Si-killed steel wire rod and spring

Patent metadata

Field	Value
Publication number	US-9725779-B2
Application number	US-201514967520-A
Country	US
Kind code	B2
Filing date	Dec 14, 2015
Priority date	Dec 28, 2006
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A Si-killed steel wire rod for obtaining a spring excellent in fatigue properties and a spring excellent in fatigue properties obtained from such steel wire rod are provided. In the Si-killed steel wire rod of the present invention, oxide-based inclusions present in the wire rod contain SiO 2 : 30-90%, Al 2 O 3 : 2-35%, MgO: 35% or below (not inclusive of 0%), CaO: 50% or below (not inclusive of 0%), MnO: 20% or below (not inclusive of 0%) and BaO: 0.2-20% respectively, and total content of (CaO+MgO) is 3% or above.

First claim

The invention claimed is:

1. A Si-killed steel wire rod comprising:
steel and
oxide-based inclusions,
wherein the Si-killed steel wire rod comprises greater than 0 mass % to 1.2 mass % of C, 0.1-4.0 mass % of Si, 0.1-2.0 mass % of Mn, 1-30 ppm of Al, and 0.5-30 ppm in total of Mg and/or Ca, based on the total mass of the Si-killed steel wire rod, and
the oxide-based inclusions in steel comprise 30-90 mass % of SiO 2 , 2-35 mass % of Al 2 O 3 , greater than 0 mass % to 35 mass % of MgO, greater than 0 mass % to 50 mass % of CaO, greater than 0 mass % to 20 mass % of MnO and 0.2-20 mass % of BaO, and the total content of MgO and CaO is 3% or greater, each based on the total mass of the oxide-based inclusions, and
wherein the balance is Fe and inevitable impurities.

2. The Si-killed steel wire rod of claim 1 , wherein the Si-killed steel wire rod further comprises 0.1-20 mass % of Li 2 O as the oxide-based inclusion, based on the total mass of the oxide-based inclusions, and wherein a content of Li in the Si-killed steel wire rod is 0.03-20 ppm, based on the total mass of Si-killed steel wire rod.

3. The Si-killed steel wire rod of claim 1 , further comprising at least one element selected from the group consisting of Cr, Ni, V, Nb, Mo, W, Cu, Ti, Co, and a rare earth element, wherein a content of Cr is 0.5-3.0 mass %, of Ni is 0.5 mass % or less, of V is 0.5 mass % or less, of Nb is 0.1 mass % or less, of Mo is 0.5 mass % or less, of W is 0.5 mass % or less, of Cu is 0.1 mass % or less, of Ti is 0.1 mass % or less, of Co is 0.5 mass % or less, and of the rare earth element is 0.05% or less, based on the total mass of the Si-killed steel wire rod.

4. A spring obtained from the Si-killed steel wire rod of claim 1 .

5. The Si-killed steel wire rod of claim 1 , wherein a content of Ba in the Si-killed steel wire rod is 0.03-30 ppm, based on the total mass of the Si-killed steel wire rod.

6. The Si-killed steel wire rod of claim 2 , wherein a content of Li in the Si-killed steel wire rod is 0.2-20 ppm, based on the total mass of the Si-killed steel wire rod.

7. The Si-killed steel wire rod of claim 1 , wherein the oxide-based inclusions comprise 1-10 mass % of BaO, based on the total mass of the oxide-based inclusions.

8. The Si-killed steel wire rod of claim 1 , wherein the Si-killed steel wire rod further comprises 15 mass % or less of SrO, as the oxide-based inclusion, based on the total mass of the oxide-based inclusions.

9. The Si-killed steel wire rod of claim 2 , wherein the Si-killed steel wire rod comprises 2.0-20 mass % of Li 2 O, as the oxide-based inclusion, based on the total mass of the oxide-based inclusions.

10. The Si-killed steel wire rod of claim 1 , wherein the Si-killed steel rod comprises 1.4-4.0 mass % of Si, based on the total mass of the Si-killed steel rod.

11. The Si-killed steel wire rod of claim 1 , wherein the Si-killed steel rod comprises 1.9-4.0 mass % of Si, based on the total mass of the Si-killed steel rod.

12. The Si-killed steel wire rod of claim 1 , wherein the Si-killed steel rod comprises 1.4-3.0 mass % of Si, based on the total mass of the Si-killed steel rod.

13. The Si-killed steel wire rod of claim 1 , wherein a content of Ba in the Si-killed steel wire rod is 0.2-10 ppm, based on the total mass of the Si-killed steel rod.

14. The Si-killed steel wire rod of claim 1 , wherein the Si-killed steel wire rod comprises 7-20 mass % of BaO, as the oxide-based inclusion, based on the total mass of the oxide-based inclusions.

Assignees

• Kobe Steel Ltd

Inventors

• Sugimura Tomoko
• Sakamoto Koichi

Classifications

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

• C22C38/14

  containing titanium or zirconium · CPC title

• C22C38/46

  with vanadium · CPC title

• C22C38/04 Primary

  containing manganese · CPC title

• C22C38/24

  with vanadium · CPC title