This invention provides a threaded connection for pipes or tubes having high over-torque performance, and a method for producing the threaded connection for pipes or tubes. A threaded connection for pipes or tubes according to the present embodiment includes a pin and a box. The pin and the box include a contact surface including a threaded portion and a metal contact portion. The threaded connection for pipes or tubes includes a solid lubricant coating layer on at least one of the contact surfaces of the pin and the box, the solid lubricant coating layer including a resin, a solid lubricant powder, and Cr.sub.2O.sub.3.

The composition according to the present embodiment is a composition for forming a lubricant coating layer on a threaded connection for pipes or tubes, and contains Cr.sub.2O.sub.3, a metal soap, a wax and a basic metal salt of an aromatic organic acid. The threaded connection for pipes or tubes according to the present embodiment includes a pin and a box. The pin and the box each include a contact surface including a threaded portion. The threaded connection for pipes or tubes includes, as an outermost layer, a lubricant coating layer formed from the aforementioned composition on at least one of the contact surfaces of the pin and the box.

The composition according to the present embodiment is a composition for forming a lubricant coating layer on a threaded connection for pipes or tubes, and contains Cr.sub.2O.sub.3, a metal soap, a wax and a basic metal salt of an aromatic organic acid. The threaded connection for pipes or tubes according to the present embodiment includes a pin and a box. The pin and the box each include a contact surface including a threaded portion. The threaded connection for pipes or tubes includes, as an outermost layer, a lubricant coating layer formed from the aforementioned composition on at least one of the contact surfaces of the pin and the box.

Fuels, hydraulic fluids and lubricants made of or comprising a portion of renewable hydrocarbon raw materials, as well as biodegradable fuels, hydraulic fluids and lubricants are known to support microbial growth. Highly toxicorganic biocides have been added to reduce microbial growth. The use of such biocides can now be avoided, by instead using a stable solution of boric acid in a solvent, the boric acid being completely dissolved or at least free from any particles larger than 100 nm in size, and adding this solution to the fuel, hydraulic fluid or lubricant to give a final concentration of boron in the range of 1-100 ppm, preferably 1-50 ppm in the product. While preventing microbial growth, the addition of boron also reduces corrosion, in particular microbiologically induced corrosion (MIC).

This invention provides a threaded connection for pipes or tubes having high over-torque performance, and a method for producing the threaded connection for pipes or tubes. A threaded connection for pipes or tubes according to the present embodiment includes a pin and a box. The pin and the box include a contact surface including a threaded portion and a metal contact portion. The threaded connection for pipes or tubes includes a solid lubricant coating layer on at least one of the contact surfaces of the pin and the box, the solid lubricant coating layer including a resin, a solid lubricant powder, and Cr.sub.2O.sub.3.

A device includes a tribological assembly including first and second mechanical components in relative motion with respect to each other, the assembly having a silver-alloy surface and an additive lubricant including at least one component of the formulas (Ia) or (II): M.sub.xNO.sub.y (Ia), where M is Ca, V, Sb, Ni, or Ag, x (M:N ratio) is any number between 0.25 and 2, and y (O:N ratio) is any number between 1 and 8; M.sub.xSiO.sub.y (II), where M is Mg or Al, x (M:Si ratio) is any number between 0.5 and 2, and y (O:Si ratio) is any number between 2.5 and 6, the device being a sealed constant-pressure device.

A device includes a tribological assembly including first and second mechanical components in relative motion with respect to each other, the assembly having a silver-alloy surface and an additive lubricant including at least one component of the formulas (Ia) or (II): M.sub.xNO.sub.y (Ia), where M is Ca, V, Sb, Ni, or Ag, x (M:N ratio) is any number between 0.25 and 2, and y (O:N ratio) is any number between 1 and 8; M.sub.xSiO.sub.y (II), where M is Mg or Al, x (M:Si ratio) is any number between 0.5 and 2, and y (O:Si ratio) is any number between 2.5 and 6, the device being a sealed constant-pressure device.

Fuels, hydraulic fluids and lubricants made of or comprising a portion of renewable hydrocarbon raw materials, as well as biodegradable fuels, hydraulic fluids and lubricants are known to support microbial growth. Highly toxicorganic biocides have been added to reduce microbial growth. The use of such biocides can now be avoided, by instead using a stable solution of boric acid in a solvent, the boric acid being completely dissolved or at least free from any particles larger than 100 nm in size, and adding this solution to the fuel, hydraulic fluid or lubricant to give a final concentration of boron in the range of 1-100 ppm, preferably 1-50 ppm in the product. While preventing microbial growth, the addition of boron also reduces corrosion, in particular microbiologically induced corrosion (MIC).