JPH0775884A - Method for joining dissimilar material by detonation - Google Patents

Abstract

PURPOSE:To improve the joinability by detonation in manufacturing a joint by dissimilar materials. CONSTITUTION:A joint of dissimilar materials where the ductility is improved and the excellent interface condition without surface oxidation is obtained can be manufactured by preliminarily heating and keeping the material 1 to be joined by detonation by a heater 4 in the temperature range where the elongation is increased and executing the detonation joining of the material 1 to be joined to the base metal 2 by the explosive 5 within an atmosphere shut-off case 7 which is in the inert gas atmosphere or in the vacuum condition. The ductility in the joining can be improved without reduction of the mechanical strength due to the adjustment of the material composition, and the dissimilar materials having excellent interface condition with little residual stress can be joined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining dissimilar materials by bombardment.

[0002]

2. Description of the Related Art In the explosive joining method, the joining material is instantly pressure-bonded to the base metal surface by the high energy of the explosion, so that the heat at the time of the explosion hardly affects the joining material, and as a result, the cold-bonding is performed. Becomes Therefore, it is necessary to consider deformation of the joining material due to explosive force during joining, work hardening, joining failure at the interface of different materials, and the like.

In order to solve this problem, in the conventional explosive joining method, from the viewpoint of prevention of joining defects, the joining material is thinned and laminated in multiple layers, or heat treatment is performed after joining in order to alleviate work hardening of the joining material. It was carried out.

Taking the dissimilar material joining method using zirconium as an example, Onuma, Funamoto et al. "Characteristics of stainless steel, tantalum, and zirconium explosive joining materials", Atomic Energy Society of Japan, Vol.
32, No. 8, pp 803-812 (1990), it is described that the ductility and impact characteristics of the zirconium part can be improved by performing a heat treatment after joining, and good joining can be achieved.

Onuma, Funamoto et al., "Development of dissimilar material joining method of stainless steel and zirconium by explosive joining method", Atomic Energy Society of Japan, Vol. 30, No. 9, pp. 793-801.
According to (1988), since the joining material is joined with a large plastic deformation, particularly when joining a material having a small Young's modulus, the chemical composition is adjusted to improve the joining ability by using a material having good elongation. Describe that.

Japanese Patent Publication No. 4-71636 discloses that the elongation of zirconium as a bonding material is at least 25 from the viewpoint of bondability.
% Or more, preferably 30% or more, and it is disclosed that the better the elongation, the thicker the bonding material.

However, as shown in FIG. 5, in order to increase the elongation of zirconium, it is necessary to keep the contents of the constituent elements oxygen and nitrogen low, which may lower the mechanical strength of the bonding material. Has been revealed.

[0008]

Each of the above-mentioned heat treatments of the prior art is intended to improve the mechanical properties of the hot-rolled dissimilar material composite sheet, which is carried out after joining.
However, in the conventional dissimilar material joining method, the pressure at the time of explosion hardly affects the material because the crimping is completed instantly by the explosive joining, and as a result, the cold joining is performed and the material with low ductility is joined. However, it has been considered desirable to improve ductility by adjusting the material composition, etc., since the metallurgical bondability decreases.

An object of the present invention is to provide a method for joining dissimilar materials by explosive bonding, which can improve the ductility of the material without adjusting the material composition and the like, ensure the joint strength, and obtain a good dissimilar material joint. To provide.

Another object of the present invention is to provide a method for joining dissimilar materials by explosive deposition which can prevent the oxidation of the material surfaces due to the surrounding environment at the time of joining.

[0011]

An object of the present invention is to explode an explosive after heating at least one of a base material and a bonding material which is different from the base material and which is bonded to the base material to improve ductility. This can be achieved by joining those materials.

Another object of the present invention is achieved by heating and detonating explosives in an inert gas atmosphere or a vacuum environment.

[0013]

In general, the mechanical properties of a material change depending on the material composition and the material temperature brought about by the surrounding environment, and particularly the elongation tends to show a high value in a certain temperature range. Therefore, the ductility of the material at the time of joining is improved by performing the explosive joining in the temperature range where the elongation becomes high. This eliminates the need to adjust the material composition for the purpose of improving ductility, makes it possible to carry out the joining of dissimilar materials with good interfacial state with little residual stress without deterioration of mechanical strength after joining. Become.

