles, in the liquid, imploding on the surface of the said specimen, the timer indicating the duration of the implosion and the frequency meter indicating the frequency of the vibrations.

This invention will now be described with reference to the accompanying drawings, which illustrate, by way of example, in Fig.l a layout of the said device
in Fig.2 the concentrator introduced into a liquid in a container wherein the member whose fatigue life is to be improved is submerged.
The control unit has an ultrasonic frequency power output. This is made possible by the dc power supply P, power inverter I, oscillator O and matching circuit M with dc bias D.
The time T and frequency meter F included in the
power control unit indicate, respectively, the
duration of operation of the device and the
frequency of the ultrasonic wave generated.
The ultrasonic frequency output is fed to the magnetostrictive transducer E to generate vibrations.
At least one concentrator C is coupled to the transducer E. Two or more concentrators may be used depending upon the requirements of a

particular application.
The tip of the concentrator C is introduced into the liquid L in a container Q. wherein the member J is submerged. The ultrasonic vibrations set up by the concentrator, in the liquid, give rise to innumerable gas/vapour filled bubbles in the liquid which implode on the surface of the member J simulating a shot peening effect responsible for production of high compressive stresses on the said surface, thereby improving the fatigue strength of the said member.
It will be observed that this invention can treat selected surface portions of the member , leaving the rest untouched.
The terms and expressions in this specification are of description and not of limitation, there being no intention in the use of such terms and expressions of excluding any equivalents of the features illustrated and described, having regard to the scope and ambit of this invention.

We Claim:
1.A method of manufacture of a metallic member of improved fatigue strength comprising the steps of submerging the specimen of the said material in a container of liquid; generating ultrasonic vibrations within the liquid close to the surface of the said specimen, thereby creating innumerable gas/ vapour filled bubbles, in the liquid, imploding on the surface of the said specimen.
2.A method of manufacture of a metallic member of improved fatigue strength substantially as herein described with reference to, and as illustrated in, the accompanying drawings.
3. A device for member of improved control unit incorporating means for generating an electrical output of ultrasonic frequency , a frequency meter and timer; a magnetostrictive transducer for receiving the said output and thereby generating ultrasonic vibrations; at least one concentrator coupled to the transducer, whereby whenever the tip of the concentrator is

the said member is submerged, ultrasonic vibrations set up by the concentrator in the liquid, close to the surface of the said member, create innumerable gas/ vapour filled bubbles, in the liquid, imploding on the surface of the said specimen, the timer indicating the duration of ther implosion and the frequency meter indicating the frequency of the vibrations.
4.A device for
member of improved
as herein described with reference to, and as
illustrated in, the accompanying drawings.

Documents:

875-mas-95 abstract.jpg

875-mas-95 abstract.pdf

875-mas-95 claims.pdf

875-mas-95 correspondence-others.pdf

875-mas-95 correspondence-po.pdf

875-mas-95 description (complete).pdf

875-mas-95 drawings.pdf

875-mas-95 form-1.pdf

875-mas-95 form-26.pdf

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Patent Number

191965

Indian Patent Application Number

875/MAS/1995

PG Journal Number

35/2005

Publication Date

16-Sep-2005

Grant Date

08-Aug-2005

Date of Filing

12-Jul-1995

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

IIT PO, CHENNAI 600 036.

Inventors:

#	Inventor's Name	Inventor's Address
1	PROF. RAMASWAMI VASUDEVAN	INDIAN INSTITUTE OF TECHNOLOGY, IIT PO, CHENNAI - 600 036.
2	POORNA CHANDRA MAJHEE	INDIAN INSTITUTE OF TECHNOLOGY, IIT PO, CHENNAI - 600 036.
3	MELATHERU RAMANUJAM SRIRAMAN	INDIAN INSTITUTE OF TECHNOLOGY, IIT PO, CHENNAI - 600 036.

PCT International Classification Number

F16C003/10

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA