Welding material and method for producing aluminum-steel gradient structures

Abstract

The application discloses a welding material for preparing an aluminum-steel gradient structure, which comprises alloy powder for laser cladding and aluminum-based welding wire for CMT welding; the alloy powder for laser cladding comprises the following components in percentage by mass: Zn powder 20.0-30.0%, Cu powder 20.0-30.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance of Al; the aluminum-based welding wire for CMT welding comprises powder and a welding sheath, wherein the powder comprises the following components in percentage by mass: Zn powder 20.0-30.0%, Ag powder 20.0-30.0%, Cu powder 10.0-20.0%, Si powder 5.0-10.0%, Mg powder 5.0-9.0%, and the balance of Al powder. The structure solves the problems of cracking and poor performance caused by the mismatch of thermal physical properties of aluminum-steel dissimilar structures and brittle phases. A laser+CMT composite preparation method for the aluminum-steel gradient structure is also provided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metal materials, and particularly relates to a welding material for preparing an aluminum-steel gradient structure, and further relates to a laser+CMT composite preparation method of the aluminum-steel gradient structure. BACKGROUND

[0002] Aluminum is a silver-white light metal, and has a melting point of 660 DEG C and a density of 2.7 g / cm 3 Aluminum and its alloys have the characteristics of light weight, high specific strength, good thermal conductivity, electrical conductivity, corrosion resistance, and good mechanical properties at low temperature; and steel has the characteristics of low price and reliable performance, and becomes one of the most widely used materials in the world, and is always dominant in the manufacturing industry, and has excellent cold and hot working properties, plasticity, toughness, and corrosion resistance. An aluminum / steel dissimilar metal composite structure can fully exert the inherent advantages of the two materials, and has the advantages of light weight, high strength, and good corrosion resistance, and has more and more wide applications in the fields of automobile manufacturing, aerospace, and the like.

[0003] The weldability of dissimilar metal materials depends on the metallurgical characteristics and thermal physical properties between the two. When the physical and chemical properties of the two metals to be welded are quite different, and the mutual solubility is very low, a large number of hard and brittle intermetallic compounds are easily generated, thereby seriously reducing the mechanical properties of the dissimilar metal welded joint. The aluminum / steel dissimilar metal welding also has these problems, and since the solubility between aluminum and steel is low, the thermal physical properties and mechanical properties are quite different, and hard and brittle intermetallic compounds are easily formed, which makes the aluminum / steel welding connection difficult. SUMMARY

[0004] The purpose of the present application is to provide a welding material for preparing an aluminum-steel gradient structure, and to solve the problems of cracking and poor performance caused by the mismatch of thermal physical properties and brittle phases of the aluminum-steel dissimilar structure.

[0005] Another purpose of the present application is to provide a laser+CMT composite preparation method of the aluminum-steel gradient structure.

[0006] The first technical solution adopted by the present application is a welding material for preparing an aluminum-steel gradient structure, which comprises an alloy powder for laser cladding and an aluminum-based welding wire for CMT welding.

[0007] The alloy powder for laser cladding comprises the following components in mass percentage: Zn powder 20.0-30.0%, Cu powder 20.0-30.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance of Al.

[0008] The CMT welding aluminum-based welding wire comprises a flux and a welding sheath, wherein the flux comprises the following components in percentage by mass: Zn powder 20.0-30.0%, Ag powder 20.0-30.0%, Cu powder 10.0-20.0%, Si powder 5.0-10.0%, Mg powder 5.0-9.0%, and the rest is Al powder.

[0009] The application is also characterized in that:

[0010] The purity of each raw material powder in the laser cladding alloy powder is greater than or equal to 99.9%.

[0011] The particle size of each raw material flux in the CMT welding aluminum-based welding wire is 100-200 mesh.

[0012] The welding sheath of the CMT welding aluminum-based welding wire is a pure aluminum strip with a thickness of 0.4 mm and a width of 7 mm.

[0013] The filling rate of the flux of the CMT welding aluminum-based welding wire is controlled to be 25wt%-30wt%.

[0014] The preparation method of the laser cladding alloy powder comprises the following specific steps:

[0015] Step 1: Zn powder 20.0-30.0%, Cu powder 20.0-30.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the rest is Al are weighed according to the percentage by mass, and the sum of the percentage by mass of the above components is 100%;

[0016] Step 2: the raw material powders in step 1 are mixed and vacuum melted, and the powder is prepared by using the gas atomization method;

[0017] In step 2, a vacuum melting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat degree of the melt is kept between 100-150 DEG C during the atomization process;

[0018] Step 3: the particle size of the atomized raw material powder is screened;

[0019] In step 3, the particle size of the screened raw material powder is 25-53 microns, i.e. 270-500 mesh.

[0020] The flowability of the screened raw material powder is required to be 25s / 100g-40s / 100g.

[0021] Step 4: the prepared powder is vacuum packaged and ready for use.

