Aluminum-steel composite plate butt welding material and method

Abstract

The application discloses a material for butt welding of aluminum-steel composite plates, which comprises welding materials for near-aluminum layers and near-steel layers; the welding material for the near-aluminum layer is a near-aluminum layer welding wire, which comprises a core and a sheath, wherein the core is composed of the following components in percentage by mass: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder; the welding material for the near-steel layer is a near-steel layer welding wire, which comprises a core and a sheath, wherein the core is composed of the following components in percentage by mass: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest is Fe powder. The material is specially used to solve the problems of large stress caused by mismatch of thermal physical properties and cracking caused by brittle phase generation in the butt welding process of the aluminum-steel composite plates. The application further discloses a butt welding method of the aluminum-steel composite plates.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal materials, and particularly relates to an aluminum-steel composite plate butt welding material and an aluminum-steel composite plate butt welding method using the aluminum-steel composite plate butt welding material. BACKGROUND

[0002] In the 21st century, with the rapid development of social economy and engineering science, the performance of traditional materials has been increasingly difficult to meet the needs of national construction, and people hope to obtain a cheap, easy-to-produce, and excellent-performance comprehensive material. Explosive welding is a method and technology for the instantaneous metallurgical bonding of double metals or multiple metals using explosives as energy. For dissimilar metals such as aluminum-steel, titanium-steel, and zirconium-steel materials, it is difficult to effectively weld them using conventional methods, but explosive welding can achieve this. After the completion of the welding of the composite plate, the excellent chemical and electrical properties of the noble metal can be utilized, and the excellent physical properties of the cheap metal can also be utilized, which makes the explosive welding process show a bright development prospect and can produce great economic and technical value in the future.

[0003] However, in many engineering scenarios, it is necessary to butt connect the explosive welded composite plate to realize its excellent comprehensive performance. However, due to the large difference in thermal physical properties between aluminum and steel, it is difficult to form a weld during welding and the aluminum side is prone to transition melting. Compared with physical properties, the metallurgical incompatibility between aluminum and steel (easy to generate brittle Fe-Al phase) is the main reason for the difficulty in welding connection.

[0004] The present application aims to solve the problems of large thermal stress caused by the mismatch of thermal physical properties and serious cracking caused by metallurgical incompatibility during the butt welding of aluminum-steel composite plates. SUMMARY

[0005] The purpose of the present application is to provide an aluminum-steel composite plate butt welding material, which is specifically used to solve the problems of large stress caused by the mismatch of thermal physical properties and cracking caused by the generation of brittle phase during the butt welding of aluminum-steel composite plates.

[0006] The second purpose of the present application is to provide an aluminum-steel composite plate butt welding method.

[0007] The first technical solution adopted by the present application is an aluminum-steel composite plate butt welding material, which includes welding materials for the near-aluminum layer and the near-steel layer.

[0008] The welding material for the near-aluminum layer is a near-aluminum layer welding wire, which includes a core and a sheath. The core is composed of the following components in mass percentage: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder.

[0009] The welding material for the near-steel layer is a near-steel layer welding wire, comprising a core and a sheath, wherein the core is composed of the following components in percentage by mass: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest is Fe powder.

[0010] The application is also characterized in that:

[0011] The purity of each raw material component of the core of the near-steel layer welding wire is greater than or equal to 99.90%, and the particle size of the powder is 100-200 mesh.

[0012] The purity of each raw material component of the core of the near-steel layer welding wire is greater than or equal to 99.90%, and the particle size of the powder is 100-200 mesh.

[0013] The sheath of the near-steel layer welding wire is a pure aluminum strip with a thickness of 0.3 mm and a width of 7 mm, and the filling amount of the welding wire is controlled to be 20wt%-25wt%.

[0014] The sheath of the near-steel layer welding wire is a low-carbon steel strip with a thickness of 0.3 mm and a width of 7 mm, and the filling amount of the welding wire is controlled to be 20wt%-22wt%.

