A welding wire suitable for dissimilar aluminum alloy welding and a preparation method thereof

Abstract

The application discloses a welding wire suitable for dissimilar aluminum alloy welding, which comprises the following components in mass percentage: the content of Mg is 6.0%-7.0%, the content of Mn is 0.6%-0.9%, the content of Sc is 0.4%-0.8%, the content of Ti is 0.25%-0.5%, the content of Zr is 0.25%-0.5%, the content of Cr is 0.25%-0.5%, the content of V is 0.05%-0.25%, the content of Be is 0.0004%-0.001%, and the rest is Al. The application further discloses a preparation method of the welding wire suitable for dissimilar aluminum alloy welding, which comprises the following steps: smelting aluminum, magnesium, Al-5Cr, Al-5V, Al-5Mn, Al-2Sc and Al-3Be; adding Al-3Ti and Al-3Zr in the smelting process, continuing smelting and stirring; refining, standing and casting the obtained melt after smelting in sequence to obtain a cast ingot; and extruding, annealing and drawing the cast ingot in sequence to obtain the welding wire. The welding wire is beneficial to improving the mechanical properties and crack resistance of the fusion welding joint, is suitable for 2195 / 5A06 dissimilar aluminum alloy welding and can be mass-produced in industry, and is beneficial to promoting the engineering application of 2195 aluminum lithium alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to a welding wire suitable for dissimilar aluminum alloy welding and a preparation method thereof, and belongs to the technical field of metal connection. BACKGROUND

[0002] With the development of welding technology, aluminum and aluminum alloy welded structures have been widely used in civil and military fields, such as various chemical containers, rockets, probes, aircraft, ships, rail transportation, etc., and welding is one of the main manufacturing processes. 2195 aluminum lithium alloy is considered one of the most promising structural materials in the aerospace field due to its low density, high specific strength, high specific modulus, good fatigue and corrosion resistance, etc. 5A06 aluminum alloy has high strength, good corrosion resistance and weldability, and is widely used in the manufacture of structural parts such as launch vehicle tanks, cabin bodies and pipelines. In the manufacture of new generation structural materials, due to the special structural requirements, 5A06 aluminum alloy parts are welded to 2195 aluminum lithium alloy base by argon arc welding process. Although 5B06 has good weldability, 2195 aluminum lithium alloy has poor weldability, and welding pores and welding cracks are easily formed during welding. The strength of the welded joint is much lower than that of the base metal, and cannot meet the requirements of engineering application. In practical application, the use of conventional 2325 and 5B06 welding wires for welding 5A06 / 2195 dissimilar aluminum alloys cannot control the generation of welding cracks, and there is no standardized matching welding wire production at present.

[0003] Therefore, it is necessary to develop a welding wire that can improve the microstructure of Al-Cu-Li / Al-Mg dissimilar alloy fusion welding joint, and improve the mechanical properties and crack resistance of the fusion welding joint. SUMMARY

[0004] The present application aims to overcome the above-mentioned defects, and provides a welding wire suitable for dissimilar aluminum alloy welding and a preparation method thereof, which solves the technical problem of poor weldability of dissimilar aluminum alloys. The present application is beneficial to reduce the welding crack sensitivity and is suitable for large-scale industrial production.

[0005] To achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] A welding wire suitable for dissimilar aluminum alloy welding, comprising the following components by mass percentage:

[0007]

[0008] Further, the dissimilar aluminum alloy includes 2195 / 5A06 dissimilar aluminum alloy, 5A06 / 2219 dissimilar aluminum alloy or 5A06 / 2A14 dissimilar aluminum alloy.

[0009] The preparation method of the above-mentioned welding wire suitable for dissimilar aluminum alloy welding comprises:

[0010] Al, Mg, Al-5Mn intermediate alloy, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy and Al-3Be intermediate alloy are smelted and stirred constantly;

[0011] Al-3Ti intermediate alloy and Al-3Zr intermediate alloy are added during smelting, and smelting is continued and stirring is carried out;

[0012] The smelted melt is refined, placed and cast in sequence to obtain an ingot;

[0013] The ingot is extruded, annealed and drawn in sequence to obtain a welding wire.

