| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricant which is suitable as a lubricant used at the time of expansion of a welded pipe and does especially not form a coating film reacted with iron. SOLUTION: This lubricant to be supplied between a cone and a jaw at the time of expansion of a pipe by the wedge action of the cone and the jaw of a pipe-expanding head through the pipe-expanding head of a mechanical pipe-expanding machine on the inside of the welded pipe after welded is characterized by adding silica particles having an average particle diameter of >40 nm to a base oil in an amount of 0.1 to 1 mass%. COPYRIGHT: (C)2008,JPO&INPIT |
