# US 10,480,053 B2 · Austenitic light-weight high-strength steel with excellent properties of welds, and method of manufacturing the same

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- Number: US 10,480,053 B2
- Document ID: US10480053B2
- Status: Granted
- Kind: B2
- Application number: 14/951,400
- Filed: 2015-11-24
- Published: 2016-06-02
- Granted: 2019-11-19
- Earliest claimed: 2014-11-27
- Assignees: Korea Institute of Machinery & Materials
- Applicants: Korea Institute of Machinery and Materials
- Inventors: Joon-Oh Moon; Seong-Jun Park; Chang-Hoon Lee
- Web page: https://patentgrep.com/patent/US10480053B2

## CPC

- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C21D 6/005: {containing Mn}
- C21D 6/02: Hardening by precipitation
- C21D 8/00: 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)
- C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence)
- C21D 8/0226: {Hot rolling}
- C21D 8/0263: {following hot rolling}
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/38: with more than 1.5% by weight of manganese
- C21D 2211/001: Austenite
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)

## Abstract

The present invention relates to an austenitic light-weight high-strength steel with excellent properties of welds, and a method of manufacturing the same, the method including: (a) hot-rolling a steel including 20 wt % to 30 wt % of manganese (Mn), 6 wt % to 12 wt % of aluminum (Al), 0.6 wt % to 1.5 wt % of carbon (C), 0.3 wt % to 0.95 wt % of vanadium (V), and a remaining amount of iron (Fe) and other unavoidable impurities; (b) homogenizing the hot-rolled steel; and (c) aging the homogenized steel.

## Claims

### Claim 1

A method of manufacturing an austenitic steel, the method comprising:
hot-rolling a steel including 20 wt % to 30 wt % of manganese (Mn), 6 wt % to 12 wt % of aluminum (Al), 0.6 wt % to 1.5 wt % of carbon (C), 0.3 wt % to 0.95 wt % of vanadium (V), and a remaining amount of iron (Fe) and other unavoidable impurities;
homogenizing the hot-rolled steel; and
aging the homogenized steel,
wherein hot-rolling the steel comprises:
hot-rolling the steel under a finish rolling temperature ranging from 900° C. to 1000° C.; and
cooling the steel to 600° C. or less, wherein cooling the steel comprises cooling the steel at an average cooling rate ranging from 10° C./sec to 50° C./sec, and
wherein aging the homogenized steel comprises:
aging the homogenized steel at a temperature ranging from 540° C. to 560° C. for 10 minutes or more; and
cooling the steel to a temperature of 200° C. or less, at an average cooling rate of 10° C./sec or less.

### Claim 2 (depends on 1)

The method of claim 1, wherein the steel further includes 0.02 wt % to 0.06 wt % of niobium (Nb).

### Claim 3 (depends on 2)

The method of claim 2, wherein a total amount of niobium and vanadium is 0.35 wt % to 0.95 wt %.

### Claim 4 (depends on 1)

The method of claim 1, wherein homogenizing the hot-rolled steel comprises:
homogenizing the hot-rolled steel at a temperature ranging from 1000° C. to 1200° C. for a time ranging from 1 to 3 hours; and
cooling the steel to a temperature of 600° C. or less, at an average cooling rate of 10° C./sec or more.