[0015] The specific steps of the method for preparing the near-steel layer welding wire are as follows:

[0016] Step 1: the powder is weighed according to the mass percentage: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder;

[0017] Step 2: the powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 100-150℃, and the holding time is 1-2h, so as to remove the crystal water in the powder; the dried powder is placed in a powder mixing machine for sufficient mixing, and the mixing time is 1-2h;

[0018] Step 3: the sheath is a pure aluminum strip, 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 core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the filling amount of the welding wire is controlled to be 20wt%-25wt%;

[0019] Step 4: after the first process drawing is completed, the die hole diameter is gradually reduced, and finally the core wire with a diameter of 1.2mm is obtained;

[0020] Step 5: after the core wire drawing is completed, the core wire is wound on a wire spool through a winding machine, and finally sealed in a vacuum packaging bag for use.

[0021] The specific steps of the method for preparing the near-steel layer welding wire are as follows:

[0022] Step 1: take the medicine powder by mass percentage: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest is Fe powder;

[0023] Step 2: the medicine powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 150-200 DEG C, and the holding time is 1-3 h, and the crystallization water in the medicine powder is removed; the dried medicine powder is placed in a powder mixer for sufficient mixing, and the mixing time is 1-3 h;

[0024] Step 3: low carbon steel belt is used as the welding skin, alcohol is used to remove the grease on the surface of the low carbon steel belt, the medicine powder prepared in step 2 is wrapped in pure aluminum belt through the core wire drawing equipment, and the first drawing die hole diameter is 2.6 mm; the filling amount of the welding wire is controlled at 20-22 wt%;

[0025] Step 4: after the first process drawing is completed, the die hole diameter is sequentially reduced, and finally the diameter of the cored wire is 1.2 mm;

[0026] Step 5: after the cored wire drawing is completed, the cored wire is wound on the welding wire disc through the winding machine, and finally sealed in the cored wire vacuum packaging bag for use.

[0027] The second technical scheme adopted by the application is an aluminum-steel composite plate butt welding method, and the aluminum-steel composite plate butt welding material is used for welding the aluminum-steel composite plate, and the specific steps are as follows:

[0028] (1) the aluminum-steel composite plate is opened for welding, and the gap of the butt joint test plate is set to 0.5-1 mm;

[0029] (2) the steel layer is welded, the welding adopts MAG welding, the welding current is 180-220 A, the welding material is ER50-6 welding wire, and the welding wire diameter is 1.2 mm;

[0030] (3) the test plate is turned over, and the above-mentioned near-steel layer welding wire is used to weld on the back of the above-mentioned steel layer welding seam, and the welding adopts MIG welding, and the welding current is 100-150 A;

[0031] (4) the near-aluminum layer welding is carried out on the above-mentioned near-steel layer welding seam, and the above-mentioned near-aluminum layer welding wire is selected, and the welding adopts MIG welding, and the welding current is 80-100 A;

[0032] (5) finally, ER1100 welding wire is used to complete the filling and cover welding of the aluminum side, and the welding adopts MIG welding, and the welding current is 100-150 A; and the multi-layer multi-pass welding mode is adopted.

[0033] The application also has the following characteristics:

[0034] The aluminum-steel composite plate is opened with asymmetric X-shaped groove, wherein the groove angle of the steel side is 50±5°, the groove angle of the aluminum side is 60±5°, no land is left, and the centering position of the steel side groove is 2mm-3mm below the aluminum-steel composite plate interface.

[0035] The present application has the following advantages:

[0036] (1) The present application solves the problems of brittle phase generation and thermal physical property mismatch during the welding of aluminum-steel composite plate, and the welding materials for the near-steel layer and the near-aluminum layer are developed respectively, so as to effectively improve the strength and toughness of the weld and avoid the generation of Fe-Al brittle phase.

[0037] (2) In order to solve the problem of brittle phase generation during the welding of aluminum-steel, the present application adopts the way of layer-by-layer element transition, first welding the near-steel layer weld with high Zn and Ag content on the near-steel layer, and then welding the near-aluminum layer weld with high Zn and Sn content on the near-steel layer weld, which fully heterogenizes the reaction of Fe and Al elements.

