Disclosed are a method for manufacturing a golf putter clubhead, a golf putter clubhead, and a golf putter. The steps of the method for manufacturing the golf putter clubhead include: obtaining or preparing a clubhead body, where the clubhead body includes a clubface, the clubface includes a toe portion, a middle portion, and a heel portion, the toe portion and the heel portion are respectively located at two ends of the clubface, and the middle portion is located between the toe portion and the heel portion; performing stiffening treatment on the clubface; and performing softening treatment on the middle portion after the stiffening treatment. After stiffening treatment is performed on the entire clubhead body, the softening treatment is performed on the middle portion of the clubface, so that stiffness of the toe portion and the heel portion is greater than that of the middle portion of the clubface.

A process for manufacturing compact coils of ultra-fine grained, martensite-free steel bars, the process comprising the following stages:

a) rolling a steel billet by means of a roughing rolling mill producing a steel bar;

b) performing at least one first cooling stage so that the steel bar has a surface temperature higher than the martensite start temperature, and performing at least one first equalization stage in air;

c) rolling the steel bar by means of at least one intermediate rolling mill;

d) performing at least one second cooling stage always maintaining the surface temperature higher than the martensite start temperature, and performing at least one second equalization stage in air;

e) rolling the steel bar by means of a finishing rolling mill in a non-recrystallization temperature range, maintaining the whole cross-section of the steel bar within said non-recrystallization temperature range, and with a total reduction between 25 and 50% with respect to the cross-section of the steel bar at the entry of the finishing rolling mill, in order to obtain an ultra-fine-grained austenitic matrix;

f) winding the steel bar in a compact coil, by means at least one spooling device, so that the ultra-fine-grained austenitic matrix transforms in a mixture of ferrite and pearlite.

After the winding operation is completed, the compact coil can be transferred to a storage area through a transferring device, for example a walking beam, where a natural or forced or retarded cooling is applied to the coil.

A correction apparatus for correcting the planarity of a metal strip advancing into a coating system for coating said metal strip with a layer of molten metal, said apparatus comprising

a bridle roll, which modifies the feeding direction of the metal strip exiting an annealing furnace;

only one sink roll, arranged downstream of said bridle roll and inside a tank adapted to contain a bath of said molten metal;

a correction device for correcting the planarity of the metal strip arranged between said bridle roll and said sink roll;

wherein said correction device comprises at least two motorized rolls;

wherein a first motorized roll of said at least two motorized rolls is distal from said bridle roll in a fixed position with respect to a feeding path of the metal strip, said first motorized roll being arranged on a first side of said feeding path;

wherein said bridle roll is also arranged on said first side;

and wherein a second motorized roll of said at least two motorized rolls is proximal to said bridle roll and movable along the direction of the strip thickness, said second motorized roll being arranged on a second side, opposite to the first side, of said feeding path.

Steel materials for continuously variable transmissions sheaves, and methods for manufacturing a continuously variable transmission sheaves, are provided. In the disclosed steel materials for continuously variable transmission sheaves, the steel materials satisfy the following expressions: 13.9≤Fn1≤15.5, and 1.20≤Fn2≤4.35 (in which Fn1=7×Cr−6×Si+4×Mn; and Fn2=Al×N×10.sup.4).

There is provided a metal sheet producing method that can avoid a decrease in magnetic properties. The metal sheet producing method is a method for producing metal sheets by applying heat treatment to metal sheets made of amorphous soft magnetic material while conveying the metal sheets along a bar and thus crystallizing the amorphous soft magnetic material into nano-crystal soft magnetic material. The method includes attaching the plurality of metal sheets in a laminated state to an upstream portion of the bar, separating the plurality of metal sheets from each other using magnetic force and moving the metal sheets while applying heat treatment thereto so as to allow them to pass by a midstream portion of the bar, and sequentially laminating the metal sheets that have passed by the midstream portion on a downstream portion of the bar.

Embodiments are described herein of a bifurcated heat treatment apparatus and methods for localized heat treatment of a golf club hosel or golf club head. The heat treating method comprises a bifurcated process in which the golf club head is treated in the first heating unit via induction heating and then moved to the second heating unit for convection heating. Both steps are to localize the hosel heat treatment. The heat treatment apparatus may also include a cooling component, such as a heat sink, to ensure the body of the club head remains at the correct temperature during the second heating stage when the hosel is heated in isolation. The overall bifurcated method and apparatus of the localized heat treatment leads to a hosel or golf club head with at least two different hardness values to allow for manipulation of the material without cracking or fracturing.

This vehicle body structure includes a frame member with a first top section, a corner section, a vertical wall section, and a second top section, and a first support section and a second support section provided at the second top section. L/h≤6.7 is satisfied where the h represents a length between an outer surface of the first top section and an outer surface of the second top section, and the L represents a length between the first support section and the second support section.

This vehicle body structure includes a frame member with a first top section, a corner section, a vertical wall section, and a second top section, and a first support section and a second support section provided at the second top section. L/h≤6.7 is satisfied where the h represents a length between an outer surface of the first top section and an outer surface of the second top section, and the L represents a length between the first support section and the second support section.

The present disclosure relates to a heat treatment method and a heat treatment furnace that enable characteristics on an equal level to those when bluing processing is performed to be obtained without the bluing processing being performed in stress-relief annealing of a motor core. A heat treatment method according to one aspect is a heat treatment method in stress-relief annealing of a motor core. The heat treatment method includes an annealing step of annealing the motor core by using an exothermic converted gas as a furnace atmospheric gas, and a cooling step of cooling the motor core obtained in the annealing step, by using an exothermic converted gas as a furnace atmospheric gas, in a temperature range from a temperature in the annealing step to 500° C. at a cooling rate exceeding 600° C. per hour.

The present disclosure relates to a heat treatment method and a heat treatment furnace that enable characteristics on an equal level to those when bluing processing is performed to be obtained without the bluing processing being performed in stress-relief annealing of a motor core. A heat treatment method according to one aspect is a heat treatment method in stress-relief annealing of a motor core. The heat treatment method includes an annealing step of annealing the motor core by using an exothermic converted gas as a furnace atmospheric gas, and a cooling step of cooling the motor core obtained in the annealing step, by using an exothermic converted gas as a furnace atmospheric gas, in a temperature range from a temperature in the annealing step to 500° C. at a cooling rate exceeding 600° C. per hour.