High-strength steel wire material exhibiting excellent cold-drawing properties, and high-strength steel wire

Patent metadata

Field	Value
Publication number	US-9540718-B2
Application number	US-201414767208-A
Country	US
Kind code	B2
Filing date	Mar 25, 2014
Priority date	Mar 28, 2013
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A technique with which air blast cooling can be used to produce a high-strength steel wire material that achieves uniform high strength and high ductility, even when cold drawn; a high-strength steel wire produced from this high-strength steel wire material; and a zinc-plated high-strength steel wire. This high-strength steel wire material includes 0.80-1.3% of C, 0.1-1.5% of Si, 0.1-1.5% of Mn, more than 0% but not more than 0.03% of P, more than 0% but not more than 0.03% of S, 0.0005-0.01% of B, 0.01-0.10% of Al, and 0.001-0.006% of N, the remainder being iron and unavoidable impurities. The area ratio of pearlite in the structure of the high-strength steel wire material is at least 90%. The average grain size number (P ave ) of pearlite nodules and the standard deviation (Pσ) thereof respectively satisfy formula (1), namely 7.0≦P ave ≦10.0, and formula (2), namely Pσ≦0.6.

First claim

The invention claimed is:

1. A high-strength steel wire rod having good rod drawability, comprising:
C: 0.80 to 1.3% (by mass percent (the same applies to the following for the components));
Si: 0.1 to 1.5%;
Mn: 0.1 to 1.5%;
P: more than 0% and 0.03% or less;
S: more than 0% and 0.03% or less;
B: 0.0005 to 0.01%;
Al: 0.01 to 0.10%;
N: 0.001 to 0.006%; and
the remainder being iron and inevitable impurities,
wherein, in a microstructure of the steel wire rod, an area ratio of pearlite is 90% or more, and an average P ave and standard deviation Pσ of a pearlite nodule size number satisfy Formulas (1) and (2), respectively,
7.0≦ P ave ≦10.0  (1) and

Pσ≦ 0.6  (2).

2. The high-strength steel wire rod according to claim 1 , wherein an area ratio of grain-boundary ferrite grains is 1.0% or less.

3. The high-strength steel wire rod according to claim 1 , wherein C eq is 0.85 to 1.45%, the C eq being represented by Formula (3)
C eq =[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14  (3),

where [C], [Si], [Mn], [Ni], [Cr], [Mo], and [V] represent the respective contents (by mass percent) of C, Si, Mn, Ni, Cr, Mo, and V.

4. The high-strength steel wire rod according to claim 3 , further comprising at least one element selected from:
(a) Cr: more than 0% and 0.5% or less;
(b) V: more than 0% and 0.2% or less;
(c) at least one element selected from the group consisting of Ti: more than 0% and 0.2% or less and Nb: more than 0% and 0.5% or less;
(d) at least one element selected from the group consisting of W: more than 0% and 0.5% or less and Co: more than 0% and 1.0% or less;
(e) Ni: more than 0% and 0.5% or less; and/or
(f) at least one element selected from the group consisting of Cu: more than 0% and 0.5% or less and Mo: more than 0% and 0.5% or less.

5. A high-strength steel wire produced through wire-drawing of the high-strength steel wire rod according to claim 4 .

6. A high-strength galvanized steel wire produced by performing hot-dip galvanization on the high-strength steel wire according to claim 5 , wherein standard deviation WTSσ of tensile strength TS satisfies Formula (4)
WTSσ≦ 40(MPa)  (4).

Assignees

• Kobe Steel Ltd

Inventors

• Ishida Tomonobu
• Yoshihara Nao

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C22C38/001

  containing N · CPC title

• C22C38/08

  containing nickel {(C22C38/105 takes precedence)} · CPC title

• C22C38/24

  with vanadium · CPC title