[0014] Further, the purity of Al is ≥99.999%, the purity of Mg is ≥99.999%, and the alloying mass percentage of the intermediate alloy is ≤5%.

[0015] Further, the smelting temperature before adding the Al-3Ti intermediate alloy and the Al-3Zr intermediate alloy is 820-840℃, and the smelting temperature after adding the Al-3Ti intermediate alloy and the Al-3Zr intermediate alloy is 860-880℃.

[0016] Further, the smelted melt is refined by a gas refining method, and the specific method is as follows: using Ar-Cl2 mixed gas, refining for 20-30min;

[0017] The melt is placed for 10-15min after refining.

[0018] Further, the temperature for casting the melt is 840-860℃, and the pulling speed of the ingot from the crystallizer during casting is 70-80mm / min.

[0019] Further, when the ingot is extruded, the ingot is placed in an extrusion die, and the extrusion is carried out after heat preservation for 6-8h, and the temperature of the extrusion die is 460-480℃.

[0020] Further, the temperature for annealing the ingot is 450-480℃.

[0021] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0022] (1) The present application creatively proposes a welding wire suitable for dissimilar aluminum alloy welding, which is beneficial to reduce welding crack sensitivity and improve normal temperature performance of a welded joint;

[0023] (2) The combination of Mn, Ti, Zr, Sc and V grain refiners proposed in the present application can effectively refine the weld structure, and improve the strength and plasticity of the fusion welded joint;

[0024] (3) The welding wire obtained by the method has good casting performance, is suitable for large-scale industrial production, and is particularly suitable for butt and corner fusion welding of 2195 / 5B06 dissimilar aluminum alloys, has low welding crack sensitivity, and has excellent room temperature performance of the welded joint, thereby solving the problems of poor weldability and easy formation of hot cracks during fusion welding of 2195 / 5B06 dissimilar aluminum alloys. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Microstructure of a fusion welded joint of Example 1 of the present application;

[0026] Figure 2 Microstructure of a fusion welded joint of Example 2 of the present application. DETAILED DESCRIPTION

[0027] The features and advantages of the present application will become more apparent from the detailed description in conjunction with the accompanying drawings.

[0028] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Although various aspects of an implementation can be described herein as being a preferred or advantageous implementation, no inference should be drawn that other aspects necessarily are inferior or inferior to other aspects or implementations.

[0029] In the manufacturing of new generation structural materials, due to special structural requirements, there is an application of welding 5A06 aluminum alloy parts to a 2195 aluminum-lithium alloy base by argon arc welding process. Although the weldability of 5B06 is good, the weldability of 2195 aluminum-lithium alloy is poor, and welding pores and welding hot cracks are easily formed during welding, the strength of the welded joint is far lower than that of the base metal, and the engineering application requirements cannot be met. In actual application, the use of conventional 2325 and 5B06 welding wires for welding 5A06 / 2195 dissimilar aluminum alloys cannot control the generation of welding cracks, and there is no standardized matching welding wire output. To solve these problems, the present application develops a new type of welding wire, which has good manufacturing process, is suitable for butt and corner fusion welding of 5A06 / 2195 dissimilar aluminum alloys, has crack sensitivity K1 < 2% and K2 = 0%, has excellent room temperature mechanical properties, and has a fusion welded joint tensile strength of more than 285 MPa and an elongation of more than 4%, which can be used as a matching welding wire for 5A06 / 2195 dissimilar aluminum alloys, and can be popularized to fusion welding of 5A06 / 2219 dissimilar aluminum alloys and 5A06 / 2A14 dissimilar aluminum alloys.

[0030] The present application provides a welding wire suitable for welding of dissimilar aluminum alloys, which comprises Mg, Mn, Sc, Zr, Ti, V, Cr, Be and Al, and the mass percentage of each component is as follows:

[0031] The content of Mg is 6.0%-7.0%, the content of Mn is 0.6%-0.9%, the content of Sc is 0.4%-0.8%, the content of Ti is 0.25%-0.5%, the content of Zr is 0.25%-0.5%, the content of Cr is 0.25%-0.5%, the content of V is 0.05%-0.25%, the content of Be is 0.0004%-0.001%, and the rest is Al.

[0032] The application discloses a preparation method of a welding wire suitable for welding of 5A06 / 2195 dissimilar aluminum alloys.

