CN116551241A - A kind of crackless aluminum alloy flux-cored welding wire and its preparation method and application - Google Patents

Abstract

The invention belongs to the technical field related to welding materials, and discloses a non-crack aluminum alloy flux-cored welding wire and its preparation method and application. The welding wire includes a tube and powder filled in the tube, and the powder includes the following parts by mass: Components: 4 to 6.8 parts of Cu, 0.8 to 1.2 parts of Mg, 0.1 to 0.6 parts of Mn, 0.05 to 0.4 parts of Cr, 0.2 to 0.5 parts of Ti, 0.1 to 0.25 parts of Zr, 2 to 4 parts of composite materials, more than 0 parts And less than 0.1 part of Si, greater than 0 and less than 0.1 part of Fe, 1-2 parts of TiC, and the balance is Al powder; wherein, the composite material is a mixture of zirconia and carbon nanotubes. In the invention, heterogeneous nucleation particles and reinforcing phase are added to the α-Al aluminum matrix to form an aluminum-based composite material, so that the weld metal grains are refined and have high thermal cracking resistance, hardness and tensile strength.

Description

A kind of crackless aluminum alloy flux-cored welding wire and its preparation method and application

technical field

The invention belongs to the technical field related to welding materials, and more specifically relates to a non-crack aluminum alloy flux-cored welding wire and its preparation method and application.

Background technique

The 2-series high-strength aluminum alloy has the advantages of high specific strength, specific stiffness, good stress corrosion resistance, high fracture toughness and excellent processing performance, and is widely used in aerospace, weaponry, transportation and other fields. Especially in the field of aerospace, it occupies a very important position and is one of the most important structural materials in this field. Although this type of high-strength aluminum alloy has high specific strength, its welding performance is poor, and solidification cracks are easily formed during the welding process, which seriously damages its mechanical properties and limits its industrial application. As a solid-phase welding technology, the friction stir welding technology will not produce coarse grain structure and solidification crack defects because the base metal will not melt during the welding process. At the same time, the joint strength generally reaches more than 75% of the base metal strength, and has been successfully applied. Welding of such high-strength aluminum alloys. However, friction stir welding requires relatively large upsetting pressure and forward driving force, and the equipment is relatively complicated and cumbersome, especially for complex welds, which hinders its wide application in such high-strength aluminum alloys. Therefore, fusion welding is still the main welding method for such high-strength aluminum alloys, but how to suppress solidification crack defects faces severe challenges.

Changing the chemical composition of welds by adding welding materials is a common method to solve solidification crack defects in high-strength aluminum alloys. The currently used 2-series aluminum alloy welding wires mainly include ER2319 (Al-Cu) welding wire and ER4043 (Al-Si) welding wire. Although the joint strength of ER2319 welding wire is high, it has a tendency of hot cracking and cannot meet the needs of the aerospace industry. Require. ER4043 welding wire is widely used in the actual production process due to its better casting performance and easier wire making process. The strength of the obtained joint is not high, and it is difficult to meet the use requirements of fields with high performance requirements.

Contents of the invention

In view of the above defects or improvement needs of the prior art, the present invention provides a non-crack aluminum alloy flux-cored welding wire and its preparation method and application. By adding heterogeneous nucleation particles and reinforcing phases to the α-Al aluminum matrix, Composition of aluminum-based composite materials makes the weld metal grain refinement, with high thermal cracking resistance, hardness and tensile strength.

In order to achieve the above object, according to one aspect of the present invention, a non-cracked aluminum alloy flux-cored welding wire is provided, the welding wire includes a tube and powder filled in the tube, and the powder includes the following components in parts by mass: 4-6.8 parts of Cu, 0.8-1.2 parts of Mg, 0.1-0.6 parts of Mn, 0.05-0.4 parts of Cr, 0.2-0.5 parts of Ti, 0.1-0.25 parts of Zr, 2-4 parts of composite materials, more than 0 parts and less than 0.1 parts Si, more than 0 parts and less than 0.1 parts of Fe, 1-2 parts of TiC, and the balance of Al powder; wherein, the composite material is a mixture of zirconia and carbon nanotubes.