In addition, since the ambient environment at the time of bonding is set to a vacuum or an atmosphere under an inert gas by using an air shutoff case, it is possible to prevent the bonding material from being oxidized and the like. It is possible to prevent the influence of the surrounding environment at the time of joining on the material due to the high surface temperature.

Since there is a heat insulating effect between the joining material and the explosive used for joining in a vacuum environment or by using a heat insulating material, there is no fear of initiation due to the surface temperature of the material being transmitted to the explosive. There is no problem above.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for joining dissimilar materials by bombardment, which is an embodiment of the present invention, will be described in detail below with reference to FIG.

First, after the explosive bonding material 1 and the base material 2 are cut into a predetermined size, the flatness is corrected and the surface is polished so that they are fitted together without a gap when the two materials are stacked.

After the surface is polished, the explosive bonding material 1 is stacked on the base material 2 with a gap of several millimeters. A heater 3 and a thermometer 4 for measuring the surface temperature are attached to the stacked explosive joining materials 1.
Further, the explosive 5 is set on the explosive bonding material 1 so as to cover the entire surface thereof, and the heat insulating material 6 is inserted therebetween, and then all of them are placed in the atmosphere blocking case 7. From the viewpoint of preventing surface oxidation of the explosive bonding material 1 at a high temperature, the air shutoff case 7 has a pressure-proof structure having a function of maintaining airtightness, and has a pressure gauge 8, a gas inlet 9, and a gas. The one equipped with the outlet 10 is used.

Next, the gas inlet 9 of the atmosphere shutoff case 7 is closed, and the air inside is sucked out from the gas outlet 10 by the vacuum pump 11 to the outside to bring it into a vacuum state. After confirming the internal vacuum state with the pressure gauge 8, the explosive bonding material 1 is heated with the heater 3 while measuring the surface temperature of the explosive bonding material 1 with the thermometer 4 and heated and maintained at a temperature at which the ductility is improved.

After heating, the detonator 12 detonates the explosive 5 from one end. The explosive 5 that has been detonated is crimped by the explosive force of the explosive joining material 1 to instantly collide with the base material 2 from above the heat insulating material 6.

After the pressure bonding, the explosive bonding material 1 is cooled with a thermometer 4 in a vacuum state in the air shielding case 7 until the surface temperature thereof reaches room temperature.

After cooling, the gas inlet 9 was opened and the pressure gauge 8 was used to confirm that the inside of the atmosphere blocking case 7 was at atmospheric pressure.
The explosive joining material 1 that has been crimped with is taken out, the distortion caused by joining is corrected by a press, and the joint is cut into a required joint shape.

By the above joining method, the explosive joining material 1 has improved ductility during explosive joining and can be easily pressure-bonded while preventing surface oxidation, and after joining, the material strength before joining can be secured.
A good dissimilar material joint can be obtained.

In the case of explosive bonding in a vacuum state as in the above embodiment, in order to shorten the cooling time of the bonding material after pressure bonding, an inert gas is blown into the atmosphere blocking case 7 to improve the cooling efficiency. Try.

Next, a method of joining dissimilar materials by bombardment, which is another embodiment of the present invention, will be described with reference to FIG. This example shows an example in which the base material side is heated in a vacuum state to perform explosive bonding.

After the flatness correction and the surface polishing, the explosive bonding material 1 is superposed on the base material 2 with a gap of several millimeters therebetween, as in the above. At this time, the heater 3 and the thermometer 4 for measuring the surface temperature are attached to the base material 2. Further, the explosive 5 is set on the explosive bonding material 1 so as to cover the entire surface thereof, and all of them are placed in the air shielding case 6. From the viewpoint of preventing surface oxidation of the explosive bonding material 1 at a high temperature, the atmosphere shutoff case 6 has a pressure-resistant structure having a function of keeping airtightness, and has a pressure gauge 7, a gas inlet 8, and a gas. Use the one with the outlet 9 attached.

