A method of controlling a weld penetration profile on a workpiece (306) having an outer region and an inner region is described. The method comprises the step of applying energy to the outer region of the workpiece with a welder (302) to produce a weld pool (304). The method also comprises the steps of penetrating the workpiece (306) such that the weld pool (304) spans between the outer region and inner region, and also applying a shielding gas to the inner region at a pressure that provides a force that limits weld penetration. A corresponding apparatus is also defined.

A low-back-pressure penetrating arc welding apparatus and a welding method using the same are disclosed. Through vacuuming a central vacuum chamber of a low-back-pressure protection device by a suction device, a plume of a penetrating arc located in the central vacuum chamber, as well as a back side of a keyhole molten pool, are maintained in a negative-pressure vacuum state relative to an argon gas ambience. A pressure gradient in the keyhole molten pool is thus generated that points from a front side of the keyhole molten pool to the back side of the keyhole molten pool. The pressure gradient thus further enhances a stiffness of the front side of the keyhole molten pool as well as a stability of the penetrating arc, resulting in an enhancement in the piercing capability of the penetrating arc, without changing a force distribution and a temperature gradient of the keyhole molten pool.

A low-back-pressure penetrating arc welding apparatus and a welding method using the same are disclosed. Through vacuuming a central vacuum chamber of a low-back-pressure protection device by a suction device, a plume of a penetrating arc located in the central vacuum chamber, as well as a back side of a keyhole molten pool, are maintained in a negative-pressure vacuum state relative to an argon gas ambience. A pressure gradient in the keyhole molten pool is thus generated that points from a front side of the keyhole molten pool to the back side of the keyhole molten pool. The pressure gradient thus further enhances a stiffness of the front side of the keyhole molten pool as well as a stability of the penetrating arc, resulting in an enhancement in the piercing capability of the penetrating arc, without changing a force distribution and a temperature gradient of the keyhole molten pool.

A pre-assembled insulated weld backing ring for a tubular section of the pipeline. The weld backing ring includes a metal cylinder and an insulation layer. The metal cylinder has a ring-shaped anterior portion and a ring-shaped raised posterior portion with a step therebetween. The posterior portion has a larger diameter than the anterior portion to define an insulation pocket. The insulation layer is positioned on the external surface of the metal cylinder. The insulation layer is made of an insulated material positioned in the insulation pocket to define a protective barrier to protect the tubular section during welding. The weld backing ring may also include a second metal cylinder positioned on the insulation layer. The weld backing ring may be pre-assembled by applying a tubular metal section material to a sheet of metal and rolling the sheet of metal to form the metal cylinder.

A consumable insert for welding a first component to a second component is provided. The first component is positioned with respect to the second component in such a manner that a gap is defined between adjacent surfaces thereof. The consumable insert includes a body having a profile. The profile of the body matches a scan of a profile of the gap between the adjacent surfaces. The consumable insert also includes a dam portion having a profile. The profile of the dam portion matches, at least in part, a scan of corresponding surfaces of the first component and the second component respectively. The dam portion is provided in contact with at least one end of the body. The dam portion is configured to control an overflow of a weld puddle therefrom. The body and the dam portion are formed using three dimensional printing.

A consumable insert for welding a first component to a second component is provided. The first component is positioned with respect to the second component in such a manner that a gap is defined between adjacent surfaces thereof. The consumable insert includes a body having a profile. The profile of the body matches a scan of a profile of the gap between the adjacent surfaces. The consumable insert also includes a dam portion having a profile. The profile of the dam portion matches, at least in part, a scan of corresponding surfaces of the first component and the second component respectively. The dam portion is provided in contact with at least one end of the body. The dam portion is configured to control an overflow of a weld puddle therefrom. The body and the dam portion are formed using three dimensional printing.

A cracked gas cooling heat exchanger includes a tube connection between an uncooled tube (1) and a cooled tube (2), having a cooled inner tube (3) enclosed by a jacket tube (4), with a tube intermediate space (5) for flowing cooling medium. A gas inlet header (11) has a GI tube inner part (12) and a GI tube outer part (13) and a cooling space (14) with an insulating layer (15). The GI tube outer part connects via a water chamber (6) to the jacket tube. The GI tube inner part faces the inner tube and is connected on a face (8) of the water chamber. A weld backing ring (16), between an end face (9) of the cooling space and a bottom face (8) of the water chamber, is in the insulating layer of the cooling space, arranged in a turn-out/groove (17) in the insulating layer.

A rail welding method and device are provided. The method includes: welding a bottom of rail, wherein welding is repeatedly performed along a first swing trajectory in a lengthwise direction of a weld seam, from one end of the bottom of rail to the other end of the bottom of rail; welding a waist of rail, wherein welding is repeatedly performed in the lengthwise direction of the weld seam along a second swing trajectory, from one end of the waist of rail, and the second swing trajectory is divided into two regions for respective welding in a width direction of the weld seam; and welding a head of rail, wherein welding is performed in the lengthwise direction of the weld seam along the first swing trajectory, between one end of the head of rail and the other end of the head of rail.

A rail welding method and device are provided. The method includes: welding a bottom of rail, wherein welding is repeatedly performed along a first swing trajectory in a lengthwise direction of a weld seam, from one end of the bottom of rail to the other end of the bottom of rail; welding a waist of rail, wherein welding is repeatedly performed in the lengthwise direction of the weld seam along a second swing trajectory, from one end of the waist of rail, and the second swing trajectory is divided into two regions for respective welding in a width direction of the weld seam; and welding a head of rail, wherein welding is performed in the lengthwise direction of the weld seam along the first swing trajectory, between one end of the head of rail and the other end of the head of rail.