Further, the mass ratio of the zirconia to the carbon nanotubes is (3-5):2.

Further, the zirconia is yttrium-stabilized zirconia powder, with a specific surface area of 5 m ² /g, a density of 6 g/cm ³ , a purity greater than 99.9%, and a particle size of 30 μm to 50 μm.

Further, the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 30nm-50nm, an inner diameter of 5nm-12nm, a length of 10μm-15μm, a specific surface area of 250m ² /g, and a density of 0.01g/cm ³ , The purity is greater than 99%, and the particle size is less than 25 μm.

Further, the medicinal powder includes the following components: 6.8 parts of Cu, 1 part of Mg, 0.4 parts of Mn, 0.2 parts of Cr, 0.4 parts of Ti, 0.2 parts of Zr, 3 parts of composite materials, more than 0 parts and less than 0.1 parts Si, more than 0 parts and less than 0.1 parts of Fe, 2 parts of nano-TiC, and the balance is Al powder.

Further, the tube is prepared from a 1060 pure aluminum strip with a wall thickness of 0.5 mm to 0.8 mm and a width of 14 mm to 16 mm.

Further, the filling rate of the welding wire is 45%-60%, and the filling rate is the ratio of the mass of the powder to the sum of the powder and the aluminum strip.

Further, the particle diameters of copper, magnesium, chromium, manganese, titanium, and zirconium are all 50 μm˜125 μm, and the average particle diameter of nano-titanium carbide is 40 nm.

The present invention also provides a method for preparing a non-cracked aluminum alloy flux-cored welding wire. The preparation method is used for preparing the above-mentioned non-cracked aluminum alloy flux-cored welding wire.

The present invention also provides an application of the above-mentioned non-cracked aluminum alloy flux-cored welding wire in welding.

Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the crack-free aluminum alloy flux-cored welding wire provided by the present invention and its preparation method and application mainly have the following beneficial effects:

1. The welding wire provided by the present invention is flexibly added powder and alloyed in situ, and the addition of yttrium-stabilized zirconia and nano-titanium carbide can be used as nucleation cores to promote α-Al to generate fine equiaxed crystals, because fine equiaxed crystals are easier to Coordinate the deformation between grains to suppress solidification cracks, and at the same time, the fine equiaxed grain structure has higher strength; in addition, carbon nanotubes help to reduce the pores in the 2XXX aluminum alloy weld by an order of magnitude, promote the increase of precipitated phases, and increase The dislocation density provides the basis for dislocation strengthening. At the same time, carbon nanotubes can be tightly combined with the surrounding aluminum matrix to improve the load transfer process. The addition of multi-walled carbon nanotubes and their dispersed distribution can further improve the corresponding joint strength.

2. The present invention solves the problems of 2-series high-strength aluminum alloys prone to thermal cracks, joint softening and low joint strength. Using this welding wire to weld 2-series aluminum alloys, the thermal stability and weld strength of the welds have been significantly improved, and some The weld strength can approach the joint strength obtained by solid phase friction stir welding.

3. The welding wire can be made into a diameter of 1.2mm, which is used for gas shielded welding or laser arc hybrid welding, or can be made into a diameter of 3.6mm, which is suitable for high-current welding, and the production efficiency is further improved.

4. The welding wire can be of any length, and it can also be wound into coils in layers. It is suitable for continuous automatic welding. In addition to gas shielded welding, it can also be used in various welding methods such as laser filler wire welding and laser arc hybrid welding.

5. Welding wire provides a new way of thinking for other difficult-to-weld material systems, such as nickel-based superalloys and dissimilar metals, and is expected to improve the welding between different materials. It can be used for additive manufacturing to prepare large and complex components.

