JPH08164494A - Brazing filler metal paste and welding method using it - Google Patents

Abstract

PURPOSE: To prevent oxidation, to keep the welding quality constant and to improve the workability by incorporating fine powder of silver brazing filler metal containing at least silver and copper and the specified materials in the silver brazing filler metal paste. CONSTITUTION: The silver brazing filler metal paste contains the fine powder of the silver brazing filler metal containing at least silver and copper, the oxidation preventing agent, and solvent. The brass brazing filler metal paste contains the fine powder of the brass brazing filler metal containing at least copper and zinc, the oxidation preventing agent and the solvent. Brazing filler metals 30, 31 containing the fine powder of the brass brazing filler metal containing at least copper and zinc, and the solvent are applied to at least either of first second parts 11, 21 to be joined, and brazing is achieved in the non-oxidizing gas atmosphere while the parts 11, 21 to be joined in the joined condition are carried by a conveyor 110 in a furnace 10 having the prescribed temperature profile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing paste and a welding method using the same, and more particularly to a silver brazing paste or brass brazing paste and a welding method using them.

[0002]

2. Description of the Related Art Conventionally, a work has been welded using a hard solder such as silver solder. In the conventional welding method using silver braze, the joint part of the work is heated by using an oxygen burner, etc., an antioxidant is applied to this joint part, and then a rod-shaped silver braze is brought close to the joint part with an oxygen burner. It melted while heating, and the work was joined by this.

However, in the conventional welding method, since it was heated in the air, it was easily oxidized, and it was necessary to remove the oxide film formed by this.

Further, in the conventional welding method using silver brazing, since the adjustment of welding conditions such as heating temperature and heating holding time mainly depends on the experience of the operator, the welding conditions vary and the welding quality is not stable. There was a problem.

Further, since the welding process in the conventional welding method is carried out manually by an operator, there is a problem that the workability is poor and mass production cannot be performed.

Therefore, according to the present invention, a wax paste which can prevent oxidation in welding, and an oxidation in welding can be prevented, the welding quality can be kept constant, workability is improved, and mass production is improved. It is an object of the present invention to provide a possible welding method.

[0006]

In order to achieve the above object, according to the present invention, a fine powder of silver wax containing at least silver and copper, an antioxidant and a solvent are included. A silver wax paste is provided.

Further, according to the present invention, there is provided a brass brazing paste comprising fine brass brazing powder containing at least copper and zinc, an antioxidant and a solvent.

Since the silver brazing paste and the brass brazing paste of the present invention contain an antioxidant, it is possible to prevent oxidation when welding is performed using this brazing paste.

In the silver solder paste of the present invention, the silver solder contains at least silver and copper, and may further contain zinc, cadmium and phosphorus. As for the component ratio of the silver braze, it is preferable that silver is 5 to 80% by weight, zinc is 0 to 25% by weight, cadmium is 0 to 18% by weight, phosphorus is 0 to 8% by weight, and the balance is copper. Further, in the present invention, the particle size of the fine silver brazing powder is preferably 1 μm to 50 μm.

On the other hand, in the brass braze paste of the present invention, the brass braze contains at least copper and zinc. The component ratio of this brass braze is preferably 60% by weight of copper and 40% by weight of zinc. Further, in the present invention, the particle size of the fine powder of brass brazing is preferably 1 μm to 50 μm.

As the antioxidant in the present invention, flux F101 (manufactured by Nike Co., Ltd.) or the like can be used for both the silver brazing paste and the brass brazing paste.

As the solvent in the present invention, thinner 8250 (manufactured by DuPont) or the like can be used for both the silver brazing paste and the brass brazing paste.

Further, the compounding ratio of the fine silver wax powder, the antioxidant and the solvent is 60 to 80% by weight of the fine silver wax powder, 5 to 20% by weight of the antioxidant and the solvent. It is preferable to set it to 5 to 30% by weight. On the other hand, the compounding ratio of the fine powder of brass wax, the antioxidant and the solvent is 60 wt% to 80 wt% of the fine powder of brass wax, 5 wt% to 20 wt% of the antioxidant, and 5 wt% of the solvent. It is preferably set to -30% by weight.