[0038] (3) In order to solve the problem of large stress caused by thermal physical property mismatch during the welding of aluminum-steel, the welding materials for the near-steel layer and the near-aluminum layer are designed as low-melting-point welding wires, so as to effectively reduce the welding heat input and the residual stress during the welding of aluminum-steel dissimilar joints.

[0039] (4) The present application adopts the groove form, which can effectively control the metallurgical mixing between aluminum and steel under the premise of considering welding efficiency and operability, so as to reduce the generation of brittle phase in the weld.

[0040] (5) The welding wire developed by the present application has few types of powder and is easy to mass-produce. The wire diameter of the welding wire is 1.2mm, which can be used for MIG welding and TIG welding, and has wide adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The aluminum-steel composite plate butt welding groove form used in the present application method;

[0042] Figure 2 The aluminum-steel composite plate butt welding sequence in the present application method;

[0043] Figure 3 The scanning electron microscope picture of the near-aluminum layer of the aluminum-steel butt joint prepared in Example 2 of the present application;

[0044] Figure 4 The tensile fracture morphology of the aluminum-steel butt joint prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0045] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0046] The present application provides an aluminum-steel composite plate butt welding material, comprising a near-aluminum layer and a near-steel layer welding material;

[0047] The near-aluminum layer welding material is a near-aluminum layer welding wire, comprising a core and a sheath, wherein the core consists of the following components in mass percentage: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder, and the sum of the mass percentages of the above components is 100%.

[0048] The near-steel layer welding material is a near-steel layer welding wire, comprising a core and a sheath, wherein the core consists of the following components in mass percentage: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest is Fe powder, and the sum of the mass percentages of the above components is 100%.

[0049] The purity of each raw material component constituting the core of the near-aluminum layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 mesh.

[0050] The purity of each raw material component constituting the core of the near-steel layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 mesh.

[0051] The sheath of the near-aluminum layer welding wire is a pure aluminum strip with a thickness of 0.3 mm and a width of 7 mm, and the filling amount of the welding wire is controlled at 20wt%-25wt%.

[0052] The sheath of the near-steel layer welding wire is a low-carbon steel strip with a thickness of 0.3 mm and a width of 7 mm, and the filling amount of the welding wire is controlled at 20wt%-22wt%.

[0053] The method for preparing the near-aluminum layer welding wire comprises the following specific steps:

[0054] Step 1: The powder is weighed according to the mass percentage: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder, and the sum of the mass percentages of the above components is 100%.

[0055] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 100-150°C for 1-2h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing for 1-2h;

[0056] Step 3: using pure aluminum strip as the welding skin, using alcohol to remove the grease on the surface of the pure aluminum strip, wrapping the powder prepared in step 2 in the pure aluminum strip through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the filling amount of the welding wire is controlled at 20wt%-25wt%;

[0057] Step 4: after the first process drawing is completed, the die hole diameter is sequentially reduced, and a diameter of 1.2mm of the cored wire is finally obtained;

[0058] 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.

[0059] The specific steps of the method for preparing the near-steel layer welding wire are as follows:

[0060] Step 1: the powder is weighed according to the mass percentage: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest is Fe powder, and the sum of the mass percentages of the above components is 100%;

[0061] Step 2: the powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 150-200℃, and the holding time is 1-3h 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 1-3h;

[0062] Step 3: using low-carbon steel strip as the welding skin, using alcohol to remove the grease on the surface of the low-carbon steel strip, wrapping the powder prepared in step 2 in the pure aluminum strip through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the filling amount of the welding wire is controlled at 20wt%-22wt%;

[0063] Step 4: after the first process drawing is completed, the die hole diameter is sequentially reduced, and a diameter of 1.2mm of the cored wire is finally obtained;

[0064] 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.

