Aspects of the present disclosure relate to methods of coating a coiled tubing string, methods of conducting tubing operations using a coated tubing string, and associated apparatus thereof. In one implementation, a method of conducting a coiled tubing operation, includes forming a tubing string. The tubing string has a central annulus, an inner surface, and an outer surface, and the tubing string is formed from a metallic material. The method also includes coiling the tubing string onto a spool, and moving a coating into the central annulus. The method also includes curing the coating onto the inner surface of the tubing string to form a layer of the coating on the inner surface of the tubing string.

A method for manufacturing an electric resistance welded metal pipe by butting side ends of a metal strip against each other and then welding the side ends by high frequency heating to manufacture an electric resistance welded metal pipe, each side end being provided with an inner surface side corner portion located on an inner surface side of the electric resistance welded metal pipe, the method includes a step of forming an inclined surface at the inner surface side corner portion before butting the side ends of the metal strip, and wherein the side ends are butted and welded to each other such that the inclined surface remains on an excess metal of the metal pipe after electric resistance welding and a discharged metal is not welded to the excess metal.

A method for manufacturing an electric resistance welded metal pipe by butting side ends of a metal strip against each other and then welding the side ends by high frequency heating to manufacture an electric resistance welded metal pipe, each side end being provided with an inner surface side corner portion located on an inner surface side of the electric resistance welded metal pipe, the method includes a step of forming an inclined surface at the inner surface side corner portion before butting the side ends of the metal strip, and wherein the side ends are butted and welded to each other such that the inclined surface remains on an excess metal of the metal pipe after electric resistance welding and a discharged metal is not welded to the excess metal.

Disclosed is a vertical strip accumulator. The vertical strip accumulator includes an inner drum unit having an inner drum; an outer drum unit installed at an outer side of the inner drum unit; a central drum unit installed at an inner side of the inner drum unit; and an input unit configured to carry a skelp supplied from an uncoiler to the outer drum unit. The outer drum unit includes an outer drum configured to selectively rotate forward and reverse; a first power source configured to provide a power to the outer drum; an outer roller installed to the outer drum; and a first control unit connected to the first power source to control the operation of the first power source. The input unit includes a carrying roller provided in contact with the skelp; a second power source configured to supply a power to the carrying roller; and a second control unit connected to the second power source to control the operation of the second power source.

A steel strip for an electric-resistance-welded steel pipe or tube having a strength of X70 grade or more and excellent HIC resistance and SSC resistance is provided. A steel strip for an electric-resistance-welded steel pipe or tube has a chemical composition containing, in mass %: C: 0.02% to 0.06%; Si: 0.1% to 0.3%; Mn: 0.8% to 1.3%; P: 0.01% or less; S: 0.001% or less; V: 0.04% to 0.07%; Nb: 0.04% to 0.07%; Ti: 0.01% to 0.04%; Cu: 0.1% to 0.3%; Ni: 0.1% to 0.3%; Ca: 0.001% to 0.005%; Al: 0.01% to 0.07%; and N: 0.007% or less, with a balance being Fe and incidental impurities, contents of C, Nb, V, and Ti satisfying the following Expression (1)

[C]−12([Nb]/92.9+[V]/50.9+[Ti]/47.9)≦0.03%  (1),

wherein a ferrite area ratio is 90% or more.

A steel strip for an electric-resistance-welded steel pipe or tube having a strength of X70 grade or more and excellent HIC resistance and SSC resistance is provided. A steel strip for an electric-resistance-welded steel pipe or tube has a chemical composition containing, in mass %: C: 0.02% to 0.06%; Si: 0.1% to 0.3%; Mn: 0.8% to 1.3%; P: 0.01% or less; S: 0.001% or less; V: 0.04% to 0.07%; Nb: 0.04% to 0.07%; Ti: 0.01% to 0.04%; Cu: 0.1% to 0.3%; Ni: 0.1% to 0.3%; Ca: 0.001% to 0.005%; Al: 0.01% to 0.07%; and N: 0.007% or less, with a balance being Fe and incidental impurities, contents of C, Nb, V, and Ti satisfying the following Expression (1)

[C]−12([Nb]/92.9+[V]/50.9+[Ti]/47.9)≦0.03%  (1),

wherein a ferrite area ratio is 90% or more.

An embossing roll (1) having a cylindrical surface (2) comprising a central portion (3) having an embossing pattern (10) and side portions (4a, 4b) arranged on each side of the central portion, which are free from embossing pattern, wherein circumferential buffer channels (5) are provided on each side of the central portion (3), between the central portion and the side portions, along the cylindrical surface (2) of the embossing roll.

Aspects of the present disclosure relate to methods of coating a coiled tubing string, methods of conducting tubing operations using a coated tubing string, and associated apparatus thereof. In one implementation, a method of conducting a coiled tubing operation, includes forming a tubing string. The tubing string has a central annulus, an inner surface, and an outer surface, and the tubing string is formed from a metallic material. The method also includes coiling the tubing string onto a spool, and moving a coating into the central annulus. The method also includes curing the coating onto the inner surface of the tubing string to form a layer of the coating on the inner surface of the tubing string.

Provided is a method for manufacturing an electric resistance welded metal pipe by butting side ends of a metal strip against each other and then welding the side ends by high frequency heating to manufacture an electric resistance welded metal pipe, each side end being provided with an inner surface side corner portion located on an inner surface side of the electric resistance welded metal pipe, wherein the method comprises a step of forming an inclined surface at the inner surface side corner portion before butting the side ends of the metal strip; and wherein the side ends are butted and welded to each other such that the inclined surface remains on an excess metal of the metal pipe after electric resistance welding and a discharged metal is not welded to the excess metal.

Provided is a method for manufacturing an electric resistance welded metal pipe by butting side ends of a metal strip against each other and then welding the side ends by high frequency heating to manufacture an electric resistance welded metal pipe, each side end being provided with an inner surface side corner portion located on an inner surface side of the electric resistance welded metal pipe, wherein the method comprises a step of forming an inclined surface at the inner surface side corner portion before butting the side ends of the metal strip; and wherein the side ends are butted and welded to each other such that the inclined surface remains on an excess metal of the metal pipe after electric resistance welding and a discharged metal is not welded to the excess metal.