Casting method

A casting method of pressure filling a molten metal from a lower side through a sprue into a cavity defined by an upper die and a lower die or into a cavity defined by the upper die, the lower die and a side die to solidify the molten metal, which comprises:

• using, as a material forming the sprue, a material whose heat conductivity in an operating temperature of 150° C.-550° C. is 34-41 W·(m·K)−1, by mass content, 0.15% or more and 0.35% or less of C, 0.05% or more and less than 0.20% of Si, 0.05% or more and 1.50% or less of Mn, 0.20% or more and 2.50% or less of Cr, 0.50% or more and 3.00% or less of Mo, 0.05% or more and 0.30% or less of V, and the balance essentially Fe, and whose heat conductivity increases as the temperature decreases, and controlling the sprue to be forcibly cooled at the same time that the supply of the molten metal into the cavity is stopped.

A casting method of pressure filling a molten metal from a lower side through a sprue into a cavity defined by an upper die and a lower die or into a cavity defined by the upper die, the lower die and a side die so as to solidify the molten metal, wherein, as a material for an air vent, an insert or a casting pin for hole, a material whose heat conductivity in an operating temperature of 150° C.-550° C. is 34-41 W·(m·K)−1, by mass content, 0.15% or more and 0.35% or less of C, 0.05% or more and less than 0.20% of Si, 0.05% or more and 1.50% or less of Mn, 0.20% or more and 2.50% or less of Cr, 0.50% or more and 3.00% or less of Mo, 0.05% or more and 0.30% or less of V, and the balance essentially Fe, and whose heat conductivity increases as the temperature decreases, is used for making the temperature within the cavity uniform.