[0022] The preparation method of the CMT welding aluminum-based welding wire comprises the following specific steps:

[0023] Step 1: take Zn powder 20.0~30.0%, Ag powder 20.0~30.0%, Cu powder 10.0~20.0%, Si powder 5.0~10.0%, Mg powder 5.0~9.0% by mass percentage respectively, and the rest is Al powder, the sum of the mass percentage of the above components is 100%;

[0024] Step 2: the powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 100~160℃, and the holding time is 1h~2h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1h~2h;

[0025] Step 3: alcohol is used to remove the grease on the surface of the pure aluminum strip, and the powder prepared in step 2 is wrapped in the pure aluminum strip through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the powder filling rate is controlled at 25wt%-30wt%;

[0026] Step 4: after the first process drawing is completed, the die hole diameter is gradually reduced, and finally the diameter of the flux-cored wire is 1.2mm;

[0027] Step 5: after the flux-cored wire drawing is completed, it is wound on the welding wire disc through the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0028] The second technical scheme adopted by the application is a laser+CMT composite preparation method of aluminum-steel gradient structure, which uses the prepared laser cladding powder and CMT welding aluminum-based wire to prepare the aluminum-steel gradient structure, and the specific steps are as follows:

[0029] (1) First, the above-mentioned laser cladding alloy powder is used to prepare a laser cladding layer on a steel substrate (Q345), the laser power is 1kW~3kW, and the cladding layer thickness is 1.0mm~1.5mm;

[0030] (2) Then, the above-mentioned CMT welding aluminum-based wire is used to perform overlay welding on the above-mentioned laser cladding layer, the welding current is 150A~180A during the first layer of overlay welding, and the overlay layer thickness is 2mm~3mm; the welding current is 180A~200A during the second layer of overlay welding, and the overlay layer thickness is 3mm~4mm; the interlayer temperature is controlled at 50℃~100℃ during CMT overlay welding;

[0031] (3) Finally, ER1100 pure aluminum wire is used to perform arc overlay welding on the above-mentioned second layer of CMT overlay layer to prepare an aluminum layer, the welding current is 150A~200A, the overlay layer thickness is 10mm~15mm, and the interlayer temperature is controlled at 50℃~100℃ during the overlay welding.

[0032] The beneficial effects of the application are:

[0033] (1) The present application adopts laser cladding+CMT arc composite process to prepare aluminum-steel gradient structure, fully utilizes the advantages of high laser cladding precision and high CMT arc surfacing efficiency, so as to obtain high-quality aluminum-steel gradient structure while having broad industrial popularization value. The problem of cracking and poor performance caused by the mismatch of thermal physical properties of aluminum-steel dissimilar structures and brittle phase is solved.

[0034] (2) The method of the present application first prepares a laser cladding layer on the steel substrate. The cladding layer is mainly of Al-Zn-Cu-Si alloy system, and the added Zn, Cu and Si have high solid solubility in aluminum, which can fully ensure the quality of the laser cladding layer. Moreover, the melting points of these elements are relatively low, and the dilution rate is low when the laser cladding layer is prepared on the steel, which has the effect of brazing.

[0035] (3) The CMT arc surfacing aluminum-based welding wire of the present application is used for laser cladding and surfacing preparation. The welding wire is mainly of Al element, and is added with alloy elements such as Zn, Ag and Cu. The welding wire has low melting point, and the surfacing layer has good metallurgical combination with the laser cladding layer.

[0036] (4) The laser+CMT composite preparation method of the aluminum-steel gradient structure of the present application can effectively block the generation of brittle phases between Al and Fe elements, thereby ensuring the joint performance. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a schematic diagram of the aluminum-steel gradient structure prepared by the laser+CMT composite preparation method of the aluminum-steel gradient structure used in the present application;

[0038] Figure 2 is the microstructure of the laser cladding layer in the aluminum-steel gradient structure prepared by Example 2;

[0039] Figure 3 is the microstructure of the CMT surfacing layer in the aluminum-steel gradient structure prepared by Example 2;

[0040] Figure 4 is the scanning electron microscope observation morphology of the tensile fracture of the aluminum-steel gradient structure prepared by Example 2. DETAILED DESCRIPTION

[0041] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0042] The present application provides a welding material for preparing aluminum-steel gradient structure, which comprises laser cladding alloy powder and CMT welding aluminum-based welding wire;

[0043] The alloy powder for laser cladding comprises the following components in percentage by mass: Zn powder 20.0-30.0%, Cu powder 20.0-30.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance of Al;

[0044] The aluminum-based welding wire for CMT welding comprises flux powder and a welding sheath, wherein the flux powder comprises the following components in percentage by mass: Zn powder 20.0-30.0%, Ag powder 20.0-30.0%, Cu powder 10.0-20.0%, Si powder 5.0-10.0%, Mg powder 5.0-9.0%, and the balance of Al powder.

[0045] The functions of the main components in the laser cladding alloy powder and the CMT welding wire are as follows:

[0046] (1) A large amount of Al element is added in both the laser cladding alloy powder and the CMT welding wire: the laser cladding layer is prepared on a steel substrate, and the addition of Al element can ensure good metallurgical bonding performance between the laser cladding layer and the electric arc cladding layer. The CMT cladding layer is connected to the laser cladding layer on one side and to the aluminum layer on the other side, and therefore a large amount of Al element contained in the CMT cladding layer can ensure the metallurgical bonding between the laser cladding layer and the CMT cladding layer and between the CMT cladding layer and the aluminum layer.