Next, the gas inlet 8 of the atmosphere shutoff case 6 is closed, and the air inside is sucked out from the gas outlet 9 by the vacuum pump 10 to the outside to bring it into a vacuum state. After confirming the internal vacuum state with the pressure gauge 7, the explosive bonding material 1 is heated with the heater 3 while measuring the surface temperature of the explosive bonding material 1 with the thermometer 4, and is heated and maintained at a temperature at which the ductility is improved.

After heating, the detonator 11 detonates the explosive 5 from one end. The explosive 5 that has been detonated is crimped by the explosive force causing the explosive joining material 1 to instantly collide with the base material 2.

After the pressure bonding, the explosive bonding material 1 is cooled with a thermometer 4 in a vacuum state in the air shielding case 6 until the surface temperature thereof reaches room temperature.

After cooling, the gas inlet 8 was opened and the pressure gauge 7 was used to confirm that the atmosphere shut-off case 6 was at atmospheric pressure.
The explosive joining material 1 that has been crimped with is taken out, the distortion caused by joining is corrected by a press, and the joint is cut into a required joint shape.

By the above-described joining method, the explosive joining material 1 has improved ductility during explosive joining and can be easily crimped while preventing surface oxidation, and after joining, the material strength before joining can be secured.
A good dissimilar material joint can be obtained.

In the above embodiment, since the base material 2 is heated in a vacuum, the heat is not transferred to the explosive 5 and a heat insulating material for preventing initiation during heating is unnecessary.

Next, another embodiment of the present invention in which the explosive bonding material is heated in an atmosphere of an inert gas will be described with reference to FIG.

Similarly to the above, after the flatness correction and the surface polishing, the explosive bonding material 1 is superposed on the base material 2 with a gap of several millimeters. At this time, the heater 3 and the thermometer 4 for measuring the surface temperature are attached to the explosive bonding material 2. Further, the explosive 5 is set on the explosive bonding material 1 so as to cover the entire surface thereof, and the heat insulating material 6 is inserted therebetween, and then all of them are placed in the atmosphere blocking case 7. From the viewpoint of preventing surface oxidation of the explosive bonding material 1 at a high temperature, the atmosphere shutoff case 7 has an inert gas atmosphere inside the case, has a pressure resistant structure having a function of maintaining airtightness, and has a pressure gauge 8 and an oxygen concentration. The one equipped with a total of 9, a gas inlet 10 and a gas outlet 11 is used.

Next, the gas inlet 10 of the atmosphere shutoff case 7 is closed, and the air inside is sucked out to the outside from the gas outlet 11 by the vacuum pump 12 to create a vacuum state. After confirming the internal vacuum state with the pressure gauge 8, the vacuum pump 12 is removed, the gas outlet 11 is closed, and an inert gas is blown into the atmosphere blocking case 7 from the gas inlet 10. After confirming with the pressure gauge 8 that the pressure of the inert gas in the atmosphere shutoff case 7 is equal to or higher than the atmospheric pressure, the gas outlet 11 is gradually opened while supplying the inert gas from the gas inlet 10. The opening of the gas outlet 11 is constantly adjusted so that the inert gas pressure in the atmosphere blocking case 7 is always equal to or higher than the atmospheric pressure, and the air remaining in the atmosphere blocking case 7 is discharged to the outside together with the inert gas to remove the atmosphere blocking case. Keep the inert gas purity in 7 constant.

After confirming the purity of the inert gas in the atmosphere blocking case 7 with the oxygen concentration meter 9, the surface temperature of the explosive bonding material 1 is measured with the thermometer 4 while heating with the heater 3 to a temperature at which the ductility is improved. Keep heating.

After heating, the detonator 13 detonates the explosive 5 from one end. The explosive 5 that has been detonated is crimped by the explosive force of the explosive joining material 1 to instantly collide with the base material 2 from above the heat insulating material 6.

After the pressure bonding, the explosive bonding material 1 is cooled by the thermometer 4 with the inert gas in the air blocking case 7 until the surface temperature of the explosive bonding material 1 reaches the room temperature.

