Aluminum-based transition layer material for welding aluminum-steel composite panels and method and groove form

Abstract

The application discloses an aluminum-based transition layer material for aluminum-steel composite plate welding, which comprises a medicine core and a welding skin, wherein the medicine core is composed of the following components in percentage by mass: Zn powder 30-40%, Si powder 20-30%, Mn powder 5-10%, Mg powder 1-2%, CeO2 powder 0.5-0.8%, and the balance of Al powder, and the sum of the above component percentages is 100%. The material solves the problem of brittle phase generation during the preparation of the aluminum-steel composite structure. The application further discloses a preparation method of the aluminum-based transition layer material for aluminum-steel composite plate welding, a bevel form and a welding method.

Description

Technical Field

[0001] This invention belongs to the field of metal material welding technology, specifically relating to an aluminum-based transition layer material for welding aluminum-steel composite plates. This invention also relates to the preparation method, bevel form, and welding method of the aluminum-based transition layer material for welding aluminum-steel composite plates. Background Technology

[0002] Aluminum and its alloys have low density and good corrosion resistance; steel is characterized by high strength. Joining aluminum and steel together through explosive welding to form aluminum-steel composite plates combines the excellent corrosion resistance and low density of aluminum with the high strength of steel, making it an ideal choice for energy conservation, emission reduction, and green development in recent engineering applications. However, according to the Al-Fe binary phase diagram, Al and Fe in the liquid phase react to form various brittle intermetallic compounds (FeAl, FeAl3, Fe2Al5, etc.), leading to direct cracking of the weld joint. However, direct fusion welding of aluminum and steel is unavoidable during the fabrication of aluminum-steel composite plates. Therefore, achieving high-quality direct fusion welding of aluminum-steel composite plates is a major challenge that needs to be addressed in engineering practice. Summary of the Invention

[0003] The first objective of this invention is to provide an aluminum-based transition layer material for welding aluminum-steel composite plates, which solves the problem of brittle phase formation during the preparation of aluminum-steel composite structures.

[0004] The second objective of this invention is to provide a method for preparing an aluminum-based transition layer material for welding aluminum-steel composite plates.

[0005] A third objective of this invention is to provide a bevel form for welding aluminum-steel composite plates using the aforementioned aluminum-based transition layer material.

[0006] A fourth objective of this invention is to provide a method for welding aluminum-steel composite plates using the aforementioned aluminum-based transition layer material for welding aluminum-steel composite plates.

[0007] The first technical solution adopted in this invention is an aluminum-based transition layer material for welding aluminum-steel composite plates, comprising a flux core and a weld coat, wherein the flux core is composed of the following components by mass percentage: 30-40% Zn powder, 20-30% Si powder, 5-10% Mn powder, 1-2% Mg powder, 0.5-0.8% CeO2 powder, and the balance being Al powder, and the sum of the mass percentages of the above components is 100%.

[0008] The invention is further characterized in that,

[0009] The purity of each powder is greater than 99.9%, and the particle size of each powder is 200-300 mesh.

[0010] The welding material is made of pure aluminum strip, which is 0.3mm thick and 7mm wide.

[0011] The aluminum-based transition layer material for welding aluminum-steel composite plates is flux-cored welding wire, wherein the filling amount of flux-cored powder in the flux-cored welding wire is controlled at 20wt% to 25wt%.

[0012] The second technical solution adopted in this invention is a method for preparing the aluminum-based transition layer material for welding aluminum-steel composite plates, the specific steps of which are as follows:

[0013] Step 1: Weigh out 30-40% Zn powder, 20-30% Si powder, 5-10% Mn powder, 1-2% Mg powder, 0.5-0.8% CeO2 powder by mass percentage, with the remainder being Al powder. The sum of the mass percentages of the above components is 100%.

[0014] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 100℃~120℃, and the heat preservation time is 1h~1.5h. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1h~1.5h.

[0015] Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm.

[0016] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0017] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 20wt% to 25wt%.