[0065] The roles and functions of each alloy component in the near-aluminum layer welding wire and the near-steel layer welding wire are as follows:

[0066] (1) Zn element:

[0067] Zn powder is added to the near-steel layer welding wire powder at 40-50%: from the Fe-Zn binary phase diagram, the solubility of Zn element is high in both bcc-Fe and fcc-Fe. The melting point of Zn is relatively low, about 419℃, while the melting point of Fe is 1536℃, so the addition of Zn can effectively reduce the melting point of the welding wire. When the arc acts on the welding wire, Zn becomes a liquid film spread on the substrate surface due to its low melting point, thereby reducing the melting of the substrate metal.

[0068] Zn powder is added to the near-steel layer welding wire powder at 40-50%: from the Fe-Zn binary phase diagram, the solubility of Zn element is high in both bcc-Fe and fcc-Fe. The melting point of Zn is relatively low, about 419℃, while the melting point of Fe is 1536℃, so the addition of Zn can effectively reduce the melting point of the welding wire. When the arc acts on the welding wire, Zn becomes a liquid film spread on the substrate surface due to its low melting point, thereby reducing the melting of the substrate metal.

[0069] (2) Ag element:

[0070] Ag powder is added to the near-steel layer welding wire powder at 30-35%: from the Ag-Fe binary phase diagram, no brittle intermetallic compound is formed between the two, and the weld metal of the two is mainly composed of Ag-based solid solution and Fe-based solid solution. From the Ag-Al binary phase diagram, the solubility of Ag in Al is large, and the weldability of the two is good. Therefore, the addition of Ag element in the near-steel layer welding wire can not only reduce the melting point of the near-steel layer welding wire, but also ensure the metallurgical bonding performance between the near-steel layer and the near-aluminum layer.

[0071] (3) Si element:

[0072] Si powder is added to the near-steel layer welding wire powder at 5-10%: from the Fe-Si binary phase diagram, Si can be maximally solid-soluted in fcc-Fe at 10.9wt.%. Si, as a strengthening phase in Fe, can increase the strength of Fe weld. In addition, Si has a deoxidizing effect, which reduces the oxygen content in the weld metal.

[0073] (4) Sn element:

[0074] Sn powder is added to the near-steel layer welding wire powder at 20-25%: from the Al-Sn binary phase diagram, no brittle phase is formed between the two, and the weld of the two is mainly composed of Al-based solid solution and Sn-based solid solution. The melting point of Sn is relatively low (231℃), and the melting point of Al is 660℃, so the addition of Sn can effectively reduce the melting point of the aluminum side welding wire, thereby reducing the welding heat input and stress concentration. From the Sn-Zn binary phase diagram, eutectic reaction occurs between the two at about 91℃, so the melting point of the aluminum side welding wire can be further reduced.

[0075] (5) Ti element:

[0076] 5~10% Ti powder is added in the near-aluminum layer welding wire powder: from the Al-Ti binary phase diagram, the solid solubility of Al element in bcc-Ti can reach 33.8wt.%, so there is a certain solid solubility between the two. The addition of Ti element can improve the strength of the Al-based weld.

[0077] (6) Mg element:

[0078] 5~10% Mg powder is added in the near-aluminum layer welding wire powder: from the Al-Mg binary phase diagram, the solid solubility of Mg in Al can reach 17.1wt.% at most, so adding Mg element in the Al welding wire can play a role in solid solution in the Al matrix to improve the strength of the weld. The Mg2Si phase generated by Mg and Si can be dispersedly distributed in the Al weld to improve the strength and toughness of the weld.

[0079] (7) Re element:

[0080] 1~3% Re rare earth element is added in the near-aluminum layer welding wire powder: the addition of rare earth elements in aluminum alloy can refine the grain, reduce the secondary intergranular spacing, reduce the gas and inclusions in the alloy, and make the inclusions tend to be spherical. It can also reduce the surface tension of the melt and increase the fluidity, which has a significant influence on the welding process performance.

