Abstract: A Co-base alloy including, by weight, 0.03-0.10% C, not more than 1.0% Si, not more than 1.0% Mn, 20-30% Cr, 15-23% Ni, 3-10% W, 5-10% Ta and 0.05-0.7% Zr, is used as a welding material. A gas turbine nozzle has a crack repaired with a multi-layer weld using the Co-base alloy and a gas turbine for power generation employs the nozzle.

Abstract: A method of forming a non-circular pipe having a different sectional shape in the longitudinal direction thereof by bending a raw pipe while applying pressure to the inside of the raw pipe, wherein the circumference of a section of the raw pipe is substantially equalized to the circumference of a section, corresponding to the section of the raw pipe, of the non-circular pipe after formed.

Abstract: A method of welding opposite end surfaces of two titanium alloy parts kept in alignment by a high energy-density welding process such as electron beam welding, laser beam welding or TIG arc welding, characterized by closely interposing an insert member of either practically pure titanium or Ti-Al binary alloy containing up to 3 Wt % of Al. Owing to thorough alloying of the inserted titanium with the constituents of the fused base metal, the weld metal in a weld joint obtained by this method is sufficiently high in both strength and toughness. By an optional postwelding heat treatment, the strength of the weld metal can further be enhanced.

Abstract: A vacuum chamber for welding in which to place a workpiece is hermetically connected to a vacuum chamber for an electron beam gun in which to place an electron beam gun, and the former is kept at a vacuum of 1.times.10.sup.-4 Torr while the latter, at a vacuum of 1.times.10.sup.-6 Torr. The distance between the electron beam gun and the surface of the workpiece is made greater than the mean free path of gas molecules and metal vapor molecules generated in treating, e.g., 1.85 m. Two focusing coils are arranged to prevent the expansion of the electron beams.

Abstract: An electron beam welding machine comprises an electron gun including a first beam adjusting means, a second beam adjusting means disposed spaced from the first beam adjusting means so as to be movable in the direction of an electron beam path, and position adjusting means for adjusting the position of the second beam adjusting means through rotary movement about an axis perpendicularly crossing the electron beam path and linear movements on a plane perpendicular to the electron beam path. The machine further includes a mirror and light source mounted on the electron gun to emit light on the electron beam path, and photodetectors mounted on the opposite sides of the second beam adjusting means so as to face the electron gun and a workpiece, whereby the correct position of the second beam adjusting means is detected.

Abstract: An electron beam welding apparatus is provided with a magnetic shielding pipe for preventing electron beams emitted from being deflected by stray magnetic fields, and a removing device for removing metal deposit accumulated on a tip portion of the magnetic shielding pipe, which tip portion faces to a weld formed by welding of materials to be welded. The removing device is provided with at least a pair of shutters which move along a tip face of the tip portion to prevent the metal deposit from accumulating on the tip portion. The pair of shutters provides in their central portion a hole for passing electron beams therethrough when they are closed so that welding can continue irrespectively of the movement of the shutters.

Abstract: A method whereby defect-free welds can be produced in joining metallic members of dissimilar materials by electron-beam welding. The method consists in inserting one of the metallic members in openings formed in a metallic plate of the same material as the other metallic member and welding one metallic member to the metallic plate by providing a weld metal, providing by overlay welding on the weld metal a padding metal of a material substantially similar to that of the other metallic member but lower in oxygen content, effecting machining of the outer surface of the padding metal to form a faying surface, and joining by electron beam welding the faying surface of the padding metal to a faying surface formed on the other metallic member whereby the faying surfaces can be rigidly welded.

Abstract: A method for welding dissimilar metals, wherein the end of one of said dissimilar metals is welded to a metal plate by using a filler metal, the material of said metal plate being the same as that of another of said dissimilar metals; and electron beam welding is applied along the interface formed between such a joint surface of said metal plate, which does not include the aforesaid welded portion, and the joint surface of another of said dissimilar metals.

Abstract: A method for welding dissimilar metals, wherein a filler metal is deposited on one end of the aforesaid dissimilar metals to be jointed, said filler metal being of the same material as that of another of said dissimilar metals; the outer surface of the weld metal thus deposited is machined to provide a joint surface adapted for welding; and an electron beam welding is applied along the interface formed between said joint surface of said weld metal thus deposited and the joint surface of another of said dissimilar metals.