A coupling assembly includes a coupling, a protective ring and two tubulars, the coupling of generally cylindrical shape with a channel therethrough, the coupling having at least one internal thread and two coupling ends and a pin end of at least one of the two tubulars having an external thread for threaded mating therewith so that the coupling assembly provides a connection between the two tubulars, the protective ring including a ring body for positioning adjacent an interior wall of the coupling between the two ends thereof, the ring body being generally cylindrical and having a ring channel therethrough, the protective ring includes one of a tongue and groove and at least one of the ends of at least one of the two tubulars having the other of a tongue and groove.

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.

This invention provides a threaded connection for pipes or tubes having excellent misalignment resistance and high torque on shoulder resistance, and also having excellent corrosion resistance properties, as well as a method for producing the threaded connection for pipes or tubes. The threaded connection for pipes or tubes includes a pin and a box. The pin and the box include contact surfaces having threaded portions and unthreaded metal contact portions. The threaded connection for pipes or tubes includes, on at least one of the contact surfaces of the pin and the box, surface roughness, a Zn—Ni alloy plating layer, a Cu—Sn—Zn alloy plating layer and a solid lubricant coating layer. These are deposited from the contact surface side in the order of: surface roughness, the Zn—Ni alloy plating layer, the Cu—Sn—Zn alloy plating layer and the solid lubricant coating layer.

Disclosed is a tubing component for the oil and gas industry. The tubing component includes an outer tube and an inner tube within the outer tube, said tubes being so configured to create a space between each other over a specified length. Each end of the inner tube is secured to the internal surface of the outer tube by a frustoconical fillet weld so that said space is leak-tight. The inner tube has a first internal diameter ID along a first length starting from each end of said tube, and a second, smaller internal diameter ID′ along a second length beyond the first length. The tubing component further includes a protective metallic layer extending at least over the fillet weld. Also disclosed is a method for producing this tubing component.

A connection includes first and second lined tubular members having a coincident bore and a protective ring. The first lined tubular member has a pin end and the second lined tubular member has a box end. Each lined tubular member includes a tubular body, an annular liner, and a mortar filled annulus therebetween. The mortar filled annulus has an annular recess therein at at least one of the pin end and box end for receiving a part of the protective ring. The part received may be a flange on the ring.

A cover for a tubular having at least one threaded region. The cover has an inner sleeve having a closed end and an open end and formed of a fluid absorbent material. The inner sleeve is positionable about the threaded region of the tubular. The cover further has an outer sleeve having a closed end and an open end and formed of fluid resistant material. The outer sleeve is disposed about the inner sleeve.

A fastener for connecting a coated conduit to a fitting comprises: a locking nut having a first end, a second end, and internal threading extending between the first end and the second end; a gasket formed at the first end of the locking nut by coating the locking nut with a polymeric material; and a flexible sleeve extending from the second end of the locking nut that is formed by coating the locking nut with the polymeric material. The internal threading of the locking nut is threaded onto exposed threading of the coated conduit such that the flexible sleeve fits over a circumference of the coated conduit and the gasket forms a sealed connection with the fitting when the exposed threading of the coated conduit is connected to the fitting.

A seal-off fitting for a conduit system includes a conduit body defining an inner cavity, at least one conduit port adapted to receive a conduit, and at least one threaded sealing port. The seal-off fitting further includes a threaded seal-off cover engageable with the sealing port, a first coating applied to at least a portion of the conduit body, and a second coating applied to at least of portion of the seal-off cover. At least a portion of the threads of the sealing port and at least a portion of the threads the seal-off cover remain uncoated, with the uncoated threads of the sealing port and the uncoated threads of the seal-off cover defining a flame path for flue gases exiting the conduit body.

A system for use in corrosive environments includes a first tubular including a first connector portion, and a second tubular including a second connector portion. The first connector portion overlaps the second connector portion to form a connection joint. A magnesium element is arranged between the first connector portion and the second connector portion at the connection joint.

Provided is a method capable of producing a plated black heart malleable cast iron member having a plating layer with excellent adhesiveness to a black heart malleable cast iron member, while having less burden on the environment, compared to conventional methods.