[0018] The third technical solution adopted in this invention is to use the aluminum-based transition layer material for welding aluminum-steel composite plates to form the bevel when welding aluminum-steel composite plates. The aluminum-steel composite plate is opened with an asymmetrical X-shaped bevel, with a bevel angle of 60±5° on the aluminum side and 50±5° on the steel side. The blunt edge is opened on the steel side, and the width of the blunt edge is 1mm to 2mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate, and the peeling length on one side is 2mm to 3mm.

[0019] The fourth technical solution adopted in this invention is a method for welding aluminum-steel composite plates using the aforementioned aluminum-based transition layer material for welding aluminum-steel composite plates, specifically as follows:

[0020] (1) The aluminum-steel composite panel is modified by adopting the above-mentioned bevel form so that the gap between the modified aluminum-steel composite panel assembly is 1mm to 2mm;

[0021] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding power supply and welding current 180A~200A. The shielding gas is a mixed gas, which is composed of the following components by volume percentage: 80%Ar+20%CO2.

[0022] (3) Turn the bevel over and use the aluminum-based transition layer material for welding aluminum-steel composite plates to weld on the steel weld. Select CMT power supply for welding, welding current of 100A to 130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 1.5mm to 2.0mm.

[0023] (4) Select pure aluminum welding wire, grade ER1070, select CMT power supply, welding current 50A~80A, welding speed 50cm / s~60cm / s, shielding gas is 100%Ar, and complete the filling and cover welding of aluminum side weld.

[0024] The beneficial effects of this invention are:

[0025] (1) The aluminum-based transition layer material for welding aluminum-steel composite plates of the present invention is an aluminum-based welding wire with a large amount of Zn element added, which effectively reduces the melting point of the welding wire and achieves the direct fusion-brazing effect with the bottom steel weld.

[0026] (2) The aluminum-based transition layer material for welding aluminum-steel composite plates of the present invention also contains Si, Mn, Mg and CeO2 elements, which improve the strength of aluminum-based weld and reduce defects while ensuring excellent bonding with the bottom steel weld; and solves the problem of brittle phase formation during the preparation of aluminum-steel composite structure.

[0027] (3) The present invention adopts a bevel form to peel out the steel layer. By taking advantage of the difference in melting points between aluminum and steel, the mutual melting of aluminum and steel weld liquid can be effectively controlled when welding the aluminum side transition layer.

[0028] (4) The method of the present invention can replace the traditional galvanizing process, thereby reducing environmental pollution;

[0029] (5) The aluminum-based transition layer material for welding aluminum-steel composite plates of the present invention has fewer alloying elements, the preparation process is simple, and it is easy to carry out large-scale mass production.

[0030] (6) The aluminum-based transition layer material for welding aluminum-steel composite plates of the present invention is used to solve the welding problem of the aluminum-side transition layer when aluminum-steel composite plates are welded together. Using this aluminum-based welding wire, in conjunction with the selected CMT welding power source, the joint fusion-brazing effect can be achieved. Attached Figure Description

[0031] Figure 1 This refers to the bevel form used in the welding of aluminum-steel composite plates in this invention when using the aluminum-based transition layer material for welding aluminum-steel composite plates described above.

[0032] Figure 2 This is a schematic diagram of the welding sequence for aluminum-steel composite plates.

[0033] Figure 3 The microstructure of the transition layer weld when the aluminum-based transition layer material for welding aluminum-steel composite plates prepared in Example 2 is welded at the aluminum side bevel;

[0034] Figure 4 The aluminum-steel composite plate prepared in Example 2 was welded using an aluminum-based transition layer material. The aluminum-steel composite plate was subjected to a tensile test, and the resulting aluminum-steel composite plate was obtained by scanning electron microscopy of the aluminum side fracture surface. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] This invention provides an aluminum-based transition layer material for welding aluminum-steel composite plates, comprising a flux core and a weld coat, wherein the flux core is composed of the following components by mass percentage: 30-40% Zn powder, 20-30% Si powder, 5-10% Mn powder, 1-2% Mg powder, 0.5-0.8% CeO2 powder, and the balance being Al powder, and the sum of the mass percentages of the above components is 100%.

[0037] The purity of each powder is greater than 99.9%, and the particle size of each powder is 200-300 mesh.

