| abstract |
A threaded joint for steel pipe formed on a pin and a box having a contact surface including threaded parts and a non-threaded metal contact part and capable of stably assuring a galling resistance and an airtightness without applying compound grease threreto, wherein a solid lubricating film formed with lubricating powder (e.g., molybdenum disulfide) and organic or inorganic binder is formed on the contact surface of at least one of the pin and the box, the ratio of area occupied by the secondary particles of 15 to 60 µm in equi-area equivalent diameter of the lubricating powder in the cross section of the solid lubricating film in thickness direction is 5 to 90%, and fiber-like filler (e.g., inorganic substance whisker) in addition to the lubricating powder is mixed into the solid lubricating film at the mass ratio of the fiber-like filler to the binder of 0.01 to 0.5, whereby, particulary, the galling resistance at high temperatures can be improved. |