CN101811237B - Al-Si-Cu-Ni alloy foil-shaped solder and preparation method thereof - Google Patents

Abstract

The invention relates to a preparation method of an Al-Si-Cu-Ni alloy state foil-shaped brazing material, which comprises the following steps of: (1) confirming the components of brazing material alloy raw material: weighing a quaternary alloy component comprising 18-20 percent of Cu, 5.5-6.5 percent of Si, 2.0-2.4 percent of nickel and the balance of aluminum as a basic component of a low-temperature aluminum brazing material; (2) preparing intermediate alloy, wherein the intermediate alloy needing casting comprises the intermediate alloy of Al-Cu50 and Al-Si30, and the nonvaccumintermediate frequency furnace smelting is adopted in preparation; (3) smelting and casting a brazing material alloy plate; casting an alloy ingot by adopting a nonvaccum intermediate frequency inducing furnace; (4) heating to 400 DEG C in an annealing furnace and preserving the temperature for more than 12 hours to remove cast ingot segregation and tiny defects; (5) hot rolling and coldly rolling for molding. The prepared brazing material has a melting point of 518-538 DEG C, a width larger than 100 mm and a thickness 0.07-0.15 mm.

Description

Al-Si-Cu-Ni alloy foil-shaped solder and preparation method thereof

technical field

The invention relates to an aluminum alloy low-melting point four-component solder, in particular to an Al-Si-Cu-Ni alloy foil-shaped solder and a preparation method thereof, belonging to the technical field of aluminum alloy brazing.

Background technique

The melting point of the existing GB400 aluminum-silicon eutectic solder is as high as 577°C, and the brazing temperature is generally 595-605°C. Excessively high brazing temperature makes many low-melting point aluminum alloys unable to be connected by brazing. Currently, it can be brazed The only aluminum alloys available are pure aluminum, 3A21, and 6063. In addition, too high welding temperature will easily lead to the growth of the base metal grains, affecting the mechanical properties of the structure, and it will also easily cause the base metal to dissolve excessively, resulting in dissolution defects.

Adding Cu element to aluminum-silicon solder can greatly reduce the melting point of the solder, and the Al-Si-Cu-Ni quaternary aluminum alloy is considered to be a low-melting aluminum-based solder with a low melting point and excellent comprehensive properties[ 2] [3], but the addition of Cu element in the solder reduces the melting point of the solder and also increases the brittleness of the solder [1], and the low melting point alloy solder is difficult to process into a foil solder, only It can be prepared into a foil shape by melt quenching and rotating rapid solidification method[2], electroplating method[1] or composite rolling of Al-Si and Cu-Ni platform gold with an appropriate thickness ratio[2][3 ].

Literature [1] describes the preparation method of Al-Si-Cu-Ni quaternary aluminum alloy by electroplating method; Literature [2] mentions Al-Si-Cu-Ni quaternary aluminum alloy foil melt quenching rotation rapid solidification method and compound rolling method.

The principle of the aluminum alloy foil melt quenching and rotating quick solidification method is to first cast the master alloy of the aluminum solder into a rod shape, put it into a quartz tube (crucible) with a slit nozzle at one end, and the other end of the quartz tube is passed into a Inert gases such as argon and helium at a certain pressure. The quartz tube is covered with an induction coil, and there is a roller that can rotate at a high speed below, and the roller is made of copper with good thermal conductivity. After the equipment is started, the solder alloy is melted by induction heating. Due to the effect of surface tension, the melt will not flow down from the slit nozzle. After the alloy is completely melted, an inert gas with a certain pressure is introduced from the upper end of the quartz tube. It is sprayed under pressure to the side of the high-speed rotating roller, and is rapidly cooled and solidified into a thin strip at the moment of contact with the roller surface, and moves and falls along the tangential direction of the roller surface circumference under the action of centrifugal force. The melt rotation method can usually be made into a thin strip of continuous brazing filler metal with a width of several millimeters and a length of more than ten meters and a uniform structure. The melt quenching and rotating rapid solidification method can keep the roll speed constant during the preparation process, but it cannot keep the braze The overall thickness of the foil strip is uniform in the length and width direction, especially the surface roughness of the free surface of the foil strip (the opposite side of the contact surface with the roller) is poor, which brings difficulties to welding and assembly.