[0081] The application also discloses an aluminum-steel composite plate butt welding method, which uses the aluminum-steel composite plate butt welding material to weld the aluminum-steel composite plate, as shown in the drawing, and the specific steps are as follows: Figure 2

[0082] (1) The aluminum-steel composite plate is opened and welded with a groove, and the gap of the butt test plate is 0.5mm~1mm;

[0083] (2) The steel layer is welded, the welding adopts MAG welding, the welding current is 180A~220A, the welding material is ER50-6 welding wire, and the welding wire diameter is 1.2mm;

[0084] (3) The test plate is turned over, the near-steel layer welding wire is used to weld on the back of the above-mentioned steel layer weld, the welding adopts MIG welding, and the welding current is 100A~150A;

[0085] (4) The near-aluminum layer welding is carried out on the above-mentioned near-steel layer weld, the near-aluminum layer welding wire is selected, the welding adopts MIG welding, and the welding current is 80A~100A;

[0086] (5) Finally, the ER1100 welding wire is used to complete the filling and cover welding of the aluminum side, the welding adopts MIG welding, the welding current is 100~150A, and the multi-layer and multi-pass welding mode is adopted.​

[0087] An asymmetric X-type groove of an aluminum-steel clad plate, as shown in the figure, wherein the steel side groove angle is 50±5°, the aluminum side groove angle is 60±5°, no root face is left, and the centering position of the steel side groove is 2mm~3mm below the aluminum-steel clad plate interface. Figure 1

[0088] Example 1

[0089] The specific steps of the method for preparing the near-al layer welding wire for butt welding of aluminum-steel clad plates are as follows:

[0090] Step 1: The powder is weighed according to the mass percentage: Zn powder 40%, Sn powder 20%, Ti powder 5%, Mg powder 5%, Re powder 1%, and the rest is Al powder. The sum of the mass percentages of the above components is 100%. The purity of each raw material component constituting the core of the near-al layer welding wire is ≥99.90%, and the particle size of the powder is 100~200 mesh.

[0091] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 100℃ for 1h 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.

[0092] Step 3: Pure aluminum tape is used as the sheath, and alcohol is used to remove the grease on the surface of the pure aluminum tape. The powder prepared in step 2 is wrapped in the pure aluminum tape through the wire drawing equipment of the flux-cored wire, and the first drawing die has a hole diameter of 2.6mm. The sheath of the near-al layer welding wire is pure aluminum tape with a thickness of 0.3mm and a width of 7mm, and the filling amount of the welding wire is controlled at 20wt%.

[0093] 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 1.2mm is obtained.

[0094] Step 5: After the drawing of the flux-cored wire is completed, it is wound on the wire spool by the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0095] The specific steps of the method for preparing the near-al layer welding wire for butt welding of aluminum-steel clad plates are as follows:

[0096] Step 1: The powder is weighed according to the mass percentage: Zn powder 40%, Ag powder 30%, Si powder 5%, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0097] The purity of each raw material component constituting the core of the near-al layer welding wire is ≥99.90%, and the particle size of the powder is 100~200 mesh.

[0098] ​Step 2: The medicine powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 150℃, and the holding time is 1h, to remove the crystal water in the medicine powder; the dried medicine powder is placed in a powder mixer for thorough mixing, and the mixing time is 1h;

[0099] Step 3: A low-carbon steel strip is used as the welding sheath, alcohol is used to remove the grease on the surface of the low-carbon steel strip, the medicine powder prepared in step 2 is wrapped in a pure aluminum strip through a cored wire drawing equipment, and the first drawing die has a hole diameter of 2.6mm; the welding sheath of the near-steel layer welding wire is a low-carbon steel strip with a thickness of 0.3mm and a width of 7mm, and the filling amount of the welding wire is controlled at 20wt%.

[0100] Step 4: After the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally a cored wire with a diameter of 1.2mm is obtained;

[0101] Step 5: After the cored wire drawing is completed, the cored wire is wound on a wire spool through a wire winding machine, and finally sealed in a vacuum packaging bag for cored wire for use.

