发明申请
- 专利标题: High Strength Formed Article Comprising Hyperfine Grain Structure Steel and Manufacturing Method of the Same
- 专利标题(中): 包含超细晶粒结构钢的高强度成形品及其制造方法
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申请号: US11884948申请日: 2006-02-28
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公开(公告)号: US20080135140A1公开(公告)日: 2008-06-12
- 发明人: Shiro Torizuka , Eijrio Muramatsu , Kotobu Nagai
- 申请人: Shiro Torizuka , Eijrio Muramatsu , Kotobu Nagai
- 优先权: JP2005-054261 20050228
- 国际申请: PCT/JP2006/003797 WO 20060228
- 主分类号: C21D9/52
- IPC分类号: C21D9/52 ; C22C38/04
摘要:
A wire rod or a steel wire of a bamboonano-stricture, whose mean grain diameter in a C-direction section is 200 nm or smaller, is prepared by applying a hot or warm working and additionally applying a cold working to a steel and next, by performing a forging, by a tool or a die such as cold pressure production, to a section, of a desired, limited site, other than a section parallel to an L-direction, an equiaxed nano-structure, whose mean grain diameter is 200 nm or smaller, is formed in this site. As a typical example of a formed article, there is enumerated a screw, and there is enumerated a high strength micro screw in which a shaft outer diameter is 1.6 mm or smaller, a surface layer part of a head part recess is the equiaxed nano-structure and a hardness HV≧300, and a screw main body portion is the bamboo nano-structure and a hardness Hv≧250. A constituent composition is a carbon steel of C