High strength aluminum alloy general-purpose welding wire and its manufacturing method

Abstract

To provide a manufacturing method of a general-purpose welding wire of a high strength aluminum alloy, and to provide a welding wire.SOLUTION: A manufacturing method of a general-purpose welding wire of a high strength aluminum alloy includes: a step (1) of melting an Al-Zn-Mg-Cu-based aluminum alloy, upsetting in a semi-solid state a billet obtained by injection molding to form an ingot, and forming the ingot in a coil form after hot extrusion; and a step (2) of obtaining a general-purpose welding wire of a high strength aluminum alloy by tempering a coil-shaped rod material, performing rolling / wire drawing for a plurality of passes continuously to a necessary diameter of a welding wire, and performing sizing, rounding, and glazing. The welding wire is manufactured by using as the base material, an Al-Zn-Mg-Cu-based aluminum alloy, and adding B of 0.1-1% of the weight of the base material, and Zr of 0.1-1% of the weight of the base material. Welding of a high strength aluminum alloy of 7XXX series of various grades has general-purpose properties, and weld joint after welding is excellent in mechanical characteristics, and has high strength and plasticity.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the technical field of welding high strength aluminum alloys, in particular to a universal welding wire for high strength aluminum alloys and a method for producing the same. [Background technology]

[0002] 7XXX series aluminum alloys such as 7050, 7055, 7075, 7475 and 7085 belong to Al-Zn-Mg-Cu based superhard aluminum alloys, which have high specific strength and are widely used in aerospace, rail transportation and other fields. Al-Zn-Mg-Cu based aluminum alloys have high strength but low plasticity, and cannot be smoothly processed into welding wire by traditional wire drawing methods. In addition, the welded joint is prone to thermal cracking and stress corrosion cracking during welding, which makes welding of Al-Zn-Mg-Cu aluminum alloys difficult and leads to poor weldability. At present, there is a shortage of bulk wires with excellent welding performance for welding Al-Zn-Mg-Cu based high-strength aluminum alloys, and especially there is a shortage of general-purpose wires suitable for welding most high-strength aluminum alloys.

[0003] In response to the above technical problems, Chinese patent application No. CN112831735A discloses a method for producing high-strength aluminum alloy wire / strip, which involves making a billet by injection molding, followed by extrusion and hot extrusion in a semi-solid state to obtain Al-Zn-Mg-Cu high-strength aluminum alloy wires of various specifications. However, the wires produced by this method can only be welded to corresponding specific grades of aluminum alloys, which are not versatile for most aluminum alloys, especially 7XXX series high-strength aluminum alloys, which is inconvenient to use and limits the application of high-strength aluminum alloys, especially ultra-high-strength aluminum alloys.

[0004] At present, there are some progresses in the research situation in China, some people are studying the effect of Sc or Zr-Sc on the microstructure and properties of Al-Mg-Sc alloy welded joints, and some people are using conventional ER5356 welding wire and ER5356 welding wire with Sc, Zr, Er added to perform tungsten electrode inert gas shielded welding of 7A52 aluminum alloy to study the effect of Sc, Zr, Er on the mechanical properties of welded joints. However, these have not solved the problem of mass production of welding wire raw materials, and the high price greatly restricts the processing and application of Al-Zn-Mg-Cu high strength aluminum alloy structural parts. Summary of the Invention

[0005] Conventional welding wires have a technical problem in that they are not versatile for most Al-Zn-Mg-Cu high-strength aluminum alloys and are difficult to mass-produce. In order to solve the technical problem, the present invention provides a versatile welding wire for high-strength aluminum alloys and a manufacturing method thereof. The welding wire obtained by the method of the present invention has excellent welding performance for structural parts made of most Al-Zn-Mg-Cu high-strength aluminum alloys and is easy to mass-produce.