After cooling, the gas inlet 10 was opened and the pressure gauge 8 was used to confirm that the inside of the atmosphere blocking case 7 was at atmospheric pressure. Then, the base material 2 and the explosive bonding material 1 that had been crimped were taken out and the distortion caused by the joining was pressed. Correct and cut to desired joint shape.

By the above-mentioned joining method, the explosive joining material 1 has improved ductility during explosive joining and can be easily crimped while preventing surface oxidation, and after joining, the material strength before joining can be secured.
A good dissimilar material joint can be obtained.

Argon gas and helium gas are examples of the inert gas used.

Next, another embodiment of the present invention, in which the base material is heated in an atmosphere of an inert gas, will be described with reference to FIG.

Similarly to the above, after the flatness correction and the surface polishing, the explosive bonding material 1 is superposed on the base material 2 with a gap of several millimeters. At this time, the heater 3 and the thermometer 4 for measuring the surface temperature are attached to the base material 2. Further, the explosive 5 is set on the explosive bonding material 1 so as to cover the entire surface thereof, and all of them are placed in the air shielding case 6. Atmosphere shutoff case 6 consists of base material 2
From the viewpoint of preventing surface oxidation at high temperatures, the case is made to have an atmosphere under an inert gas, and has a pressure resistant structure having an airtight holding function, and has a pressure gauge 7, an oxygen concentration meter 8, a gas inlet 9, a gas outlet 10 Use with the attached.

Next, the gas inlet 9 of the atmosphere shutoff case 6 is closed, and the air inside is sucked out from the gas outlet 10 by the vacuum pump 11 to the outside to bring it into a vacuum state. After confirming the internal vacuum state with the pressure gauge 7, the vacuum pump 11 is removed, the gas outlet 10 is closed, and an inert gas is blown into the atmosphere blocking case 6 through the gas inlet 9. After confirming with the pressure gauge 7 that the pressure of the inert gas in the atmosphere shutoff case 6 has reached the atmospheric pressure or higher, the gas outlet 10 is gradually opened while supplying the inert gas from the gas inlet 9. The opening of the gas outlet 10 is adjusted so that the inert gas pressure in the atmosphere blocking case 6 is always equal to or higher than the atmospheric pressure, and the air remaining in the atmosphere blocking case 6 is discharged to the outside together with the inert gas to remove the atmosphere blocking case. Keep the inert gas purity in 6 constant.

After confirming the purity of the inert gas in the air-shielding case 6 with the oxygen concentration meter 8, the temperature is measured by the heater 3 while the surface temperature of the base material 2 is being measured with the thermometer 4 so that the ductility is improved. Hold.

After heating, the detonator 12 detonates the explosive 5 from one end. The explosive 5 that has been detonated is crimped by the explosive force causing the explosive joining material 1 to instantly collide with the base material 2.

After the pressure bonding, the thermometer 4 cools the base material 1 with an inert gas in the air shielding case 6 until the surface temperature of the base material 1 reaches room temperature.

After cooling, the gas inlet 9 was opened and the pressure gauge 7 was used to confirm that the atmosphere shut-off case 6 was at atmospheric pressure.
The explosive joining material 1 that has been crimped with is taken out, the distortion caused by joining is corrected by a press, and the joint is cut into a required joint shape.

By the above-mentioned joining method, the base material 1 has improved ductility during explosion joining while preventing surface oxidation, and is easily pressure-bonded, and after joining, the material strength before joining can be secured, and a good dissimilar joint can be obtained. can get.

Further, as another embodiment of the present invention, in the case of explosively joining materials having particularly low ductility, both the explosive joining material and the base material are heated and explosively joined as in the above embodiments. As a typical example of explosive joining, explosive joining material 1
There is an example in which pure zirconium (ASTM Grade R60702) is applied, tantalum is used as the intermediate joining material, and stainless steel is used as the base material 2. In this case, as shown in FIG. 6, the ductility tends to be improved from 200 ° C., and in the case of pure zirconium, the temperature needs to be 450 ° C. or lower in order to keep the recrystallization temperature or lower. Therefore, the heating temperature range is from 200 ° C to 450 ° C.

