The invention relates to the field of construction, particularly to welding of above- and underground high-strength pipelines with controlled heat input. Application of the invention will increase the load-bearing capacity of the pipelines made with the use of butt-welded pipes, pipe spools, pipe strings. The method includes joining of two or more cylindrical metal pipes, pipe spools and pipe strings by the welded ring butt with the use of the arc welding for the whole perimeter of the pipe. Criteria for a high-quality welded joint include optimal selection of parameters of the welding thermic cycle. The suggested welding method allows to have the optimal structure, high strength and viscoplastic properties in areas of the welded joint, to provide for the required load-bearing capacity of the pipeline and its reliability during operation.

A system for rapidly assembling solar receiving tubes and solar energy systems comprises a welding station is described. The welding station provides for rapidly assembling solar receiver tubes by welding together two or more solar receiving tubes and comprises means for receiving and restraining solar receiver tubes and a welding station comprising an orbital or a rotational weld head.

A robotic welding system comprises a supporting arm for attaching to a repositionable support structure, the supporting arm comprising a first mounting portion connectable to the repositionable support structure, and a second mounting portion rotatably coupled to the first mounting portion. A yaw rotary actuator rotates the second mounting portion about a yaw axis. A welding arm comprises a third mounting portion rotatably coupled to the second mounting portion of the supporting arm. A pitch rotary actuator rotates the third mounting portion about a pitch axis generally perpendicular to the yaw axis. A roll rotary actuator rotates a torch holder shaft about a roll axis generally perpendicular to the pitch axis. The shaft has a torch mounting portion for mounting a welding torch at an end thereof. A controller is operably coupled to the actuators to cause the welding torch to execute a welding pattern.

A heavy weight drill pipe may include a tube body formed of AISI 1340 alloy steel, and first and second tool joints at respective ends of the tube body, and which are formed of an AISI 41XX series alloy steel. The first and second tool joints may be welded to the tube body at a weld line within a weld region. A Charpy impact toughness at the weld line or surrounding weld region may be least 12 ft-lbs. (16.5 N-m). Yield and tensile strengths at the weld line or weld region may be at least 65 ksi (448.0 MPa) and at least 106 ksi (731.0 MPa), respectively. Material properties at the weld line or weld region may be achieved by heat treating after welding. Heat treating may include austenitizing, quenching, and tempering the weld line and/or the surrounding weld region.

A welding system can manage wire feeders such that unused wire feeders are conveniently stowed. The welding system include two or more wire feeders individually attachable to a welding torch. The welding system includes one or more mount points to secure unused wire feeders and enable convenient swapping of an active wire feeder.

A welding support block supports, from the rear surface of a joint to be welded, a weld pool created during a welding process. The welding support block comprises a block of metal and an outer layer of ceramic material providing a supporting surface. The ceramic material layer has a thickness between 0.25 mm and 1.5 mm. The metal material immediately beneath the ceramic material layer is made of steel. An internal line-up clamp for holding pipes in end-to-end alignment ready for welding may include multiple such welding support blocks. The use of such welding support blocks is particularly useful when laying a sour service carrying pipeline (high H.sub.2S content).

A welding support block supports, from the rear surface of a joint to be welded, a weld pool created during a welding process. The welding support block comprises a block of metal and an outer layer of ceramic material providing a supporting surface. The ceramic material layer has a thickness between 0.25 mm and 1.5 mm. The metal material immediately beneath the ceramic material layer is made of steel. An internal line-up clamp for holding pipes in end-to-end alignment ready for welding may include multiple such welding support blocks. The use of such welding support blocks is particularly useful when laying a sour service carrying pipeline (high H.sub.2S content).

An automated welding system includes a welding robot and control circuitry. The welding bug robot includes a welding torch. The welding bug robot is configured to move on a track disposed around a circumference of a first pipe and perform a root pass welding operation at a joint between the first pipe and a second pipe. The control circuitry is configured to control movement of the welding bug robot around the circumference of the first pipe, apply a high energy welding phase via the welding torch to establish a first root condition, and apply a low energy welding phase via the welding torch to establish a second root condition.

Properties and performance of weld material between metals in a weldment is controlled by modifying one or more of the nitrogen content and the carbon content to produce carbide (e.g. MC-type), nitride and/or complex carbide/nitride (e.g. MX-type) type precipitates. Fusion welding includes (i) adjusting shield gas composition to increase nitrogen/carbon gas and nitride/carbide species, (ii) adjusting composition of nitrogen/carbon in materials that participate in molten welding processes, (iii) direct addition of nitrides/carbides (e.g. powder form), controlled addition of nitride/carbide forming elements (e.g. Ti, Al), or addition of elements that increase/impede solubility of nitrogen/carbon or nitride/carbide promoting elements (e.g. Mn), and (iv) other processes, such as use of fluxes and additive materials. Weld materials have improved resistance to different cracking mechanisms (e.g., hot cracking mechanisms and solid state cracking mechanisms) and improved tensile related mechanical properties.

A welding torch includes a gas lens of a lattice structure that straightens a shielding gas. The welding torch includes a non-consumable electrode, an electrode holder into which the non-consumable electrode is inserted, and a torch body including a sleeve that holds the electrode holder, a flow path forming portion that forms a shielding gas flow path around the sleeve, and a nozzle that forms a shielding gas guiding space around a distal end of the non-consumable electrode, the distal end extending from the electrode holder, in which the gas lens is provided so as to separate the shielding gas flow path from the shielding gas guiding space.