[0102] The butt joint groove form of the aluminum-steel composite plate is shown in FIG. 1, and the aluminum-steel composite plate is opened into an asymmetric X-shaped groove, wherein the groove angle of the steel side is 45°, the groove angle of the aluminum side is 55°, no blunt edge is left, and the centering position of the steel side groove is 2mm below the aluminum-steel composite plate interface. Figure 1 The method for butt welding the aluminum-steel composite plate by using the near-aluminum layer welding wire and the near-steel layer welding wire provided in Example 1 is shown in FIG. 2, and the specific steps are as follows:

[0103] Figure 2 (1) The aluminum-steel composite plate is opened into the above groove form, and the gap of the butt joint test plate is set to 0.5mm;

[0104] (2) The welding of the steel layer is performed, the welding adopts MAG welding (welding current 180A), the welding material is ER50-6 welding wire, and the welding wire diameter is 1.2mm;

[0105] (3) The test plate is turned over, and the near-steel layer welding wire of the present application is used to weld on the back of the above steel layer weld;

[0106] (4) The near-aluminum layer welding is performed on the above near-steel layer weld, the near-aluminum layer welding wire of the present application is selected, and the welding adopts MIG welding (welding current 80A);

[0107] (5) Finally, the ER1100 welding wire is used to complete the filling and cap welding of the aluminum side, the welding adopts MIG welding (welding current 100A), and a multi-layer and multi-pass welding method is adopted.

[0108] (5) Finally, the ER1100 welding wire is used to complete the filling and cap welding of the aluminum side, the welding adopts MIG welding (welding current 100A), and a multi-layer and multi-pass welding method is adopted.

[0109] ​The butt joint of the obtained aluminum-steel composite plate was observed, tensile strength test and microhardness test, and the results were as follows:

[0110] (1) No defects were found in the near-steel layer weld and the near-aluminum layer weld;

[0111] (2) The tensile strength of the joint was 372 MPa, and the elongation was 25%

[0112] (3) The microhardness of the near-steel layer weld was 287HV0.3, and the microhardness of the near-aluminum layer weld was 218HV0.3.

[0113] Example 2

[0114] The method for preparing the near-aluminum layer welding wire for butt welding of aluminum-steel composite plate comprises the following specific steps:

[0115] Step 1: The powder is weighed according to the mass percentage: Zn powder 50%, Sn powder 25%, Ti powder 10%, Mg powder 10%, Re powder 3%, and the rest is Al powder. The sum of the mass percentages of the above components is 100%.

[0116] The purity of each raw material component constituting the core of the aluminum layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 mesh.

[0117] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated to 150°C for 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.

[0118] Step 3: Pure aluminum tape is used as the welding skin, and alcohol is used to remove the grease on the surface of the pure aluminum tape. The powder prepared in step 2 is wrapped in the pure aluminum tape by using the wire drawing equipment of the flux-cored wire, and the first drawing die hole diameter is 2.6mm; the welding skin of the near-aluminum layer welding wire is pure aluminum tape with a thickness of 0.3mm and a width of 7mm, and the filling amount of the welding wire is controlled at 25wt%.

[0119] Step 4: After the first drawing process is completed, the die hole diameter is gradually reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained;

[0120] Step 5: After the drawing of the flux-cored wire is completed, it is wound on the welding wire disc by the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0121] The method for preparing the near-steel layer welding wire for butt welding of aluminum-steel composite plate comprises the following specific steps:

[0122] Step 1: The powder is weighed according to the mass percentage: Zn powder 50%, Ag powder 35%, Si powder 10%, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0123] The purity of each raw material component constituting the core of the near-steel layer welding wire is ≥ 99.90%, and the particle size of the powder is 100-200 meshes.

[0124] Step 2: The powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 200℃, and the holding time is 3h, 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 3h;

[0125] Step 3: A low-carbon steel strip is used as the welding skin, alcohol is used to remove the grease on the surface of the low-carbon steel strip, the powder prepared in step 2 is wrapped in a pure aluminum strip through a flux-cored wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the welding skin of the near-steel layer welding wire is a low-carbon steel strip with a thickness of 0.3mm and a width of 7mm, and the filling amount of the welding wire is controlled at 22wt%.