Description of drawings

Fig. 1 is a scanning electron microscope structure diagram of the deposited metal provided by Example 1 of the present invention;

Fig. 2 is the SEM structure diagram of the deposited metal provided by Comparative Example 1 of the present invention;

Fig. 3 is a scanning electron microscope structure diagram of the deposited metal provided in Comparative Example 2 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

The invention provides a non-crack aluminum alloy flux-cored welding wire. The welding wire includes a tube and powder filled in the tube. The powder includes the following components in parts by mass: 4-6.8 parts of Cu, 0.8-1.2 parts Mg, 0.1-0.6 parts of Mn, 0.05-0.4 parts of Cr, 0.2-0.5 parts of Ti, 0.1-0.25 parts of Zr, 2-4 parts of composite materials, more than 0 parts and less than 0.1 parts of Si, more than 0 parts and less than 0.1 parts of Fe , 1-2 parts of TiC, the balance being Al powder; wherein, the composite material is a mixture of zirconia and carbon nanotubes.

In this embodiment, the mass ratio of the zirconia to the carbon nanotubes is (3-5):2, which is prepared by a ball milling method. The zirconia is yttrium-stabilized zirconia powder, with a specific surface area of 5m ² /g, a density of 6g/cm ³ , a purity greater than 99.9%, and a particle size of 30-50 μm.

The carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 30nm-50nm, an inner diameter of 5nm-12nm, a length of 10μm-15μm, a specific surface area of 250m ² /g, a density of 0.01g/cm ³ , and a purity greater than 99 %, the particle size is less than 25 μm.

The ball milling conditions for composite materials are as follows: dry milling process is adopted, the balls are zirconia (homogenous to the material to be ground, to avoid mixing of impurities), the ball-to-material ratio is 6:1-8:1, and the ball milling time is 2-3 hours , with a rotation speed of 800 rpm to 1000 rpm; control the ball-to-material ratio, milling time and rotational speed, so that the milled multi-walled carbon nanotubes firmly adhere to the surface of yttrium-stabilized zirconia ceramic particles, and the particle size of the material after ball milling 5 μm to 8 μm.

In one embodiment, the medicated powder includes the following components: 6.8 parts of Cu, 1 part of Mg, 0.4 parts of Mn, 0.2 parts of Cr, 0.4 parts of Ti, 0.2 parts of Zr, 3 parts of composite materials, greater than 0 parts and Less than 0.1 part of Si, greater than 0 and less than 0.1 part of Fe, 2 parts of nano-TiC, and the balance is Al powder.

The pipe is prepared from a 1060 pure aluminum strip with a wall thickness of 0.5 mm to 0.8 mm and a width of 14 mm to 16 mm. The filling rate of the welding wire is 45%-60% (the ratio of the filling rate to the sum of the mass of the powder and the mass of the powder and the aluminum strip).

The Cu content of the copper powder is not less than 99.9% by mass percentage, the Mg content of the magnesium powder is not less than 99.9% by mass percentage, the Cr content of the chromium powder is not less than 99.5% by mass percentage, and the Mn content of the manganese powder is not less than 99.5% by mass percentage. Less than 99.8%, the Ti content of titanium powder is not less than 99.6% by mass percentage, the Zr content of zirconium powder is not less than 99.9% by mass percentage, the composition of yttrium-stabilized zirconia is not less than 99.9% by mass percentage, and the _ZrO2 content is not less than 99.9%; the composition of multi-walled carbon nanotubes is calculated by mass percentage, and the purity is not less than 99%; the composition of nano-titanium carbide has a TiC content of not less than 99.9% by mass percentage.

For the alloy powder of this embodiment, it is preferred that the copper powder, magnesium powder, metal chromium powder, manganese powder, titanium powder, and zirconium powder all have a particle size of 50 μm to 125 μm, and the particle size of yttrium-stabilized zirconia is 30 μm to 50 μm. The particle size of the walled carbon nanotube is less than 25 μm, and the average particle size of the nano-titanium carbide is 40 nm.

