Method for producing high cleanness steel excellent in fatigue strength or cold workability
US7615099B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2008 |
| Grant date | Nov 10, 2009 |
| Priority date | — |
| Expiry date | Apr 23, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P10/20
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention relates to a high-cleanliness steel having a high fatigue strength and high cold workability, and a method of making the high-cleanliness steel. The method adds a Li—Si alloy having a Li content between 20 and 40% and/or Li2CO3 as a Li-containing substance to a molten steel. The Li-containing substance is added to the molten steel after the completion of a series of steps of a ladle refining process including composition adjustment, temperature adjustment and slag refining. The high-cleanliness steel has a total-Li content between 0.020 and 20 ppm by mass and contains 1.0 or below oxide inclusion particle having a major diameter of 20 μm or above at a maximum in 50 g of the steel wire. The steel contains an oxide inclusion that has a CaO content between 15 and 55%, SiO2 content between 20 and 70%, an Al2O3 content of 35% or below, a MgO content of 20% or below and a Li2O content between 0.5 and 20%. The high-cleanliness steel has improved fatigue characteristics and improved cold workability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.