Composite rolled solder alloy foil is prepared by dividing the solder into Al-Si and Cu-Ni two-component alloys, forming them into foils or sheets respectively, and then composite-rolling the two components with an appropriate thickness. , the uniformity of each component in the solder is difficult to guarantee, and the melting point range is also wide.

Relevant literature search:

1) Preparation and performance research of low melting point aluminum-based composite solder, 2009, Vol. 39, No. 11 of Electric Welding Machine, Li Pei et al.

2) A new type of low-melting point aluminum brazing material for non-ferrous metals and rare earth applications Translated by Qi Feng from Welding Journal 1996.V0175, N08

3) A New Aluminum Filler Metal, Welding Journal 1996. D.M.Jacbson, G.Humpston S.P.sangha,

Contents of the invention

1. Technical problems to be solved:

The present invention aims at the shortage of existing foils of the existing Al-Si-Cu-Ni brazing filler metal, and prepares Al-Si-Cu-Ni medium-temperature brazing alloy state by adopting a process method combining hot rolling, intermediate treatment and cold rolling Foil.

2. Technical solution:

A preparation method of Al-Si-Cu-Ni alloy state foil-shaped solder, characterized in that: the steps are as follows:

1) Determination of the composition of the brazing alloy raw material

Taking Cu content: 18-20%, Si content: 5.5-6.5%, Nickel content: 2.0-2.4%, aluminum balance quaternary alloy components as the basic components of low-temperature aluminum solder;

2) Master alloy preparation

The master alloys for Al-Si-Cu-Ni quaternary alloys to be cast include Al-Cu50 and Al-Si30 master alloys; this master alloy is prepared by non-vacuum intermediate frequency furnace melting, and the specific method is as follows:

Preparation of Al-Cu50 master alloy: After adding aluminum ingot into the graphite clay crucible, heat up; after the aluminum ingot is melted, add oxygen-free copper to raise the furnace temperature to 800-850°C, stir well, and wait until the copper ingot is completely melted , cast into a ≠15mm thin plate; the alloy casting temperature is 700-750°C, the casting mold is cast iron mold, and the wall thickness is 30mm;

Preparation of Al-Si30 master alloy: After adding aluminum ingot into the graphite clay crucible, heat up; after the aluminum ingot is melted, add polysilicon, raise the furnace temperature to 780-820°C, stir well, and wait until the polysilicon is completely melted, then cast into ≠15mm thin plate; the alloy casting temperature is 700～730℃, the casting mold adopts cast iron mold, and the wall thickness is 30mm;

3) Melting and casting of solder alloy plates

Use a non-vacuum intermediate frequency induction furnace to melt and cast alloy ingots. The specific method is: put pure aluminum into a graphite crucible, heat up, and after the aluminum ingots are completely melted, add Al-Cu50 and Al-Si10 master alloys in turn; wait until the master alloys are completely melted. Finally, metal Ni is added; after Ni is completely melted, the temperature is raised to 750°C and kept for 15 minutes, and hexachloroethane is pressed into the bottom of the alloy liquid with a graphite cover and stirred for degassing and slagging. The amount of hexachloroethane is the furnace amount 0.3-0.4% of the slag removal, after sprinkling a little refining agent, remove the scum on the surface; raise the temperature to 680-720°C, fully stir, and cast ingots;

After the master alloy is prepared, in order to ensure the accuracy of the composition of the solder alloy, it is necessary to analyze the content of the master alloy before batching to ensure the accuracy of the batch; after the master alloy is made into an ingot, multi-point sampling is used for composition analysis, that is, the sampling points must be greater than or equal to three Point, the sampling method of three points is: take one point on each side of the left and right sides, and one point in the middle. When the chemical composition of the sampling point meets the following requirements, it can be known that the chemical composition of the developed aluminum alloy ingot is qualified, that is, the main component percentage Cu is 19 ±1%, Si is 6±0.5%, Ni is 2.2±0.2%, Al is the balance; the percentage of secondary components is Fe≤0.3%, Zn≤0.2%; after the composition is qualified, the surface of the solder alloy ingot is processed to remove casting defects and inclusions;

heat treatment

The heat treatment system is determined according to the melting point of the alloy ingot tested, that is, the temperature is raised to 400°C in the annealing furnace, and the temperature is kept for more than 12 hours to eliminate the segregation and small defects of the ingot;

