Abstract: A threaded joint for steel pipes comprises a pin (1) and a box (2) each having a threaded portion (3a or 3b) and an unthreaded metal-to-metal contact portion (4a or 4b) as contact surfaces which contact each other when the joint is fastened. The contact surfaces (3a and 4a and/or 3b and 4b) of at least one of the pin (1) and the box (2) are coated with a lower layer of a solid lubricating coating containing a solid lubricating powder (e.g., molybdenum disulfide, tungsten disulfide, or graphite) and a binder (e.g., an epoxy or other organic resin) and an upper layer of a solid corrosion protective coating formed by an organic resin which does not contain solid particles.

Abstract: In a protector for protecting a trapezoidal female thread of a pipe formed to an end thereof, the protector has a male thread formed thereto so as to be threaded with the female thread as well as the height of the thread of the male thread is made larger than the height of the thread of the female thread. With this arrangement, a surface treatment applied to the surface of the female thread or a male thread formed to the end of the pipe can be prevented from being damaged, and in particular, a surface treatment applied to a guide flank surface, a load flank surface, a corner portion, and the like of the thread can be prevented from being subjected to wear, damage, and the like.

Abstract: In a protector for protecting a trapezoidal female thread of a pipe formed to an end thereof, the protector has a male thread formed thereto so as to be threaded with the female thread as well as the height of the thread of the male thread is made larger than the height of the thread of the female thread. With this arrangement, a surface treatment applied to the surface of the female thread or a male thread formed to the end of the pipe can be prevented from being damaged, and in particular, a surface treatment applied to a guide flank surface, a load flank surface, a corner portion, and the like of the thread can be prevented from being subjected to wear, damage, and the like.