JP3395438B2 - Induction heating bonding method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hot diffusion bonding of metal materials and the like, and is particularly suitable for bonding materials that have severe bonding conditions and require rapid control of bonding temperature, and bonding between materials having large hardness differences. .

[0002]

2. Description of the Related Art A joining technique has been conventionally known in which a plurality of metal materials are pressed into contact with each other and the contact portions are heated to perform hot diffusion bonding. As a method of heating the bonding site,
A method using resistance heating means such as a heater and a method using induction heating means such as a high frequency induction coil are known. Usually, when hot diffusion bonding is performed, the bonding site is heated to several hundred degrees, and therefore resistance heating requires several tens of minutes to heat to a predetermined temperature. However, according to the induction heating means, rapid heating can be performed within a few minutes, and moreover, only the joining portion can be locally heated. Therefore, it is desirable to use the induction heating means.

On the other hand, by quenching after the joining is completed,
The joining material can be made into a supersaturated solid solution and can be hardened by aging treatment. Cooling is performed by introducing a refrigerant gas from a gas inlet provided on the wall of the airtight chamber.

[0004]

Generally, since this kind of joining treatment is performed between different kinds of metals, the hardness of both metal materials is different. Therefore, although the joint itself can be strengthened, it is mechanically discontinuous,
When a force is applied to a series of bonded products from the outside, the stress is not evenly distributed, and a shearing force is generated at the discontinuous portion, resulting in damage. As a result, a solid bonded product cannot be obtained as a whole. Was holding.

Further, even if the airtight chamber is filled with the refrigerant gas, only the gas existing in the vicinity of the bonding material actually contributes to the cooling due to the retention, and the cooling capacity of the refrigerant gas is lowered to prolong the cooling. It takes time. Further, since the rapid cooling cannot be performed, the bonding reaction progresses during the cooling, the control accuracy of the bonding conditions deteriorates, and the desired bonding conditions cannot be realized. Furthermore, because it cannot be rapidly cooled, a supersaturated solid solution cannot be formed in the material, and age hardening cannot be expected,
In particular, when a precipitation hardening material such as JIS6061 series aluminum is used, it is difficult to improve the strength unless it can be rapidly cooled.

[0006] The present invention has been made to solve the above problems, and is excellent in rapid heating and rapid cooling performance, and induction heating welding that enables strong joining with less mechanical discontinuity in the materials after joining. It is an object to provide a method and a device.

[0007]

In order to solve the above-mentioned problems, in the induction heating bonding method according to the present invention, the bonding material is hot diffusion bonded by induction heating, and at the same time, the bonding material is melted at a solution temperature. To a saturated solution.
After forming a body, it is heated again to be subjected to artificial aging treatment and hardened to reduce the mechanical discontinuity by reducing the hardness difference between the joining materials, and to further strengthen the state of the materials after joining. Characterize.

Further, the induction heating bonding apparatus according to the present invention is
An airtight chamber having an openable / closable gas introduction port and an exhaust port, a holding unit for pressing and holding the joints of a plurality of bonding materials, a heating unit for inductively heating the bonding materials, and monitoring the temperature of the bonding materials. It is also composed of a temperature measuring means and a fan for forced gas circulation arranged in the chamber.

[0009]

According to the above construction, the refrigerant gas staying in the vicinity of the joining material is forcibly circulated by the fan, and the refrigerant gas having a high cooling capacity is always sequentially supplied in the vicinity of the joining material to improve the joining material. Quench quickly. As a result, the hardness of the joint is increased, the control of the joint conditions is improved, and the desired joint conditions can be realized.

Further, between different materials, the entire material is hardened by artificial aging treatment to reduce the difference in hardness between the materials, so that the state of mechanical discontinuity in a series of joined products becomes small, The stress from is evenly distributed,
A strong joint resistant to shear damage can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

(Structure of Embodiment) FIG. 1 is a schematic view showing an example of the structure of an induction heating bonding apparatus according to the present invention. In the induction heating bonding apparatus 1, the bonding materials 3 and 4 are arranged in an airtight chamber 2 having a gas inlet 9 and an exhaust port 8 which can be opened and closed by a valve or the like, and the bonding materials 3 and 4 are bonded by pressure contact holding means 5a and 5b. The joint surface of is held under pressure contact. An induction heating coil 6 is provided around the bonding materials 3 and 4, and a temperature measuring means 7 for the bonding material is arranged. In order to control the atmosphere in the hermetic chamber 2, an exhaust means (not shown) is provided at the exhaust port 8 and an atmosphere gas and / or
Alternatively, a refrigerant gas supply source is connected, and a fan 10 for forced convection of the refrigerant gas is provided together with a known fan drive mechanism (not shown).