5) Hot rolling and cold rolling forming

●Determination of billet opening temperature

After the casting plate is completed, the first process to the solder foil is called blanking; the rolling temperature of the blank is determined by measuring the melting point of the aluminum alloy solder, and the rolling temperature is considered from the following two aspects: proper consideration of extrusion In the case of deformation heat generated, the upper limit of the ingot heating temperature should be slightly lower than the eutectic melting temperature of the alloy; the general billet opening temperature is the melting point of the alloy -30°C, and the billet rolling temperature of this method is 480°C. The middle roll should not be lower than 300°C;

●Rolling process

Hot rolling of the solder is carried out after the billet is opened. During the rolling process, the deformation rate of the solder is strictly controlled. After each rolling, the ingot should be placed in an annealing furnace to continue heating. The furnace temperature is 450 ° C and kept for 15 minutes to increase the material plasticity Continuously repeat the hot rolling and annealing process. When the thickness of the ingot is rolled below 1.5mm, cold rolling is adopted. During the cold rolling process, the deformation rate of the foil must be controlled. After each rolling, the ingot is placed in the annealing furnace Continue to heat, keep warm for 30 minutes to increase the plasticity of the material, and roll again after cooling to ensure the shape of the solder foil.

The preparation method of Al-Si-Cu-Ni alloy state foil-shaped solder is obtained by the Al-Si-Cu-Ni alloy state foil-shaped solder, which is characterized in that its melting point is 518°C to 538°C, its width is greater than 100mm, and its thickness is 0.07mm. mm to 0.15mm.

3. Beneficial effects:

Compared with the composite rolling and melt quenching process of solder, the process of the present invention can prepare Al-Si-Cu-Ni alloy foils with a melting point of 518°C to 538°C, a width greater than 100mm, and a thickness of 0.07mm to 0.15mm. The brazing material and the solder foil have a uniform composition and a smooth appearance, which is convenient for welding and assembly, and expands the application occasions and scope of the soldering material. The invention can be used for relatively low-temperature aluminum brazing of pure aluminum, 6063, 6061, 3A21 and other aluminum alloys.

Description of drawings

Fig. 1 is the prepared Al-Si-Cu-Ni alloy state foil-shaped solder sample;

Figure 2 is a map of the multi-point sampling locations of alloy ingots.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

The steps of preparing Al-Si-Cu-Ni alloy state foil-shaped solder are as follows:

1) Determination of the composition of the brazing alloy raw material

By referring to the relevant phase diagram and data of low-temperature aluminum brazing filler metals, it can be known that the Al-Si-Cu-Ni four-component brazing filler metal with a melting point lower than the Al-Si eutectic 30-50°C can realize pure aluminum, 6061, 6063, 3A21 aluminum Lower temperature brazing of alloys. As close as possible to the eutectic point of the Al-Si-Cu-Ni quaternary alloy, the Cu content is selected to be about A%: 18-20%, and the Si content is about B% on the basis of taking into account metallurgy, material scarcity, and economy: 5.5-6.5%, the nickel content is about C%: 2.0-2.4%, the quaternary alloy composition of the aluminum balance is used as the basic composition of low-temperature aluminum solder.

2) Master alloy preparation

Al-Cu50 and Al-Si30 master alloys are the master alloys that need to be melted and cast for Al-Si-Cu-Ni quaternary alloys after research. When preparing master alloys, due to the large difference between the solid and liquid phases in the phase diagram of the master alloy components and the large difference in the specific gravity of elements, it is easy to cause composition segregation. The intermediate alloy of the present invention is prepared by melting in a non-vacuum intermediate frequency furnace, and the specific method is as follows:

Preparation of Al-Cu50 master alloy: After adding aluminum ingot into graphite clay crucible, heat up. After the aluminum ingot is melted, add oxygen-free copper, raise the furnace temperature to 800-850°C, stir well, and after the copper ingot is completely melted, cast it into a ≠15mm thin plate. The casting temperature of alloy is 700～750℃. The casting mold is cast iron mold with a wall thickness of 30mm.

Preparation of Al-Si30 master alloy: after adding aluminum ingot into graphite clay crucible, heat up. After the aluminum ingot is melted, add polysilicon, raise the furnace temperature to 780-820°C, stir well, and after the polysilicon is completely melted, cast it into a ≠15mm thin plate. The casting temperature of alloy is 700～730℃. The casting mold is cast iron mold with a wall thickness of 30mm.