Further, according to the present invention, in the welding method for joining the first joint portion of the first work and the second joint portion of the second work with the brazing paste, at least silver and copper are contained. A wax paste containing fine silver brazing powder and a solvent is applied to at least one of the first and second joints, and the first and second joints are combined to form the first paste. And a second work is brazed in a non-oxidizing gas atmosphere while being conveyed by a conveyor in a furnace having a predetermined temperature profile.

Further, according to the present invention, the first of the first work is
In the welding method for joining the joint portion of the second work piece and the second joint portion of the second work by using the braze paste, a braze paste containing fine powder of brass braze containing at least copper and zinc and a solvent is used. And at least one of the second joints, and in a state where the first and second joints are combined, the first and second works are conveyed by a conveyor in a furnace having a predetermined temperature profile. A welding method is provided which comprises brazing in a non-oxidizing gas atmosphere while being transported.

In the welding method of the present invention, the first and second workpieces are brazed in a non-oxidizing gas atmosphere in a state where the first and second joints are combined, so that oxidation associated with brazing is prevented. can do. Further, in the welding method of the present invention, since the first and second workpieces are brazed while being conveyed by a conveyor in a furnace having a predetermined temperature profile, almost the same welding conditions can be applied to any workpiece. , The welding quality can be kept constant. Also,
Welding workability is improved and mass production is possible. In addition, the working environment for welding is greatly improved.

As the brazing paste used in the welding method of the present invention, the above-mentioned silver brazing paste or brass brazing paste is preferably used.

In the welding method of the present invention, the brazing paste does not necessarily need to contain an antioxidant because it is brazed in a non-oxidizing gas atmosphere, but it is more preferable to use a brazing paste containing an antioxidant. preferable. This is because when the brazing paste contains an antioxidant, even if air is mixed in the non-oxidizing gas atmosphere, the antioxidant contained in the brazing paste prevents oxidation in welding.

When the brazing paste is applied to the joints of the works, it may be applied to the joints of the respective works to be welded, or to any one of the joints. Further, as a method of applying the wax paste, any method such as brush coating, screen printing, or coating with a dispenser can be used.

When the silver brazing paste is used in the welding method of the present invention, first, at a temperature rising rate of 10 ° C. to 50 ° C./min, preferably 300 ° C. to 400 ° C., more preferably 35 ° C.
The temperature is raised to 0 ° C., the temperature is maintained for 1 to 5 minutes to evaporate the solvent, and then the temperature is increased from 5 ° C. to 50 ° C./min, preferably 550 ° C. to 900 ° C., more preferably 585 ° C. The temperature is raised, this temperature is maintained for 1 to 5 minutes for preheating, and then the temperature is raised from 5 ° C to 50 ° C / min, preferably from 635 ° C to
It is preferable to raise the temperature to 1000 ° C., more preferably 735 ° C., and maintain the temperature for 0 to 5 minutes to determine the temperature profile of the furnace and the work transfer speed so that the wax paste can be melted. . The "holding this temperature for 0 to 5 minutes""when holding the wax paste for 0 minutes" when melting the wax paste means that the temperature lowering is started when the temperature is reached.

On the other hand, when the brass brazing paste is used in the welding method of the present invention, first, the temperature is raised from 10 ° C. to 50 ° C./min, preferably 300 ° C. to 400 ° C., more preferably 350 ° C. Then, this temperature is maintained for 1 to 5 minutes to evaporate the solvent, and then at a temperature rising rate of 5 ° C to 50 ° C / min, preferably 550 ° C to 900 ° C, more preferably 8 ° C.
The temperature is raised to 35 ° C., this temperature is maintained for 1 to 5 minutes to perform preheating, and then the temperature is raised from 5 ° C. to 50 ° C./min, preferably 635 ° C. to 1000 ° C., more preferably 985.
It is preferable to determine the temperature profile of the furnace and the work transfer speed so that the temperature can be raised to 0 ° C. and this temperature can be maintained for 0 to 5 minutes to melt the wax paste. In addition, when melting the above-mentioned wax paste, "this temperature is set to 0
The term "hold for 0 minute" of "hold for 5 minutes" means to start decreasing the temperature when the temperature is reached.