[0033] Step 1: ingredient mixing, the ingredients include high-purity aluminum, high-purity magnesium, Al-3Ti intermediate alloy, Al-3Zr intermediate alloy, Al-5Mn intermediate alloy, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy and Al-3Be intermediate alloy, the intermediate alloy is selected to be a low-alloy intermediate alloy to avoid agglomeration and segregation of precipitated phases, and the high-purity aluminum, high-purity magnesium, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy and Al-3Be intermediate alloy are added first;

[0034] Step 2: smelting, the smelting temperature is 820-840 DEG C.

[0035] Step 3: feeding, the Al-3Ti intermediate alloy and the Al-3Zr intermediate alloy are added;

[0036] Step 4: smelting, the smelting temperature is increased to 860-880 DEG C., and the smelting is continuously stirred;

[0037] Step 5: gas removal and slag removal, a gas refining method is used, Ar-Cl2 mixed gas is used for refining for 20-30 min, and the melt is statically placed for 10-15 min;

[0038] Step 6: casting, the casting temperature is 840-860 DEG C., and the ingot is drawn out from the crystallizer at a speed of 70-80 mm / min;

[0039] Step 7: cutting head and tail and skinning;

[0040] Step 8: extrusion, the extrusion die temperature is 460-480 DEG C., and the hot extrusion is performed after heat preservation for 4-6 hours;

[0041] Step 9: annealing, the annealing temperature is 450-480 DEG C.

[0042] Step 10: drawing.

[0043] Further, the smelting temperature before adding Al-3Ti and Al-3Zr is 820-840 DEG C, and the smelting temperature after adding Al-3Ti and Al-3Zr is 860-880 DEG C.

[0044] Further, the obtained melt after smelting is refined by using gas refining method, and the specific method is as follows: using Ar-Cl2 mixed gas, refining for 20-30 min.

[0045] The melt after refining is placed for 10-15 min.

[0046] Further, the temperature for casting the melt is 840-860 DEG C, and the pulling speed of the ingot from the crystallizer during casting is 70-80 mm / min.

[0047] Further, when extruding the ingot, the temperature of the extrusion die is 460-480 DEG C, the ingot is placed in the extrusion die, and the extrusion is carried out after heat preservation for 6-8 hours.

[0048] Further, the temperature for annealing the ingot is 450-480 DEG C.

[0049] The present application firstly uses Al-Mg-Sc welding wire to weld 2195 aluminum lithium alloy, specifically, the present application firstly uses high Mg welding wire to weld 2195 aluminum lithium alloy and Al-Mg alloy, improves the Mg content in the weld, the Mg:Cu content is close to 4:1, forms Al-Mg-Cu phase in the weld, reduces the crack sensitivity of the fusion welding joint, and when the traditional Al-Cu welding wire for welding 2195 aluminum lithium alloy is used, the ratio of Cu and Mg in the weld is close, and the crack resistance of the weld is poor. In addition, since the micro-alloying elements in the 5A06 alloy only contain a small amount of Ti and Mn, the present application adds Mn, Sc, Zr, Ti, V and Cr alloying element combination in the welding wire, the total content of the alloying elements exceeds the content of the alloying elements in the existing Al-Mg welding wire, improves the microstructure of the fusion welding joint by increasing the number of nucleation points and strengthening phase in the fusion welding joint, and improves the crack resistance and mechanical properties of the fusion welding joint. At the same time, the grain refiner combination selected by the present application does not conflict with each other, and is metallurgically compatible with 2195 aluminum lithium alloy and 5A06 aluminum alloy base material, and the type and amount of the added alloying elements will not cause segregation of precipitated phase, among which Mn can significantly refine the recrystallized grains, and can also dissolve impurity Fe, reduce the harmful effect of Fe, the addition of Ti+Zr and Sc+Zr in the alloy has the function of promoting the nucleation of the refiner combination to achieve the purpose of refining the grains, and the addition of V and Cr improves the repair welding performance. The welding wire of the present application is suitable for welding 2195 / 5A06, 5A06 / 2219, 5A06 / 2A14 and other dissimilar aluminum alloys, and can realize large-scale industrial production, which is conducive to promoting the engineering application of high-strength aluminum lithium alloy.

