Hard pipe and automobile oil pipe

The invention discloses a hard pipe, which comprises a hard-pipe body, an outer hard-pipe sleeve and an inner hard-pipe sleeve, wherein the inner hard-pipe sleeve sleeves the hard-pipe body and is hermetically and detachably connected onto the hard-pipe body; outer threads are arranged on the outer surface of the inner hard-pipe sleeve, inner threads which are matched with the inner hard-pipe sleeve are arranged on the inner surface of one end of the outer hard-pipe sleeve, a hole for installing a flexible pipe is formed in the other end of the outer hard-pipe sleeve, and an annular projection for limiting and sealing the hard-pipe body is also arranged at the inner part of the outer hard-pipe sleeve. Because the hard-pipe body and the inner hard-pipe sleeve are detachably connected, and the space of the hole for installing the flexible pipe is larger than that of a scheme recorded in the prior art, when the hard-pipe body and the inner hard-pipe sleeve are coated, the coating uniformity of the inner surfaces and the outer surfaces of the hard-pipe body and the inner hard-pipe sleeve can be guaranteed. Moreover, because the coating uniformity of the hard pipe is improved, before warehousing or flexible-pipe installation, when the hard pipes are stored in batches, the occurrence of a hard-pipe rusting phenomenon can be reduced, and the use safety of the hard pipe is improved. The invention also discloses an automobile oil pipe.