[0126] Step 4: After the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally a diameter of 1.2mm of the flux-cored wire is obtained;

[0127] Step 5: After the drawing of the flux-cored wire is completed, it is wound on the welding wire disc through a winding machine, and finally sealed in a vacuum packaging bag for use.

[0128] The butt joint groove form of the aluminum-steel composite plate is shown as in the drawing Figure 1 , the aluminum-steel composite plate is opened with an asymmetric X-shaped groove, the groove angle of the steel side is 55°, the groove angle of the aluminum side is 65°, no blunt edge is left, and the centering position of the steel side groove is 3mm below the aluminum-steel composite plate interface.

[0129] The near-aluminum layer welding wire and the near-steel layer welding wire provided in Example 2 are used to perform the method of butt welding of the aluminum-steel composite plate (as shown in the drawing Figure 2 ), and the specific steps are as follows:

[0130] (1) The aluminum-steel composite plate is opened in the above groove form, and the gap of the butt joint test plate is set to 1mm;

[0131] (2) The welding of the steel layer is performed, the welding adopts MAG welding (welding current 220A), and the welding material is ER50-6 welding wire with a diameter of 1.2mm;

[0132] (3) The test plate is turned over, and the near-steel layer welding wire of the present application is used to perform welding on the back of the above steel layer weld;

[0133] (4) The near-aluminum layer welding is performed on the above near-steel layer weld, the near-aluminum layer welding wire of the present application is selected, and the MIG welding (welding current 100A) is used for welding;

[0134] (5) Finally, ER1100 welding wire is used to complete the filling and cap welding of the aluminum side, and MIG welding (welding current 150A) is used, and multi-layer and multi-pass welding is used.

[0135] The aluminum-steel composite plate butt joint welded is observed in structure, tested in tensile strength and tested in microhardness, and the results are as follows:

[0136] (1) No defects are found in the near-steel layer weld and the near-aluminum layer weld;

[0137] (2) The tensile strength of the joint is 377 MPa, and the elongation is 25.6%;

[0138] (3) The microhardness of the near-steel layer weld is 288HV0.3, and the microhardness of the near-aluminum layer weld is 212HV0.3.

[0139] Figure 3 The scanning electron microscope picture of the near-aluminum layer of the aluminum-steel butt joint prepared in example 2 of the application. As can be seen from the picture, Figure 3 no cracks, pores and other defects are observed in the near-aluminum layer weld. The weld structure is uniformly distributed, and presents columnar dendritic crystal morphology.

[0140] Figure 4 The tensile fracture morphology of the aluminum-steel butt joint prepared in example 2 of the application. As can be seen from the picture, Figure 4 the fracture is mainly in the form of dimple, which indicates good toughness.

[0141] Example 3

[0142] The method for preparing the near-aluminum layer welding wire for aluminum-steel composite plate butt welding has the following specific steps:

[0143] Step 1: The medicine powder is weighed according to the mass percentage: Zn powder 45%, Sn powder 23%, Ti powder 7%, Mg powder 7%, Re powder 2%, and the rest is Al powder, and the sum of the mass percentages of the above components is 100%.

[0144] The purity of each raw material component of the medicine core in the near-aluminum layer welding wire is ≥99.90%, and the particle size of the medicine powder is 100-200 meshes.

[0145] Step 2: The medicine powder weighed in step 1 is placed in a vacuum heating furnace and heated, the heating temperature is 130℃, and the holding time is 1.5h, and the crystal water in the medicine powder is removed; the dried medicine powder is placed in a powder mixer for sufficient mixing, and the mixing time is 1.52h;

[0146] Step 3: The pure aluminum strip is used as the welding skin, and 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 the core wire drawing equipment. The first drawing die hole diameter is 2.6 mm. The near-aluminum layer welding wire has a pure aluminum strip as the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the welding wire is controlled at 21 wt%.

[0147] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a diameter of 1.2 mm of the core wire is obtained.

[0148] Step 5: After the core wire drawing is completed, the wire is wound on the wire spool through the winding machine, and finally sealed in the core wire vacuum packaging bag for use.