3) Melting and casting of solder alloy plates

The non-vacuum intermediate frequency induction furnace is used to melt and cast alloy ingots. The specific method is: put pure aluminum into a graphite crucible, heat up, and after the aluminum ingots are completely melted, add Al-Cu50 and Al-Si10 intermediate alloys in sequence. After the master alloy is completely melted, metal Ni is added. After the Ni is fully melted, raise the temperature to 750°C and keep it warm for 15 minutes. Use a graphite cover to press hexachloroethane into the bottom of the alloy liquid and stir for degassing and slagging. The amount of hexachloroethane is 0.3-0.4% of the furnace capacity. After removing the scum, sprinkle a little refining agent to remove the surface scum. Raise the temperature to 680-720°C, fully stir, and cast ingots.

After the master alloy is prepared, in order to ensure the accuracy of the composition of the solder alloy, it is necessary to analyze the content of the master alloy before batching to ensure the accuracy of the batching. After the intermediate alloy is made into an ingot, multi-point sampling is used for component analysis. The sampling number positions are 1 and 3 on the left and right sides, and the sampling number in the middle part is 2 (as shown in Figure 2 below). When the chemical composition of the sampling point meets the table 1 When required, it can be known that the chemical composition of the developed aluminum alloy ingot is qualified, and after the composition is qualified, the surface of the solder alloy ingot is processed to remove casting defects and inclusions;

Table 1 The measured alloy composition of ingot sampling points must meet the requirements

4) heat treatment

The heat treatment system is determined according to the melting point of the alloy ingot tested, that is, the temperature is raised to 400°C in the annealing furnace, and the temperature is kept for more than 12 hours to eliminate the segregation and small defects of the ingot.

5) Hot rolling and cold rolling forming

●Determination of billet opening temperature

After the casting plate is completed, the first process to the brazing foil is called blanking. The rolling temperature of the billet is determined by measuring the melting point of the aluminum alloy solder. The rolling temperature is considered from the following two aspects: when the deformation heat generated by extrusion is properly considered, the upper limit of the ingot heating temperature should be slightly lower than that of the alloy. Melting and eutectic melting temperature; the general blanking temperature is (alloy melting point-30°C), the blanking and rolling temperature of the present invention is 480°C, and the rolls during the blanking process should be guaranteed not to be lower than 300°C.

●Rolling process

Hot rolling of the solder is carried out after the billet is opened. During the rolling process, the deformation rate of the solder is strictly controlled. After each rolling, the ingot should be placed in an annealing furnace to continue heating. The furnace temperature is 450 ° C and kept for 15 minutes to increase the material plasticity Continuously repeat the hot rolling and annealing process. When the thickness of the ingot is rolled below 1.5mm, cold rolling is adopted. During the cold rolling process, the deformation rate of the foil must be controlled. After each rolling, the ingot is placed in the annealing furnace Continue to heat, keep warm for 30 minutes to increase the plasticity of the material, and roll again after cooling to ensure the shape of the solder foil.

Through the above process, an Al-Si-Cu-Ni alloy foil-shaped brazing filler metal with a melting point of 518°C to 538°C, a width of more than 100mm, and a thickness of 0.07mm to 0.15mm can be prepared, as shown in Figure 1 . The composition of the solder foil is uniform and the appearance is smooth, which is convenient for soldering and assembly, and expands the application occasions and scope of the solder. The differential thermal analysis spectrum of Al-Si-Cu-Ni alloy foil solder is shown in Figure 2.

Claims (2)

1. the preparation method of an Al-Si-Cu-Ni alloy state foil-shaped brazing material, it is characterized in that: step is as follows:

1) the brazing filler metal alloy composition of raw material is determined

Getting Cu content is: 18-20%, and Si content is: 5.5-6.5%, nickel content is: 2.0-2.4%, the quaternary alloy composition of aluminium surplus is as the basis of low temperature almit;

2) intermediate alloy preparation

The Al-Si-Cu-Ni quaternary alloy needs the intermediate alloy of founding that Al-Cu50, Al-Si30 intermediate alloy are arranged; Antivacuum intermediate frequency furnace melting is adopted in the preparation of this intermediate alloy, and concrete grammar is:

