JP2003239015A - Heat treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain deformation and strain in quenching in a heat treatment of a metal and to obtain a uniform quenched structure. <P>SOLUTION: In the heat treatment method for applying rapid cooling after heating a metallic member provided with both of a thin part and a thick part, after heating, a shape-keeping means which applies stress at the opposite side to a deforming direction of a deforming portion in the metallic member at cooling time, is applied. Further, as the above shape-keeping means, the deforming portion is fixed or the cooling liquid is spouted from the deforming direction side to the deforming portion to apply the cooling. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal heat treatment method.

[0002]

2. Description of the Related Art Generally, quenching is an operation in which an object to be treated is heated to a temperature not lower than a desired transformation point and then immersed in a cooling liquid such as oil, water or a water-soluble coolant to rapidly cool it. For example, a quenching device 27 as shown in FIG. 4 is used.
This quenching device includes a cooling tank 29 that stores a cooling liquid 28 that is a quenching agent, a propeller stirrer 30 that is offset from the cooling tank 29, and a liquid flow 31 in the tank that is generated by the propeller stirrer 30. And a rectifying plate 32 arranged so as to go from the top to the top. Further, there is also one that uses a jet pump instead of the propeller stirrer 30. In this way, by stirring and cooling the coolant, it is possible to adjust the quality such as the target metallographic structure and strain amount.

In the conventional method, there is a problem that a uniform flow velocity of the coolant cannot be obtained and a difference in cooling ability occurs, resulting in a large distortion of the object to be treated.

In addition, recently, Japanese Unexamined Patent Publication No. 2001-4933 is also available.
As shown in 2, a stirring vibration device is provided in the cooling tank,
In some cases, a horizontal flow is formed in the cooling liquid to eliminate the difference in cooling capacity and allow uniform quenching.

[0005]

However, when cooling a member having both a thin portion and a thick portion, since the thin portion has a higher cooling capacity than the thick portion due to the difference in heat capacity, it quickly cools and shrinks, There is a problem that internal stress is generated at the boundary between the thick part and the thick part, resulting in quenching deformation such as heat treatment distortion and bending.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a heat treatment method capable of suppressing the deformation and distortion generated during heat treatment.

[0007]

The present invention has been made based on the above-mentioned problems, and in a heat treatment method of quenching after heating a metal member having both a thin portion and a thick portion, cooling after heating. A heat treatment method is characterized in that shape maintaining means for applying a stress on the opposite side to the deformation direction of the deformed portion of the metal member at the time is applied.

According to the present invention, when a member having both a thin wall portion and a thick wall portion is cooled, the thin wall portion has a higher cooling ability than the thick wall portion, so that the thin wall portion quickly cools and shrinks, and the boundary between the thin wall portion and the thick wall portion is reduced. Since internal stress is generated in the metal member and the metal member is deformed, in order to maintain the shape of the metal member after heating as it is, the stress opposite to the deformation direction is fixed so that the position of the deformed portion is fixed. By adding it, the deformation is prevented. In this case, if residual stress remains after cooling, it is desirable to remove the residual stress by annealing at low temperature after cooling.

Further, as the shape maintaining means, a method of fixing the deformed portion with a pin or the like so as to maintain the shape of the metal member when it is put into the cooling tank is a relatively simple method.

Further, as the shape maintaining means, the cooling liquid is jetted from the deformation direction side to the deformed portion for cooling, so that the stress deformed by the jet pressure is canceled, and the metal member is not deformed. The shape can be maintained. The method of jetting the cooling liquid is a desirable method because it can reduce the formation of a vapor film that may occur when the heated member is put into the cooling tank and may cause uneven cooling. Since the vapor film has an adiabatic effect, the adiabatic effect hinders the control of the cooling rate, but by ejecting the cooling liquid, the vapor film can be prevented from being formed or can be removed immediately by the jetting force.

As another invention, in a heat treatment method in which a metal member having both a thin portion and a thick portion is heated and then rapidly cooled, in the heating portion, after the heating, the cooling rate is reduced to the thick portion of the metal member. The heat treatment method is characterized by speeding up compared with the above.

According to the present invention, the deformation caused by the difference in the cooling capacity is aimed at achieving the uniform cooling capacity of the entire metal member, and the cooling rate of the portion having the low cooling capacity is increased to achieve the deformation. is there. In some cases, the cooling rate may be adjusted to a lower cooling capacity, but it is better to adjust the cooling capacity to a higher cooling capacity in many cases because the structure is adjusted by rapid cooling. The fact that the cooling rate can be kept constant means that a uniform crystal structure can be adjusted, and a stable member can be provided in terms of quality such as mechanical properties of the metal member.

Further, the cooling rate can be controlled by controlling the amount of the cooling liquid jetted to the metal member to activate heat exchange in a portion having a low cooling capacity to increase the cooling rate.