The present invention also provides a method for preparing a crack-free aluminum alloy flux-cored welding wire, the method comprising the following steps:

S1, weighing yttrium-stabilized zirconia and multi-walled carbon nanotubes according to the powder formula and performing dry ball milling to obtain a composite material; weighing the components according to the proportion of the powder formula, adding the composite material and mixing to obtain the powder. Wherein, a powder mixer is used to mix the powder for 30 minutes to 60 minutes to obtain the medicinal powder.

The medicinal powder includes the following components in parts by mass: 4-6.8 parts of Cu, 0.8-1.2 parts of Mg, 0.1-0.6 parts of Mn, 0.05-0.4 parts of Cr, 0.2-0.5 parts of Ti, 0.1-0.25 parts of Zr, 2- 4 parts of composite materials, more than 0 parts and less than 0.1 parts of Si, more than 0 parts and less than 0.1 parts of Fe, 1 to 2 parts of TiC, and the balance is Al powder; wherein, the composite material is a mixture of zirconia and carbon nanotubes , the mass ratio of the two is 3-5:2, the particle size of yttrium-stabilized zirconia is 30 μm to 50 μm, the particle size of multi-walled carbon nanotubes is less than 25 μm, the average particle size of nano-titanium carbide is 40nm, and the particle size of other powders The diameter is 50 μm to 125 μm.

S2, use a scraper to remove the oxide film on the upper surface of the 1060 pure aluminum strip with a width of 14mm to 16mm and a thickness of 0.5mm to 0.8mm, and then clean it with an ultrasonic cleaning device, then use the existing flux cored wire production equipment to roll the above aluminum strip Make a U-shape, then add the drug powder prepared in step S1 into the U-shaped pot, and the filling rate (ratio of the mass of the drug powder to the mass of the flux-cored wire) is 45% to 60%.

S3, close the U-shaped groove so that the medicine powder is wrapped in it, and the closing part adopts an overlapping connection mode (the width of the overlapping part is 1 mm to 2 mm, which is guaranteed by the forming roller of the existing flux-cored wire production equipment); through the wire drawing die, after 15 to 25 passes of drawing and diameter reduction, annealing at 250°C to 400°C for 30 minutes in each pass, and finally the diameter reaches 0.8mm to 2.4mm.

S4, winding the obtained flux-cored wire layer into a coil to obtain a new type of crack-free high-strength aluminum alloy flux-cored wire.

When using the welding wire mentioned above for welding, it is recommended to use the laser swing-arc hybrid welding process. The specific welding process is: laser power 5000W ~ 10000W, welding speed 20mm/s ~ 40mm/s, amplitude 1.5mm ~ 2.5mm , the swing frequency is 150Hz-250Hz, the defocus is 0mm, the distance between the light wires is 4mm-6mm, the dry elongation of the welding wire is 14mm-22mm, the welding current is 175A-300A; the voltage is 24V-38V; the gas flow rate is 15L/min ～25L/min, the dry elongation of welding wire is 16mm. The welding wire has good process performance, stable arc, less spatter and good crack resistance.

The present invention is further described in detail with several specific examples below. In the following examples, the preparation method of the composite material is as follows: using yttrium-stabilized zirconia and multi-walled carbon nanotubes as raw materials, using a dry grinding process, and the grinding balls are: For zirconium dioxide, the ball-to-material ratio is 8:1-10:1, the ball milling time is 2 hours to 3 hours, the rotation speed is 800 rpm to 1000 rpm, and the particle size of the material after ball milling is 5 μm to 8 μm.

Example 1

A non-crack aluminum alloy flux-cored welding wire provided in Embodiment 1 of the present invention, the welding wire mainly includes the following steps:

S1: Prepare the following components by mass according to the powder formula: 6.8 parts of Cu, 1.0 parts of Mg, 0.4 parts of Mn, 0.2 parts of Cr, 0.4 parts of Ti, 0.2 parts of Zr, 3 parts of composite materials, greater than 0 parts and less than 0.1 parts Si, more than 0 parts and less than 0.1 parts of Fe, 2 parts of nano-TiC, and the balance is Al powder; 3molY ₂ O ₃ is used to stabilize zirconia, the particle size is 30μm-50μm, and the particle size of multi-walled carbon nanotubes is less than 25μm, nano The average particle size of the titanium carbide powder is 40 nm, and the particle size of other powders is 50 μm to 125 μm.

