Abstract: Provided are: a flame-retardant magnesium alloy which is prevented from the occurrence of the molten metal combustion during the melting of the alloy in casting; and a method for producing the flame-retardant magnesium alloy. A magnesium alloy containing a specific element in a specified amount and also containing a specific rare earth element (RE) in a specified amount. The magnesium alloy makes it possible to form an oxide film of the rare earth element (RE) which is dense and thin and is rarely cracked on the outermost surface of a molten metal. More specifically a flame-retardant magnesium alloy which contains, in % by mass, less than 9.0% of Ca, 0.5% or more and less than 5.7% of Al, 1.3% or less of Si, 0.4% or more and less than 1.3% of a rare earth element and a remainder made up by Mg and unavoidable impurities, wherein the requirement represented by the formula: Al+8Ca?20.5% is satisfied.

Abstract: A method for die-casting a magnesium alloy comprises the step of casting a die cast product free of any hot tearing, shrinkage tearing and shrinkage cavity starting from a magnesium alloy comprising i) 1 to 10% by weight of aluminum; ii) at least one member selected from the group consisting of 0.2 to 5% by weight of a rare earth metal, 0.02 to 5% by weight of calcium and 0.2 to 10% by weight of silicon; and iii) not more than 1.5% by weight of manganese, and the balance of magnesium and inevitable impurities, using a cold chamber type die-casting machine, wherein a) the temperature of the molten magnesium alloy is maintained at 650 to 750°C.; b) the charging velocity of the molten metal is set at {fraction (1/100)} to {fraction (10/100)} second; and c) the intensified pressure after the charging is set at a level of not less than 200 kgf/cm2.

Abstract: A metallic mold-casting method excellent in the resistance to penetration is herein disclosed and the method comprises the steps of forming a coating layer by applying a mixture comprising at least one member selected from the group consisting of high melting metals, ceramic materials and graphite, and an aqueous surfactant solution or low boiling liquid oils and fats to at least part of the surface of a metallic mold on its cavity side, then applying heat to the coated portion to thus adhere the mixture to the inner surface of the mold, and thereafter repeatedly casting a magnesium alloy in the metallic mold provided with the coating layer. The metallic mold-casting method permits the metallic mold casting of magnesium alloys with good resistance to penetration and this accordingly leads to the production of a cheap and high quality cast magnesium alloy product.

Abstract: A metallic mold-casting method excellent in the resistance to penetration is herein disclosed and the method comprises the steps of forming a coating layer by applying a mixture comprising at least one member selected from the group consisting of high melting metals, ceramic materials and graphite, and an aqueous surfactant solution or low boiling liquid oils and fats to at least part of the surface of a metallic mold on its cavity side, then applying heat to the coated portion to thus adhere the mixture to the inner surface of the mold, and thereafter repeatedly casting a magnesium alloy in the metallic mold provided with the coating layer. The metallic mold-casting method permits the metallic mold casting of magnesium alloys with good resistance to penetration and this accordingly leads to the production of a cheap and high quality cast magnesium alloy product.

Abstract: A sample is taken out of a molten magnesium alloy, the cooling curve of the sample during solidification is measured, the content of the aluminum component in the sample is determined by the use of the crystallization temperature of a phase appearing in the cooling curve, together with cooling curves, and if the results of bath analysis show the components to deviate from the standard values and target values, an aluminum-manganese master alloy, aluminum or magnesium is added to the molten magnesium alloy to adjust the components to an appropriate amount of aluminum or an appropriate iron/manganese ratio, whereby a magnesium alloy is produced.