[0047] (2) A large amount of Zn element is added in both the laser cladding alloy powder and the CMT welding wire: according to the Al-Zn binary phase diagram, Zn has the largest solid solubility in Al (up to 83.1wt.%), and the melting point of Zn is low. Therefore, the addition of Zn element in the laser cladding layer on steel can not only improve the metallurgical quality of the cladding layer itself, but also reduce the melting point of the cladding layer, so that the dilution rate is low when the cladding layer is cladded on the steel substrate, thereby inhibiting the Fe element in the steel from entering the laser cladding layer. The function of Zn element in the CMT welding wire is similar to that in the laser cladding layer, that is, it can not only ensure good metallurgical bonding performance of the welding wire (ensure that the CMT cladding layer is well combined with the laser cladding layer and the aluminum layer above), but also reduce the melting point of the welding wire, thereby reducing the interdiffusion between elements.

[0048] (3) A large amount of Cu element is added in both the laser cladding alloy powder and the CMT welding wire: according to the Al-Cu binary phase diagram, the solid solubility of Cu in Al is also high. The laser cladding layer is cladded on a steel substrate, and from the Cu-Fe binary phase diagram, it can be seen that no brittle phase is generated between the two, and therefore the addition of Cu in the laser cladding layer can ensure the bonding performance between the cladding layer and the steel substrate. In the CMT welding wire, Cu can be solid-solved in Al to improve the strength of the CMT cladding layer.

[0049] (4) Ag element is added in the CMT welding wire: from the Al-Ag binary phase diagram, the solid solubility of Ag in Al is high, so the addition of Ag in the welding wire can not only improve the fluidity of the welding wire, but also improve the strength of the cladding layer. In addition, the melting point of Ag is higher than that of Al, which can play a role in stabilizing the arc.

[0050] (5) Si element is added in both the laser cladding alloy powder and the CMT welding wire: according to the Al-Si phase diagram, the solid solubility of Si in Al is second only to Zn and Ag. Therefore, the addition of Si in both the laser cladding layer and the CMT cladding layer can play a solid solution strengthening effect, improving the strength of the laser cladding layer and the CMT cladding layer. The solubility of Si in Fe is also large, so the addition of Si in the laser cladding layer can improve the bonding performance between the laser cladding layer and the steel layer. In addition, Si is a deoxidizing element, which can play a role in deoxidizing the cladding layer, thereby avoiding the oxidation of the remaining alloy elements.

[0051] (6) Sn element is added in the laser cladding alloy powder: from the Al-Sn binary phase diagram, the two will not generate brittle phase. The melting point of Sn is relatively low, which is 231℃. Sn together with Zn and Cu can form a low melting point alloy, thereby further reducing the melting point of the laser cladding layer and reducing the diffusion of Fe elements in the steel matrix, thereby fundamentally inhibiting the generation of Fe-Al brittle phase.

[0052] (7) Mg element is added in the CMT welding wire: according to the Al-Mg binary phase diagram, Mg can be solid-solubilized in Al up to 17.1wt.%, so the added Mg is solid-solubilized in the Al matrix, thereby strengthening the Al cladding layer and improving the strength of the aluminum-steel gradient joint.

[0053] The purity of each raw material powder in the laser cladding alloy powder is ≥99.9%.

[0054] The particle size of each raw material powder in the CMT welding aluminum-based welding wire is 100-200 mesh.

[0055] The welding skin of the CMT welding aluminum-based welding wire is a pure aluminum strip with a thickness of 0.4mm and a width of 7mm.

[0056] The powder filling rate of the CMT welding aluminum-based welding wire is controlled at 25wt%-30wt%.

[0057] The preparation method of the laser cladding alloy powder comprises the following specific steps:

[0058] Step 1: weigh Zn powder 20.0-30.0%, Cu powder 20.0-30.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance is Al, according to the mass percentage; the sum of the mass percentages of the above components is 100%.

[0059] Step 2: after mixing the raw material powders of step 1, vacuum smelting is carried out, and a gas atomization method is used for powdering;

[0060] In step 2, a vacuum smelting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat of the melt is kept between 100-150 DEG C during the atomizing process;

[0061] Step 3: particle size screening is performed on the atomized raw material powder;

[0062] In step 3, the particle size range of the screened raw material powder is 25-53 microns, i.e. 270-500 mesh;

[0063] The flowability of the screened raw material powder is required to be 25-40 s / 100g;

[0064] Step 4: the prepared powder is vacuum packaged and ready for use.

