Disclosure of Invention
The invention solves the problems that the existing adhesive tape brazing filler metal has thicker adhesive tape, poorer applicability, poor alloy uniformity, low alloy content, larger residual quantity, does not meet the requirement of environmental protection and has at least one aspect of harm to the health of production personnel.
In order to solve the problems, the invention provides a preparation method of a binder for a tape solder, which comprises the following steps: according to the weight ratio of the components, 30-70% of epoxy resin, 21-63% of plasticizer and 3-21% of toughening agent are placed in a stirrer and stirred for 5-15min at the speed of 30-60r/min to prepare the adhesive.
Preferably, the plasticizer comprises terpene resin and a first diluent, and is prepared by placing 10-50 wt% of terpene resin and 50-90 wt% of the first diluent in a stirrer and stirring at 30-60r/min for 5-15 min.
Preferably, the first diluent is selected from one or more of N-methyl pyrrolidone, acetone, ethyl acetate and dibutyl phthalate.
Preferably, the toughening agent comprises an elastomer and a second diluent, and is prepared by placing 60-95% of the elastomer and 5-40% of the second diluent in a stirrer in a weight ratio and stirring at a speed of 30-60r/min for 5-15 min.
Preferably, the elastomer is selected from one or more of ethyl cellulose, styrene thermoplastic elastomer, acrylonitrile-butadiene-styrene terpolymer and butadiene rubber.
Preferably, the second diluent is selected from one or more of ethyl acetate, absolute ethyl alcohol and acetone.
Compared with the prior art, the binder for the solder with the adhesive tape is suitable for various solders, simple in preparation process, free of pollution to the environment and low in residual carbon content after welding. The prepared adhesive tape brazing filler metal has good flexibility, can be processed into various shapes, is suitable for vacuum brazing under complex conditions, and has uniform joint structure and excellent performance after welding.
In order to solve the technical problems, the invention also provides a tape bonding brazing filler metal which comprises brazing filler metal powder and a binder prepared by the preparation method of the binder for the tape bonding brazing filler metal, wherein the tape bonding brazing filler metal is prepared by placing 6-14% of the binder and 86-94% of the brazing filler metal powder in a stirrer in a weight ratio and stirring at the speed of 30-60r/min for 20-60 min.
Preferably, the brazing filler metal powder is high-temperature brazing filler metal powder, and the brazing filler metal powder is selected from one of nickel-based brazing filler metal powder, cobalt-based brazing filler metal powder or copper-based brazing filler metal powder.
Preferably, the brazing filler metal powder comprises four particles with different particle sizes, and the weight ratio of the four particles with different particle sizes is 5-25%, 20-35%, 25-35% and 15-25% in the increasing order of the particle sizes.
Compared with the prior art, the adhesive tape brazing filler metal has good flexibility, can be processed into various shapes, is suitable for vacuum brazing under complex conditions, and has uniform joint structure after welding, excellent performance and low carbon residue after welding.
In order to solve the technical problem, the invention also provides a brazing method, which comprises the following steps:
step S1, polishing the surface of a workpiece to be welded smoothly, ultrasonically cleaning the part to be welded of the workpiece to be welded for 5-10min by using acetone, and then attaching the adhesive tape brazing filler metal to the part to be welded;
s2, placing the whole workpiece to be welded in a vacuum brazing furnace, closing a furnace door, vacuumizing the furnace, heating to 550-600 ℃ at the heating rate of 8-10 ℃/min, and preserving heat for 5-10min to fully decompose the components of the binder;
and step S3, continuously heating to 700-750 ℃ at the heating rate of 8-10 ℃/min, preserving heat for 5-10min, heating to the first preset temperature at the heating rate of 5 ℃/min, preserving heat for 5-10min, and finally cooling to room temperature at the cooling rate of 10 ℃/min to finish welding.
Preferably, the first preset temperature in step S3 is the melting temperature of the sticky solder.
