A method of connecting together two unit elements (2, 4) of an undersea fluid transport pipe that is subjected to fatigue, by welding together two metallic or bi-metallic unit pipe elements that have been put into abutment via their respective free ends (2a, 4a), the welding being done by making three distinct weld beads (6, 8, 10), with a last weld bead (8) being deposited between two lateral first weld beads (6, 10), and being followed directly by controlled sanding of the weld beads in order to apply compression stresses on them.

A method of connecting together two unit elements (2, 4) of an undersea fluid transport pipe that is subjected to fatigue, by welding together two metallic or bi-metallic unit pipe elements that have been put into abutment via their respective free ends (2a, 4a), the welding being done by making three distinct weld beads (6, 8, 10), with a last weld bead (8) being deposited between two lateral first weld beads (6, 10), and being followed directly by controlled sanding of the weld beads in order to apply compression stresses on them.

A method for preparing a metal composite plate by rolling includes the following steps: 1) rolling composite surfaces of a base plate and a cladding plate, respectively, to obtain the base plate corrugation and the cladding plate corrugation for mating with each other; 2) cleaning the composite surfaces of the base plate and the cladding plate to expose the metal matrixes of the base plate and the cladding plate; 3) laminating the base plate and the cladding plate sequentially so that the base plate corrugation on the base plate and cladding plate corrugation on the cladding plate mate with each other, compacting, and performing welding sealing treatment to the base plate and the cladding plate to obtain a composite plate slab; and 4) rolling the composite plate slab after inspection by using a compositing machine to a desirable thickness, to obtain a metal composite plate.

A method for preparing a metal composite plate by rolling includes the following steps: 1) rolling composite surfaces of a base plate and a cladding plate, respectively, to obtain the base plate corrugation and the cladding plate corrugation for mating with each other; 2) cleaning the composite surfaces of the base plate and the cladding plate to expose the metal matrixes of the base plate and the cladding plate; 3) laminating the base plate and the cladding plate sequentially so that the base plate corrugation on the base plate and cladding plate corrugation on the cladding plate mate with each other, compacting, and performing welding sealing treatment to the base plate and the cladding plate to obtain a composite plate slab; and 4) rolling the composite plate slab after inspection by using a compositing machine to a desirable thickness, to obtain a metal composite plate.

A steel plate has a chemical composition containing, by mass %, C: 0.03% or more and 0.08% or less, Si: 0.01% or more and 1.0% or less, Mn: 1.2% or more and 3.0% or less, P: 0.015% or less, S: 0.005% or less, Al: 0.08% or less, Nb: 0.005% or more and 0.07% or less, Ti: 0.005% or more and 0.025% or less, N: 0.010% or less, O: 0.005% or less and the balance being Fe and inevitable impurities, a structure being a dual-phase structure consisting of a bainite phase and island martensite, wherein the area fraction of the island martensite is 3% to 15%, the equivalent circle diameter of the island martensite is 3.0 m or less, and the remainder of the structure is a bainite phase.

A steel plate has a chemical composition containing, by mass %, C: 0.03% or more and 0.08% or less, Si: 0.01% or more and 1.0% or less, Mn: 1.2% or more and 3.0% or less, P: 0.015% or less, S: 0.005% or less, Al: 0.08% or less, Nb: 0.005% or more and 0.07% or less, Ti: 0.005% or more and 0.025% or less, N: 0.010% or less, O: 0.005% or less and the balance being Fe and inevitable impurities, a structure being a dual-phase structure consisting of a bainite phase and island martensite, wherein the area fraction of the island martensite is 3% to 15%, the equivalent circle diameter of the island martensite is 3.0 m or less, and the remainder of the structure is a bainite phase.

Strip cladding heads and strip cladding systems are disclosed. A disclosed example strip feeder for a strip cladding system includes; a drive roller to advance a cladding strip along a strip feed path through contact plates; a first guide rail having a first slot extending across an entirety of the strip feed path; a first adjustable bearing and a second adjustable bearing located within the first slot, the first adjustable bearing and the second adjustable bearing capable of being secured at positions within the first slot using corresponding first and second strip width adjusters; a second guide rail having a second slot extending across an entirety of the strip feed path and positioned at a different location than the first guide rail along the strip feed path; and a third adjustable bearing and a fourth adjustable bearing located within the second slot, the third adjustable bearing and the fourth adjustable bearing capable of being secured at positions within the second slot using corresponding third and fourth strip width adjusters, the first, second, third, and fourth strip width adjusters to, when secured, define a location and a width of an effective strip feed path.

Strip cladding heads and strip cladding systems are disclosed. A disclosed example strip feeder for a strip cladding system includes; a drive roller to advance a cladding strip along a strip feed path through contact plates; a first guide rail having a first slot extending across an entirety of the strip feed path; a first adjustable bearing and a second adjustable bearing located within the first slot, the first adjustable bearing and the second adjustable bearing capable of being secured at positions within the first slot using corresponding first and second strip width adjusters; a second guide rail having a second slot extending across an entirety of the strip feed path and positioned at a different location than the first guide rail along the strip feed path; and a third adjustable bearing and a fourth adjustable bearing located within the second slot, the third adjustable bearing and the fourth adjustable bearing capable of being secured at positions within the second slot using corresponding third and fourth strip width adjusters, the first, second, third, and fourth strip width adjusters to, when secured, define a location and a width of an effective strip feed path.

The present disclosure relates to electro-conduction devices and methods for submerged arc welding of straight-seam steel pipes and in particular to a lateral electro-conduction device and method for multi-wire submerged arc inner/outer welding of a straight-seam steel pipe. The present disclosure aims to overcome the problem of poor closing of the electromagnetic field resulting from the existing negative-pole electro-conduction mechanism and the problem of unstable welding process resulting from bending deformation in the steel pipe welding process. The device includes: a floating surface contact electro-conduction device, capable of forming a surface contact with an outer surface of the straight-seam steel pipe; a lateral electro-conduction brush device, including multiple electro-conduction brushes and electrically connected with the floating surface contact electro-conduction device; a lateral electro-conduction metal plate, electrically connected with a negative-pole wire harness of a welding machine and electrically connected with the lateral electro-conduction brush device. Therefore, an electro-conduction circuit is formed by the negative-pole wire harness, the lateral electro-conduction metal plate, the lateral electro-conduction brush device, the floating surface contact electro-conduction device, the straight-seam steel pipe and a welding wire electrode.

The present disclosure relates to electro-conduction devices and methods for submerged arc welding of straight-seam steel pipes and in particular to a lateral electro-conduction device and method for multi-wire submerged arc inner/outer welding of a straight-seam steel pipe. The present disclosure aims to overcome the problem of poor closing of the electromagnetic field resulting from the existing negative-pole electro-conduction mechanism and the problem of unstable welding process resulting from bending deformation in the steel pipe welding process. The device includes: a floating surface contact electro-conduction device, capable of forming a surface contact with an outer surface of the straight-seam steel pipe; a lateral electro-conduction brush device, including multiple electro-conduction brushes and electrically connected with the floating surface contact electro-conduction device; a lateral electro-conduction metal plate, electrically connected with a negative-pole wire harness of a welding machine and electrically connected with the lateral electro-conduction brush device. Therefore, an electro-conduction circuit is formed by the negative-pole wire harness, the lateral electro-conduction metal plate, the lateral electro-conduction brush device, the floating surface contact electro-conduction device, the straight-seam steel pipe and a welding wire electrode.