[0038] The welding material is made of pure aluminum strip, which is 0.3mm thick and 7mm wide.

[0039] The aluminum-based transition layer material for welding aluminum-steel composite plates is flux-cored welding wire, wherein the filling amount of flux-cored powder in the flux-cored welding wire is controlled at 20wt% to 25wt%.

[0040] The roles and functions of each component in this flux-cored welding wire are as follows:

[0041] (1) Al is the main component of flux-cored wire. As can be seen from the Fe-Al binary phase diagram, the two react to form a variety of brittle intermetallic compounds (FeAl, FeAl3, Fe2Al5, etc.). However, due to the large difference in melting points between the two (Al melting point is about 660℃, Fe melting point is about 1545℃), the two can be connected by fusion-brazing (Al melts, while Fe does not melt).

[0042] (2) The main alloying element in flux-cored welding wire is Zn. According to the Al-Zn binary phase diagram, both have very high solid solubility at high temperatures, with up to 83.1% of Zn being soluble in Al. Furthermore, Zn has a melting point of 419℃, lower than that of Al. Therefore, adding Zn to the welding wire flux powder can lower the melting point of the welding wire through reaction with Al, improving the fluidity of the liquid weld metal and facilitating subsequent brazing. In addition, according to the Fe-Zn binary phase diagram, Zn has high solid solubility in Fe, thus ensuring a good bond between the steel matrix and the nickel-based transition layer.

[0043] (3) Si is the main component of the flux powder. According to the Al-Si binary phase diagram, the two can form a eutectic structure with a eutectic temperature of 577℃, which is lower than the melting point of Al. Therefore, the addition of Si can lower the melting point of the welding wire. The solid solution of Si in Al can improve the strength of aluminum-based welds. In addition, Si, together with Mn, can also play a deoxidizing role, reducing the generation of porosity defects in the weld.

[0044] (4) Mn is the main component of the flux powder. According to the Al-Mn binary phase diagram, Mn can improve the strength of Al by dissolving it in Al. Mn can also reduce the melting of some Fe, which leads to the formation of the Fe-Al brittle phase. In addition, Mn together with Si has a deoxidizing effect, which reduces the occurrence of porosity in the weld.

[0045] (5) Mg is the main component of the powder. According to the Al-Mg binary phase diagram, Mg has a high solid solubility in Al, which can reach 14.9% at the eutectic temperature (450℃). It has a good solid solution strengthening effect and a melting point lowering effect (eutectic reaction).

[0046] (6) CeO2 is added in small amounts to the powder. As a rare earth oxide, CeO2 can refine the grains of aluminum welds, purify grain boundaries, and improve the grain boundary bonding strength. In addition, the addition of rare earth oxides can increase the transition coefficient of rare earth elements.

[0047] The present invention also provides a method for preparing the aluminum-based transition layer material for welding the above-mentioned aluminum-steel composite plate, the specific steps of which are as follows:

[0048] Step 1: Weigh out 30-40% Zn powder, 20-30% Si powder, 5-10% Mn powder, 1-2% Mg powder, 0.5-0.8% CeO2 powder by mass percentage, with the remainder being Al powder. The sum of the mass percentages of the above components is 100%.

[0049] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 100℃~120℃, and the heat preservation time is 1h~1.5h. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1h~1.5h.

[0050] Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm.

[0051] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0052] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 20wt% to 25wt%.

[0053] The present invention also provides a bevel form for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material for welding aluminum-steel composite plates. The aluminum-steel composite plate has an asymmetrical X-bevel, with a bevel angle of 60±5° on the aluminum side and 50±5° on the steel side. The blunt edge is on the steel side, with a width of 1mm to 2mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate, with a single-sided peeling length of 2mm to 3mm.

[0054] The present invention also provides a method for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material for welding aluminum-steel composite plates, such as... Figure 2 As shown, specifically:

[0055] (1) The aluminum-steel composite panel is modified by the above-mentioned bevel form so that the gap between the modified aluminum-steel composite panel assembly is 1mm to 2mm.