[0050] Example 1

[0051] This example prepares a welding wire suitable for dissimilar aluminum alloy welding, the composition of the welding wire consisting of Mg, Mn, Sc, Zr, Ti, V, Cr, Be and Al.

[0052] The specific steps of the preparation method are as follows:

[0053] Step 1: batching, the batching including high-purity aluminum, high-purity magnesium, Al-3Ti intermediate alloy, Al-3Zr intermediate alloy, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy and Al-3Be intermediate alloy, the intermediate alloy being selected to be a low-alloy intermediate alloy to avoid agglomeration segregation of precipitates, and the high-purity aluminum, high-purity magnesium, Al-5Mn intermediate alloy, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy and Al-3Be intermediate alloy being added first;

[0054] Step 2: melting, the melting temperature being 823℃;

[0055] Step 3: adding, the Al-3Ti intermediate alloy and the Al-3Zr intermediate alloy being added;

[0056] Step 4: melting, the melting temperature being increased to 862℃, and the stirring being continuously performed;

[0057] Step 5: degassing and deslagging: gas refining method, Ar-Cl2 mixed gas being used, the refining being performed for 25min, and the melt being rested for 12min;

[0058] Step 6: casting, the casting temperature being 841℃; and the ingot being drawn out from the crystallizer at a speed of 78mm / min;

[0059] Step 7: cutting head and tail, and skinning;

[0060] Step 8: extrusion, the extrusion die temperature being 463℃, and the hot extrusion being performed after the temperature being kept for 4-6 hours;

[0061] Step 9: annealing, the annealing temperature being 475℃;

[0062] Step 10: drawing.

[0063] The drawing is performed according to the following table: The process produced 80 Kg of welding wire with a diameter of 3.0 mm. The chemical composition was: Mg content of 6.40%, Sc content of 0.52%, Mn content of 0.68%, Ti content of 0.29%, Zr content of 0.28%, Cr content of 0.30%, V content of 0.10%, Be content of 0.0004%, and the rest was Al. The welding thickness of 5A06 / 2195 dissimilar aluminum alloys was 6 mm, and the butt weld and fillet weld were both well formed. The appearance and internal quality of the joint met the requirements of QJ-2698 AI grade weld, the crystallization crack sensitivity K1 was less than 1.8%, and the liquefaction crack sensitivity K2 was 0%. Table 1 shows the room temperature mechanical properties of the fusion welding joint, wherein samples 1, 2, and 3 were parallel samples. The average room temperature mechanical properties of the joint obtained from samples 1, 2, and 3 were: joint strength of 296.8 MPa, and elongation of 5.7%. Figure 1 For the microstructure of the fusion welding joint, the weld structure was uniform, and no crack defects were found.

[0064] Table 1 Room temperature mechanical properties of fusion welding joint

[0065] Sample No. b (MPa) ​ δ (%) 1 305.5 6.5 2 286.4 6.7 3 298.5 3.9 Average 296.8 5.7

[0066] Example 2

[0067] This example prepared a welding wire suitable for welding of 5A06 / 2195 dissimilar aluminum alloys. The composition of the welding wire was composed of Mg, Mn, Sc, Zr, Ti, V, Cr, Be, and Al.

[0068] The specific steps of the preparation method were as follows:

[0069] Step 1: batching, which included high-purity aluminum, high-purity magnesium, Al-3Ti intermediate alloy, Al-3Zr intermediate alloy, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy, and Al-3Be intermediate alloy. The intermediate alloys were selected to be low-alloy intermediate alloys to avoid the aggregation and segregation of precipitates. First, high-purity aluminum, high-purity magnesium, Al-5Mn, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy, and Al-3Be intermediate alloy were added.

[0070] Step 2: melting, with a melting temperature of 820-840 ℃;

[0071] Step 3: feeding, adding Al-3Ti intermediate alloy and Al-3Zr intermediate alloy;

[0072] Step 4: melting, increasing the melting temperature to 867 ℃, and continuously stirring;

[0073] Step 5: gas refining and slag removal, using Ar-Cl2 mixed gas for refining for 22 min, and the melt was left to stand for 11 min.

