Fe—Mn—C-based TWIP steel having remarkable mechanical performance at very low temperature, and preparation method thereof

Patent metadata

Field	Value
Publication number	US-10144982-B2
Application number	US-201214399515-A
Country	US
Kind code	B2
Filing date	Aug 17, 2012
Priority date	May 14, 2012
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

Provided is a Fe—Mn—C-based twinning-induced plasticity (TWIP) steel which includes 13 wt % to 24 wt % of manganese (Mn), 0.4 wt % to 1.2 wt % of carbon (C), and iron (Fe) as well as other unavoidable impurities as a remainder, is manufactured by caliber rolling, has a microstructure including elongated grains that are elongated in a rolling direction, and has an average grain size of the elongated grains in a direction perpendicular to the rolling direction of 1 μm or less.

First claim

The invention claimed is:

1. A method of manufacturing a twinning-induced plasticity (TWIP) steel, the method comprising the steps of:
(a) processing an alloy including 13 wt % to 24 wt % of manganese (Mn), 0.4 wt % to 1.2 wt % of carbon (C), and iron (Fe) as well as other unavoidable impurities as a remainder into a form capable of caliber rolling;
(b) heating the processed alloy to 700° C. to 1100° C. for 30 minutes to 5 hours, and then water-cooling the heated alloy; and
(c) heating the water-cooled alloy to 400° C. to 550° C. for 30 minutes to 5 hours, and then caliber rolling the heated alloy,
wherein the caliber rolling is performed at a reduction of area of 80% or more.

2. The method of claim 1 , wherein the heating in the step (b) is performed for 30 minutes to 2 hours.

3. The method of claim 1 , wherein the heating in the step (c) is performed for 30 minutes to 2 hours.

4. The method of claim 1 , wherein the reduction of area is achieved through 6 to 12 passes.

5. The method of claim 1 , wherein the TWIP steel is formed in a shape of a rod through the caliber rolling.

6. The method of claim 1 , wherein a microstructure of the TWIP steel comprises elongated grains that are elongated in a rolling direction, and an average grain size of the elongated grains in a direction perpendicular to the rolling direction is 1 μm or less.

7. The method of claim 1 , wherein the microstructure of the TWIP steel comprises elongated grains that are elongated in the rolling direction, and the average grain size of the elongated grains in the direction perpendicular to the rolling direction is 0.5 μm or less.

8. The method of claim 1 , wherein, when temperature is at −160° C., the TWIP steel has a yield strength of 1,000 MPa or more, a tensile strength of 1,600 MPa or more, and an elongation of 20% or more.

9. The method of claim 1 , wherein the TWIP steel has a product of tensile strength and total elongation of 40,000 MPa % or more at −160° C.

Assignees

• Lee Tae Kyung
• Lee Chong Soo
• Song Seok Weon
• Kim Jae Hyung
• Tsuzaki Kaneaki
• Koyama Motomichi
• Postech Acad Ind Found

Inventors

• Lee Tae Kyung
• Lee Chong Soo
• Song Seok Weon
• Kim Jae Hyung
• Tsuzaki Kaneaki
• Koyama Motomichi

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• C21D8/00 Primary

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• C21D6/005

  containing Mn · CPC title

• C21D8/065

  Chemistry & Metallurgy · mapped topic

• C21D8/005 Primary

  Chemistry & Metallurgy · mapped topic