Abstract: An internally-chilled piston for an internal combustion engine is provided. This piston comprises a piston body made of an aluminum alloy and a piston head including a cylindrical member and a ring-shaped member engaging the outer peripheral surface of the cylindrical member by a shrink fit bonding. The cylindrical member constitutes the central portion of the piston head, while the ring-shaped member constitutes the periphery thereof. On the surface of the ring-shaped member which contacts with the melt forming the piston body during casting, an aluminized layer is formed which chemically connects the ring-shaped member and the piston body to increase the mechanical strength of bonding therebetween.

Abstract: A dome shaped ceramic insert which defines a portion of a swirl chamber is formed at the crown portion with a single aperture through which both the fuel injector and the glow plug can extend. The cylinder head is formed with a portion which fits into the aperture and which has a wall portion which cooperates with the inner walls of the insert to define the upper section of the swirl chamber.

Abstract: A gas turbine including a joint structure is disclosed. According to the joint structure, a ceramic shaft is received in a bore formed in an end portion of a metallic shaft. Brazing filler metal made of Ag-Cu alloy is distributed between the closely fitted surfaces of the ceramic shaft and bore wall, and it extends axially toward the open end of the bore up to a predetermined plane where a ring seal groove formed on the end portion of the metallic shaft lies. The open end of the bore is closed to prevent entrance of exhaust gas into the bore.

Abstract: A welding wire for automatic arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die. The welding wire consists of a continuous tubular metal casing and a core composition charged in the interior of the casing and comprises such amounts of Ni, Si, B, Nb and C as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.4% of B, 0.3-1.8% of Nb and 0.2-1.5% of C, all by weight. Preferably, either a practically pure Ni strip or an Fe-Ni alloy strip is used as the material of the casing, and the core composition in the form of a powder mixture contains necessary amounts of Ni, Si, B, Nb and C, optionally with the addition of a small amount of Zr. The deposited metal given by this welding wire has high wear resistance and good antifrictional property and seldom suffers from weld cracks.

Abstract: A covered electrode for shielded metal arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die. The covered electrode comprises such amounts of Ni, Si, B, Nb, C and Zr as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.5% of B, 0.3-2.0% of Nb, 0.2-1.5% of C and 0.01-0.20% of Zr, all by weight. In a preferred form, either Ni wire or Fe--Ni wire is used as the core wire, and the covering contains necessary amounts of all the essential alloying elements except Ni. The deposited metal has high wear resistance and good antifrictional property, and the presence of Zr is highly effective for preventing the occurrence of weld cracks.