A threaded joint for pipes disclosed herein includes a pin and a box. The pin and the box each include a contact surface including a threaded portion and a metal contact portion. The threaded joint for pipes includes a solid lubricant coating on at least one of the contact surfaces of the pin and the box, the solid lubricant coating including a binder, a lubricant additive, an anti-rust additive, and a plasticizer.

A threaded joint for pipes disclosed herein includes a pin and a box. The pin and the box each include a contact surface including a threaded portion and a metal contact portion. The threaded joint for pipes includes a solid lubricant coating on at least one of the contact surfaces of the pin and the box, the solid lubricant coating including a binder, a lubricant additive, an anti-rust additive, and a plasticizer.

Use of a guanidinium-based ionic liquid as detergent in a lubricant composition, notably for lubricating marine engines. A lubricant composition including a guanidinium-based ionic liquid.

The present invention relates to a lubricating oil composition containing a base oil (A), a molybdenum dithiocarbamate (B), an ester-based ashless friction modifier (C), and a metal salicylate (D), wherein the content of a molybdenum atom derived from the molybdenum dithiocarbamate (B) is 650 ppm by mass or more on the basis of the whole amount of the lubricating oil composition; a content ratio [C/B.sub.Mo] of the ester-based ashless friction modifier (C) to a molybdenum atom derived from the molybdenum dithiocarbamate (B) is 5.0 to 10 in terms of a mass ratio; the content of a salicylate soap group derived from the metal salicylate (D) is 0.50% by mass or more on the basis of the whole amount of the lubricating oil composition; and a kinematic viscosity at 100° C. is 4.0 mm.sup.2/s or more and less than 9.3 mm.sup.2/s, and a high-temperature high-shear viscosity at 150° C. is 1.7 mPa.Math.s or more and less than 2.9 mPa.Math.s. In accordance with the present invention, a viscosity-reduced lubricating oil composition in which nonetheless a molybdenum dithiocarbamate and an ashless friction modifier are jointly used, not only friction can be reduced early after commencement of lubrication, but also such a state can be maintained, is provided.

A lubricating oil composition for internal combustion engines containing a base oil (A), a metal-based detergent (B) containing a calcium-based detergent (B1), a zinc dialkyldithiophosphate (C), and a molybdenum-containing compound (D), wherein a calcium atom-equivalent content of the calcium-based detergent (B1) is more than 100 ppm by mass and 600 ppm by mass or less, based on a total amount of the composition, a magnesium atom-equivalent content of a magnesium-based detergent (B2) is less than 200 ppm by mass, based on the total amount of the composition, a sodium atom-equivalent content of a sodium-based detergent (B3) is less than 200 ppm by mass, based on the total amount of the composition, a content ratio of phosphorus derived from the zinc dialkyldithiophosphate (C) to calcium derived from the calcium-based detergent (B1) [P/Ca] is 0.25 or more by mass, and a sulfated ash content is 0.7% by mass or less; and a method for producing the composition.

Provided are a lubricating oil composition containing (A) a specific amide compound and (B) a metal-based detergent, wherein the content of the metal-based detergent (B) as converted in terms of metal atom is, based on the total amount of the composition, more than 300 ppm by mass and 1,000 ppm by mass or less, and having a high intermetallic friction coefficient and excellent clutch anti-shudder performance; and a lubrication method and a transmission using the composition.

Provided is a lubricating oil composition for a gas engine, comprising a base oil (A), a calcium-based detergent (B), and an alkenyl succinimide (C), wherein a content of calcium atoms is 0.09 to 0.17 mass % based on the total amount of the lubricating oil composition, the component (C) comprises a non-boron-modified alkenyl bis-succinimide (C1), and a content of boron atoms derived from the component (C) is less than 0.02 mass % based on the total amount of the lubricating oil composition.

A lubricating oil composition containing a base oil, an organic molybdenum compound, and a metallic detergent, wherein the metallic detergent contains calcium sulfonate, and the content of the calcium sulfonate in terms of calcium atoms is 0.12% by mass or more based on the mass of the composition, the content ratio of molybdenum atoms derived from the organic molybdenum compound to soap groups derived from the metallic detergent based on the lubricating oil composition, [Mo/soap groups], is 0.02 or more at a mass ratio, and the HTHS viscosity at 150° C. is 1.3 mPa.Math.s or more and less than 2.3 mPa.Math.s. The lubricating oil composition has low viscosity and excellent lubricity.

A lubricating oil composition containing a base oil, an organic molybdenum compound, and a metallic detergent, wherein the metallic detergent contains calcium sulfonate, and the content of the calcium sulfonate in terms of calcium atoms is 0.12% by mass or more based on the mass of the composition, the content ratio of molybdenum atoms derived from the organic molybdenum compound to soap groups derived from the metallic detergent based on the lubricating oil composition, [Mo/soap groups], is 0.02 or more at a mass ratio, and the HTHS viscosity at 150° C. is 1.3 mPa.Math.s or more and less than 2.3 mPa.Math.s. The lubricating oil composition has low viscosity and excellent lubricity.

Provided is a low sulfated ash engine oil lubricant composition containing organic friction modifiers with improved fuel economy and corrosion resistance. The lubricant composition includes one or more metal free corrosion inhibitors having an organic acid group and/or one or more organo metallic naphthalene molecules having a ASTM D2896 total base number less than 3 mg KOH/g. The resulting lubricant composition improves ASTM D6557 corrosion protection for low sulfated ash engine oils containing organic friction modifiers, while maintaining exceptional fuel economy performance.