[0065] The preparation method of the aluminum-based welding wire for CMT welding is as follows:

[0066] Step 1: Zn powder 20.0-30.0%, Ag powder 20.0-30.0%, Cu powder 10.0-20.0%, Si powder 5.0-10.0%, Mg powder 5.0-9.0%, and the rest is Al powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0067] Step 2: the powder weighed in step 1 is placed in a vacuum heating furnace and heated, the heating temperature is 100-160 DEG C, and the holding time is 1-2 hours to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1-2 hours;

[0068] Step 3: alcohol is used to remove the grease on the surface of the pure aluminum strip, and the powder prepared in step 2 is wrapped in the pure aluminum strip through a flux-cored wire drawing equipment, and the first drawing die has a hole diameter of 2.6 mm; the powder filling rate is controlled at 25wt%-30wt%;

[0069] Step 4: after the first process drawing is completed, the die hole diameter is gradually reduced, and finally a diameter of 1.2 mm of the flux-cored wire is obtained;

[0070] Step 5: after the flux-cored wire drawing is completed, it is wound on the wire spool by a winding machine, and finally sealed in a vacuum packaging bag for use.

[0071] The application also provides a laser+CMT composite preparation method of aluminum-steel gradient structure, which uses the prepared laser cladding powder and the aluminum-based welding wire for CMT welding to prepare the aluminum-steel gradient structure, such as Figure 1The specific steps are as follows:

[0072] (1) First, the above-mentioned alloy powder for laser cladding is used to prepare a laser cladding layer on a steel substrate (Q345), the laser power is 1kW~3kW, and the cladding layer thickness is 1.0mm~1.5mm;

[0073] (2) Then, the above-mentioned aluminum-based welding wire for CMT welding is used to perform surfacing on the above-mentioned laser cladding layer, the welding current is 150A~180A when the first layer is surfacing, and the surfacing layer thickness is 2mm~3mm; the welding current is 180A~200A when the second layer is surfacing, and the surfacing layer thickness is 3mm~4mm; the interlayer temperature is controlled at 50℃~100℃ when CMT surfacing;

[0074] (3) Finally, the ER1100 pure aluminum welding wire is used to perform arc surfacing on the above-mentioned second layer of CMT surfacing layer to prepare an aluminum layer, the welding current is 150A~200A, the surfacing layer thickness is 10mm~15mm, and the interlayer temperature is controlled at 50℃~100℃ when surfacing.

[0075] Example 1

[0076] The specific steps of the preparation method of the alloy powder for laser cladding are as follows:

[0077] Step 1: Zn powder 20.0%, Cu powder 20.0%, Si powder 5.0%, Sn powder 5.0%, and the balance of Al are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0078] Step 2: After mixing the raw material powders of step 1, vacuum melting is performed, and gas atomization method is used for powder preparation;

[0079] Step 3: The particle size of the atomized raw material powder is screened.

[0080] Step 4: The prepared powder is vacuum packaged and ready for use.

[0081] In step 2, a vacuum melting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6MPa, and the superheat degree of the melt is maintained at 100℃ during the atomizing process.

[0082] In step 3, the particle size of the screened raw material powder is 25μm.

[0083] The flowability of the screened raw material powder is required to be 25s / 100g.

[0084] The purity of each raw material powder in the laser cladding alloy powder is ≥99.9%;

[0085] The specific steps of the preparation method of the aluminum-based welding wire for CMT welding are as follows:

[0086] Step 1: Zn powder 20.0%, Ag powder 20.0%, Cu powder 10.0%, Si powder 5.0%, Mg powder 5.0%, and the rest is Al powder are weighed by mass percentage, and the sum of the mass percentages of the above components is 100%;

[0087] The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 100 mesh.

[0088] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 100°C for 1 hour to remove the crystal water in the powder. The dried powder is placed in a powder mixer for thorough mixing for 1 hour.

[0089] Step 3: Alcohol is used to remove the grease on the surface of the pure aluminum strip. The powder prepared in step 2 is wrapped in the pure aluminum strip through a cored wire drawing equipment, and the first drawing die has a hole diameter of 2.6 mm. The pure aluminum strip has a thickness of 0.4 mm and a width of 7 mm. The powder filling rate of the aluminum-based welding wire for CMT welding is controlled at 25wt%.

[0090] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a cored wire with a diameter of 1.2 mm is obtained.

[0091] Step 5: After the cored wire drawing is completed, it is wound on a welding wire reel through a winding machine and finally sealed in a vacuum packaging bag for cored wire for use.

[0092] The laser+CMT composite preparation method of aluminum-steel gradient structure is as follows (as shown in Figure 1 ):

[0093] (1) First, the above-mentioned alloy powder for laser cladding is used to prepare a laser cladding layer on a steel substrate, with a laser power of 1 kW and a cladding layer thickness of 1.0 mm.

[0094] (2) Then, the above-mentioned aluminum-based welding wire for CMT welding is used to perform two-layer CMT overlay welding on the above-mentioned laser cladding layer. The welding current is 150 A for the first layer of overlay welding, and the overlay layer thickness is 2 mm. The welding current is 180 A for the second layer of overlay welding, and the overlay layer thickness is 3 mm. The interlayer temperature is controlled at 50°C during CMT overlay welding.

[0095] (3) Finally, ER1100 pure aluminum welding wire is used to perform arc welding on the above-mentioned CMT overlay layer to prepare an aluminum layer, with a welding current of 150 A and an overlay layer thickness of 10 mm. The interlayer temperature is controlled at 50°C during welding.

[0096] Through testing, the tensile strength of the aluminum-steel gradient structure is 251 MPa.

