High carbon steel pipe excellent in cold formability and high frequency hardenability and method for producing the same
US6736910B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 2002 |
| Grant date | May 18, 2004 |
| Priority date | — |
| Expiry date | Jan 29, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/909
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The invention provides a high-carbon steel pipe having superior cold workability and induction hardenability, and a method of producing the steel pipe. The method comprises the steps of heating or soaking a base steel pipe having a composition containing C: 0.3 to 0.8%, Si: not more than 2%, and Mn: not more than 3%, and then carrying out reducing rolling on the base steel pipe at least in the temperature range of (Ac1, transformation point −50° C.) to Ac1, transformation point with an accumulated reduction in diameter of not less than 30%. A structure in which the grain size of cementite is not greater than 1.0 &mgr;m is obtained, thus resulting in improved cold workability and induction hardenability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.