Patent ID: 11493155

Abstract:
A threaded connection for pipe includes a pin and a box. The threaded connection for pipe includes a Zn—Ni alloy plated layer and a solid lubricant coating. The Zn—Ni alloy plated layer is formed on a contact surface of at least one of the pin and the box and contains 10 to 16 mass % of Ni. The solid lubricant coating is formed on the Zn—Ni alloy plated layer. The contact surface on which the Zn—Ni alloy plated layer is formed is ground. Now define arithmetic average roughness of the surface of the Zn—Ni alloy plated layer as Ra1, and arithmetic average roughness of the contact surface as Ra2. Ra1 ranges from 0.1 to 3.2 μm. Ra1 is more than Ra2.