Compared with the prior art, the brazing method provided by the invention has the advantages that the full decomposition of the binder is ensured through two times of heat preservation before the brazing temperature, the integral temperature uniformity of the workpiece to be welded is improved, the residual carbon content of the brazed joint after welding is low, the structure is uniform, and the performance is excellent.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
In the description of the present invention, it is to be understood that the description of the term "some specific embodiments" means that a particular feature, structure, material, or characteristic described in connection with the embodiments or examples is included in at least one embodiment or example of the present invention. Throughout this specification, the schematic representations of the terms used above do not necessarily refer to the same implementation or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The embodiment of the invention provides a preparation method of a binder for a tape-bonding brazing filler metal, which comprises the following steps: according to the weight ratio of the components, 30-70% of epoxy resin, 21-63% of plasticizer and 3-21% of toughening agent are placed in a stirrer and stirred for 5-15min at the speed of 30-60r/min to prepare the adhesive.
The epoxy resin in the embodiment is used for bonding the solder powder, and in some preferred embodiments, the epoxy resin is E44, bisphenol A type epoxy resin, and has strong bonding force and thermal decomposition temperature Td385-413 ℃, and low residual carbon after welding. Compared with polymethyl methacrylate which is mostly used in the prior art, the epoxy resin E44 is low in price and has cost advantage, the polymethyl methacrylate is solid at normal temperature, needs to be heated in the preparation process and has a complex process, the epoxy resin E44 is liquid at room temperature, has certain viscosity, needs short stirring time in the mixing process, does not need to be dried for a long time after the preparation is completed, simplifies the process, and further reduces the energy consumption.
The plasticizer is used for increasing the plasticity of the sticky brazing filler metal during rolling, and in some preferred embodiments, the plasticizer comprises terpene resin and a first diluent, and the plasticizer is prepared by placing 10-50% of terpene resin and 50-90% of the first diluent in a stirrer in a weight ratio and stirring at a speed of 30-60r/min for 5-15 min.
In this example, the terpene resin has the formula (C)10H16)nThe material has high cohesive force and strong adhesive force, can increase the plasticity of the adhesive, improve the processing performance and improve the thermal decomposition temperature T of the terpene resindAbout 160 ℃ and low carbon residue after welding.
In this embodiment, the first diluent swells the plasticizer to make the plasticizer become a liquid that is easy to add and mix at room temperature, and in some preferred embodiments, the first diluent is selected from one or more of N-methyl pyrrolidone, acetone, ethyl acetate, and dibutyl phthalate.
In the embodiment, the toughening agent is used for increasing the toughness of the solder-attached strip in rolling, in some preferred embodiments, the toughening agent comprises an elastomer and a second diluent, and the toughening agent is prepared by placing 60-95% of the elastomer and 5-40% of the second diluent in a stirrer in a weight ratio and stirring at a speed of 30-60r/min for 5-15 min.
In some preferred embodiments, the elastomer is selected from one or more of ethyl cellulose, styrene thermoplastic elastomer, acrylonitrile-butadiene-styrene terpolymer and butadiene rubber.
In the embodiment, the second diluent swells the toughening agent, so that the toughening agent becomes a liquid state which is easy to add and mix at room temperature, and in some preferred embodiments, the second diluent is selected from one or more of ethyl acetate, absolute ethyl alcohol and acetone.
Therefore, the binder for the solder with the adhesive tape is suitable for various solders, has simple preparation process, does not pollute the environment and has low carbon residue after welding. The prepared adhesive tape brazing filler metal has good flexibility, can be processed into various shapes, is suitable for vacuum brazing under complex conditions, and has uniform joint structure and excellent performance after welding.
The embodiment of the invention also provides a tape bonding brazing filler metal, which comprises brazing filler metal powder and a binder prepared by the preparation method of the binder for the tape bonding brazing filler metal, wherein the tape bonding brazing filler metal is prepared by placing 6-14% of the binder and 86-94% of the brazing filler metal powder in a stirrer in a weight ratio, stirring at the speed of 30-60r/min for 20-60min, and rolling into the tape bonding brazing filler metal with the thickness of 0.1-2mm after fully mixing.