[0056] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding power supply and welding current 180A~200A. The shielding gas is a mixed gas, which is composed of the following components by volume percentage: 80%Ar+20%CO2.

[0057] (3) Turn the bevel over and use the aluminum-based transition layer material for welding aluminum-steel composite plates to weld on the steel weld. Select CMT power supply for welding, welding current of 100A to 130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 1.5mm to 2.0mm.

[0058] (4) Select pure aluminum welding wire, grade ER1070, select CMT power supply, welding current 50A~80A, welding speed 50cm / s~60cm / s, shielding gas is 100%Ar, and complete the filling and cover welding of aluminum side weld.

[0059] Example 1

[0060] Step 1: Weigh out 30% Zn powder, 20% Si powder, 5% Mn powder, 1% Mg powder, 0.5% CeO2 powder by mass percentage, with the remainder being Al powder. The sum of the mass percentages of the above components is 100%.

[0061] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 100℃ and the heat preservation time is 1 hour. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1 hour.

[0062] Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm.

[0063] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0064] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 20wt%.

[0065] When welding aluminum-steel composite plates using the aluminum-based transition layer material prepared in Example 1, the bevel form (e.g.) is as follows: Figure 1 As shown): The aluminum-steel composite plate is cut with an asymmetrical X-groove, with a 55° bevel angle on the aluminum side and a 45° bevel angle on the steel side. The blunt edge is cut on the steel side with a width of 1mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate with a single-sided peeling length of 2mm.

[0066] The method for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material (e.g.) Figure 2 As shown):

[0067] (1) The aluminum-steel composite panel is modified by the above-mentioned bevel form so that the gap between the modified aluminum-steel composite panel assembly is 1mm.

[0068] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding and welding current 180-200A. The shielding gas is a mixture of the following components by volume percentage: 80% Ar + 20% CO2.

[0069] (3) Turn the bevel over, grind the steel side weld, and use the aluminum-based welding wire of the present invention to weld on the steel weld. Select CMT power supply for welding, welding current of 100-130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 1.5mm.

[0070] (4) Select pure aluminum welding wire, wire grade ER1070, select CMT power supply, welding current 50~80A, welding speed 50~60cm / s, shielding gas is 100%Ar, and complete the filling and cover welding of aluminum side weld.

[0071] The test results of the aluminum-steel composite structure obtained by the above welding are as follows:

[0072] (1) The joint was inspected by X-ray and no cracks or pores were found;

[0073] (2) The steel side welds are mainly composed of needle-like ferrite and have no defects;

[0074] (3) The aluminum-based transition layer weld is mainly composed of α-Al, with a small amount of Mg2Si phase distributed between the grains;

[0075] (4) Tensile test specimens of the joint were prepared. The test results showed that the tensile strength of the joint was 451 MPa and the elongation after fracture was 15%.

[0076] Example 2

[0077] Step 1: Weigh out 40% Zn powder, 30% Si powder, 10% Mn powder, 2% Mg powder, 0.8% CeO2 powder, and the remainder is Al powder, according to the following mass percentages. The sum of the mass percentages of the above components is 100%.

[0078] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 120℃, and the heat preservation time is 1.5h. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1.5h.

[0079] Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm.

[0080] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0081] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 25wt%.

[0082] When welding aluminum-steel composite plates using the aluminum-based transition layer material prepared in Example 2, the bevel form (e.g.) is as follows: Figure 1 As shown): The aluminum-steel composite plate is cut with an asymmetrical X-shaped bevel, with a bevel angle of 65° on the aluminum side and 55° on the steel side. The blunt edge is cut on the steel side with a width of 2mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate with a single-sided peeling length of 3mm.

[0083] The method for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material (e.g.) Figure 2 As shown):

[0084] (1) The aluminum-steel composite panel is modified by the above-mentioned bevel form so that the gap between the modified aluminum-steel composite panel assembly is 2mm;

[0085] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding and welding current 180-200A. The shielding gas is a mixture of the following components by volume percentage: 80% Ar + 20% CO2.