In the above structure, the hermetic chamber 2
Is processed with a material that is highly durable, corrosion resistant, and pressure resistant, such as stainless steel. An evacuation mechanism such as a vacuum pump and a degassing channel are connected to the exhaust port 8 and are provided airtightly by a valve or the like. If necessary, the inlet port for the atmospheric gas and the inlet port for the refrigerant gas may be provided separately, or the exhaust port for evacuation and the exhaust port for venting the cooling gas may be provided separately.

The pressure contact holding means 5a, 5b may be rod-shaped, plate-shaped, or the like, and the holding direction may be vertical or horizontal as long as it is a direction in which the joint portion is pressed. It is desirable that the pressure mechanism also has a well-known structure that is variable in pressure contact force, such as an actuator and a pressure sensor, but it is easy to use various types of springs to obtain only the minimum pressure contact force required for diffusion bonding. It can also be a structure. Also, the pressure contact holding means 5a, 5b
May be configured so as to project downward from the airtight chamber 2 in an airtight manner, or may be arranged completely inside.

The induction heating coil 6 is a high-frequency induction heating coil or the like, and may have any shape such as a coil shape, a circular shape, a horseshoe shape, or the number of turns such as single, double, and triple. It is desirable that the bonding material be appropriately selected according to the size and shape of the material so that the required portion of the bonding material can be efficiently heated.

The temperature measuring means 7 is capable of constantly monitoring the temperature change of the bonding material, and various known radiation type temperature measuring means may be used in addition to the direct temperature measuring means such as a thermocouple. The number of temperature measuring means 7 to be installed may be one at a position where the temperature of the bonding site can be measured at a minimum, but it is provided at a plurality of positions in consideration of the size and shape of the material, the temperature distribution of the material in the aging treatment, and the like. You may do it.

The atmosphere in the airtight chamber 2 may be atmospheric air during the processing, may be evacuated from the exhaust port 8 by a known vacuum pump or the like, and may be hydrogen from the gas inlet port 9 or the like. Reducing gas, nitrogen, helium,
An inert gas such as argon may be introduced, or a mixed atmosphere of a reducing gas and an inert gas may be used. In particular, the inert gas atmosphere is desirable because it has the advantage that the joint portion is not oxidized and the same gas can be used as the refrigerant gas.
When replacing the inside of the airtight chamber 2 with a gas atmosphere,
The exhaust port 8 may be configured by a simple valve to be in an open state and then an inert gas may be introduced and replaced through the gas introduction port 9, or the inert gas may be introduced in an airtight state after exhausting to form a pressure atmosphere. good.

The fan 10 for forced convection rotates or linearly reciprocates by a known drive mechanism (not shown) to forcibly convect the atmosphere in the airtight chamber 2. Further, as the timing of turning on / off the fan 10,
Except when the reducing atmosphere is positively used, it is turned ON mainly during cooling.

(Operation of Embodiment) In such a structure, a case of performing hot solid phase diffusion bonding between an aluminum alloy and stainless steel in a vacuum will be described as an example.

The above-mentioned joining material is carried in from a door (not shown) of the airtight chamber 2, and is clamped by the fixing rods 5a and 5b so that a pressure contact force of about 40t is applied to the joining surface. After the airtight chamber 2 is evacuated from the exhaust port 8 to a vacuum degree of 5 × 10 ⁻⁵ Torr or less, preferably 1 × 10 ⁻⁵ Torr or less by using a vacuum pump, high frequency induction heating around the material. The coil 6 rapidly heats the material to 500 ° C. The temperature control during heating and cooling is performed while the current temperature of the bonding material is monitored by the temperature measuring means 7. After maintaining the temperature at 500 ° C for 90 minutes to perform the hot solid phase diffusion bonding, the cooling process is started.