[0097] Example 2

[0098] The preparation method of the alloy powder for laser cladding is as follows:

[0099] Step 1: Zn powder 30.0%, Cu powder 30.0%, Si powder 10.0%, Sn powder 10.0%, and the balance of Al are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0100] The purity of each raw material powder in the laser cladding alloy powder is ≥99.9%;

[0101] Step 2: After mixing the raw material powders of step 1, vacuum melting is carried out, and the powder is prepared by gas atomization method;

[0102] Step 3: The particle size of the atomized raw material powder is screened.

[0103] Step 4: The prepared powder is vacuum packaged and ready for use.

[0104] In step 2, a vacuum melting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat degree of the melt is maintained between 150°C during the atomizing process.

[0105] In step 3, the particle size of the screened raw material powder is 50 μm.

[0106] The flowability of the screened raw material powder is required to be 30 s / 100g.

[0107] The preparation method of the aluminum-based welding wire for CMT welding is as follows:

[0108] Step 1: Zn powder 30.0%, Ag powder 30.0%, Cu powder 20.0%, Si powder 10.0%, Mg powder 9.0%, and the balance of Al powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0109] The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 200 mesh;

[0110] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated, the heating temperature is 160°C, and the holding time is 2h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 2h;

[0111] Step 3: Alcohol is used to remove the grease on the surface of the pure aluminum strip, and the powder prepared in step 2 is wrapped in the pure aluminum strip by the drug core welding wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the pure aluminum strip, thickness 0.4mm, width 7mm; the powder filling rate of the aluminum-based welding wire for CMT welding is controlled at 30wt%.

[0112] Step 4: After the first pass of drawing is completed, the hole diameter of the mold is sequentially reduced, and finally a diameter of 1.2 mm of the flux-cored wire is obtained.

[0113] Step 5: After the drawing of the flux-cored wire is completed, it is wound on the welding wire disc by the wire winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0114] The laser+CMT composite preparation method of the aluminum-steel gradient structure is as follows (as shown in Figure 1 ):

[0115] (1) First, the laser cladding layer is prepared on the steel substrate using the above-mentioned alloy powder for laser cladding, the laser power is 3 kW, and the cladding layer thickness is 1.5 mm;

[0116] (2) Then, two layers of CMT overlaying layers are overlaid on the above-mentioned laser cladding layer using the above-mentioned aluminum-based welding wire for CMT welding, the welding current is 180 A during the first layer of overlaying, the overlaying layer thickness is 3 mm; the welding current is 200 A during the second layer of overlaying, the overlaying layer thickness is 4 mm; the interlayer temperature is controlled at 100°C during CMT overlaying.

[0117] (3) Finally, an aluminum layer is prepared by arc welding on the above-mentioned CMT overlaying layer using ER1100 pure aluminum welding wire, the welding current is 200 A, the overlaying layer thickness is 15 mm, and the interlayer temperature is controlled at 100°C during welding.

[0118] Figure 2 The microstructure of the laser cladding layer in the aluminum-steel gradient structure prepared using Example 2 is shown. As can be seen from the figure, the laser cladding layer is mainly Al solid solution, and no cracks, pores and other defects are observed.

[0119] Figure 3 The microstructure of the CMT overlaying layer in the aluminum-steel gradient structure prepared using Example 2 is shown. As can be seen from the figure, the CMT overlaying layer is mainly Al solid solution, and the dendritic morphology is obvious, and no cracks, pores and other defects are observed.

[0120] Figure 4 The tensile fracture scanning electron microscope observation morphology of the aluminum-steel gradient structure prepared in Example 2 is shown. As can be seen from the figure, the fracture is mainly in the form of dimples, indicating that the aluminum-steel gradient structure has good toughness, and it also proves that the gradient structure does not generate Fe-Al brittle phase.

[0121] After testing, the tensile strength of the aluminum-steel gradient structure is 267 MPa.

[0122] Example 3

[0123] The preparation method of the alloy powder for laser cladding is as follows:

[0124] Step 1: Zn powder 25.0%, Cu powder 25.0%, Si powder 7.0%, Sn powder 7.0%, and the balance of Al are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0125] The purity of each raw material powder in the laser cladding alloy powder is ≥ 99.9%;

[0126] Step 2: After mixing the raw material powders of step 1, vacuum melting is carried out, and the powder is prepared by gas atomization method;

[0127] Step 3: The particle size of the atomized raw material powder is screened.

[0128] Step 4: The prepared powder is vacuum packaged and ready for use.

[0129] In step 2, a vacuum melting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat of the melt is maintained between 130°C during the atomizing process.

[0130] In step 3, the particle size of the screened raw material powder is 53 μm.

[0131] The flowability of the screened raw material powder is required to be 40 s / 100g.

