| abstract |
A lubricating coating that does not contain harmful heavy metals is formed on an improved pipe threaded joint consisting of a nipple and a sleeve, each of which has a contact surface including a threaded part and a non-threaded metal contact part (sealing surface and shoulder) to provide abrasion resistance , gas tightness and anticorrosion properties of this compound in order to prevent the transition to the state of fluidity of a threaded metal contact part even when twisting the connection with high torque. The lubricating coating comprises one or both of rosin and calcium fluoride, a metal soap, wax and a base salt of a metal and aromatic organic acid, and preferably it further includes a lubricating powder, magnesium carbonate and / or carbohydrate, in particular cyclodextrin. |