Lubricant film-forming composition and screw joint for steel pipe
View Patent ↗A lubricant film-forming composition includes as a composition: 40 to 80 mass % of a base oil consisting of one or more selected from pentaerythritol fatty acid ester and trimethylolpropane fatty acid ester; 5 to 20 mass % of a solidifying agent consisting of paraffin wax; and 10 to 40 mass % of a solid lubricant consisting of one or more selected from alkali metal salt of hydroxystearic acid and alkali earth metal salt of hydroxystearic acid. A total content of the base oil, the solidifying agent, and the solid lubricant is 85 mass % or more and 100 mass % or less, and the lubricant film-forming composition does not contain heavy metals.
1. A lubricant film-forming composition, comprising, as a composition:
40 to 80 mass % of a base oil selected from the group consisting of pentaerythritol fatty acid ester, trimethylolpropane fatty acid ester, and mixtures thereof;
5 to 20 mass % of a solidifying agent consisting of paraffin wax; and
10 to 40 mass % of a solid lubricant selected from the group consisting of alkali metal salt of hydroxystearic acid, alkali earth metal salt of hydroxystearic acid, and mixtures thereof, wherein
a total content of the base oil, the solidifying agent, and the solid lubricant is 85 mass % or more and 100 mass % or less, and
the lubricant film-forming composition does not contain Pb or Zn.
2. The lubricant film-forming composition according to claim 1 , wherein
the base oil is selected from the group consisting of pentaerythritol tetraoleate, trimethylol propane trioleate, trimethylol propane triisostearate, and mixtures thereof.
3. The lubricant film-forming composition according to claim 1 , wherein
the solid lubricant is selected from the group consisting of calcium hydroxystearate, lithium hydroxystearate, sodium hydroxystearate, and mixtures thereof.
4. A screw joint for steel pipe, the screw joint comprising:
a pin; and
a box, wherein
each of the pin and the box has a threaded portion and an unthreaded metal contact portion as fitting parts,
the screw joint for steel pipe is provided with a lubricant film, which is formed of the lubricant film-forming composition according to claim 1 , on a surface of the fitting part of at least one of the pin and the box.
5. The lubricant film-forming composition according to claim 2 , wherein
the solid lubricant is selected from the group consisting of calcium hydroxystearate, lithium hydroxystearate, sodium hydroxystearate, and mixtures thereof.
6. A screw joint for steel pipe, the screw joint comprising:
a pin; and
a box, wherein
each of the pin and the box has a threaded portion and an unthreaded metal contact portion as fitting parts,
the screw joint for steel pipe is provided with a lubricant film, which is formed of the lubricant film-forming composition according to claim 2 , on a surface of the fitting part of at least one of the pin and the box.
7. A screw joint for steel pipe, the screw joint comprising:
a pin; and
a box, wherein
each of the pin and the box has a threaded portion and an unthreaded metal contact portion as fitting parts,
the screw joint for steel pipe is provided with a lubricant film, which is formed of the lubricant film-forming composition according to claim 3 , on a surface of the fitting part of at least one of the pin and the box.
8. A lubricant film-forming composition, comprising, as a composition:
40 to 80 mass % of a base oil comprising one or more of pentaerythritol fatty acid ester or trimethylolpropane fatty acid ester;
5 to 20 mass % of a solidifying agent comprising paraffin wax; and
10 to 40 mass % of a solid lubricant comprising one or more of alkali metal salt of hydroxystearic acid or alkali earth metal salt of hydroxystearic acid, wherein
a total content of the base oil, the solidifying agent, and the solid lubricant is 85 mass % or more and 100 mass % or less, and
the lubricant film-forming composition does not contain Pb or Zn.