[0132] The preparation method of the aluminum-based welding wire for CMT welding is as follows:

[0133] Step 1: Zn powder 25.0%, Ag powder 25.0%, Cu powder 15.0%, Si powder 7.0%, Mg powder 7.0%, and the balance of Al powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0134] The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 200 mesh;

[0135] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated, the heating temperature is 130°C, and the holding time is 1.5h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.5h;

[0136] Step 3: Alcohol is used to remove the grease on the surface of the pure aluminum strip, and the powder prepared in step 2 is wrapped in the pure aluminum strip through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the thickness of the pure aluminum strip is 0.4mm, and the width is 7mm; the powder filling rate of the aluminum-based welding wire for CMT welding is controlled at 28wt%;

[0137] Step 4: After the first drawing process is completed, the die hole diameter is gradually reduced, and finally a core wire with a diameter of 1.2mm is obtained.

[0138] Step 5: After the core wire is drawn, it is wound on a wire spool by a wire winding machine, and finally sealed in a vacuum packaging bag of the core wire for use.

[0139] The laser+CMT composite preparation method of the aluminum-steel gradient structure is specifically as follows (as shown in Figure 1 ):

[0140] (1) First, the laser cladding alloy powder is used to prepare a laser cladding layer on a steel substrate, the laser power is 2 kW, and the cladding layer thickness is 1.3 mm;

[0141] (2) Then, the CMT welding aluminum-based wire is used to perform two-layer CMT overlay welding on the above laser cladding layer, the welding current is 170 A when the first layer is welded, and the overlay layer thickness is 2.5 mm; the welding current is 190 A when the second layer is welded, and the overlay layer thickness is 3.5 mm; the interlayer temperature is controlled at 70°C during CMT overlay welding.

[0142] (3) Finally, the ER1100 pure aluminum wire is used to perform arc welding on the above CMT overlay layer to prepare an aluminum layer, the welding current is 170 A, the overlay layer thickness is 13 mm, and the interlayer temperature is controlled at 70°C during welding.

[0143] Test results show that the tensile strength of the aluminum-steel gradient structure is 228 MPa.

[0144] Example 4

[0145] The preparation method of the laser cladding alloy powder is as follows:

[0146] Step 1: Zn powder 22.0%, Cu powder 22.0%, Si powder 6.0%, Sn powder 6.0%, and the balance of Al are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0147] The purity of each raw material powder in the laser cladding alloy powder is ≥99.9%;

[0148] Step 2: After mixing the raw material powders in step 1, vacuum melting is performed, and the powder is prepared by gas atomization method;

[0149] Step 3: The particle size of the atomized raw material powder is screened.

[0150] Step 4: The prepared powder is vacuum packaged for use.

[0151] In step 2, a vacuum melting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat degree of the melt is maintained at 120°C during the atomization process.

[0152] In step 3, the particle size of the screened raw material powder is 45 μm.

[0153] The flowability of the screened raw material powder is required to be 35 s / 100g.

[0154] The preparation method of the aluminum-based welding wire for CMT welding is as follows:

[0155] Step 1: Zn powder 22.0%, Ag powder 22.0%, Cu powder 12.0%, Si powder 6.0%, Mg powder 6.0%, and the rest is Al powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%.

[0156] The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 100 mesh.

[0157] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 120°C for 1.2 hours to remove the crystal water in the powder. The dried powder is placed in a powder mixer for thorough mixing for 1.2 hours.

[0158] Step 3: Alcohol is used to remove the grease on the surface of the pure aluminum strip. The powder prepared in step 2 is wrapped in the pure aluminum strip through a flux-cored wire drawing equipment. The first drawing die has a hole diameter of 2.6 mm. The pure aluminum strip has a thickness of 0.4 mm and a width of 7 mm. The filling rate of the powder in the aluminum-based welding wire for CMT welding is controlled at 25wt%.

[0159] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a flux-cored wire with a diameter of 1.2 mm is obtained.

[0160] Step 5: After the flux-cored wire drawing is completed, it is wound on a welding wire reel through a winding machine and finally sealed in a vacuum packaging bag for use.

[0161] The laser+CMT composite preparation method of aluminum-steel gradient structure is as follows (as shown in Figure 1 ):

[0162] (1) First, the above-mentioned alloy powder for laser cladding is used to prepare a laser cladding layer on a steel substrate. The laser power is 1.5 kW, and the cladding layer thickness is 1.2 mm.

[0163] (2) Then, the above-mentioned aluminum-based welding wire for CMT welding is used to perform two-layer CMT overlay welding on the above-mentioned laser cladding layer. The welding current is 165 A for the first layer of welding, and the overlay welding layer thickness is 2.2 mm. The welding current is 185 A for the second layer of welding, and the overlay welding layer thickness is 3.2 mm. The interlayer temperature is controlled at 60°C during CMT welding.

[0164] (3) Finally, ER1100 pure aluminum welding wire is used to perform arc welding on the CMT cladding layer to prepare an aluminum layer, the welding current is 165 A, the cladding layer has a thickness of 10-15 mm, and the temperature between layers is controlled at 60 DEG C during cladding.

[0165] The tensile strength of the aluminum-steel gradient structure is 255 MPa after testing.

[0166] Example 5

[0167] The preparation method of the alloy powder for laser cladding includes the following specific steps:

[0168] Step 1: Zn powder 29.0%, Cu powder 29.0%, Si powder 9.0%, Sn powder 9.0%, and the balance of Al are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0169] The purity of each raw material powder in the laser cladding alloy powder is greater than or equal to 99.9%;

[0170] Step 2: After mixing the raw material powders in step 1, vacuum melting is performed, and a gas atomization method is used for powdering;

[0171] Step 3: The particle size of the atomized raw material powder is screened.