[0006] To achieve the above objectives, the present invention uses the following technical solutions:

[0007] The manufacturing method of high strength aluminum alloy general-purpose welding wire is as follows: (1) mixing an Al-Zn-Mg-Cu based aluminum alloy with B and Zr, and then melting the alloy, and then obtaining a billet by injection molding, and then upsetting the billet in a semi-solid state to form an ingot, and then hot extruding the ingot to obtain a rod and coil it; and (2) tempering the coiled rod, then subjecting it to multiple passes of rolling and drawing to the required welding wire diameter, followed by sizing, rounding, polishing with a polycrystalline die, fine polishing, cleaning and drying in sequence to obtain a high-strength aluminum alloy general-purpose welding wire. If the rod is continuously rolled to the required dimensions after tempering, the tempering step in the rolling process can be omitted, and there is little cracking and no breakage.

[0008] Furthermore, the Al-Zn-Mg-Cu based aluminum alloy contains, by weight percentage, 5 to 8% Zn, 1.5 to 5% Mg, and 1 to 3% Cu, with the remainder being Al.

[0009] Furthermore, the Al-Zn-Mg-Cu based aluminum alloy contains, by weight percentage, 7 to 8% Zn, 2 to 3% Mg, and 1.5 to 2.5% Cu, with the remainder being Al.

[0010] Furthermore, the amount of each of B and Zr added is 0.1 to 1% by weight based on the weight of the Al-Zn-Mg-Cu based aluminum alloy.

[0011] Furthermore, the amount of B and Zr added is 0.1-0.5% by weight based on the weight of the Al-Zn-Mg-Cu based aluminum alloy. If the total amount of the trace elements B and Zr exceeds 1% by weight, the material becomes more brittle.

[0012] Furthermore, the upsetting in the semi-solid state in step (1) is upsetting the billet at 460 to 575°C, and the tempering in step (2) is maintaining the temperature at 200 to 300°C for at least 10 hours.

[0013] Furthermore, the hot extrusion in step (1) is performed by hot extruding the ingot having a diameter of 150 to 300 mm at a temperature of 380 to 480° C. into a bar having a diameter of 5 to 10 mm.

[0014] Furthermore, the rolling and wire drawing process in step (2) involves continuously drawing at least five passes of wire with a horizontal roller die wire drawing machine, with the compression ratio of the wire drawing surface in each pass being 6 to 8%, and drawing to a diameter of 0.8 to 1.6 mm.

[0015] Another aspect of the present invention provides a general-purpose welding wire of high strength aluminum alloy obtained by the above manufacturing method, the welding wire being manufactured by using an Al-Zn-Mg-Cu-based aluminum alloy as a base material and adding 0.1 to 1% of B and 0.1 to 1% of Zr based on the weight of the base material, and the welding wire is versatile in welding Al-Zn-Mg-Cu-based aluminum alloys, and is particularly applicable to welding Al-Zn-Mg-Cu superhard aluminum alloys such as 7050, 7055, 7075, 7475, and 7085.

[0016] The beneficial technical effects are as follows: In the present invention, trace elements B and Zr are added to the Al-Zn-Mg-Cu aluminum alloy, and after melting, a base material with fine grains and uniform components is obtained by injection molding; the billet of Al-Zn-Mg-Cu high-strength aluminum alloy contains trace elements B and Zr, which can maintain fine grains during welding and solidification; and by upsetting in the semi-solid state, the lamellar microstructure formed by injection molding is eliminated, and the billet becomes dense; the wire obtained after hot extrusion and wire drawing has fine and dense grains, uniform microstructure, clear grain boundary, no precipitates, no lamellar microstructure, and has excellent mechanical properties, structural properties and welding performance. The welding of 7XXX series high-strength aluminum alloys has versatility, can provide high-quality raw materials for welding 7XXX series high-strength aluminum alloys, and can obtain a wide process window for welding high-strength aluminum alloys. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is an external view of a welded joint after welding a 7075 base metal using the welding wire of Example 3, and symbols 1 to 9 in the figure indicate the external appearance of the welded joint under different welding process conditions.

