Disclosed is a hot-pressed member that can exhibit very high tensile strength after hot pressing, excellent delayed fracture resistance, and high tensile shear stress after resistance spot welding by properly adjusting its chemical composition and its microstructure such that at least 20 Nb-based precipitates having a grain size of less than 0.10 m are present on average per 100 m.sup.2 of a cross section parallel to a thickness direction of the member, a prior austenite average grain size is 8 m or less, an average aspect ratio of prior austenite grains is 2.5 or less, and a volume fraction of martensite is 90% or more, and such that a standard deviation of Vickers hardness measured every 200 m on a surface of the member is 40 or less.

A forging apparatus and a forged product manufacturing method aim to prevent decrease in the temperature of a forging space and the temperature of a forging material, efficiently maintain the uniformity of the temperatures of upper and lower dies, and improve forging efficiency. In the forging apparatus and the forged product manufacturing method according to the present invention, the upper and lower dies are heated by a heating mechanism in a housing in which a charging port of an integrally formed housing body is closed by a door, the upper and lower dies are moved relatively in a facing direction of the upper and lower dies, the heating mechanism is moved relatively in the facing direction with respect to at least one of the relatively moving upper and lower dies, and whereby the forging material is forged between the upper and lower dies. Furthermore, the forged product manufacturing method is used to manufacture a forged product from the forging material.

A forging apparatus and a forged product manufacturing method aim to prevent decrease in the temperature of a forging space and the temperature of a forging material, efficiently maintain the uniformity of the temperatures of upper and lower dies, and improve forging efficiency. In the forging apparatus and the forged product manufacturing method according to the present invention, the upper and lower dies are heated by a heating mechanism in a housing in which a charging port of an integrally formed housing body is closed by a door, the upper and lower dies are moved relatively in a facing direction of the upper and lower dies, the heating mechanism is moved relatively in the facing direction with respect to at least one of the relatively moving upper and lower dies, and whereby the forging material is forged between the upper and lower dies. Furthermore, the forged product manufacturing method is used to manufacture a forged product from the forging material.

A manufacture method for partial structure refinement of a forged iron golf club head includes a preparing step, a first preforming step, a second preforming step, a fine-forging shaping step, a partial structure refinement step, and a final shaping step. The manufacture method is capable of partially refining the particle structure of the final workpiece. The hardness of a hitting surface of the final workpiece is reinforced to generate clear and loud sounds and to achieve better hitting performance and experience.

A manufacture method for partial structure refinement of a forged iron golf club head includes a preparing step, a first preforming step, a second preforming step, a fine-forging shaping step, a partial structure refinement step, and a final shaping step. The manufacture method is capable of partially refining the particle structure of the final workpiece. The hardness of a hitting surface of the final workpiece is reinforced to generate clear and loud sounds and to achieve better hitting performance and experience.

A forge and method of forging is provided. The forge converts an asymmetric railroad rail to a symmetric railroad rail through a combination of vertical and horizontal forging operations. The rail is linearly translated to heating and forging stations on a roller table. The asymmetric to symmetric conversion can be completed without the need for reorienting the rail except along a single translational axis.

Disclosed is a making method for mass-producing non-spherical solder balls. The making method includes: inserting spherical solder balls into non-spherical accommodation grooves; melting the spherical solder balls by heating and filling the accommodation grooves with the molten solder; making non-spherical solder balls by cooling the molten solder; and withdrawing the non-spherical solder balls from the accommodation grooves.

Disclosed is a making method for mass-producing non-spherical solder balls. The making method includes: inserting spherical solder balls into non-spherical accommodation grooves; melting the spherical solder balls by heating and filling the accommodation grooves with the molten solder; making non-spherical solder balls by cooling the molten solder; and withdrawing the non-spherical solder balls from the accommodation grooves.

A manufacture method for partial structure refinement of a forged iron golf club head includes a preparing step, a first preforming step, a second preforming step, a fine-forging shaping step, a partial structure refinement step, and a final shaping step. The manufacture method is capable of partially refining the particle structure of the final workpiece. The hardness of a hitting surface of the final workpiece is reinforced to generate clear and loud sounds and to achieve better hitting performance and experience.

A manufacture method for partial structure refinement of a forged iron golf club head includes a preparing step, a first preforming step, a second preforming step, a fine-forging shaping step, a partial structure refinement step, and a final shaping step. The manufacture method is capable of partially refining the particle structure of the final workpiece. The hardness of a hitting surface of the final workpiece is reinforced to generate clear and loud sounds and to achieve better hitting performance and experience.