A method for manufacturing an electric resistance welded steel pipe having an identifiable seam portion. The method includes electric resistance welding a steel pipe, cutting an inner surface bead and an outer surface bead of the steel pipe in such a manner so as to cut: (i) a whole the outer surface bead and a part of the inner surface bead to leave an uncut portion in the inner surface bead, or (ii) a whole of the inner surface bead and a part of the outer surface bead to leave an uncut portion in the outer surface bead, coating the steel pipe with zinc phosphate, and cold drawing the steel pipe using a plug and a die to make the seam portion of the steel pipe identifiable.

A method for manufacturing an electric resistance welded steel pipe having an identifiable seam portion. The method includes electric resistance welding a steel pipe, cutting an inner surface bead and an outer surface bead of the steel pipe in such a manner so as to cut: (i) a whole the outer surface bead and a part of the inner surface bead to leave an uncut portion in the inner surface bead, or (ii) a whole of the inner surface bead and a part of the outer surface bead to leave an uncut portion in the outer surface bead, coating the steel pipe with zinc phosphate, and cold drawing the steel pipe using a plug and a die to make the seam portion of the steel pipe identifiable.

A plasma arc torch includes a cathode extending along an axis of the torch, a pilot arc conductor, and a nozzle body. A first fluid conduit and second fluid conduit extend parallel to the axis of the torch. A first offset fitting includes a first duct coupled to and in fluid communication with the first fluid conduit, and a second duct in fluid communication with the first duct and outwardly radially offset from the first duct and extending away from the first duct in a proximal direction. A second offset fitting includes a third duct coupled to and in fluid communication with the second fluid conduit, and a fourth duct in fluid communication with the third duct and outwardly radially offset from the third duct and extending away from the third duct in the proximal direction. A spring compression plug electrically connects the pilot arc conductor to the nozzle body.

A plasma arc torch includes a cathode extending along an axis of the torch, a pilot arc conductor, and a nozzle body. A first fluid conduit and second fluid conduit extend parallel to the axis of the torch. A first offset fitting includes a first duct coupled to and in fluid communication with the first fluid conduit, and a second duct in fluid communication with the first duct and outwardly radially offset from the first duct and extending away from the first duct in a proximal direction. A second offset fitting includes a third duct coupled to and in fluid communication with the second fluid conduit, and a fourth duct in fluid communication with the third duct and outwardly radially offset from the third duct and extending away from the third duct in the proximal direction. A spring compression plug electrically connects the pilot arc conductor to the nozzle body.

A bed mesh combination device includes a feeding assembly movable in a first direction, two groups of welding cutter assemblies and a welding head assembly oppositely arranged in a second direction. The feeding assembly can lay a spring string on the welding cutter assembly, the welding cutter assembly includes a plurality of welding cutters extending in a third direction, the welding cutters of a same group are arranged at intervals along the first direction, the welding cutters of different groups are staggered in the first direction, the two groups of welding cutter assemblies respectively correspond to first and second welding positions of the spring string. The welding cutter assembly can push the spring string to move in the second direction and can be close to or far away from the spring string in the third direction. The welding head assembly includes an ultrasonic welding head and a first driving member.

A bed mesh combination device includes a feeding assembly movable in a first direction, two groups of welding cutter assemblies and a welding head assembly oppositely arranged in a second direction. The feeding assembly can lay a spring string on the welding cutter assembly, the welding cutter assembly includes a plurality of welding cutters extending in a third direction, the welding cutters of a same group are arranged at intervals along the first direction, the welding cutters of different groups are staggered in the first direction, the two groups of welding cutter assemblies respectively correspond to first and second welding positions of the spring string. The welding cutter assembly can push the spring string to move in the second direction and can be close to or far away from the spring string in the third direction. The welding head assembly includes an ultrasonic welding head and a first driving member.

An electric resistance welded steel pipe having an identifiable seam portion and a method for manufacturing the same. The electric resistance welded steel pipe includes a steel pipe portion with a seam portion, which is formed by electric resistance welding, and a coating portion of zinc phosphate. The coating portion covers at least an outer surface side of the steel pipe portion. A part of the coating portion that is immediately above the seam portion forms a color difference portion that has a width W along a pipe circumferential direction of greater than or equal to 0.1 times a wall thickness of the pipe and less than or equal to the wall thickness of the pipe. The color difference portion has a visually identifiable color difference from the other parts of the coating portion.

An electric resistance welded steel pipe having an identifiable seam portion and a method for manufacturing the same. The electric resistance welded steel pipe includes a steel pipe portion with a seam portion, which is formed by electric resistance welding, and a coating portion of zinc phosphate. The coating portion covers at least an outer surface side of the steel pipe portion. A part of the coating portion that is immediately above the seam portion forms a color difference portion that has a width W along a pipe circumferential direction of greater than or equal to 0.1 times a wall thickness of the pipe and less than or equal to the wall thickness of the pipe. The color difference portion has a visually identifiable color difference from the other parts of the coating portion.

Embodiments of the present invention include systems and methods of using a plasma arc torch to cut holes and contours in workpieces having varying thickness and material properties. The systems and methods of the present invention allow for the cutting of holes and contours without the need for using secondary processing by using particular overburn, tail out and/or cutting parameters.

Embodiments of the present invention include systems and methods of using a plasma arc torch to cut holes and contours in workpieces having varying thickness and material properties. The systems and methods of the present invention allow for the cutting of holes and contours without the need for using secondary processing by using particular overburn, tail out and/or cutting parameters.