Abstract: A welding apparatus having a welding tool and a weld cooling apparatus for forced cooling of the weld zone. The welding tool has a welding nozzle with a longitudinal axis, and the weld cooling apparatus uses a source of CO2 as the coolant. A coolant delivery conduit is arranged to move with the welding tool and has a first tube with a longitudinal axis that extends alongside the welding tool, and a second tube with a longitudinal axis extending downwardly and away from the welding tool. A coolant nozzle is located at the end of the second tube to eject coolant at the weld zone. The coolant nozzle outlet is spaced from the workpiece and arranged to direct a jet of coolant behind the welding tool onto the weld zone at least 10 mm from the longitudinal axis of the first tube.

Abstract: A method for purging air from a structure to be joined by welding by feeding a liquid cryogen to the structure. The liquid cryogen will enter the structure, warm up and enter the gaseous phase very rapidly. The gaseous cryogen will displace the air that is present in the structure out of the structure and reduce the content of oxygen in the structure to about 10 parts per million when welding can begin.

Abstract: A method of manufacturing an article comprising titanium and/or titanium alloy using an additive manufacturing method comprising: providing a substrate; providing a feedstock; and fusing the feedstock to the substrate using a heat source, wherein the substrate and/or feed stock comprises titanium and/or titanium alloy, and the fusing is conducted under a shielding gas comprising an inert gas and an oxidant gas.

Abstract: A welding apparatus having a welding tool and a weld cooling apparatus for forced cooling of the weld zone. The welding tool has a welding nozzle with a longitudinal axis, and the weld cooling apparatus uses a source of CO2 as the coolant. A coolant delivery conduit is arranged to move with the welding tool and has a first tube with a longitudinal axis that extends alongside the welding tool, and a second tube with a longitudinal axis extending downwardly and away from the welding tool. A coolant nozzle is located at the end of the second tube to eject coolant at the weld zone. The coolant nozzle outlet is spaced from the workpiece and arranged to direct a jet of coolant behind the welding tool onto the weld zone at least 10 mm from the longitudinal axis of the first tube.

Abstract: A method for purging air from a structure to be joined by welding by feeding a liquid cryogen to the structure. The liquid cryogen will enter the structure, warm up and enter the gaseous phase very rapidly. The gaseous cryogen will displace the air that is present in the structure out of the structure and reduce the content of oxygen in the structure to about 10 parts per million when welding can begin.

Abstract: In a method of cleaning metal surfaces to be welded together, at least one jet carrying particles of solid carbon dioxide is caused to come into contact with the surfaces, where the solid carbon dioxide is allowed to sublime at the surfaces. The jet is formed by passing a stream of pressurised liquid carbon dioxide through a nozzle under pressure.

Abstract: In a method of cleaning metal surfaces to be welded together, at least one jet carrying particles of solid carbon dioxide is caused to come into contact with the surfaces, where the solid carbon dioxide is allowed to sublime at the surfaces. The jet is formed by passing a stream of pressurised liquid carbon dioxide through a nozzle under pressure.