High-strength and high-toughness ultrafine wire rod

Patent metadata

Field	Value
Publication number	US-9322075-B2
Application number	US-201113695121-A
Country	US
Kind code	B2
Filing date	May 6, 2011
Priority date	May 6, 2010
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

Provided is an ultra-fine grained, high-strength, high-toughness carbon steel wire rod manufactured through control of a microstructure by process control without addition of relatively expensive alloying elements. More particularly, the material provided is an ultra-fine grained, high-strength, high-toughness carbon steel wire rod having a microstructure including a ferrite structure having an area fraction of 60% or more and a cementite structure as a remainder, wherein an average grain diameter of ferrite grains is 15 μm or less. Also provided is a method of manufacturing the wire rod.

First claim

The invention claimed is:

1. An ultra-fine grained, high-strength, high-toughness wire rod having a microstructure comprising:
a ferrite structure having an area fraction of 60% or more; and
a cementite structure as a remainder,
wherein an average grain diameter of ferrite grains is 15 μm or less and the ferrite grains have a shape of bainitic ferrite,
wherein the wire rod comprises 0.15 wt % to 0.5 wt % of carbon (C), 0.1 wt % to 0.2 wt % of silicon (Si), 0.1 wt % to 0.7 wt % of manganese (Mn), and iron (Fe) as well as other unavoidable impurities as a remainder.

2. The ultra-fine grained, high-strength, high-toughness wire rod of claim 1 , wherein the ferrite has a crystal orientation measured by electron backscattered diffraction (EBSD) of 30 degrees or less.

3. The ultra-fine grained, high-strength, high-toughness wire rod of claim 1 , wherein the wire rod has a tensile strength of 1100 MPa or more and an elongation of 20% or more.

4. The ultra-fine grained, high-strength, high-toughness wire rod of claim 1 , wherein the wire rod has an ECO-index (tensile strength×ductility) of 2000 or more.

Assignees

• Kim Dong-Hyun
• Shin Woo-Gi
• Lee You-Hwan
• Posco

Inventors

• Kim Dong-Hyun
• Shin Woo-Gi
• Lee You-Hwan

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• C22C38/04 Primary

  containing manganese · CPC title

• C21D8/065

  Chemistry & Metallurgy · mapped topic

• C21D9/52 Primary

  for wires; for strips {; for rods of unlimited length} · CPC title

• C22C38/02

  containing silicon · CPC title