Preferably, the brazing filler metal powder is high-temperature brazing filler metal powder, and the brazing filler metal powder is selected from one of nickel-based brazing filler metal powder, cobalt-based brazing filler metal powder or copper-based brazing filler metal powder, so that the preparation of various band-bonding brazing fillers can be met, and the application range is wide.
Preferably, the brazing filler metal powder comprises four particles of different particle sizes, and the weight ratio of the four particles of different particle sizes is 5-25%, 20-35%, 25-35% and 15-25% in the increasing order of particle size. In some specific embodiments, the solder powder comprises particles with four diameters of 5 μm, 10 μm, 30 μm and 50 μm, and the weight ratio of each component is as follows: 5-25% of particles with a diameter of 5 μm, 20-35% of particles with a diameter of 10 μm, 25-35% of particles with a diameter of 30 μm, and 15-35% of particles with a diameter of 50 μm. Therefore, in the embodiment, by adjusting the proportion of the particles with each size, the gaps in the coarse particles are just filled by the medium particles, and the gaps in the medium particles are just filled by the fine particles, so that the materials are most densely stacked, the stacking density of the brazing filler metal powder is increased, and the welding quality of the adhesive brazing filler metal is improved.
Therefore, the tape bonding brazing filler metal disclosed by the embodiment of the invention is good in flexibility, can be processed into various shapes, is suitable for vacuum brazing under complex conditions, and is uniform in joint structure after welding, excellent in performance and low in carbon residue after welding.
As shown in fig. 1, an embodiment of the present invention further provides a brazing method, including the following steps:
step S1, pre-welding, namely, polishing the surface of a workpiece to be welded smoothly by using 100-2000-mesh abrasive paper, ultrasonically cleaning the part to be welded of the workpiece to be welded for 5-10min by using acetone, and then attaching adhesive tape brazing filler metal to the part to be welded;
s2, placing the whole workpiece to be welded in a vacuum brazing furnace, closing a furnace door, pumping the furnace into a vacuum state by using a vacuum pump, heating to 600 ℃ at the temperature rise rate of 8-10 ℃/min, and preserving heat for 5-10min, wherein the temperature reaches the decomposition temperature of the binder component in the adhesive tape brazing filler metal, the binder component is fully decomposed, and the decomposition product is discharged by the vacuum pump;
and step S3, continuing to heat to 700-750 ℃ at the heating rate of 8-10 ℃/min, preserving heat for 5-10min to ensure the uniformity of the overall temperature of the workpiece to be welded, then heating to a first preset temperature at the heating rate of 5 ℃/min, preserving heat for 5-10min, melting brazing filler metal powder, forming good metallurgical bonding with the alloy on the two sides, and finally cooling to room temperature at the cooling rate of 10 ℃/min to finish welding.
Preferably, the first preset temperature in step S2 is the melting temperature of the solder with solder, so as to ensure that the solder powder melts and forms a good metallurgical bond with the alloy on both sides.
Compared with the prior art, the brazing method provided by the invention has the advantages that the full decomposition of the binder is ensured through two times of heat preservation before the brazing temperature, the integral temperature uniformity of the workpiece to be welded is improved, the structure is uniform, and the performance is excellent. The residual carbon content of the soldered joint after welding is only 0.05-0.5%.
Example 1
The embodiment of the invention provides a preparation method of a binder for a tape-bonding brazing filler metal, which comprises the following steps:
uniformly mixing 40g of terpene resin and 60g of dibutyl phthalate, sealing the container, standing for 18h, transferring the mixture into a stirrer, and stirring at the speed of 60r/min for 5min to prepare a plasticizer; wherein, the dibutyl phthalate can be replaced by one or more of N-methyl pyrrolidone, acetone or ethyl acetate, and the mass of the dibutyl phthalate is configured according to the weight ratio of each component;
uniformly mixing 75g of ethyl cellulose and 25g of absolute ethyl alcohol, sealing the container, standing for 18h, transferring the mixture into a stirrer, and stirring at the speed of 60r/min for 5min to prepare a toughening agent; wherein the ethyl cellulose can be replaced by one or more of styrene thermoplastic elastomer, acrylonitrile-butadiene-styrene terpolymer and butadiene rubber, and the anhydrous ethanol can be one or two of ethyl acetate and acetone;
50g of epoxy resin E44, 40g of plasticizer and 10g of toughening agent are placed in a stirrer and stirred for 5min at the speed of 60r/min to obtain the adhesive.