Al-Cu50 intermediate alloy preparation: after in the graphite clay pot, adding aluminium ingot, heat up; After treating aluminium ingot fusing, add oxygen-free copper, make furnace temperature rise to 800～850 ℃, fully stir, treat copper ingot all molten clear after, be cast into ≠ the 15mm thin plate; 700～750 ℃ of alloy cast temperatures, casting die adopts pig mold, wall thickness 30mm;

Al-Si30 intermediate alloy preparation: after in the graphite clay pot, adding aluminium ingot, heat up; After treating aluminium ingot fusing, add polysilicon, make furnace temperature rise to 780～820 ℃, fully stir, treat polysilicon all molten clear after, be cast into ≠ the 15mm thin plate; 700～730 ℃ of alloy cast temperatures, casting die adopts pig mold, wall thickness 30mm;

3) melting of brazing filler metal alloy sheet material and casting

Adopt antivacuum intermediate frequency furnace founding alloy pig, concrete grammar is: fine aluminium is put into graphite crucible, heat up, treat that aluminium ingot all after the fusing, adds Al-Cu50, Al-Si10 intermediate alloy successively; After treating that intermediate alloy all melts clearly, add metal Ni; After treating the Ni fine melt, be warming up to 750 ℃, be incubated 15 minutes, with the graphite cover with carbon trichloride be pressed into alloy liquid bottom stir outgas, slag making, the carbon trichloride consumption is 0.3～0.4% of a stove amount, skimming finishes, spread a little refining agent after, remove surface scum; Be warming up to 680～720 ℃, fully stir ingot casting;

Intermediate alloy preparation back needs before the batching middle alloy is made content analysis for guaranteeing the accurate of brazing filler metal alloy composition, to guarantee to prepare burden accurately; Intermediate alloy adopts multidraw to carry out constituent analysis after making ingot casting, be that sample point is greater than and equals 3 points, 3 sampling mode is: the right and left is respectively got a bit, get some the middle part, when the chemical composition of sample point meets following the requirement, Yan Zhi aluminium alloy cast ingot chemical composition is qualified as can be known, and promptly main component percentage Cu is 19 ± 1%, Si is 6 ± 0.5%, Ni is 2.2 ± 0.2%, Al is a surplus; Submember percentage Fe≤0.3%, Zn≤0.2%; After composition is qualified casting flaw is removed in brazing filler metal alloy ingot surface processing and be mingled with;

4) heat treatment

Alloy cast ingot fusing point according to chemical examination is determined heat treating regime, promptly is warming up to 400 ℃ in annealing furnace, is incubated more than 12 hours to eliminate ingotism and tiny flaw;

5) hot rolling and cold roll forming

● determining of cogging temperature

After founding sheet material is finished, be called cogging to first road of solder paper tinsel processing; Determine the split rolling method temperature by the fusing point of measuring aluminium alloy brazing filler metal, rolling temperature is considered from following two aspects: under the situation of the distortion heat that extruding with due regard to produces, the ingot casting heating-up temperature upper limit should be lower than alloy low melting eutectics fusion temperature slightly; General cogging temperature is an alloy melting point-30 ℃, and this method split rolling method temperature is 480 ℃, and roll should guarantee to be not less than 300 ℃ in the cogging process;

● the operation of rolling

Carry out the hot rolling system of solder after the cogging, the strict control of operation of rolling solder deformation rate, ingot blank should be positioned over annealing furnace after per pass is rolling and continue heating, furnace temperature is 450 ℃, insulation 15min is to increase material plasticity, repeat hot rolling system and annealing process continuously, after ingot blank thickness is rolling to below the 1.5mm, take cold rolling processing, must control paper tinsel material deformation rate in the cold-rolled process, after per pass is rolling ingot blank is positioned over annealing furnace and continue heating, insulation 30min increases material plasticity, rolling once more after the cooling, guarantee that repeatedly the solder paper tinsel is shaped.

2. by preparation method's gained Al-Si-Cu-Ni alloy state foil-shaped brazing material of the described Al-Si-Cu-Ni alloy state foil-shaped brazing material of claim 1, it is characterized in that: its fusing point is that 518 ℃～538 ℃, width are greater than 100mm, thickness 0.07mm to 0.15mm.

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