Preheating before melting the brazing paste has the effect of making the temperature of the work uniform and the melting of the brazing paste uniform.

As the non-oxidizing gas, nitrogen gas,
An inert gas such as argon gas or a reducing gas such as hydrogen gas can be used. Particularly, nitrogen gas is preferably used in terms of cost and safety. When hydrogen gas is used, it is preferable to mix it with nitrogen gas or the like from the viewpoint of safety.

Further, the welding method of the present invention can be applied to the case of joining homogeneous metals or dissimilar metals.

[0025]

An embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view showing an embodiment of a work for explaining a welding method of the present invention, FIG. 2 is a perspective view showing a state in which a brazing paste is applied to a joint portion of the work shown in FIG. 1, and FIG. 2 is a perspective view showing a state in which the joined portions of the work shown in FIG. 2 are combined, and FIG. 4 is a perspective view showing a state after welding of the work shown in FIG. 5 is a plan view showing an example of a belt conveyor furnace used in the welding method of the present invention, FIG. 6 is a sectional view of the belt conveyor furnace shown in FIG. 5, and FIG. 7 is a heating temperature in the welding method of the present invention. It is a graph which shows an example of a profile.

Embodiment 1 In this embodiment, a cylindrical first metal block 10 and a second metal block 20 as shown in FIG. 1 are connected to a joining surface 11 of the first metal block 10 and a second metal block 20. Welding is performed using a silver brazing paste so that the joint surface 21 of the metal block 20 is matched.

In this embodiment, 60% by weight of silver and 1% of zinc are used.
5% by weight, 5% by weight of cadmium, 3% by weight of phosphorus and the balance of copper, and a fine particle of silver wax having a particle size of 1 μm to 50 μm, and a flux F1 as an antioxidant.
01 (manufactured by Nike Corporation) and thinner 8 as a solvent
250 (manufactured by DuPont) was blended at a blending ratio of 70% by weight of fine powder of silver wax, 10% by weight of antioxidant and 20% by weight of solvent to obtain a silver wax paste. The melting point of the silver solder was 635 ° C.

As shown in FIG. 2, the silver brazing pastes 30 and 31 are applied to the joint surface 11 of the first metal block 10 and the joint surface 21 of the second metal block 20, respectively, by using a bud or brush. Applied.

In this embodiment, the silver wax paste 3 is used.
Although 0 and 31 were applied to the joint surface 11 of the first metal block 10 and the joint surface 21 of the second metal block 20, respectively, the joint surface 11 of the first metal block 10 and the second metal block 20 were coated. It may be applied only to one of the joint surfaces 21. Further, the application method may be, for example, screen printing or dispenser application other than fluffing or brush coating.

Next, the bonding surface 11 of the first metal block 10 and the bonding surface 21 of the second metal block 20 coated with the silver brazing pastes 30 and 31 are aligned as shown in FIG. The metal block 10 and the second metal block 20 were aligned at appropriate joining positions to form a metal block 50.

Next, as shown in FIGS. 5 and 6, the metal block 50 was placed on a belt conveyor 110 and passed through a belt conveyor furnace 100.

The belt conveyor furnace 100 is provided with a heater 130, and the work is heated by passing the work through a heating zone 160 in which the heater 130 is provided. The temperature in the furnace 170 can be adjusted from room temperature to 1000 ° C. Further, a belt conveyor 110 is provided in the lower part of the furnace 170, and the work transfer speed can be adjusted between 0 and 200 mm / min.