[0086] (3) Turn the bevel over and use the aluminum-based welding wire of the present invention to weld on the steel weld. Select CMT power supply for welding, welding current of 100-130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 2.0mm.

[0087] (4) Select pure aluminum welding wire, grade ER1070, CMT power supply, welding current 50-80A, welding speed 50-60cm / s, shielding gas 100% Ar, and complete the filling and capping welding of the aluminum side weld. The test results of the aluminum-steel composite structure obtained by the above welding are as follows:

[0088] (1) The joint was inspected by X-ray and no cracks or pores were found;

[0089] (2) The steel side welds are mainly composed of needle-like ferrite and have no defects;

[0090] (3) The aluminum-based transition layer weld is mainly composed of α-Al, with a small amount of Mg2Si phase distributed between the grains;

[0091] (4) Tensile test specimens of the joint were prepared. The test results showed that the tensile strength of the joint was 439 MPa and the elongation after fracture was 18%.

[0092] Figure 3 The image shows the microstructure of the aluminum-based transition layer weld. As can be seen from the image, the weld is mainly composed of α-Al, with a small amount of Mg2Si phase distributed between the grains.

[0093] Figure 4 The tensile fracture morphology of the aluminum-steel composite plate is shown in the figure. It can be seen from the figure that the aluminum side fracture is dominated by bremsstrahlung and has good toughness, thus proving that the Fe-Al brittle phase did not form in the joint.

[0094] Example 3

[0095] Step 1: Weigh out 35% Zn powder, 25% Si powder, 7% Mn powder, 1.5% Mg powder, 0.7% CeO2 powder, and the balance is Al powder, according to the following mass percentages. The sum of the mass percentages of the above components is 100%.

[0096] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 110℃ and the heat preservation time is 1.3h. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1.3h.

[0097] Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm.

[0098] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0099] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 22wt%.

[0100] When welding aluminum-steel composite plates using the aluminum-based transition layer material prepared in Example 3, the bevel form (e.g.) is as follows: Figure 1 As shown): The aluminum-steel composite plate is cut with an asymmetrical X-groove, with a 65° bevel angle on the aluminum side and a 45° bevel angle on the steel side. The blunt edge is cut on the steel side, with a width of 1-2 mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate, with a single-sided peeling length of 2.5 mm.

[0101] The method for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material (e.g.) Figure 2 As shown):

[0102] (1) The aluminum-steel composite panel is modified by the above-mentioned bevel form so that the assembly gap of the modified aluminum-steel composite panel is 1.5mm;

[0103] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding and welding current 180-200A. The shielding gas is a mixture of the following components by volume percentage: 80% Ar + 20% CO2.

[0104] (3) Turn the bevel over and use the aluminum-based welding wire of the present invention to weld on the steel weld. Select CMT power supply for welding, welding current of 100-130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 1.7mm.

[0105] (4) Select pure aluminum welding wire, wire grade ER1070, select CMT power supply, welding current 50~80A, welding speed 50~60cm / s, shielding gas is 100%Ar, and complete the filling and cover welding of aluminum side weld.

[0106] The test results of the aluminum-steel composite structure obtained by the above welding are as follows:

[0107] (1) The joint was inspected by X-ray and no cracks or pores were found;

[0108] (2) The steel side welds are mainly composed of needle-like ferrite and have no defects;

[0109] (3) The aluminum-based transition layer weld is mainly composed of α-Al, with a small amount of Mg2Si phase distributed between the grains;

[0110] (4) Tensile test specimens of the joint were prepared. The test results showed that the tensile strength of the joint was 470 MPa and the elongation after fracture was 14%.

[0111] Example 4

[0112] Step 1: Weigh out 37% Zn powder, 27% Si powder, 6% Mn powder, 1.2% Mg powder, 0.58% CeO2 powder, and the balance is Al powder, according to the following mass percentages. The sum of the mass percentages of the above components is 100%.

[0113] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 115℃ and the heat preservation time is 1.1h. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1.1h.

[0114] Step 3: Remove the grease from the surface of the pure aluminum strip with alcohol, and wrap the flux powder prepared in step 2 inside the pure aluminum strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm; the pure aluminum strip is 0.3 mm thick and 7 mm wide.

