Abstract: By hot pressing a cold rolled &bgr; type titanium alloy which has not been subjected to solution heat treatment into a predetermined shape, it is possible to obtain a part with a cold rolled metallurgical texture in its approximately central portion in the thickness direction, and a solution heat treatment metallurgical texture in its other portions, and a golf club head is manufactured using this part as a face member.

Abstract: A golf club head which includes a ball hitting face having a central portion and a peripheral portion surrounding at least a part of the central portion. The golf club head is made of a metal, and the hardness of the peripheral portion is smaller than the hardness of the central portion. The difference in the hardness between the central portion and the peripheral portion is equal to or greater than 50 in terms of the Vickers hardness, and the width of the peripheral portion of the hitting face is in a range between about 5 and 20 mm.

Abstract: By hot pressing a cold rolled &bgr; type titanium alloy which has not been subjected to solution heat treatment into a predetermined shape, it is possible to obtain a part with a cold rolled metallurgical texture in its approximately central portion in the thickness direction, and a solution heat treatment metallurgical texture in its other portions, and a golf club head is manufactured using this part as a face member.

Abstract: A method for producing a golf club head made of joined component pieces in which a mold black is split into separate first molds. Each of the first molds have a cavity patterned after one of the joined component pieces. In one embodiment, superplastic alloy plates are positioned within the first molds. The alloy plates are heated and pressurized fluid is simultaneously introduced into the cavities of the first mold for superplastic deformation of the plates. The alloy plates are then positioned within second molds and pressed to form the component pieces. The formed component pieces have shaped piece sections having small radii of curvature. The component pieces are joined to form the golf head. In another embodiment, one of the alloy plates is pressed by the second molds prior to being inserted within the first molds. The pressed alloy plate corresponds to one of the component pieces and has piece sections having a small radius of curvature.

Abstract: This invention relates to a process of making golf club head, comprising the steps of preparing a sectional forming mold having a cavity which duplicates the shape of the head to be produced; preparing a coupled body, having a channel within, consisting of metal sheets made of a superplastic material; clamping the coupled body in the forming mold, heating the coupled body to a range of superplastic forming temperatures and applying fluid pressure to the sheets through the channel opening to force the sheets to conform to the shape of the head by superplastic forming; and trimming the formed product to shape to obtain the golf club head. The invented process is able to produce heads of fine uniform microstructure because the process does not involve conventional casting process, providing freedom from damaging porosities and segregation.

Abstract: To construct a magnetic recording medium to be used for an encoder adapted for detection of an angular or linear displacement of a mobile object such as a robot arm, a substrate is at least partly covered with a Sm-Co alloy thin layer bearing magnetic information with a magnetization pitch which is at least three times as large as the crystal diameter of the magnetic particles in the alloy. A resultant high coercive force obtained with that alloy allows detection with an enlarged detective distance, and the above-mentioned proper ratio of crystal diameter with respect to the magetization pitch allows detection with low percentage of output variation, thereby enabling easy assembly of the encoder and detection with high precision.

Abstract: This invention concerns a new type of golf club head bodies produced by electrolytic deposition of metals, alloys and electrolytic codeposition of metal-matrix composite materials. The golf club heads so produced are comparatively free from structural defects, thus enabling production of high performance golf clubs having thin-walled heads to provide both lightness and strength.