A welding device for welding a workpiece using a welding robot includes a welding control device that controls operation of the welding robot and a preheating device that preheats the workpiece. The welding control device includes an input unit through which at least one or both of dimensions of the workpiece and a shape of a welding joint, and preheating information are inputted, and a storage unit that includes at least welding robot operation orbit teaching data, welding condition data, and preheating condition data. The welding control device automatically provides a preheating condition, a welding robot operation orbit, and a welding condition for the welding joint to be welded, and preheating and welding are performed.

A method connects at least two components made of different materials by thermal joining. The two components include a first component made of a material that is suitable for thermal joining and a second component made of a material that cannot be processed using the thermal joining method of the first component. The method includes introducing an auxiliary joining part into the second component forming a form-locking connection and/or a force locking connection. The auxiliary joining part of is made of a material that can be thermally joined to the first component. The first component is thermally joined to the auxiliary joining part in the second component so as to produce a connection between the first component and the second component. The thermal joining is carried out by a beam welding method.

A method connects at least two components made of different materials by thermal joining. The two components include a first component made of a material that is suitable for thermal joining and a second component made of a material that cannot be processed using the thermal joining method of the first component. The method includes introducing an auxiliary joining part into the second component forming a form-locking connection and/or a force locking connection. The auxiliary joining part of is made of a material that can be thermally joined to the first component. The first component is thermally joined to the auxiliary joining part in the second component so as to produce a connection between the first component and the second component. The thermal joining is carried out by a beam welding method.

The present invention provides a repairing method for a hydraulic-end valve cage cavity. First, a to-be-repaired hydraulic-end valve cage cavity is mechanically processed to reserve a unilateral repair size of the cavity; shot blasting and cleaning are performed on the cavity; basic repairing is performed on the cavity to form a backing welding layer, and welding and cladding repairing are performed on the backing welding layer for n layers, to form n repair-welding layers; and finally machine finishing is performed on the cavity having undergone welding repair. The repairing method is also applicable to repairing of a plunger-end seal hole. The repairing method provided in the present invention is simple and is easy to be controlled, and a repaired hydraulic-end valve cage and plunger-end seal hole can be used in on-site fracturing construction in a condition of 50 MPa to 100 MPa for 200 h. By repairing the hydraulic-end valve cage and the plunger-end seal hole, equipment costs for oil fracturing can be significantly reduced.

The present invention provides a repairing method for a hydraulic-end valve cage cavity. First, a to-be-repaired hydraulic-end valve cage cavity is mechanically processed to reserve a unilateral repair size of the cavity; shot blasting and cleaning are performed on the cavity; basic repairing is performed on the cavity to form a backing welding layer, and welding and cladding repairing are performed on the backing welding layer for n layers, to form n repair-welding layers; and finally machine finishing is performed on the cavity having undergone welding repair. The repairing method is also applicable to repairing of a plunger-end seal hole. The repairing method provided in the present invention is simple and is easy to be controlled, and a repaired hydraulic-end valve cage and plunger-end seal hole can be used in on-site fracturing construction in a condition of 50 MPa to 100 MPa for 200 h. By repairing the hydraulic-end valve cage and the plunger-end seal hole, equipment costs for oil fracturing can be significantly reduced.

A teaching system rewinds a welding wire in accordance with a detection that a tip of a welding wire contacts a teach subject, and feeds the welding wire in accordance of a non-detection that the tip of the welding wire contacts the teach subject. Furthermore, the teaching system, if a current protruding length of the welding wire is less than a predetermined length, moves a robot in a direction away from the teach subject, and, if the current protruding length is greater than the predetermined length, moves the robot in a direction closer to the teach subject. The teaching system, if a determination that the current protruding length is equal to the predetermined length, stops feeding and rewinding of the welding wire and stops the robot, and stores a stop position of the robot as a teaching position.

A teaching system rewinds a welding wire in accordance with a detection that a tip of a welding wire contacts a teach subject, and feeds the welding wire in accordance of a non-detection that the tip of the welding wire contacts the teach subject. Furthermore, the teaching system, if a current protruding length of the welding wire is less than a predetermined length, moves a robot in a direction away from the teach subject, and, if the current protruding length is greater than the predetermined length, moves the robot in a direction closer to the teach subject. The teaching system, if a determination that the current protruding length is equal to the predetermined length, stops feeding and rewinding of the welding wire and stops the robot, and stores a stop position of the robot as a teaching position.

The application relates to a method for producing a double-walled pipe (1) and a pipe (1) of this type, having an outer pipe (3) which is press-fitted with an inner pipe (2) consisting of a corrosion-resistant alloy, wherein an adhesive (4) is inserted at least in regions between the outer pipe (3) and the inner pipe (2), wherein, after adhering the inner pipe (2) with the outer pipe (3), the inner pipe (2) and the adhesive layer (4) are removed at the pipe ends, and the inner side of the outer pipe (3) is plated via an integral connection with the inner pipe (2).

The application relates to a method for producing a double-walled pipe (1) and a pipe (1) of this type, having an outer pipe (3) which is press-fitted with an inner pipe (2) consisting of a corrosion-resistant alloy, wherein an adhesive (4) is inserted at least in regions between the outer pipe (3) and the inner pipe (2), wherein, after adhering the inner pipe (2) with the outer pipe (3), the inner pipe (2) and the adhesive layer (4) are removed at the pipe ends, and the inner side of the outer pipe (3) is plated via an integral connection with the inner pipe (2).

An example welding accessory includes: a weld input configured to receive first welding-type power; and power conversion circuitry configured to: convert a first portion of the first welding-type power to second welding-type power; output the second welding-type power to a weld circuit; convert a second portion of the first welding-type power to preheating power; and output the preheating power to a preheater.