Patent ID: 7520043

Claim:
A method of securing a tube of substantially cylindrical shape in a bore passing through a spherical wall along an axial direction, the method comprising the steps of: machining an annular facing in an inside surface of the spherical wall at the periphery of a zone of the spherical wall through which the bore for securing the tube subsequently passes; depositing a buttering first welding material in the facing; machining the first welding material; making the bore by drilling through a portion of the spherical wall surrounded by the facing; engaging the tube tightly in the bore; depositing a second welding material in the facing at the periphery of the tube in order to weld the tube to the first welding material previously deposited in the facing, at least one of the operations of depositing the first and second welding materials in the facing is sequentially performed automatically by the steps: moving the welding head through a predetermined fixed distance in a direction perpendicular to the axis of the bore to correctly position an electrode of an automatic welding torch relative to the facing; and simultaneously: (a) causing the automatic welding torch to rotate about an axis of the bore for securing the tube therein; (b) moving the automatic welding torch in a direction parallel to the axis of the bore to correctly position the electrode relative to the facing; (c) causing the automatic welding torch to pivot about an axis orthogonal to the axis of the bore while the welding torch is being turned, so as to deposit the welding material in the facing in the form of a weld bead having characteristics that are constant; (d) continuously feeding welding material to the torch electrode for melting the welding material, (e) automatically controlling the movement in (a), (b), and (c); (f) automatically controlling the rate of feeding welding material; and (g) automatically controlling current flow to the torch electrode; the simultaneous movement and control of (a)-(g) resulting in consistent deposited welding material beads; wherein at least one of the first and second welding materials is deposited automatically by successive passes by repeating the automatic sequential steps above to deposit successive weld beads extending all around the periphery of the annular facing and juxtaposed in a direction perpendicular to the axis of the bore for securing the tube.