The cooling rate may be controlled by the difference in the temperature of the cooling liquid jetted to the thick portion and the thin portion.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
A golf club (iron head) having an asymmetrical shape and having both a thin portion and a thick portion will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of a heat treatment apparatus 1 according to the present invention. As the configuration, as shown in FIG.
The cooling tank 2 includes a support base 5 on which a deformation preventing jig 4 is arranged according to the shape of the golf club head 10, and a nozzle 5 for ejecting the cooling liquid 9 on the periphery thereof.

A plurality of nozzles 5 are arranged at positions corresponding to the shape of the golf club head 10 which is the work.
The cooling liquid 9 ejected from the cooling water channel 6 is pumped by the pump 7.
Be sent out via. Further, the controller 8 can control the amount of cooling liquid ejected from each nozzle 5, the pressure, and the ejection timing. Further, depending on the shape of the work, a plurality of ring-shaped cooling water channels 1 as shown in FIG.
The nozzle 20 may be attached to the 9.

A method of quenching a golf club head having such a structure will be described. First, the golf club head 10 is heated to a predetermined temperature. At this time, since the golf club head 10 has a complicated three-dimensional shape and cannot support each part on a flat surface, the shaft portion 11 and the face portion 12 are not supported. The angle of is deformed by its own weight. For this reason, the deformation that can occur at the time of heating can be forced by installing the deformation prevention jig 4 arranged in the position of the original golf club head shape. The deformation preventing jig 4 has an inlet opening toward the peripheral portion so that the golf club head 10 deformed in advance can be inserted into the jig.

Further, when the work is heated, the work is restrained in advance so as to be deformed in the direction opposite to the strain caused by the quenching and the work is heated, so that even if the work shape has a larger heat treatment strain or bending, the quenching deformation is prevented. can do.

Further, when the golf club head 14 is quenched, the golf club head 14 has a complicated three-dimensional shape and various portions have various wall thickness differences, so that a difference in cooling ability partially occurs. Therefore, it is partially deformed. In particular, since the boundary between the face portion 15, the shaft portion 16 and the soul portion 17 has a large thickness, deformation occurs in the direction of the arrow. As a result, deformation is performed as shown by the deformation prediction line 19. Therefore, as shown in FIG. 3, the deformation preventing jig 23 is arranged in advance in a portion which is easily deformed.

After that, the golf club head 22 is set in the deformation preventing jig 21, and then the cooling liquid is ejected from each nozzle 20. By carrying out quenching in this way, it is possible to suppress deformation and distortion during quenching. Furthermore, by lowering the pressure of the cooling liquid jetted to the face portion 25 as compared with the other portions, the entire golf club head 22 can be cooled uniformly. Therefore, the deformation and distortion during quenching can be suppressed more, and the structure can be made uniform. Also, instead of generating the pressure difference of the cooling liquid, the same effect can be obtained by using the flow rate, the temperature, and the timing difference of the ejection.

[0021]

As described above, according to the present invention, it is possible to suppress the deformation and distortion of the metal during the heat treatment.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an outline of a cooling device.

FIG. 2 is a diagram illustrating a deformation behavior during quenching of a golf club head.

FIG. 3 is a diagram illustrating how the cooling liquid is ejected.

FIG. 4 Conventional quenching device

[Explanation of symbols]

1, 27 ... Cooling device, 2, 29 ... Cooling bowl, 3, 26 ... Support base, 4, 21 ... Deformation preventing jig, 5, 20 ... Nozzle,
6, 19 ... Cooling water channel, 7 ... Pump, 8 ... Control device, 9,
28 ... Coolant, 10, 14, 22 ... Golf club head, 11, 16, 24 ... Shaft part, 12, 15, 25
... Face part, 13, 17, 23 ... Soul part, 18 ... Expected deformation line, 30 ... Propeller stirrer, 31 ... Liquid flow, 32 ...
rectifier

Claims (6)

[Claims] 1. A heat treatment method in which a metal member having both a thin portion and a thick portion is heated and then rapidly cooled. In the heat treatment method, after the heating, a stress on a side opposite to a deformation direction of a deformed portion of the metal member is applied. A heat treatment method characterized in that a shape maintaining means is added. 2. The heat treatment method according to claim 1, wherein a deformed portion is fixed as the shape maintaining means. 3. The heat treatment method according to claim 1, wherein as the shape maintaining means, a cooling liquid is jetted from a deformation direction side to a deformation portion to cool it. 4. A heat treatment method in which a metal member having both a thin portion and a thick portion is heated and then rapidly cooled. In the heat treatment method, after the heating, the cooling rate to the thick portion of the metal member is faster than that of the thin portion. Characterizing heat treatment method. 5. The cooling rate is controlled by the amount of cooling liquid jetted to the metal member.
The heat treatment method described. 6. The heat treatment method according to claim 4, wherein the cooling rate is controlled by a difference in temperature of the cooling liquid jetted to the thick portion and the thin portion.