An alloy consisting of titanium, zirconium, cobalt, and nickel, and its fabrication.

Described herein is a method for treating a metallic golf club head in a series of post-assembly steps, to provide a hardened dark coating. The method described herein includes a quench-polish-quench (QPQ) process that results in a surface coating with improved hardness, uniformity, and porosity characteristics, thereby reducing visible surface deformation and durability loss.

Methods for using a mold to partially harden semifinished products, which are comprised of hardenable steel and have at least partially an open-profile or closed-profile cross section, may involve a number of steps. For example, such methods may involve heating regions of a semifinished product above an A.sub.C1 temperature, positioning the semifinished producing in a mold, positioning an active mold cooling element adjacent to or in contact with the heated regions of the semifinished product, and cooling the regions of the semifinished product at a defined cooling rate so that a hardened microstructure in the cooled regions. These methods and corresponding devices provide low cost solutions that dispense with complete hardening of semifinished products and/or employing welded connections to provide various mechanical properties.

A steel sheet for hot-pressing includes a specific chemical component composition. In the steel sheet, an average equivalent-circle diameter of a Ti-containing precipitate having an equivalent-circle diameter of 30 nm or less among Ti-containing precipitates contained in the steel sheet is 3 nm or more. A precipitated Ti amount and a total Ti amount in the steel satisfy the relationship of: Precipitated Ti amount (mass %)3.4[N]0.5[(total Ti amount (mass %))3.4[N]], in which [N] indicates the content (mass %) of N in the steel. A ferrite fraction in the metal microstructure of the steel sheet is 30 area % or more.

An apparatus (100) for manufacturing a stress relieved length of steel having an oxidised surface layer is disclosed. The apparatus (100) comprises: a heating chamber (102); a reaction chamber (104) coupled to the heating chamber (102); and a conveying mechanism arranged to convey the length of steel along a path through the heating chamber (102) and reaction chamber (104). The heating chamber (102) comprises a heating apparatus arranged to heat the length of steel in a heating portion (110) of the path. The apparatus (100) further comprises a control means comprising a sealed unit defined by the heating chamber (102) and the reaction chamber (104). The control means is arranged to control both the temperature of the length of steel and the atmosphere to which the length of steel is exposed in an oxidisation portion (112) of the path within the reaction chamber (104) in which the oxidised surface layer is formed. A method (100) of manufacturing a stress relieved length of steel having an oxidised surface layer is also disclosed.

A heating step, in which a stainless member is heated to a temperature within or above a heating phase-transformation temperature range (Ar) in which the stainless member is phase-transformed, is executed. A cooling step in which the stainless member heated in the heating step is cooled to a temperature below a cooling phase-transformation temperature range (Mr) in which the stainless member is phase-transformed, is executed. In the cooling step, cooling of the stainless member is suppressed in a control temperature range including the cooling phase-transformation temperature range (Mr).

A heating step, in which a stainless member is heated to a temperature within or above a heating phase-transformation temperature range (Ar) in which the stainless member is phase-transformed, is executed. A cooling step in which the stainless member heated in the heating step is cooled to a temperature below a cooling phase-transformation temperature range (Mr) in which the stainless member is phase-transformed, is executed. In the cooling step, cooling of the stainless member is suppressed in a control temperature range including the cooling phase-transformation temperature range (Mr).

A method of annealing a metal member includes: disposing a first heater in an inner space of a hollow cylindrical metal member having an inner peripheral surface provided with plural teeth protruding toward a central direction, the first heater radiating infrared light and being disposed so as to extend parallel to a direction of a central axis of the metal member; heating the metal member from the inner space with the first heater; and gradually cooling the metal member after heating.

A method of annealing a metal member includes: disposing a first heater in an inner space of a hollow cylindrical metal member having an inner peripheral surface provided with plural teeth protruding toward a central direction, the first heater radiating infrared light and being disposed so as to extend parallel to a direction of a central axis of the metal member; heating the metal member from the inner space with the first heater; and gradually cooling the metal member after heating.

Provided is an induction heating apparatus including a conveying device, which is configured to convey a rotatable workpiece along a linear guiding conveyance path, and a heating coil, which is configured to inductively heat the workpiece being conveyed along the guiding conveyance path. The conveying device includes a first shaft member and a second shaft member, which are arranged in parallel so as to be separated from each other, and a rotary mechanism, which is configured to rotationally drive at least one of the first shaft member and the second shaft member about an axis thereof. The second shaft member is formed of a threaded shaft having a helical convex portion formed along an outer periphery of the second shaft member. The guiding conveyance path is formed by a groove bottom surface of a helical groove defined on the second shaft member by the helical convex portion.