Threaded joint for pipes having a lubricating coating
US8420581B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 30, 2010 |
| Grant date | Apr 16, 2013 |
| Priority date | — |
| Expiry date | Apr 30, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10N2080/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A lubricating coating which is free from harmful heavy metals is formed on a premium threaded joint for pipes constituted by a pin and a box each having a contact surface comprising a threaded portion and an unthreaded metal contact portion (a sealing surface and shoulder) in order to provide the joint with galling resistance, gas-tightness, and anticorrosive properties such that the unthreaded metal contact portion is prevented from yielding even when the joint is made up with a high torque. The lubricating coating comprises one or both of a rosin and calcium fluoride; metal soap; wax; and a basic metal salt of an aromatic organic acid, and preferably it further includes a lubricating powder, magnesium carbonate, and/or a carbohydrate, particularly a cyclodextrin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.