[0074] Step 6: Casting, casting temperature is 846℃; the ingot is pulled out of the crystallizer at a speed of 75mm / min;

[0075] Step 7: Cut off the head and tail, and peel off the skin;

[0076] Step 8: Extrusion. The extrusion die temperature is 461℃. After holding at this temperature for 4-6 hours, hot extrusion is performed.

[0077] Step 9: Annealing, the annealing temperature is 477℃;

[0078] Step 10: Perform the pulling action.

[0079] Press when pulling The process produced 80 kg of welding wire with a diameter of 3.0 mm. The chemical composition was: Mg 6.60%, Sc 0.48%, Mn 0.65%, Ti 0.32%, Zr 0.32%, Cr 0.28%, V 0.11%, Be 0.0005%, with the remainder being Al. Welding was performed on 6 mm thick 5A06 / 2195 dissimilar aluminum alloy. Both the butt weld and fillet weld were well-formed, and the internal quality of the joint met the QJ-2698 AI grade weld requirements. The crystallization crack sensitivity K1 < 1.2% and the liquefaction crack sensitivity K2 = 0%. Table 2 shows the room temperature mechanical properties of the welded joint: joint strength 290.8 MPa, elongation 5.7%. Figure 2 The microstructure of the weld joint is uniform, and no cracks or defects were found.

[0080] Table 2 Mechanical properties of fusion-welded joints at room temperature

[0081] Sample No. σb (MPa) δ (%) 1 297.6 4.5 2 285.6 6.6 3 288.7 6.0 Average 290.6 5.7

[0082] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0083] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A welding wire suitable for welding dissimilar aluminum alloys, characterized in that, The components include the following mass percentage contents:

2. The welding wire suitable for dissimilar aluminum alloy welding according to claim 1, characterized by, The dissimilar aluminum alloy includes 2195 / 5A06 dissimilar aluminum alloy, 5A06 / 2219 dissimilar aluminum alloy or 5A06 / 2A14 dissimilar aluminum alloy.

3. A method of producing a welding wire suitable for welding dissimilar aluminum alloys according to claim 1 or 2, characterized in that, The method comprises the following steps: Al, Mg, Al-5Mn intermediate alloy, Al-5Cr intermediate alloy, Al-5V intermediate alloy, Al-2Sc intermediate alloy and Al-3Be intermediate alloy are smelted and stirred constantly; Al-3Ti intermediate alloy and Al-3Zr intermediate alloy are added during smelting, and smelting and stirring are continued; The smelted melt is refined, placed and cast in sequence to obtain a cast ingot; The cast ingot is extruded, annealed and drawn in sequence to obtain a welding wire.

4. The method of producing a welding wire suitable for dissimilar aluminum alloy welding according to claim 3, characterized by, The purity of Al is ≥99.999%, and the purity of Mg is ≥99.999%.

5. The method for preparing a welding wire suitable for welding dissimilar aluminum alloys according to claim 3, characterized in that, The alloying mass percentage of the intermediate alloy is ≤5%.

6. The method of making a welding wire suitable for welding dissimilar aluminum alloys of claim 3, wherein, The smelting temperature before adding the Al-3Ti intermediate alloy and the Al-3Zr intermediate alloy is 820-840℃, and the smelting temperature after adding the Al-3Ti intermediate alloy and the Al-3Zr intermediate alloy is 860-880℃.

7. The method for preparing a welding wire suitable for welding dissimilar aluminum alloys according to claim 3, characterized in that, The smelted melt is refined by a gas refining method, and the specific method is as follows: Ar-Cl2 mixed gas is used for refining for 20-30min; The melt is placed for 10-15min after refining.

8. The method for preparing a welding wire suitable for welding dissimilar aluminum alloys according to claim 3, characterized in that, The temperature for casting the melt is 840-860℃, and the pulling speed of the cast ingot from the crystallizer during casting is 70-80mm / min.

9. A method for preparing a welding wire suitable for welding dissimilar aluminum alloys according to claim 3, characterized in that, When the cast ingot is extruded, the cast ingot is placed in an extrusion die, and the cast ingot is extruded after being kept warm for 6-8h, and the temperature of the extrusion die is 460-480℃.

10. The method of making a welding wire suitable for welding dissimilar aluminum alloys of claim 3, wherein, The temperature for annealing the cast ingot is 450-480℃.

Images