[0172] Step 4: The prepared powder is vacuum packaged and ready for use.

[0173] In step 2, a vacuum melting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat of the melt is maintained at between 140 DEG C during the atomizing process.

[0174] In step 3, the particle size of the screened raw material powder is 53 μm.

[0175] The flowability of the screened raw material powder is required to be 40 s / 100g.

[0176] The preparation method of the aluminum-based welding wire for CMT welding includes the following specific steps:

[0177] Step 1: Zn powder 29.0%, Ag powder 29.0%, Cu powder 19.0%, Si powder 9.0%, Mg powder 8.5.0%, and the balance of Al powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0178] The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 100 mesh;

[0179] Step 2: The drug powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 110°C, and the holding time is 1.9h to remove the crystal water in the drug powder; the dried drug powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.8h;

[0180] Step 3: Alcohol is used to remove grease from the surface of the pure aluminum strip, and the drug powder prepared in step 2 is wrapped in the pure aluminum strip through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the pure aluminum strip thickness is 0.4mm, and the width is 7mm; the drug powder filling rate of the aluminum-based welding wire for CMT welding is controlled at 25wt%.

[0181] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a diameter of 1.2mm of the cored wire is obtained.

[0182] Step 5: After the cored wire drawing is completed, it is wound on the welding wire disc through the winding machine, and finally sealed in the cored wire vacuum packaging bag for use.

[0183] The laser+CMT composite preparation method of aluminum-steel gradient structure is as follows (as shown in Figure 1 ):

[0184] (1) First, the above-mentioned alloy powder for laser cladding is used to prepare a laser cladding layer on a steel substrate, the laser power is 2.5kW, and the cladding layer thickness is 1.45mm;

[0185] (2) Then, the above-mentioned aluminum-based welding wire for CMT welding is used to perform two-layer CMT overlay welding on the above-mentioned laser cladding layer, the welding current is 175A during the first layer of overlay welding, and the overlay layer thickness is 2.1mm; the welding current is 195A during the second layer of overlay welding, and the overlay layer thickness is 3.8mm; the interlayer temperature is controlled at 55°C during CMT overlay welding.

[0186] (3) Finally, ER1100 pure aluminum welding wire is used to perform arc welding on the above-mentioned CMT overlay layer to prepare an aluminum layer, the welding current is 195A, the overlay layer thickness is 14.5mm, and the interlayer temperature is controlled at 74°C during welding.

[0187] After testing, the tensile strength of the aluminum-steel gradient structure is 268MPa.

[0188] Example 6

[0189] The preparation method of the alloy powder for laser cladding is as follows:

[0190] Step 1: Zn powder 29.0%, Cu powder 28.0%, Si powder 8.0%, Sn powder 9.0%, and the balance of Al are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0191] Step 2: After mixing the powders of step 1, vacuum smelting is performed, and the powders are prepared by gas atomization method;

[0192] Step 3: The atomized powders are sieved by particle size.

[0193] Step 4: The prepared powders are vacuum packaged and ready for use.

[0194] In step 2, a vacuum smelting device is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat of the melt is maintained between 140℃ during the atomizing process.

[0195] In step 3, the particle size of the sieved raw material powder is 53μm.

[0196] The flowability of the sieved raw material powder is required to be 40 s / 100g.

[0197] The preparation method of the aluminum-based welding wire for CMT welding is as follows:

[0198] Step 1: Zn powder 29.0%, Ag powder 29.0%, Cu powder 19.0%, Si powder 9.0%, Mg powder 7.5.0%, and the rest is Al powder, are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%;

[0199] The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 100 mesh;

[0200] Step 2: The powders weighed in step 1 are placed in a vacuum heating furnace and heated to 110℃, and the holding time is 1.9h to remove the crystal water in the powders; the dried powders are placed in a powder mixer for thorough mixing, and the mixing time is 1.8h;

[0201] Step 3: Alcohol is used to remove the grease on the surface of the pure aluminum strip, and the powders prepared in step 2 are wrapped in the pure aluminum strip by using a flux-cored wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the thickness of the pure aluminum strip is 0.4mm, and the width is 7mm; the powder filling rate of the aluminum-based welding wire for CMT welding is controlled at 25wt%.

[0202] Step 4: After the first process drawing is completed, the die hole diameter is gradually reduced, and finally a flux-cored wire with a diameter of 1.2mm is obtained.

[0203] Step 5: After the flux-cored wire drawing is completed, it is wound on the wire spool by a winding machine, and finally sealed in a vacuum packaging bag for CMT welding.

[0204] The laser+CMT composite preparation method of aluminum-steel gradient structure is as follows (as shown in Figure 1 ).

