Abstract: A method of straightening a wire rod of titanium or titanium alloy wherein the rod is hot-straightened to a straight rod at the straightening temperature T and elongation .epsilon. satisfying the expression (1) or (2). The method includes hot rolling a titanium billet of .beta. titanium alloy, (.alpha.+.beta.) titanium alloy or a near .alpha. titanium alloy into a wire rod, winding the hot rolled wire rod into a coil, cold drawing the wire rod, cutting the wire rod to obtain a bent wire rod, heating the bent wire rod to a straightening temperature T while both end portions of the bent wire rod are fixed, applying a predetermined elongation .epsilon. to the wire rod, maintaining a straightening temperature T, hot-straightening the wire in accordance with the expression (2).epsilon.(T-400).gtoreq.400 (1).epsilon.(T-500).gtoreq.200 (2)and cooling the wire rod while applying tension. The method is suitable for preparing a straight rod for use in an engine valve.

Abstract: A continuous casting apparatus comprises continuously supplying molten metal from a tundish to a cooled mold having an inlet and an outlet at least through a break ring, forming a cast section by continuously cooling the molten metal in the mold and starting the solidification of the molten metal below its surface, and intermittently withdrawing the cast section with respect to the mold through its outlet. During continuous casting, a sealing gas having a pressure higher than atmospheric and being soluble in the molten metal is invariable supplied to the entirety of the contact area of the mold and the break ring.

Abstract: A continuous casting method includes the steps of continuously supplying molten metal into a mold through at least one feed nozzle connected to the mold through a break ring, with the feed nozzle, the mold and the break ring forming at least a portion of a continuous casting apparatus, and intermittently withdrawing a cast piece formed from the molten metal in the mold thereby creating pressure in a space formed at a connecting point between the break ring, the mold and the cast piece as a result of the withdrawal from the mold. A shield means is placed to seal-off space between the at least one feed nozzle, and the mold to prevent entry of gas into the continuous casting apparatus and the pressure is reduced in the sealed-off space to thereby eliminate a pressure differential between the pressure in the sealed-off space and the pressure created in the space formed at the connecting point between the break ring, the mold and the cast piece during the intermittent withdrawal from the mold.

Abstract: A continuous cast method comprises continuously supplying molten metal from a tundish through a break ring to a cooled mold having an inlet and an outlet. A cast section is formed by continuously cooling the molten metal in the mold and starting the solidification of the molten metal below its surface and intermittently withdrawing the cast section with respect to the mold through its outlet. During continuous casting, a sealing gas having a pressure higher than atmospheric and soluble in the molten metal is constantly supplied to the entirety of the contact area of the mold and the break ring.