[0018] The specific process is shown in Table 1. JPEG0007665222000001.jpg33170 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the embodiments and drawings of the present invention, and obviously, the described embodiments are only some, but not all, embodiments of the present invention. The following description of at least one exemplary embodiment is merely exemplary in nature and should not be construed as limiting the present invention and its application or uses. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present invention.

[0020] Unless otherwise specified, the numerical values ​​in these examples do not limit the scope of the present invention. Techniques and methods known to those skilled in the art in the relevant fields may not be described in detail, but under appropriate circumstances, these techniques and methods should be considered part of this specification. In all examples shown and discussed in this specification, the specific values ​​should be interpreted as examples only and not as limitations. Therefore, other examples of the exemplary embodiments may have different values.

[0021] In the following examples, the experimental methods without specific conditions are usually measured according to national standards, and in the absence of corresponding national standards, they are carried out according to general international standards or standard requirements proposed by relevant enterprises. Unless otherwise specified, all parts are parts by weight, and all percentages are percentages by weight.

[0022] Example 1 The manufacturing method of high strength aluminum alloy general-purpose welding wire is as follows: (1) preparing an Al-Zn-Mg-Cu aluminum alloy, simple B and simple Zr, mixing them uniformly, melting the alloy, and then obtaining a billet having a diameter of 220 mm by injection molding; The composition of the Al-Zn-Mg-Cu aluminum alloy is, by weight percentage, 7.8% Zn, 2.3% Mg, and 2% Cu, with the balance being Al, and is designated as Al-7.8Zn-2.3Mg-2Cu aluminum alloy; The amount of B added is 0.1% by weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy, and the amount of Zr added is 0.1% by weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy, (1) upsetting the billet in a semi-solid state at 460°C to form an ingot of 178 mm diameter, and hot extruding the ingot at 380°C to obtain several bars of 5.8 mm diameter and coiling the bars; (2) the coiled rod is put into a vacuum tempering furnace, tempered at 300°C for 10 hours, kept at 300°C, cooled in the furnace, and then put into a horizontal roller die wire drawing machine for continuous rolling and drawing in multiple passes until the wire has a required diameter; the compression ratio of the drawn surface in each pass is 6-8%, and the diameter of the resulting welding wire is 0.8-1.6 mm; and (2) the wire is sized and rounded in a sizing die, polished in a polycrystalline die, finely ground in a polishing die, washed and dried to obtain a high-strength aluminum alloy general-purpose welding wire.

[0023] Example 2 The manufacturing process of the general-purpose welding wire of the high strength aluminum alloy of this embodiment is the same as that of Example 1, except that the amount of B added is 0.2% by weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy, and the amount of Zr added is 0.5% by weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy.

[0024] Example 3 The manufacturing process of the general-purpose welding wire of the high strength aluminum alloy of this embodiment is the same as that of Example 1, except that the amount of B added is 0.2% of the weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy, and the amount of Zr added is 0.3% of the weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy. The specification of the welding wire of this embodiment is φ1.2 mm.

[0025] Example 4 The manufacturing process of the general-purpose welding wire of the high strength aluminum alloy of this embodiment is the same as that of Example 1, except that the amount of B added is 0.4% by weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy, and the amount of Zr added is 0.4% by weight of the Al-7.8Zn-2.3Mg-2Cu aluminum alloy.

[0026] Comparative Example 1 The manufacturing process of the general-purpose welding wire of the high-strength aluminum alloy of this comparative example is the same as that of Example 3, except that B and Zr are added.

[0027] The mechanical properties of the welding wires in the above examples and comparative examples are shown in Table 2. JPEG0007665222000002.jpg41170 (Note: The welding wire specification is 1.2mm in diameter)