[0115] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0116] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 20wt%.

[0117] When welding aluminum-steel composite plates using the aluminum-based transition layer material prepared in Example 4, the bevel form (e.g.) is as follows: Figure 1 (As shown) The aluminum-steel composite plate is cut with an asymmetrical X-groove, with a 55° bevel angle on the aluminum side and a 55° bevel angle on the steel side. The blunt edge is cut on the steel side with a width of 1.2mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate with a single-sided peeling length of 2.3mm.

[0118] The method for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material (e.g.) Figure 2 As shown):

[0119] (1) The aluminum-steel composite panel is modified by the above-mentioned bevel form so that the assembly gap of the modified aluminum-steel composite panel is 1.2mm;

[0120] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding, welding current 180-200A, shielding gas 80%Ar+20%CO2.

[0121] (3) Turn the bevel over and use the aluminum-based welding wire of the present invention to weld on the steel weld. Select CMT power supply for welding, welding current of 100-130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 1.6mm.

[0122] (4) Select pure aluminum welding wire, wire grade ER1070, select CMT power supply, welding current 50~80A, welding speed 50~60cm / s, shielding gas is 100%Ar, and complete the filling and cover welding of aluminum side weld.

[0123] The test results of the aluminum-steel composite structure obtained by the above welding are as follows:

[0124] (1) The joint was inspected by X-ray and no cracks or pores were found;

[0125] (2) The steel side welds are mainly composed of needle-like ferrite and have no defects;

[0126] (3) The aluminum-based transition layer weld is mainly composed of α-Al, with a small amount of Mg2Si phase distributed between the grains;

[0127] (4) Tensile test specimens of the joint were prepared. The test results showed that the tensile strength of the joint was 453 MPa and the elongation after fracture was 16.5%.

[0128] Example 5

[0129] Step 1: Weigh out 31% Zn powder, 29% Si powder, 9% Mn powder, 1.8% Mg powder, 0.75% CeO2 powder, and the balance is Al powder, according to the following mass percentages. The sum of the mass percentages of the above components is 100%.

[0130] Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powders. The heating temperature in the vacuum heating furnace is 105℃, and the heat preservation time is 1.2h. After drying, place the powders into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1.4h.

[0131] Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm.

[0132] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm.

[0133] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 20wt%.

[0134] When welding aluminum-steel composite plates using the aluminum-based transition layer material prepared in Example 5, the bevel form (e.g.) is as follows: Figure 1 As shown): The composite plate has an asymmetrical X-groove, with a 65° bevel angle on the aluminum side and a 45° bevel angle on the steel side. The blunt edge is on the steel side with a width of 1.1 mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate with a single-sided peeling length of 2.8 mm.

[0135] The method for welding aluminum-steel composite plates using the above-mentioned aluminum-based transition layer material (e.g.) Figure 2 As shown):

[0136] (1) The aluminum-steel composite panel was modified using the above-mentioned bevel form so that the assembly gap of the modified aluminum-steel composite panel is 1.9mm;

[0137] (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding and welding current 180-200A. The shielding gas is a mixture of the following components by volume percentage: 80% Ar + 20% CO2.

[0138] (3) Turn the bevel over and use the aluminum-based welding wire of the present invention to weld on the steel weld. Select CMT power supply for welding, welding current of 100-130A, shielding gas of 100% Ar, and weld one layer with a thickness of about 1.55mm.

[0139] (4) Select pure aluminum welding wire, wire grade ER1070, select CMT power supply, welding current 50~80A, welding speed 50~60cm / s, shielding gas is 100%Ar, and complete the filling and cover welding of aluminum side weld.

[0140] The test results of the aluminum-steel composite structure obtained by the above welding are as follows:

[0141] (1) The joint was inspected by X-ray and no cracks or pores were found;

[0142] (2) The steel side welds are mainly composed of needle-like ferrite and have no defects;

[0143] (3) The aluminum-based transition layer weld is mainly composed of α-Al, with a small amount of Mg2Si phase distributed between the grains;

[0144] (4) Tensile test specimens of the joint were prepared. The test results showed that the tensile strength of the joint was 448 MPa and the elongation after fracture was 17.5%.