Another embodiment of the present invention will be described with reference to FIG. In FIG. 1, an explosive bonding material 1 is a material having a particularly low work hardening. When the crystal structure and the coefficient of thermal expansion of the base material 2 to be joined to the explosive joining material 1 are extremely different, a material having intermediate properties between the two materials is used as the intermediate material 17, and the same joining material as the joining material 1 is used. It joins with the base material 2 beforehand by the method.

The joining is carried out after the explosive joining material 1 is heated by the heater 4 to a temperature at which the ductility is improved to improve the ductility. In addition, these operations are performed in a vacuum environment or an inert gas atmosphere in the air shutoff case 7 from the viewpoint of preventing surface oxidation of the bonding material 1.

Next, while the bonding material 1 is heated and held by the heater 4, and the heat insulating material 6 is mounted between the bonding material 1 and the explosive 5 if necessary, the explosive 5 is exploded right above the bonding material 1 by the detonator 12. Let

When the explosive 5 is detonated from one end, the explosive force causes the joining material 1 to instantly collide with the base material 2 at the same time as the explosion of the explosive 5 is accompanied by the intermediate joining material 17, if any. ， Crimping is performed. After the pressure bonding, from the viewpoint of preventing surface oxidation, the bonding material 1 is cooled in the air blocking case 7 until the surface temperature reaches room temperature.

By the above-described joining method, the joining material 1 has improved ductility during explosive joining and can be easily pressure-bonded while preventing surface oxidation, and after joining, the material strength before joining can be secured, which is excellent. A dissimilar joint can be obtained.

[0056]

According to the present invention, since the ductility at the time of joining can be improved without lowering the mechanical strength of the joining material by adjusting the material composition, it is possible to obtain a different material having a small residual stress and having a good interface state. It has the effect of enabling joining.

Further, by making the surrounding environment at the time of joining a vacuum or an inert gas atmosphere, there is an effect of preventing a joining failure due to an oxide film or the like at the time of explosive joining.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for joining dissimilar materials by explosive bonding, which is a preferred embodiment of the present invention.

FIG. 2 is an explanatory view showing a method of joining dissimilar materials by bombardment, which is another embodiment of the present invention.

FIG. 3 is an explanatory view showing a method of joining dissimilar materials by bombardment, which is another embodiment of the present invention.

FIG. 4 is an explanatory view showing a method of joining dissimilar materials by explosive deposition which is another embodiment of the present invention.

FIG. 5 is an explanatory diagram showing the influence of oxygen and nitrogen on the mechanical properties of zirconium.

FIG. 6 is an explanatory diagram showing the effect of temperature on the mechanical properties of zirconium.

FIG. 7 is an explanatory view showing a method of joining dissimilar materials by explosion bonding which is another embodiment of the present invention.

[Explanation of symbols]

1 ... Explosive joining material, 2 ... Base material, 3 ... Heater, 4 ... Thermometer,
5 ... Explosive, 6 ... Insulating material, 7 ... Atmosphere blocking case, 8 ... Pressure gauge, 9 ... Gas inlet, 10 ... Gas outlet, 11 ... Vacuum pump, 12 ... Detonator.

Claims (5)

[Claims] 1. A method for explosively joining dissimilar materials, wherein at least one of a base material and a joining material different from the base material, which is joined to the base material, is heated to improve ductility, and then explosives are exploded. Method for joining dissimilar materials by explosive welding to join the above materials. 2. The method for joining dissimilar materials according to claim 1, wherein the heating and the explosion of the explosive are performed in an inert gas atmosphere. 3. The method for joining dissimilar materials according to claim 1, wherein the heating and the explosion of the explosive are performed in a vacuum environment. 4. The method for joining dissimilar materials by explosive deposition according to claim 1, wherein an explosive is attached to the joining material via a heat insulating material. 5. Pure zirconium is used as the bonding material,
The method for joining dissimilar materials by bombarding according to claim 1, wherein the joining material is bombarded to the base material after being heated from 200 ° C to 450 ° C.