[0028] The welding wires manufactured according to the above examples and comparative examples are used to test the welding process of various grades of 7XXX series aluminum alloys. The ESAB TIG 4300i AC / DC inverter AC / DC argon arc welding machine is selected, the wire feeder is WF-007A multi-function automatic argon arc wire feeder, the diameter is 1.2mm, the current is the variable parameter, and the other parameters are voltage of 20V, arc length of 3.2mm, wire feed angle of 30°, wire feed speed of 140cm / min, welding speed of 3mm / sec, and argon flow amount of 10L / min. The welding wires manufactured according to the examples and comparative examples are used to weld the base material of the 7XXX series high-strength aluminum alloy general-purpose welding wire (7050, 7055, 7075), and then T6 heat treatment or no heat treatment is performed to obtain test samples, which are tested for mechanical properties according to the room temperature tensile method of GB / T228.1-2010 Metallic Material Tensile Test Part 1, and the room temperature tensile mechanical properties of the welded parts are tested, and for each group of heat-treated samples, two identical samples are arranged and the average value is taken. The test results are shown in Table 4.

[0029] The appearance of the welded joint after welding the 7075 base metal using the welding wire of Example 3 is shown in FIG. 1, and the welding process and performance results before and after heat treatment are shown in Table 3. JPEG0007665222000003.jpg48170

[0030] As can be seen from Table 3 and FIG. 1, the welding wire of Example 3 was used to argon arc weld 7075 base metal at a current of 160 to 165 A, and excellent welding performance was obtained. Before the T6 heat treatment, the tensile strength was 270 MPa or more and the elongation rate was 5.5%. After the T6 heat treatment, the tensile strength was 500 MPa or more and the elongation rate was 13%, which shows that the welding wire of Example 3 has excellent welding performance for 7075 base metal. JPEG0007665222000004.jpg123170

[0031] As can be seen from Table 4, the welding wire in Example 1 (Al-7.8Zn-2.3Mg-2Cu as the base metal and 0.1%B+0.1%Zr added) has excellent welding performance for 7050 base metal, 7055 base metal, and 7075 base metal, respectively. Before and after heat treatment, the tensile strength of the welded joint after welding the 7050 base metal increases by 85.7%, and the elongation increases to 12.36%; the tensile strength of the welded joint after welding the 7055 base metal increases by 96.2%, and the elongation increases to 12.88%; and the tensile strength of the welded joint after welding the 7075 base metal increases by 92.7%, and the elongation increases to 12.47%.

[0032] The welding wire in Example 2 (Al-7.8Zn-2.3Mg-2Cu as base material with 0.2%B+0.5%Zr added) has excellent welding performance for 7050 base material, 7055 base material, and 7075 base material, respectively. Before and after heat treatment, the tensile strength of the welded joint after welding the 7050 base material increases by more than 100%, and the elongation increases to 11%; the tensile strength of the welded joint after welding the 7055 base material increases by 94.6%, and the elongation increases to 12.42%; and the tensile strength of the welded joint after welding the 7075 base material increases by more than 100%, and the elongation increases to 12.38%.

[0033] The welding wire in Example 3 (Al-7.8Zn-2.3Mg-2Cu as base material with 0.2%B+0.3%Zr added) has excellent welding performance for 7050 base material, 7055 base material, and 7075 base material, respectively. Before and after heat treatment, the tensile strength of the welded joint after welding the 7050 base material increases by 92.4%, and the elongation increases to 12.79%; the tensile strength of the welded joint after welding the 7055 base material increases by more than 100%, and the elongation increases to 12.56%; and the tensile strength of the welded joint after welding the 7075 base material increases by 88.3%, and the elongation increases to 13.76%.

[0034] The welding wire in Example 4 (Al-7.8Zn-2.3Mg-2Cu as the base material with 0.4%B+0.4%Zr added) has excellent welding performance for 7050 base material, 7055 base material, and 7075 base material, respectively. Before and after heat treatment, the tensile strength of the welded joint after welding the 7050 base material increases by 94.1%, and the elongation increases to 13.24%; the tensile strength of the welded joint after welding the 7055 base material increases by more than 100%, and the elongation increases to 12.84%; and the tensile strength of the welded joint after welding the 7075 base material increases by 92.0%, and the elongation increases to 13.24%.

