Abstract: The invention offers a magnesium alloy sheet material having excellent plastic processibility and rigidity and a magnesium alloy formed body having excellent rigidity. The sheet material has magnesium alloy that forms the matrix containing hard particles. The region from the surface of the sheet material to a position away from the surface by 40% of the thickness of the sheet material is defined as the surface region, and the remaining region as the center region. Hard particles existing in the center region have a maximum diameter of more than 20 ?m and less than 50 ?m, and hard particles existing in the surface region have a maximum diameter of 20 ?m or less. Because the hard particles existing at the surface side are fine particles, they are less likely to become the starting point of cracking or another defect at the time of plastic processing. Because the hard particles existing in the center region are coarse, they can increase the rigidity of the sheet material.

Abstract: The invention offers a magnesium alloy sheet having excellent warm plastic formability, a production method thereof, and a formed body produced by performing warm plastic forming on this sheet. The magnesium alloy sheet is produced by giving a predetermined strain to a rolled sheet RS that is not subjected to a heat treatment aiming at recrystallization. The sheet is not subjected to the foregoing heat treatment even after the giving of a strain. The strain is given through the process described below. A rolled sheet RS is heated in a heating furnace 10. The heated rolled sheet RS is passed between rollers 21 to give bending to the rolled sheet RS. The giving of a strain is performed such that the strain-given sheet has a half peak width of 0.20 deg or more and 0.59 deg or less in a (0004) diffraction peak in monochromatic X-ray diffraction. The alloy sheet exhibits high plastic deformability by forming continuous recrystallization during warm plastic forming through the use of the remaining strain.

Abstract: A magnesium base alloy pipe having high strength and toughness is provided along with a method of manufacturing such pipes. A magnesium base alloy pipe, wherein the pipe is produced by drawing a pipe blank of a magnesium base alloy comprising containing either of the following ingredients (1) or (2): (1) about 0.1-12.0 mass % of Al; or (2) about 1.0-10.0 mass % of Zn and about 0.1-2.0 mass % of Zr. The novel alloy pipe is manufactured by a method comprising steps of providing the above-described pipe blank, pointing the pipe blank, and drawing the pointed pipe blank. The drawing step is executed at a drawing temperature above approx. 50° C.

Abstract: It is an object of the invention to provide a magnesium welding wire excellent in surface cleanliness and a method for manufacturing the same. A welding wire according to the invention can be manufactured by drawing a base material such as an extruded material made of pure magnesium or a magnesium-based alloy and, after then, by shaving the surface of the thus drawn wire. Execution of the shaving operation makes it possible not only to effectively remove a lubricant and a coating used in the drawing operation but also to effectively remove an oxide generated during the drawing operation. Thanks to this, the thus obtained welding wire is excellent in surface cleanliness. As a lubricant to be used in the drawing operation, preferably, there may be used an oil lubricant or a wet-type lubricant which can be removed easily by a cleaning operation or by a grease removing treatment.

Abstract: A steel wire of pearlite structure containing 0.8-1.0 mass % of C and 0.8-1.5 mass % of Si is disclosed. In the cross section of the steel wire the difference in average hardness between a region up to 100 ?m from the surface thereof and a deeper region is within 50 in micro-Vickers hardness. The steel wire is manufactured by working a wire rod having the abovementioned chemical composition through shaving, patenting and drawing processes, then strain-relief annealing the resultant wire, and thereafter subjecting the thus annealed to a shot peening process. The steel wire has a high heat resistance and a high fatigue strength, and can be produced through a drawing process without applying a quenching and tempering process.

Abstract: The present invention provides a producing method of a magnesium-based alloy wrought product capable of producing a plastic processing wrought product made of magnesium-based alloy with excellent productivity. A drawn material made of magnesium-based alloy obtained by drawing processing is subjected to plastic processing into a wrought product at processing temperature of lower than 250° C. Since the alloy structure is finely divided by the drawing processing, plastic workability can be enhanced in the plastic processing even if the processing temperature is lower than 250° C. Examples of the plastic processing are forging processing, swaging processing and bending processing.

Abstract: Magnesium-based alloy wire excelling in strength and toughness, its method of manufacture, and springs in which the magnesium-based alloy wire is utilized are made available. The magnesium-based alloy wire contains, in mass %, 0.1 to 12.0% Al, and 0.1 to 1.0% Mn, and is provided with the following constitution. Diameter d that is 0.1 mm or more and 10.0 mm or less; length L that is 1000d or more; tensile strength that is 250 MPa or more; necking-down rate that is 15% or more; and elongation that is 6% or more. Such wire is produced by draw-forming it at a working temperature of 50° C. or more, and by heating it to a temperature of 100° C. or more and 300° C. or less after the drawing process has been performed.

Abstract: [Problems] It is an object of the invention to provide a producing method of a magnesium-based alloy screw capable of producing a screw made of magnesium-based alloy having excellent strength with excellent productivity, and to provide a magnesium-based alloy screw. [Means to Solve the Problem] The producing method includes a head forging step in which a head working for forming a head portion of a screw on a wire made of magnesium-based alloy obtained by drawing is carried out by warm working to produce a screw blank, and a thread rolling step in which thread rolling for forming screw thread on the screw blank is carried out by warm working to produce a screw. The head working in the head forging step is carried out using holding die which fixes the wire and a punch which forms a head portion of the screw. The holding die and the punch are heated, in which at least the holding die are heated to 140° C. or higher and 250° C. or lower, thereby heating the wire to 140° C. or higher and lower than 250° C.