Claims

1. An aluminum-based transition layer material for welding aluminum-steel composite plates, characterized in that, The material includes a flux core and a welding layer. The flux core is composed of the following components by mass percentage: 30-40% Zn powder, 20-30% Si powder, 5-10% Mn powder, 1-2% Mg powder, 0.5-0.8% CeO2 powder, and the balance is Al powder. The sum of the mass percentages of the above components is 100%. The welding layer is made of pure aluminum strip. The aluminum-based transition layer material for welding aluminum-steel composite plates is a flux-cored welding wire, wherein the filling amount of flux core powder in the flux-cored welding wire is controlled at 20wt%-25wt%.

2. The aluminum-based transition layer material for welding aluminum-steel composite plates according to claim 1, characterized in that, The purity of each powder is greater than 99.9%, and the particle size of each powder is 200-300 mesh.

3. The aluminum-based transition layer material for welding aluminum-steel composite plates according to claim 1, characterized in that, The pure aluminum strip is 0.3mm thick and 7mm wide.

4. The aluminum-based transition layer material for welding aluminum-steel composite plates according to claim 1, characterized in that, The bevel form for welding aluminum-steel composite plates using the aluminum-based transition layer material is as follows: an asymmetrical X-bevel is made in the aluminum-steel composite plate, with a bevel angle of 60±5° on the aluminum side and 50±5° on the steel side. The blunt edge is made on the steel side, with a width of 1mm~2mm. The steel layer is peeled off along the explosive welding interface of the aluminum-steel composite plate, with a single-sided peeling length of 2mm~3mm.

5. The method for preparing the aluminum-based transition layer material for welding aluminum-steel composite plates according to any one of claims 1-4, characterized in that, The specific steps are as follows: Step 1: Weigh out 30-40% Zn powder, 20-30% Si powder, 5-10% Mn powder, 1-2% Mg powder, 0.5-0.8% CeO2 powder, and the balance is Al powder, according to the following mass percentages: The sum of the mass percentages of the above components is 100%. Step 2: Place the powders weighed in Step 1 into a vacuum heating furnace for heating and heat preservation to remove the water of crystallization in the powder. The heating temperature in the vacuum heating furnace is 100℃~120℃, and the heat preservation time is 1h~1.5h. After drying, place the powder into a powder mixer for thorough mixing. The mixing time in the powder mixer is 1h~1.5h. Step 3: Use alcohol to remove the grease from the surface of the pure aluminum strip, and use a flux-cored wire drawing machine to wrap the flux powder prepared in step 2 inside the pure aluminum strip. The diameter of the first drawing die is 2.6 mm; the thickness of the pure aluminum strip is 0.3 mm and the width is 7 mm. Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.3mm, 2.0mm, 1.8mm, 1.6mm, 1.4mm and 1.2mm in sequence for drawing. The final diameter of the flux-cored welding wire is 1.2mm. Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use; the filling amount of flux-cored welding wire powder is controlled at 20wt%~25wt%.

6. A method for welding aluminum-steel composite plates using an aluminum-based transition layer material, characterized in that, Specifically: (1) The aluminum-steel composite panel is modified by the bevel form as described in claim 4, so that the gap between the modified aluminum-steel composite panel assembly is 1mm~2mm; (2) Use ER50-6 welding wire for steel side beveling welding. Select CMT power supply for welding and welding current of 180A~200A. The shielding gas is a mixture of the following components by volume percentage: 80%Ar+20%CO2. (3) Turn the bevel over and use the aluminum-based transition layer material for welding aluminum-steel composite plates as described in any one of claims 1-3 to weld on the steel weld. Select CMT power supply for welding, welding current 100A~130A, shielding gas 100%Ar, and weld one layer with a thickness of 1.5mm~2.0mm. (4) Select pure aluminum welding wire, grade ER1070, select CMT power supply, welding current 50A~80A, welding speed 50cm / s~60cm / s, shielding gas 100%Ar, and complete the filling and cover welding of aluminum side weld.

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