Abstract: The present invention provides a golf club head comprising: a face section made of a low specific gravity metal not higher than 5; and a back face section made of a clad material in which the low specific gravity metal and a high specific gravity metal not lower than 7 are metallurgically bonded to each other in advance, wherein the low specific gravity metal of the face section and the low specific gravity metal of the clad material are integrally joined to each other by welding so as to form a club head. In this case, the methods of welding of TIG, plasma arc and laser beams are used in which a U-shaped and/or V-shaped groove is formed. In this golf club head, it is possible to improve the mechanical strength of the joint portion, and it is also possible to produce the golf club head in a short period of time.

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: An interior coating material for continuous caster tundishes which consists of a mixture of 5 to 60% by weight of a lightweight magnesia aggregate having a bulk density of 2.0 or less, and 40 to 95% by weight of an aggregate which is one or more substances selected from the group consisting of electrically molten magnesia clinker, seawater magnesia clinker, burnt clinker prepared from natural magnesite, dolomite clinker and spinel clinker, plus binder, hardening agent and fibers.

Abstract: A method for producing a killed molten steel for continuous casting, which comprises;A step of preparing a molten steel with a blow-off carbon content not less than 0.05% in a converter,A step of pouring the molten steel to a ladle, andA step of degassing the molten steel in vacuum degassing vessel under a vacuum within a range of from 10 to 300 mmHg, with addition of at least one element selected from the group consisting of Al, Si and Mn, while stepwisely adjusting the vacuum in correspondence to the degree of decarburization of the molten steel.