Non-oxidizing gas supply pipes 120, 121, 122 and a non-oxidizing gas discharge pipe 125 are provided above the belt conveyor furnace 100, and nitrogen from a non-oxidizing gas supply source (not shown) is provided. The gas is supplied into the furnace 170 through the non-oxidizing gas supply pipes 120, 121, 122, and then mainly the non-oxidizing gas discharge pipe 125.
It is designed to be discharged outside the furnace. As shown in FIGS. 5 and 6, non-oxidizing gas supply pipes 120, 1
22 are provided near the inlet 161 of the heating zone 160 and near the outlet 162 of the heating zone 160, respectively.
Further, a non-oxidizing gas supply pipe 121 is provided adjacent to the non-oxidizing gas supply pipe 122 on the outlet 162 side of the heating zone 160. On the other hand, the non-oxidizing gas discharge pipe 125 is provided between the non-oxidizing gas supply pipes 120 and 121. As a result, the nitrogen gas supplied from the non-oxidizing gas supply pipes 120, 121, 122 into the furnace 170 is mainly directed toward the non-oxidizing gas discharge pipe 125, as indicated by the arrow in FIG. The flow will result in nitrogen gas being spread throughout the heating zone 160 provided with the heater 130. Further, in the vicinity of the outlet 162 of the heating zone 160, the temperature of the metal block 50 becomes high and is easily oxidized. Therefore, by providing two non-oxidizing gas supply pipes 121 and 122 in this region,
A sufficient amount of nitrogen gas is supplied to ensure the prevention of work oxidation.

The outlet 18 of the belt conveyor furnace 100
A cooling fan 140 is attached to the upper surface of the furnace wall 150 near 0, and this region serves as a cooling zone 165 for cooling the work.

Using the belt conveyor furnace 100 as described above, the aligned metal block 50 was heated. In this embodiment, the temperature profile as shown in FIG. 7 is obtained by adjusting the set temperature of the heater 130, the transport speed of the belt conveyor 110, the flow rate of nitrogen gas, and the like. That is, first, the temperature is raised to a temperature of 350 ° C. at a heating rate of 10 ° C. to 50 ° C./min, the temperature is maintained for 1 to 5 minutes to evaporate the solvent contained in the silver brazing paste, and then 5 ° C. ~ 50 ° C /
The temperature is raised to a temperature of 585 ° C. at a heating rate of 1 minute, the temperature is maintained for 1 to 5 minutes to perform preheating, and then 5 ° C. to 50 ° C.
The temperature was raised to a temperature of 735 ° C. at a heating rate of / min, and this temperature was maintained for 0 to 5 minutes to dissolve the silver solder. The preheating was performed in order to make the temperature of the work uniform and the silver solder paste to be evenly melted.

As shown in FIG. 4, in the metal block 51 thus welded, the joint surface 11 of the first metal block 10 and the joint surface 2 of the second metal block 20 are joined together.
1 and 1 were joined well by the silver brazing 40.

Example 2 Although the silver brazing paste was used in the above-mentioned Example 1, a brass brazing paste can also be used. For example, a fine powder of brass brazing (particle size: 5 μm to 50 μm) consisting of 60% by weight of copper and 40% by weight of zinc, Flux F101 (manufactured by Nike Corporation) as an antioxidant, and thinner 8250 (a solvent). DuPont) and 70% by weight of brass braze, 10% by weight of antioxidant, and 20% by weight of solvent, and the brass braze paste thus obtained was treated in the same manner as in Example 1 to prepare a metal. It was applied to the joint surfaces 11 and 21 of the blocks 10 and 20. And these metal blocks 1
The joining surfaces 11 and 21 of 0 and 20 are combined as shown in FIG. 3 to form a metal block 50.
And the belt conveyor furnace 100 shown in FIG. The melting point of the brass solder was 885 ° C.

In this embodiment, first, the temperature is raised to 350 ° C. at a temperature rising rate of 10 ° C. to 50 ° C./min, and this temperature is set to 1 to 50 ° C.
Hold for 5 minutes to evaporate the solvent contained in the wax paste,
Next, the temperature is raised to a temperature of 835 ° C. at a heating rate of 5 ° C. to 50 ° C./min, and this temperature is held for 1 to 5 minutes to perform preheating,
Then, the temperature was raised to a temperature of 985 ° C. at a temperature rising rate of 5 ° C. to 50 ° C./min, and this temperature was maintained for 0 to 5 minutes to dissolve the brass braze. The preheating was performed in order to make the temperature of the work uniform and the melting of the brass brazing paste uniform.

