Torsional severe plastic deformation method for metal bar, employing surface polishing to improve mechanical properties of metal bar

Patent metadata

Field	Value
Publication number	US-2020009631-A1
Application number	US-201816495394-A
Country	US
Kind code	A1
Filing date	Feb 6, 2018
Priority date	Mar 20, 2017
Publication date	Jan 9, 2020
Grant date	—

Abstract

The present invention relates to a torsional severe plastic deformation method for a metal bar to which surface polishing is applied to the metal bar to improve the mechanical properties of the metal bar. According to an embodiment of the present invention, there is provided a torsional severe plastic deformation method for a metal bar, which includes: applying torsion to a metal bar; and removing a surface defect on the surface of the metal bar, the surface defect being caused by the applying of torsion, wherein the removing of the surface defect is carried out in a continuous manner in which the removing of the surface defect is performed together with the applying of torsion or in a discontinuous manner in which the applying of torsion is temporarily stopped and then the applying of torsion is performed, and the removing of a surface defect increases the amount of torsional rotation or the shear strain applied to the metal bar.

First claim

1 . A torsional severe plastic deformation method for a metal bar, comprising:
applying torsion to a metal bar; and removing a surface defect on the surface of the metal bar, the surface defect being caused by the applying of torsion, wherein the removing of the surface defect is carried out in a continuous manner in which the removing of the surface defect is performed together with the applying of torsion or in a discontinuous manner in which the applying of torsion is temporarily stopped and then the applying of torsion is performed, and the removing of a surface defect increases the amount of torsional rotation or the shear strain applied to the metal bar.

2 . The torsional severe plastic deformation method for a metal bar of claim 1 , wherein the removing of a surface defect comprises a polishing process.

3 . The torsional severe plastic deformation method for a metal bar of claim 2 , wherein a silicon carbide (SiC) grinding paper is used for the polishing process.

4 . The torsional severe plastic deformation method for metal bars of claim 2 , wherein the polishing process is performed by using a polishing material that can reduce the surface roughness of the metal bar according to the increase in the amount of torsional rotation or shear strain.

5 . The torsional severe plastic deformation method for a metal bar of claim 4 , wherein when the polishing process is performed in a discontinuous manner, the polishing process is performed so that the surface roughness of the metal rod is 5 um or less per torsion process.

Assignees

• Postech Acad Ind Found

Inventors

• Kim Hyoung-Seop
• Moon Ji-Hyun
• Um Ho-Yong
• Yoon Jae-Ik
• Baek Seung-Mi

Classifications

• C21D9/0075

  for rods of limited length (of unlimited length C21D9/52) · CPC title

• C21D7/10

  of the whole cross-section, e.g. of concrete reinforcing bars · CPC title

• C21D2261/00

  Machining or cutting being involved · CPC title

• B21J1/025

  affecting grain orientation · CPC title

• B24B27/033

  for grinding a surface for cleaning purposes, e.g. for descaling or for grinding off flaws in the surface · CPC title