[0035] As can be seen from the above data, in the present invention, the welding wire produced by adding less than 1% total amount of B and Zr to Al-7.8Zn-2.3Mg-2Cu based aluminum alloy has excellent welding performance for 7XXX series high strength aluminum alloys, and the tensile strength and elongation of the welded joint after welding are both high, and it is versatile in welding 7XXX series high strength aluminum alloys such as 7050, 7055 and 7075, especially Al-Zn-Mg-Cu based high hardness aluminum alloys, which can provide high quality raw material for welding 7XXX series high strength aluminum alloys, and obtain a wide process window for welding high strength aluminum alloys.

[0036] The above contents are merely preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any replacement or modification made by those skilled in the art according to the technical solutions and concepts of the present invention within the technical scope disclosed in the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for producing a general-purpose welding wire of a high-strength aluminum alloy, comprising the steps of: (1) mixing an Al-Zn-Mg-Cu based aluminum alloy with B and Zr, melting the alloy, then obtaining a billet by injection molding, upsetting the billet in a semi-solid state to form an ingot, and hot extruding the ingot to obtain a rod and coil it; (2) tempering the coiled rod, and then subjecting it to multiple passes of rolling and drawing to a required welding wire diameter, followed by sizing, rounding, polishing with a polycrystalline die, fine polishing, cleaning and drying to obtain a high-strength aluminum alloy general-purpose welding wire; Including, The composition of the Al-Zn-Mg-Cu based aluminum alloy is, by weight percentage, 5 to 8% Zn, 1.5 to 5% Mg, and 1 to 3% Cu, with the balance being Al; A method for producing a general-purpose welding wire of a high-strength aluminum alloy, characterized in that the amounts of B and Zr added are each 0.1 to 1 wt % of the weight of the Al-Zn-Mg-Cu-based aluminum alloy.

2. A method for producing a general-purpose welding wire of a high-strength aluminum alloy, comprising the steps of: (1) mixing an Al-Zn-Mg-Cu based aluminum alloy with B and Zr, melting the alloy, then obtaining a billet by injection molding, upsetting the billet in a semi-solid state to form an ingot, and hot extruding the ingot to obtain a rod and coil it; (2) tempering the coiled rod, and then subjecting it to multiple passes of rolling and drawing to a required welding wire diameter, followed by sizing, rounding, polishing with a polycrystalline die, fine polishing, cleaning and drying to obtain a high-strength aluminum alloy general-purpose welding wire; Including, The composition of the Al-Zn-Mg-Cu based aluminum alloy is, by weight percentage, 7 to 8% Zn, 2 to 3% Mg, and 1.5 to 2.5% Cu, with the balance being Al; A method for producing a general-purpose welding wire of a high-strength aluminum alloy, characterized in that the amounts of B and Zr added are each 0.1 to 1 wt % of the weight of the Al-Zn-Mg-Cu-based aluminum alloy.

3. 3. The method for producing a general-purpose welding wire of a high-strength aluminum alloy according to claim 1, wherein the amount of B and Zr added is 0.1 to 0.5 wt % of the weight of the Al-Zn-Mg-Cu-based aluminum alloy.

4. The method for producing a general-purpose welding wire of a high-strength aluminum alloy according to claim 1 or 2, characterized in that in step (1), the upsetting in a semi-solid state is to upset the billet at 460 to 575°C, and in step (2), the tempering is to keep the billet at a temperature of 200 to 300°C for at least 10 hours.

5. 3. The method for producing a general-purpose welding wire of high strength aluminum alloy according to claim 1, wherein the hot extrusion in step (1) is performed at a temperature of 380-480° C. by hot extrusion of the ingot having a diameter of 150-300 mm into a rod having a diameter of 5-10 mm.

6. 3. The method for producing a general-purpose welding wire of a high-strength aluminum alloy according to claim 1 or 2, characterized in that the rolling and drawing process in step (2) is performed by continuously performing at least five passes of wiredrawing using a horizontal roller die wire drawing machine, the compression ratio of the wiredrawn surface in each pass is 6-8%, and the wiredrawing is performed to a diameter of 0.8-1.6 mm.

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