The metal block 5 thus welded
1 also, the joint surface 1 of both metal blocks 10 and 20
1, 21 were well joined by the brass solder 40.

In the first and second embodiments described above, nitrogen gas was supplied into the furnace 170 of the belt conveyor furnace 100. However, in the welding method of the present invention, in addition to nitrogen gas, an inert gas such as argon gas or It is also possible to supply a reducing gas such as hydrogen gas. When hydrogen gas is used, it is preferable to mix it with nitrogen gas or the like from the viewpoint of safety.

[0041]

EFFECTS OF THE INVENTION According to the silver brazing paste and the brass brazing paste of the present invention, since the silver brazing paste and the brass brazing paste contain an antioxidant, it is possible to perform welding using the brazing paste. Oxidation can be prevented.

Further, according to the welding method using the brazing paste of the present invention, since the first and second works are brazed in the non-oxidizing gas atmosphere, the oxidation during welding can be prevented. Further, in the welding method of the present invention, since the first and second workpieces are brazed while being conveyed by the conveyer in the furnace having a predetermined temperature profile, almost the same welding conditions can be applied to any workpiece. , The welding quality can be kept constant. In addition, the workability of welding is improved and mass production is possible. In addition, the working environment for welding is greatly improved.

Further, in the welding method of the present invention, if a wax paste containing an antioxidant is used, the oxidation can be prevented more reliably, and even if air is mixed in the non-oxidizing gas atmosphere, The antioxidant contained in the paste can prevent oxidation during welding.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a work for explaining a welding method of the present invention.

FIG. 2 is a perspective view showing a state in which a brazing paste is applied to a joint portion of the work shown in FIG.

FIG. 3 is a perspective view showing a state in which the joint portions of the work shown in FIG. 2 are combined.

FIG. 4 is a perspective view showing a state of the work shown in FIG. 3 after welding.

FIG. 5 is a plan view showing an example of a belt conveyor furnace used in the welding method of the present invention.

6 is a sectional view of the belt conveyor furnace shown in FIG.

FIG. 7 is a graph showing an example of a heating temperature profile in the welding method of the present invention.

[Explanation of symbols]

 10 ... 1st metal block (1st work) 11 ... 1st work joining surface (1st work joining part) 20 ... 2nd metal block (2nd work) 21 ... 2nd work Joining surface (joint portion of the second work) 30, 31 ... Wax paste 40 ... Wax after welding 50 ... Aligned work 100 ... Belt conveyor furnace 110 ... Belt conveyor 120, 121, 122 ... Non-oxidizing gas Supply pipe 125 ... Non-oxidizing gas discharge pipe 130 ... Heater 140 ... Cooling fan 150 ... Furnace wall 160 ... Heating zone 165 ... Cooling zone 170 ... Furnace

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B23K 35/30 C

Claims (5)

[Claims] 1. A silver brazing paste comprising fine silver brazing powder containing at least silver and copper, an antioxidant and a solvent. 2. A brass brazing paste comprising fine brass brazing powder containing at least copper and zinc, an antioxidant and a solvent. 3. A welding method for joining a first joint portion of a first work and a second joint portion of a second work by using a brazing paste, wherein a fine silver braze containing at least silver and copper is used. A wax paste containing a powder and a solvent is applied to at least one of the first and second joints, and the first and second workpieces are combined in a state where the first and second joints are combined. Is carried out in a non-oxidizing gas atmosphere while being conveyed by a conveyor in a furnace having a predetermined temperature profile. 4. A welding method for joining a first joint portion of a first work and a second joint portion of a second work by using a brazing paste, wherein a fineness of brass braze containing at least copper and zinc is used. A wax paste containing a powder and a solvent is applied to at least one of the first and second joints, and the first and second workpieces are combined in a state where the first and second joints are combined. Is carried out in a non-oxidizing gas atmosphere while being conveyed by a conveyor in a furnace having a predetermined temperature profile. 5. The welding method according to claim 3, wherein the brazing paste further contains an antioxidant.