A welding head for a welding apparatus, the head comprising an outer face attachable to a welding device such as an electron beam gun or laser, an inner face sealable to a workpiece, and an outer sealing ring and an inner sealing ring situated within the inner face and disposed on either side of an evacuatable region, wherein the inner face has a teardrop-shaped profile. Outer and inner sealing rings can be inflatable or formed from different materials, the outer sealing ring being formed from a material with a Shore hardness of between 50 to 70 and the inner sealing ring being formed from a material with a Shore hardness of 20 to 40. A bridging seal can extend from within the inner sealing ring to the outer sealing ring.

In an embodiment, a system is provided that includes an electron gun, a focusing system, and a housing. The electron gun can include a cold cathode electron source and an extraction electrode. The focusing system can be configured to focus a beam of electrons extracted from the electron gun to a focal region. The housing can include the electron gun and extend along a housing axis in the direction of the electron beam. The cold cathode source is configured to emit electrons at a first operating pressure that is higher than a second operating pressure at the focal region of the electron beam.

A method of manufacturing a welded structure of a ferritic heat-resistant steel is provided that prevents Type IV damage and that has good on-site operability without adding a high B concentration. The method includes: the step of preparing a base material including 8.0 to 12.0% Cr, less than 0.005% B and other elements; the step of forming an edge on the base material; a pre-weld heat treatment step in which a region located between a surface of the edge and a position distant from the surface of the edge by a pre-weld heat treatment depth of 30 to 100 mm is heated to a temperature of 1050 to 1200 C. and is held at this temperature for 2 to 30 minutes; a welding step in which the edge is welded to form the weld metal; and a post-weld heat treatment step in which a region located between the surface of the edge and a position distant from the surface of the edge by a distance not smaller than the pre-weld heat treatment depth and not greater than 100 mm is heated to a temperature of 720 to 780 C. and is held at this temperature for a time period not shorter than 30 minutes and satisfying the following formula, (1):

(Log(t)+12).Math.(T+273)<13810(1).

A method for producing a layered object is provided. The method includes a) irradiating a given surface layer of the object with an energy beam to create an interaction zone on the surface layer; b) providing relative motion between the energy beam and the given surface layer so as to control the interaction between the energy beam and the given surface layer; c) introducing feedstock into the interaction zone so that the feedstock melts and forms a hot solidified surface after leaving the interaction zone; d) applying mechanical energy to the hot solidified surface; and e) repeating steps (a) through (d) to form at least part of the layered object.

An electron beam source comprising a cathode, an anode, a means for deflecting an electron beam over a target surface and at least one vacuum pump, the electron beam source further comprising a contraction area arranged between the anode and the means for deflecting the electron beam where a hole in the contraction area is aligned with a hole in the anode with respect to the cathode, a first vacuum pump is arranged between the contraction area and the anode and a second vacuum pump is arranged above the anode, a gas inlet is provided between the contraction area and the means for deflecting the electron beam, wherein a first crossover of the electron beam is arranged between the cathode and the anode and a second crossover is arranged at or in close proximity to the contraction area.

A process and apparatus for free form fabrication of a three-dimensional work piece comprising (a) feeding raw material in a solid state to a first predetermined location; (b) depositing the raw material onto a substrate as a molten pool deposit under a first processing condition; (c) monitoring the molten pool deposit for a preselected condition; (d) comparing information about the preselected condition of the monitored molten pool deposit with a predetermined desired value for the preselected condition of the monitored molten pool deposit; (e) solidifying the molten pool deposit; (f) automatically altering the first processing condition to a different processing condition based upon information obtained from the comparing step (d); and repeating steps (a) through (f) at one or more second locations for building up layer by layer a three-dimensional work piece. The apparatus is characterized by a detector that monitors a preselected condition of the deposited material and a closed loop electronic control device for controlling operation of one or more components of the apparatus in response to a detected condition by the detector.

This disclosure describes machining units for machining a workpiece, in particular for welding a workpiece by, using a thermal machining beam. The thermal machining beam can be directed onto a workpiece along a beam incidence axis by means of the machining unit, wherein the machining unit has a rotary drive device by means of which an auxiliary module for workpiece machining is rotatable about the beam incidence axis. The machining unit includes a coupling device by which the auxiliary module can be moved between a position coupled to the rotary drive device and a position uncoupled from the rotary drive device.

A method of forming a medical device lead connection element is described. The method includes positioning an end portion of a lead filar to overlap a lead end connection element such that the positioning creates mutual interference between the lead filar and the lead end connection element, and forming an interference configuration. Then melting the end portion of the lead filar to form a weld joint and allowint the end portion of the lead filar to move towards the end connection element.

A welding method for welding a cast iron (first member) and a steel (second member) having a lower hardness than the cast iron, which comprises: a first step for inserting an insert material (third member) having a lower hardness than the steel between the cast iron and the steel; a second step for welding the boundary portion between the cast iron and the insert material; and a third step for welding the boundary portion between the steel and the insert material. Consequently, this welding method is able to improve the strength characteristics after welding.

This disclosure relates to weldability of steel alloys that provide weld joints which retain hardness values in a heat affected zone adjacent to a fusion zone and which also have improved resistance to liquid metal embrittlement due to the presence of zinc coatings.