S2: Remove the oxide film on the upper surface of the 1060 pure aluminum strip with a width of 15mm and a thickness of 0.5mm with a scraper, and then use ultrasonic cleaning equipment to clean it, and then use the existing flux-cored welding wire production equipment to roll the above-mentioned aluminum strip into a U shape. Then add the drug powder produced in step S1 into the U-shaped pot, and the filling rate (ratio of the mass of the drug powder to the mass of the flux-cored wire) is 60%.

S3: Close the U-shaped groove so that the medicine powder is wrapped in it, and the closing part adopts the lap connection method (the width of the lap part is 1.5mm, which is guaranteed by the forming roller of the existing flux-cored wire production equipment); through the wire drawing die, after 20 The diameter is reduced by drawing for each pass, and annealed at 250°C to 400°C for 30 minutes in each pass, and finally the diameter reaches 1.2mm.

S4: Winding the flux-cored wire layer obtained in step S3 into a coil to obtain a new crack-free high-strength aluminum alloy flux-cored wire product.

The above-mentioned new crack-free high-strength aluminum alloy flux-cored welding wire adopts laser swing-arc hybrid welding process, and the welding base material is 2024-T4 aluminum alloy with a thickness of 8mm. The specific welding process is: the laser power is 5000W, the welding speed is 20mm/s, the amplitude is 2.5mm, the swing frequency is 250Hz, the spot diameter is 0.1mm, the defocus is 0mm, the distance between the wires is 4mm, and the dry elongation of the welding wire is 16mm, the welding current is 175A; the voltage is 24V; the gas flow rate is 20L/min, and the dry elongation of the welding wire is 16mm. The welding wire has good process performance, stable arc, less spatter, and no solidification crack after welding, as shown in Figure 1. The microhardness of the weld is 155HV, the tensile strength of the joint is 364MPa, and the joint strength coefficient is 81%, which is equivalent to the joint strength obtained by friction stir welding.

Comparative example 1

The commercially available ER2319 aluminum-copper welding wire is used as the filler metal. The welding wire includes the following components in mass fractions: 5.8-6.8 parts Cu, 0.2-0.6 parts Mn, 0.2 parts Si, 0.3 parts Fe, 0.02 parts Mg, 0.1 parts Zn, 0.05- 0.15 parts of V, 0.1-0.2 parts of Ti, 0.1-0.25 parts of Zr; the diameter of the welding wire is 1.2mm.

The laser swing-arc hybrid welding process is adopted, and the welding base material is 8mm thick 2024-T4 aluminum alloy. The specific welding process is: the laser power is 5000W, the welding speed is 20mm/s, the amplitude is 2.5mm, the swing frequency is 250Hz, the defocus is 0mm, the distance between the light wires is 4mm, the dry elongation of the welding wire is 16mm, and the welding current is 175A ; The voltage is 24V; the gas flow rate is 20L/min, and the dry elongation of the welding wire is 16mm. The welding wire has good process performance, stable arc, less spatter, and solidification cracks after welding, as shown in Figure 2. The microhardness of the weld is 135HV, the tensile strength of the joint is 320MPa, and the joint strength coefficient is 71%.

Example 1 Compared with this comparative example, a new type of crack-free high-strength aluminum alloy flux-cored wire can suppress the welding solidification cracks of 2024 high-strength aluminum alloy, and the joint strength is increased by 14% compared with that obtained by ER2319.

Comparative example 2

Commercially available ER4043 aluminum-silicon welding wire is used as the filler metal, and the welding wire includes the following components in mass parts: 4.5 to 6.0 parts of Si, 0.8 parts of Fe, 0.3 parts of Cu, 0.05 parts of Mn, 0.05 parts of Mg, 0.1 parts of Zn and 0.2 parts of Ti . The diameter of the welding wire is 1.2 mm.

