Surface conditioning prior to chemical conversion treatment of a steel member
US7666266B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2006 |
| Grant date | Feb 23, 2010 |
| Priority date | — |
| Expiry date | Feb 2, 2027 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16L58/182
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
By subjecting a threaded joint for OCTG (oil country tubular goods) to surface conditioning with an aqueous solution of potassium tetraborate or sodium tetraborate prior to manganese phosphate chemical conversion treatment, a manganese phosphate chemical conversion coating having coarse crystal grains with an average crystal grain diameter of 10-110 micrometers is formed on the surface of the steel member which may be any steel including a high Cr steel. This manganese phosphate chemical conversion coating can hold a large amount of a liquid lubricant, and it is effective at preventing the occurrence of galling at the time of makeup of a threaded joint for OCTG.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.