Refrigerant gas is introduced into the hermetic chamber 2 through the refrigerant gas (inert gas) inlet 9, and the joining material is cooled to 100 ° C. by heat exchange. At this time, the fan 10 is turned on to forcibly convect the heat-exchanged refrigerant gas accumulated around the bonding material, and the gas having a high cooling capacity is constantly supplied to the material periphery for rapid cooling. To prevent the air pressure inside the airtight chamber 2 from becoming too high,
When the pressure reaches 1.5 kgf / cm ² or more, the exhaust port 8 is opened.

After the above cooling step, there is a large hardness difference between the joined materials, and they are in a mechanically discontinuous state. Therefore, the material is heated again to 180 ° C. by the high frequency induction heating coil 6 in the inert gas atmosphere, and the artificial aging treatment is performed for 8 hours as it is. The aging treatment especially hardens the aluminum alloy to reduce the hardness difference from stainless steel, reduces the state of mechanical discontinuity in a series of joints, and evenly disperses even when external stress is applied, resulting in shearing. A strong joint resistant to breakage was obtained.

(Demonstration Experiments of Examples) When a tensile strength test was conducted on the same material by the conventional method and the present method, it was broken at 560 kgf in the case of slow cooling after the joining treatment. Strengths up to 700 kgf were obtained.

(Other Embodiments) All the above-mentioned steps according to the present invention may be appropriately automated and consistently processed. For example, heat treatment temperature setting means, heat treatment time setting means, a timer for measuring the heat treatment execution time, a heat treatment temperature comparison and determination means for comparing the set value of the heat treatment temperature and the measured value from the object temperature measuring means, A heat treatment time comparison / determination means for comparing the set value of the heat treatment time with the measured value of the timer is provided, and the heat treatment temperature comparison / determination means controls ON / OFF of the heating means for inductively heating the bonding material to perform treatment. By adjusting the heat treatment execution temperature to the set value to the set value, starting the timer from the time when the object to be processed reaches the set temperature, and performing the heat treatment until the heat treatment time set in advance by the heat treatment temperature comparison and determination means. The hot diffusion bonding of the object to be processed and the artificial aging treatment may be integrated.

In addition, by providing a detachable non-airtight enclosure around the bonding material and providing cooling means inside the enclosure, heat exchange with the refrigerant gas is performed and the cooling capacity of the refrigerant gas is enhanced. Alternatively, the bonding material may be rapidly cooled.

In the configuration of the present invention, instead of providing the fan 10, the introduction port of the refrigerant gas is extended to the vicinity of the joining material by a nozzle or a shower, and the refrigerant gas is directly blown to the material to enhance the cooling efficiency. You can also

[0027]

According to the induction heating joining method and apparatus according to the present invention, the refrigerant gas staying in the vicinity of the joining material is forcedly circulated by the fan, and the refrigerant gas having a high cooling ability is always present in the vicinity of the joining material. Sequentially supplied to quench the bonding material well. As a result, the hardness of the joint is increased, the control of the joint conditions is improved, and the desired joint conditions can be realized.

Further, between different materials, the entire material is hardened by artificial aging treatment to reduce the hardness difference between the materials, so that the state of mechanical discontinuity in a series of joints becomes small, The stress from is evenly distributed,
A strong joint resistant to shear damage can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a configuration example of an induction heating bonding apparatus according to the present invention.

[Explanation of symbols]

1. Induction heating joining device 2 ... Airtight chamber 3, 4 ... Bonding material 5a, 5b ... ・ Pressing rod 6 ... Induction heating coil 7: Thermocouple 8: Exhaust port 9: Gas inlet 10 ... Fan

Claims (2)

(57) [Claims] 1. A plurality of bonding materials are hot-diffusion bonded by induction heating, and at the same time, the bonding materials are heated to a solutionizing temperature and then rapidly cooled to form a supersaturated solid solution, and then subjected to aging heating and artificial aging treatment. An induction heating joining method characterized by hardening to reduce a hardness difference between joining materials and further strengthening the joining. 2. An airtight chamber having an openable and closable gas introduction port and an exhaust port, holding means for pressing and holding a joint portion of a plurality of bonding materials, heating means for inductively heating the bonding material, and the bonding material. and temperature measuring means for monitoring the temperature of the supersaturated solid solution is disposed in the chamber to quench the bonding material
Induction heating bonding device including a fan for a gas forced circulation to form the body.