The embodiment of the invention provides a preparation method of a sticky brazing filler metal, which comprises the following steps:
solder particles with diameters of 5 μm, 10 μm, 30 μm and 50 μm were mixed in a ratio of 10 g: 35 g: 35 g: fully mixing 20g of the components to obtain brazing filler metal powder;
and (3) uniformly mixing 10g of binder and 90g of brazing filler metal powder, placing the mixture in a stirrer, and stirring the mixture for 60min at the speed of 50r/min to obtain the 'pasty' brazing filler metal. The 'paste' brazing filler metal is rolled into a tape-bonding brazing filler metal with the thickness of 0.5mm, and then the preparation is finished. The adhesive tape brazing filler metal has the advantages of good wettability, low residual carbon content, uniform joint structure and higher joint strength in a welding test.
Example 2
The embodiment of the invention provides a preparation method of a binder for a tape-bonding brazing filler metal, which comprises the following steps:
20g of terpene resin, 15g of dibutyl phthalate and 15g of ethyl acetate are uniformly mixed, the container is sealed and then stands for 12 hours, and the mixture is transferred into a stirrer and stirred for 10 minutes at the speed of 30 r/min.
Preparing a plasticizer;
uniformly mixing 84g of styrene thermoplastic elastomer and 16g of ethyl acetate, sealing the container, standing for 12h, transferring the mixture into a stirrer, and stirring at the speed of 50r/min for 8min to prepare a toughening agent;
fully mixing 45g of epoxy resin E44, 44g of plasticizer and 11g of toughening agent to obtain a binder;
solder particles with diameters of 5 μm, 10 μm, 30 μm and 50 μm were mixed in a ratio of 8 g: 34 g: 35 g: fully mixing 23g of the components to obtain brazing filler metal powder;
12g of binder and 88g of solder powder are evenly mixed and put into a stirrer to be stirred for 30min at the speed of 60r/min, thus obtaining the 'paste' solder. The 'paste' brazing filler metal is rolled into a tape-bonding brazing filler metal with the thickness of 1mm to finish the preparation. The adhesive tape brazing filler metal has the advantages of good wettability, low residual carbon content, uniform joint structure and higher joint strength in a welding test.
Example 3
The embodiment takes welding of a nickel-based high-temperature alloy GH536 which is a common material of an aircraft engine as an example, and provides a brazing method, which comprises the following steps:
the workpieces to be welded are two GH536 alloy parts.
And (3) polishing the surface to be welded smoothly by using 100-mesh 2000-mesh sand paper, ultrasonically cleaning the part to be welded for 5-10min by using acetone, and attaching the brazing filler metal adhesive tape prepared by the method to the part to be welded.
The whole workpiece to be welded is placed in a vacuum brazing furnace, the furnace door is closed, the furnace is pumped into a vacuum state by using a vacuum pump, then the temperature is raised to 550-600 ℃ at the heating rate of 8-10 ℃/min, the temperature is kept for 5-10min, the temperature reaches the decomposition temperature of the binder component in the adhesive tape brazing filler metal, the binder component is fully decomposed, and the decomposition product is discharged by the vacuum pump. Then heating to 700-750 ℃ at the heating rate of 8-10 ℃/min, and preserving the heat for 5-10min to ensure the uniformity of the integral temperature of the workpiece. And then heating to 1050 ℃ at the heating rate of 5 ℃/min, preserving the heat for 5-10min, melting the brazing filler metal powder at the moment, forming good metallurgical bonding with the alloys on the two sides, and finally cooling to room temperature at the cooling rate of 10 ℃/min to finish welding.