Abstract: A magnesium base alloy pipe having high strength and toughness is provided along with a method of manufacturing such pipes. A magnesium base alloy pipe, wherein the pipe is produced by drawing a pipe blank of a magnesium base alloy comprising containing either of the following ingredients (1) or (2): (1) about 0.1-12.0 mass % of Al; or (2) about 1.0-10.0 mass % of Zn and about 0.1-2.0 mass % of Zr. The novel alloy pipe is manufactured by a method comprising steps of providing the above-described pipe blank, pointing the pipe blank, and drawing the pointed pipe blank. The drawing step is executed at a drawing temperature above approx. 50 ° C.

Abstract: Magnesium-based alloy wire excelling in strength and toughness, its method of manufacture, and springs in which the magnesium-based alloy wire is utilized are made available. The magnesium-based alloy wire contains, in mass %, 0.1 to 12.0% Al, and 0.1 to 1.0% Mn, and is provided with the following constitution. Diameter d that is 0.1 mm or more and 10.0 mm or less; length L that is 1000 d or more; tensile strength that is 250 MPa or more; necking-down rate that is 15% or more; and elongation that is 6% or more. Such wire is produced by draw-forming it at a working temperature of 50° C. or more, and by heating it to a temperature of 100° C. or more and 300° C. or less after the drawing process has been performed.

Abstract: A steel wire of pearlite structure containing 0.8-1.0 mass % of C and 0.8-1.5 mass % of Si is disclosed. In the cross section of the steel wire the difference in average hardness between a region up to 100 &mgr;m from the surface thereof and a deeper region is within 50 in micro-Vickers hardness. The steel wire is manufactured by working a wire rod having the abovementioned chemical composition through shaving, patenting and drawing processes, then strain-relief annealing the resultant wire, and thereafter subjecting the thus annealed to a shot peening process. The steel wire has a high heat resistance and a high fatigue strength, and can be produced through a drawing process without applying a quenching and tempering process.

Abstract: A steel wire of pearlite structure containing 0.8-1.0 mass % of C and 0.8-1.5 mass % of Si is disclosed. In the cross section of the steel wire the difference in average hardness between a region up to 100 &mgr;m from the surface thereof and a deeper region is within 50 in micro-Vickers hardness. The steel wire is manufactured by working a wire rod having the abovementioned chemical composition through shaving, patenting and drawing processes, then strain-relief annealing the resultant wire, and thereafter subjecting the thus annealed to a shot peening process. The steel wire has a high heat resistance and a high fatigue strength, and can be produced through a drawing process without applying a quenching and tempering process.

Abstract: A method for heat-treating steel, which method uses a coolant having a large coefficient of heat transfer and which method treats the steel at low cost and in an environment-friendly manner (no pollution), and an apparatus for the method. The heat-treatment method cools austenitized steel in a coolant, which is a mixture of solid particles and water. It is desirable to cool the steel by passing it through a deposited layer of the solid particles in the water. It is desirable that the solid particles be oxides or graphite powders. It is also desirable to fluidize the solid particles. One type of the heat-treatment apparatus submerges steel in a coolant bath described below. The coolant bath comprises (a) a liquid bath that contains water and (b) a solid-particle bath that is partitioned in the liquid bath by a mesh and that contains solid particles. The mesh has openings smaller than the particle diameter of the solid particles.

Abstract: An evaporation material is used in manufacturing a VTR tape, a vertical magnetic recording thin film or the like. The evaporation material is a wire comprising a cobalt metal a cobalt--nickel alloy containing not more than 30 weight % of nickel, or a cobalt--chromium alloy containing not more than 30 weight % of chromium. This wire has a diameter of at least 1.0 mm and not more than 10 mm, a tensile strength of at least 400 MPa and not more than 1500 MPa, and an elongation and a reduction of area of at least 5%. The evaporation material has a prescribed crystal structure, with a face centered cubic lattice ratio of at least 0.1 and not more than 1. It is possible to obtain a wire having the above properties by heating the metal material to at least Tu.degree. C. and thereafter performing plastic working of reduction in area of at least 10% in a single pass at a temperature of at least Td.degree. C. and not more than (Tu+200).degree. C.

Abstract: An evaporation material is used in manufacturing a VTR tape, a vertical magnetic recording thin film or the like. The evaporation material is a wire comprising a cobalt metal, a cobalt nickel alloy containing not more than 30 weight % of nickel, or a cobalt-chromium alloy containing not more than 30 weight % of chromium. This wire has a diameter of at least 1.0, mm and not more than 10 mm, a tensile strength of at least 400 MPa and not more than 1500 MPa, and a elongation and a reduction of area of at least 5%. The evaporation material has a prescribed crystal structure, with a face centered cubic lattice ratio of at least 0.1 and not more than 1.