[0205] (1) First, the alloy powder for laser cladding described above is used to prepare a laser cladding layer on a steel substrate, the laser power is 2.5 kW, and the cladding layer thickness is 1.45 mm;

[0206] (2) Then, the aluminum-based welding wire for CMT welding described above is used to perform two layers of CMT overlay welding on the laser cladding layer described above, the welding current is 175 A when the first layer is welded, and the thickness of the cladding layer is 2.1 mm; the welding current is 195 A when the second layer is welded, and the thickness of the cladding layer is 3.8 mm; the interlayer temperature is controlled at 55°C during CMT cladding.

[0207] (3) Finally, the ER1100 pure aluminum welding wire is used to perform arc cladding on the CMT cladding layer described above to prepare an aluminum layer, the welding current is 195 A, the thickness of the cladding layer is 14.5 mm, and the interlayer temperature is controlled at 74°C during cladding.

[0208] Test results show that the tensile strength of the aluminum-steel gradient structure is 262 MPa.

Claims

1. A welding material for preparing an aluminum-steel gradient structure, characterized in that: Including alloy powder for laser cladding and aluminum-based welding wire for CMT welding; The alloy powder for laser cladding includes the following components by mass percentage: Zn powder 20.0-30.0%, Cu powder 20.0-30.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance is Al. The sum of the mass percentages of the above components is 100%. Aluminum-based welding wire for CMT welding, including flux powder and welding skin, wherein the flux powder comprises the following components by mass percentage: Zn powder 20.0-30.0%, Ag powder 20.0-30.0%, Cu powder 10.0-20.0%, Si powder 5.0-10.0%, Mg powder 5.0-9.0%, and the remainder is Al powder, and the sum of the mass percentages of the above components is 100%; The weld skin of aluminum-based welding wire for CMT welding is pure aluminum strip with a thickness of 0.4mm and a width of 7mm; The powder filling rate of aluminum-based welding wire for CMT welding is controlled at 25wt%~30wt%.

2. The welding material for preparing an aluminum-steel gradient structure according to claim 1, characterized in that: The purity of each raw material powder in the laser cladding alloy powder is ≥99.9%.

3. The welding material for preparing an aluminum-steel gradient structure according to claim 1, characterized in that: The particle size of each raw material powder in the aluminum-based welding wire for CMT welding is 100~200 mesh.

4. The welding material for preparing an aluminum-steel gradient structure according to claim 1, characterized in that: The preparation method of alloy powder for laser cladding has the following specific steps: Step 1: Weigh 20.0-30.0% Zn powder, 20.0-30.0% Cu powder, 5.0-10.0% Si powder, and 5.0-10.0% Sn powder by mass percentage, with the balance being Al. The sum of the mass percentages of the above components is 100%; Step 2: Mix the raw material powders in step 1, smelt them in vacuum, and prepare powder by gas atomization method; In step 2, vacuum melting equipment is used, N2 is used as the atomizing gas, the atomizing pressure is 6 MPa, and the superheat of the melt is maintained between 100 and 150°C during the atomization process; Step 3: Screening the atomized raw material powder for particle size; In step 3, the particle size range of the raw material powder after sieving is 25~53μm; The fluidity requirement of the raw material powder after screening is 25~40 s / 100g; Step 4: Vacuum pack the prepared powder for later use.

5. The welding material for preparing an aluminum-steel gradient structure according to claim 1, characterized in that: The preparation method of aluminum-based welding wire for CMT welding is as follows: Step 1: Weigh 20.0-30.0% Zn powder, 20.0-30.0% Ag powder, 10.0-20.0% Cu powder, 5.0-10.0% Si powder, 5.0-9.0% Mg powder, and the rest Al powder according to mass percentage. The sum of the mass percentages of the above components is 100%; Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 100-160°C for 1-2 hours to remove the crystal water in the powder; the dried powder is placed in a powder mixer and fully mixed for 1-2 hours; Step 3: Use alcohol to remove grease from the surface of the pure aluminum strip. Wrap the powder prepared in step 2 in the pure aluminum strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6mm. The powder filling rate is controlled at 25wt%~30wt%. Step 4: After the first drawing process is completed, the die aperture is reduced in sequence to finally obtain a flux-cored welding wire with a diameter of 1.2 mm; Step 5: After the flux-cored wire is drawn, it is wound onto a wire reel by a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for use.

6. A laser + CMT composite preparation method for an aluminum-steel gradient structure, characterized by the following specific steps: (1) First, the alloy powder for laser cladding according to claim 1 is used to prepare a laser cladding layer on a steel substrate, with a laser power of 1 kW to 3 kW and a cladding layer thickness of 1.0 mm to 1.5 mm; (2) Next, two layers of CMT cladding layers are clad on the laser cladding layer using the aluminum-based welding wire for CMT welding according to claim 1. The welding current for the first layer is 150A~180A, and the thickness of the cladding layer is 2mm~3mm; the welding current for the second layer is 180A~200A, and the thickness of the cladding layer is 3mm~4mm; the interlayer temperature during CMT cladding is controlled at 50℃~100℃; (3) Finally, ER1100 pure aluminum welding wire is used to perform arc surfacing on the second layer of CMT surfacing to prepare an aluminum layer. The welding current is 150A~200A, the thickness of the surfacing layer is 10mm~15mm, and the interlayer temperature is controlled at 50℃~100℃ during surfacing.

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