According to the preparation method in the embodiment, the two heat preservation platforms are arranged before the brazing temperature, so that the binder is fully decomposed, and the uniformity of the overall temperature of the workpiece to be welded is improved. The soldered joint has low carbon residue, uniform structure and excellent performance. The reason why the amount of carbon residue of the soldered joint after soldering is low in this embodiment is that the nickel-based solder is typically soldered under vacuum conditions and at a temperature of 1000 ℃. In the welding process, the decomposition temperature of the adhesive is low, and in addition, the temperature rise in the brazing process is slow and long, the adhesive is fully decomposed before the brazing filler metal is melted, and the decomposition products are discharged by a vacuum pump, so that the residual carbon content of the brazed joint is low.
Example 4
The embodiment takes welding brass as an example, and provides a brazing method, which comprises the following steps:
the workpieces to be welded are two brass alloy parts, and the copper-based strip-bonding solder is prepared by replacing nickel-based solder powder with copper-based solder powder in the strip-bonding preparation.
Pretreatment in welding: and (3) polishing the surface to be welded smoothly by using 100-mesh 2000-mesh sand paper, ultrasonically cleaning the part to be welded for 5-10min by using acetone, and attaching the brazing filler metal adhesive tape prepared by the method to the part to be welded.
The welding process comprises the following steps: the whole workpiece is placed in a vacuum brazing furnace, the furnace door is closed, the furnace is pumped into a vacuum state by using a vacuum pump, then the temperature is raised to 550-600 ℃ at the heating rate of 8-10 ℃/min, the temperature is kept for 5-10min, the temperature reaches the decomposition temperature of the binder component in the adhesive tape brazing filler metal, the binder component is fully decomposed, and the decomposition product is discharged by the vacuum pump. Then heating to 700-750 ℃ at the heating rate of 8-10 ℃/min, and preserving the heat for 10min to ensure the uniformity of the overall temperature of the workpiece. And then heating to 850 ℃ at the heating rate of 5 ℃/min, preserving the heat for 10min, melting the brazing filler metal powder, forming good metallurgical bonding with the alloys on the two sides, and finally cooling to room temperature at the cooling rate of 10 ℃/min to finish welding.
According to the preparation method in the embodiment, the two heat preservation platforms are arranged before the brazing temperature, so that the binder is fully decomposed, and the uniformity of the overall temperature of the workpiece to be welded is improved. The soldered joint has low carbon residue, uniform structure and excellent performance.
Example 5
The embodiment takes welding of a cobalt-based high-temperature alloy K640 as an example, and provides a brazing method, which comprises the following steps:
the workpieces to be welded are two K640 alloy parts, and nickel-based brazing filler metal powder is replaced by cobalt-based brazing filler metal powder in the preparation of the tape-bonding brazing filler metal to prepare the cobalt-based tape-bonding brazing filler metal.
And (3) polishing the surface to be welded smoothly by using 100-mesh 2000-mesh sand paper, ultrasonically cleaning the part to be welded for 5-10min by using acetone, and attaching the brazing filler metal adhesive tape prepared by the method to the part to be welded.
The welding process comprises the following steps: the whole workpiece is placed in a vacuum brazing furnace, the furnace door is closed, the furnace is pumped into a vacuum state by using a vacuum pump, then the temperature is raised to 550-600 ℃ at the heating rate of 8-10 ℃/min, the temperature is kept for 5-10min, the temperature reaches the decomposition temperature of the binder component in the adhesive tape brazing filler metal, the binder component is fully decomposed, and the decomposition product is discharged by the vacuum pump. Then heating to 700-750 ℃ at the heating rate of 8-10 ℃/min, and preserving the heat for 10min to ensure the uniformity of the overall temperature of the workpiece. And then heating to 1150 ℃ at the heating rate of 5 ℃/min, preserving the heat for 10min, melting the brazing filler metal powder, forming good metallurgical bonding with the alloys on the two sides, and finally cooling to room temperature at the cooling rate of 10 ℃/min to finish welding.
According to the preparation method in the embodiment, the two heat preservation platforms are arranged before the brazing temperature, so that the binder is fully decomposed, and the uniformity of the overall temperature of the workpiece to be welded is improved. The soldered joint has low carbon residue, uniform structure and excellent performance.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.