Abstract: The present invention provides a magnesium-lithium alloy having both corrosion resistance and cold workability balanced at high levels, a certain degree of tensile strength, and very light weight, as well as a rolled material and a formed article made of this alloy. The alloy of the invention contains not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, and the balance of Mg, and has an average crystal grain size of not smaller than 5 ?m and not larger than 40 ?m, and a tensile strength of not lower than 150 MPa or a Vickers hardness (HV) of not lower than 50.

Abstract: The present invention provides a very lightweight magnesium-lithium alloy which has both corrosion resistance and cold workability balanced at high levels, a certain degree of tensile strength, low surface electrical resistivity, as well as a rolled material and a formed article made of the alloy, and a method of producing the alloy, by means of a magnesium-lithium alloy containing not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, and the balance of Mg, and having an average crystal grain size of not smaller than 5 ?m and not larger than 40 ?m, a tensile strength of not lower than 150 MPa, and a surface electrical resistivity of not higher than 1? as measured with an ammeter by pressing a cylindrical two-point probe with a pin-to-pin spacing of 10 mm and a pin tip diameter of 2 mm (contact surface area of one pin is 3.14 mm2), against an alloy surface at a load of 240 g.

Abstract: The present invention provides a very lightweight magnesium-lithium alloy which has both corrosion resistance and cold workability balanced at high levels, a certain degree of tensile strength, low surface electrical resistivity, as well as a rolled material and a formed article made of the alloy, and a method of producing the alloy, by means of a magnesium-lithium alloy containing not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, and the balance of Mg, and having an average crystal grain size of not smaller than 5 ?m and not larger than 40 ?m, a tensile strength of not lower than 150 MPa, and a surface electrical resistivity of not higher than 1? as measured with an ammeter by pressing a cylindrical two-point probe with a pin-to-pin spacing of 10 mm and a pin tip diameter of 2 mm (contact surface area of one pin is 3.14 mm2), against an alloy surface at a load of 240 g.

Abstract: The present invention provides a magnesium-lithium alloy having both corrosion resistance and cold workability balanced at high levels, a certain degree of tensile strength, and very light weight, as well as a rolled material and a formed article made of this alloy. The alloy of the invention contains not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, and the balance of Mg, and has an average crystal grain size of not smaller than 5 ?m and not larger than 40 ?m, and a tensile strength of not lower than 150 MPa or a Vickers hardness (HV) of not lower than 50.

Abstract: A poppet valve in an internal combustion engine comprises a valve head and a valve stem. On a valve face of the valve head, a hardened layer of dendrites in which crystals are directed from the inside to the surface is formed, thereby increasing wear resistance of the valve face without cladding.

Abstract: A steel for exhaust valves comprises C: 0.50-0.65 wt %, Si: 0.1-0.3 wt %, Mn: 5.0-8.0 wt %, Cr: 22.0-24.0 wt %, Ni: 5.0-7.0 wt %, Cu: 0.4-1.0 wt %, Mo: 0.4-2.0 wt %, W: 0.4-2.0 wt %, Nb: 0.4-2.0 wt %, Ti: 0.1-0.3 wt %, N: 0.35-0.50 wt %, sol. Al: 0.005-0.03 wt %, B: 0.001-0.01 wt %, provided that (Cu+Ni): 5.8-7.6 wt %, and the balance being Fe and inevitable impurities and has excellent high-temperature strength, corrosion resistance at room and higher temperatures and oxidation resistance.

Abstract: A shim for a tappet is used in a valve operating mechanism in an internal combustion engine. On the surface of the shim which a cam slidably contacts, there are provided a number of bores in which lubricating oil is put. When an oil film disappears on the surface by slidable contact with the cam, oil overflows from the bores onto the surface. By increasing oil-keeping capability on the surface of the shim, frictional resistance is reduced, thereby preventing wear in the shim and the cam. The bores may be filled with a lubricating solid such as molybdenum disulfide or plastics, such as polyethylene, silicone and Teflon.RTM.. The diameter of the bores may become larger as the bores extend away from the surface of the shim, thereby preventing the solid material from being displaced from the bores. The density of the bores on the shim surface can also be varied. The density of the bores in the central area of the shim surface can be greater than in the surrounding area.

Abstract: The invention relates to a method of preparing a composite sintered body having inner and outer portions fitted with each other. The method includes the steps of: (a) preparing an inner powder compact; (b) preparing an outer powder compact; (c) fitting the inner and outer powder compacts with each other so as to prepare a composite powder compact; and (d) sintering the composite powder compact so as to prepare the composite sintered body. The inner and outer powder compacts are respectively selected such that, during the step (d), the amount of growth of the inner powder compact becomes greater than that of the outer powder compact. Each of the inner and outer composite powder compacts is made of one member selected from the group consisting of a wax-type segregation prevention powder mixture and a metal-soap-type segregation prevention powder mixture. At least one of the inner and outer composite powder compacts is made of the wax-type segregation prevention powder.

Abstract: There is provided a new method of improving properties of the surface of an internal combustion engine valve made from titanium alloy, which comprises; the steps of (a) forming a surface undercoat layer of nickel on a surface of the engine valve; (b) heating the resulting nickel undercoated valve in vacuum or in an atmosphere of inert gas, at the temperature of 450.degree. C. to 600.degree. C., for one to four hours; (c) forming further a three component coat layer comprising nickel, phosphorus and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof, on the surface of the nickel undercoat layer; and (d) heating the resulting coat layer formed on the nickel undercoat layer, at the temperature of 350.degree. C. to 550.degree. C., for one to four hours, so as to make the particles of ceramic material uniformly and homogeneously dispersed in said coat layer.

Abstract: There is provided a new structure of an engine valve made from titanium alloy, having three component coat surface layer formed on the surface of the reciprocating shaft thereof, wherein the composition of the three component coat surface layer comprises nickel, phospher and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof; said particles are uniformly dispersed in said coat surface layer; and said coat surface layer is formed via a binding layer or directly on the surface of the shaft.