The laser swing-arc hybrid welding process is adopted, and the welding base material is 8mm thick 2024-T4 aluminum alloy. The specific welding process is: the laser power is 5000W, the welding speed is 20mm/s, the amplitude is 2.5mm, the swing frequency is 250Hz, the defocus is 0mm, the distance between the light wires is 4mm, the dry elongation of the welding wire is 16mm, and the welding current is 175A ; The voltage is 24V; the gas flow rate is 20L/min, and the dry elongation of the welding wire is 16mm. The welding wire has good process performance, stable arc, less spatter, and no solidification cracks after welding, as shown in Figure 3. The microhardness of the weld is 120HV, the tensile strength of the joint is 299MPa, and the joint strength coefficient is 66%.

Compared with the comparative example in Example 1, the joint strength obtained by a new type of crack-free high-strength aluminum alloy flux-cored welding wire is 22% higher than that obtained by ER4043.

The present invention also provides an application of the above-mentioned welding wire in welding, specifically an application in welding of aerospace devices.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (10)

1. A crackless aluminum alloy flux-cored welding wire, characterized in that: The welding wire includes a tube and powder filled in the tube, and the powder includes the following components in parts by mass: 4-6.8 parts of Cu, 0.8-1.2 parts of Mg, 0.1-0.6 parts of Mn, 0.05-0.4 parts of Cr, 0.2-0.5 parts of Ti, 0.1-0.25 parts of Zr, 2-4 parts of composite materials, more than 0 parts and less than 0.1 parts of Si, more than 0 parts and less than 0.1 parts of Fe, 1-2 parts of TiC, and the balance is Al powder; , the composite material is a mixture of zirconia and carbon nanotubes. 2. The non-crack aluminum alloy flux-cored welding wire according to claim 1, characterized in that: the mass ratio of the zirconia to the carbon nanotube is (3-5):2. 3. The non-crack aluminum alloy flux-cored welding wire according to claim 2, characterized in that: the zirconia is yttrium-stabilized zirconia powder, with a specific surface area of 5 m ² /g, a density of 6 g/cm ³ , and a purity greater than 99.9 %, the particle size is 30 μm to 50 μm. 4. The non-crack aluminum alloy flux-cored welding wire according to claim 2, characterized in that: the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 30nm-50nm, an inner diameter of 5nm-12nm, and a length of 10μm- 15μm, the specific surface area is 250m ² /g, the density is 0.01g/cm ³ , the purity is greater than 99%, and the particle size is less than 25μm. 5. The non-crack aluminum alloy flux-cored welding wire according to claim 1, characterized in that: the powder contains the following components: 6.8 parts of Cu, 1 part of Mg, 0.4 parts of Mn, 0.2 parts of Cr, 0.4 parts Ti, 0.2 parts of Zr, 3 parts of composite materials, more than 0 parts and less than 0.1 parts of Si, more than 0 parts and less than 0.1 parts of Fe, 2 parts of nano-TiC, and the balance is Al powder. 6. The non-crack aluminum alloy flux-cored welding wire according to any one of claims 1-5, characterized in that: the tube has a wall thickness of 0.5 mm to 0.8 mm and a width of 14 mm to 16 mm made of 1060 pure aluminum strip made. 7. The non-crack aluminum alloy flux-cored welding wire according to any one of claims 1-5, characterized in that: the filling rate of the welding wire is 45% to 60%, and the filling rate is equal to the mass of the powder and the mass of the aluminum strip. The ratio of the sum. 8. The non-crack aluminum alloy flux-cored welding wire according to any one of claims 1-5, characterized in that the particle diameters of copper, magnesium, chromium, manganese, titanium, and zirconium are all 50 μm to 125 μm, and that of nano-titanium carbide The average particle size is 40nm. 9. A method for preparing a crack-free aluminum alloy flux-cored welding wire, characterized in that: the preparation method is used for preparing the crack-free aluminum alloy flux-cored welding wire according to any one of claims 1-8. 10. An application of the crack-free aluminum alloy flux-cored welding wire according to any one of claims 1-8 in welding.