Threaded joint for steel pipe
View Patent ↗A threaded joint for a steel pipe includes a pin and a box each of which is provided with a contact surface that includes an unthreaded metal contact portion having a seal portion and a threaded portion. This threaded joint includes an ultraviolet ray-curable resin coating film that is formed on the contact surface of at least one of the pin and the box; and an acrylic silicone resin coating film that is formed on at least a portion of a surface of the ultraviolet ray-curable resin coating film.
1. A threaded joint for a steel pipe, the threaded joint comprising:
a pin and a box, each of the pin and the box is provided with a contact surface that includes an unthreaded metal contact portion having a seal portion, and a threaded portion;
an ultraviolet ray-curable resin coating film positioned on the contact surface of at least one of the pin and the box;
an acrylic silicone resin coating film disposed on and substantially coextensive with the ultraviolet ray-curable resin coating film; and
wherein a thickness of the acrylic silicone resin coating film is 5 μm to 10 μm (0.0002 to 0.0004 inches).
2. The threaded joint according to claim 1 , wherein the ultraviolet ray-curable resin coating film contains a colorant.
3. The threaded joint according to claim 1 , wherein the ultraviolet ray-curable resin coating film is positioned on the contact surface of both the pin and the box, and the acrylic silicone resin coating film is disposed on and coextensive with the ultraviolet ray-curable resin coating film.
4. The threaded joint according to claim 3 , wherein the ultraviolet ray-curable resin coating film contains a colorant.