US 11,549,157 B2Granted

Method for modifying surface grain structure of the material and apparatus thereof

AssigneeShiv Nadar University

InventorsHarpreet Singh, Harpreet Singh Grewal, Jaskaran Singh Saini, Karthikeyan Selvam

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Abstract

The present invention provides a simple, cost effective and hassle-free method and apparatus for modifying the surface grain structure of the material, thereby providing a material with multi-modal grain structure having high strength and good formability. The present invention uses a single step processing technique known as submerged static friction stir processing for modifying the surface grain structure of the material, thereby generating a multi-modal grain structure. In the present invention since the working material is completely immersed in the coolant, this maintains the working temperature of the system. Further the present invention does not involve long processing steps and do not need any specialized equipments.

Claims14

Dependent claims

An apparatus (100) for modifying surface grain structure of a material, for generating a multi-modal grain structure, comprising of:

a. a work station (101), for processing the working material;
b. a fastener, wherein the working material of required dimension and thickness is fastened to the work station (101) by the fastener;
c. a spindle (102), positioned above the work station (101) at a pre-defined height, said height of the spindle (102) from the work station is adjustable, said spindle (102) is movable, wherein the spindle (102) is rotated at pre-defined speed;
d. a collet, affixed inside the spindle (102);
e. a probing pin, accommodated within the collet;
f. a motor, said motor is operatively connected to the spindle (102), wherein said motor provides rotational energy to the spindle (102);
g. a controller, said controller controls the movement, rotation speed and the height adjustment of the said spindle (102);
h. a chamber (103), positioned on top of the work station (101), wherein said chamber (103) accommodates the fastener, coolant, working material held in place by the fastener, an inlet (104) and an outlet (105);
i. a cooling unit (106), said cooling unit (106) conducts a cooling medium to the said chamber (103) through the said inlet (104) and the said outlet (105) wherein said coolant temperature ranges from −100 to +30 degree Celsius;
and
j. a power source, said power source supplies power to the said cooling unit (106), said motor and said work station (101),
wherein the probing pin rotating at a speed of 1000-2500 rpm generates a bi-modal grain structure comprising coarse grain of 15 μm and fine grain on the boundaries of about 1 μm.

9 more elements

A method for modifying surface grain structure of a material, for generating a multi-modal grain structure, comprising of,

a. fixing the working material to the work station (101)
b. supplying power to the work station (101), the motor, and the cooling unit (106) via the power source;
c. circulating the cooling medium from/to the cooling unit (106) to/from the chamber (103) through the inlet (104) and the outlet (105), to maintain a pre-defined temperature of the chamber, wherein the working material is submerged by the cooling medium in the chamber (103) wherein said pre-defined temperature of the cooling medium in the said chamber (103) ranges from −100 to +30 degree Celsius;
d. rotating the said probing pin affixed to the spindle (102) at a pre-defined rotational speed, wherein the said motor provides rotational energy to the spindle (102), wherein said spindle (102) rotates at a pre-defined rotational speed, thereby rotating the said probing pin;
e. bringing the rotating probing pin in contact at a specified location of the surface of the working material, wherein the said probing pin penetrates through the material at a pre-defined depth;
f. continuing the rotational process of the probing pin at a pre-defined rotational speed for a pre-defined time period at a specified location on the surface of the working material;
g. removing the rotating probing pin from the material after the pre-defined time period of rotation;
and
h. shutting off the power supply from the power source,
wherein the probing pin rotating at a speed of 1000-2500 rpm generates a bi-modal grain structure comprising coarse grain of 15 μm and fine grain on the boundaries of about 1 μm.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/631,356Filed 4 Jan 2018
Priority: IN 20171102556219 Jul 2017
Published: US 2020/0140967 A17 May 2020
Granted: 10 Jan 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

C21D 7/13
Modifying the physical properties of iron or steel by deformation: by hot working
B23K 20/1235
Controlling or monitoring the welding process: with temperature control during joining
B23K 20/1275
Using a non-consumable tool, e.g. friction stir welding: involving metallurgical change
C21D 2221/00
Treating localised areas of an article