[0149] The method for preparing the near-steel layer welding wire for aluminum-steel composite plate butt welding is as follows:

[0150] Step 1: The powder is weighed according to the mass percentage, i.e. Zn powder 45%, Ag powder 33%, Si powder 7%, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0151] The purity of each raw material component of the near-steel layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 mesh.

[0152] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace for heating. The heating temperature is 170℃, 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.

[0153] Step 3: The low-carbon steel strip is used as the welding skin, and alcohol is used to remove the grease on the surface of the low-carbon steel strip. The powder prepared in step 2 is wrapped in the pure aluminum strip through the core wire drawing equipment. The first drawing die hole diameter is 2.6 mm. The near-steel layer welding wire has a low-carbon steel strip as the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the welding wire is controlled at 21 wt%.

[0154] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a diameter of 1.2 mm of the core wire is obtained.

[0155] Step 5: After the core wire drawing is completed, the wire is wound on the wire spool through the winding machine, and finally sealed in the core wire vacuum packaging bag for use.

[0156] The aluminum-steel composite plate butt groove form (as shown in Figure 1 The aluminum-steel composite plate is opened with an asymmetric X-type groove, with a steel side groove angle of 45° and an aluminum side groove angle of 65°, without a blunt edge. The centering position of the steel side groove is 2.5 mm below the aluminum-steel composite plate interface.

[0157] The method for butt welding of aluminum-steel composite plate using the near-aluminum layer welding wire and the near-steel layer welding wire provided in Example 3 (as shown in FIG. 1) is as follows: Figure 2

[0158] (1) The aluminum-steel composite plate is opened to the above-mentioned groove form, and the gap of the butt test plate is set to 0.7 mm;

[0159] (2) The welding of the steel layer is performed, and MAG welding (welding current 200 A) is used, and the welding material is ER50-6 welding wire, and the diameter of the welding wire is 1.2 mm;

[0160] (3) The test plate is turned over, and the near-steel layer welding wire of the present application is used to perform welding on the back of the above-mentioned steel layer welding seam, and MIG welding (welding current 130 A) is used;

[0161] (4) The near-aluminum layer welding is performed on the above-mentioned near-steel layer welding seam, and the near-aluminum layer welding wire of the present application is selected, and MIG welding (welding current 90 A) is used;

[0162] (5) Finally, the ER1100 welding wire is used to complete the filling and cap welding of the aluminum side, and MIG welding (welding current 130 A) is used, and a multi-layer and multi-pass welding mode is used.

[0163] The butt joint of the aluminum-steel composite plate obtained by welding is observed in terms of structure, tested in terms of tensile strength, and tested in terms of microhardness, and the results are as follows:

[0164] (1) No defects are found in the near-steel layer welding seam and the near-aluminum layer welding seam;

[0165] (2) The tensile strength of the joint is 380 MPa, and the elongation is 23%;

[0166] (3) The microhardness of the near-steel layer welding seam is 289 HV0.3, and the microhardness of the near-aluminum layer welding seam is 233 HV0.3.

[0167] Example 4

[0168] The method for preparing the near-aluminum layer welding wire for butt welding of aluminum-steel composite plate is as follows:

[0169] Step 1: The powders are weighed according to the mass percentage, that is, Zn powder 49%, Sn powder 24%, Ti powder 9%, Mg powder 9%, Re powder 2.8%, and the rest is Al powder, and the sum of the mass percentages of the above components is 100%.

[0170] The purity of each raw material component constituting the core of the near-aluminum layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 meshes.

[0171] ​Step 2: The drug powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 140℃, 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 1.9h;

[0172] Step 3: Pure aluminum tape is used as the welding skin, alcohol is used to remove the grease on the surface of the pure aluminum tape, and the drug powder prepared in step 2 is wrapped in the pure aluminum tape through the drug core welding wire drawing equipment, and the first drawing die hole diameter is 2.6mm;

[0173] The welding skin of the near-aluminum layer welding wire is a pure aluminum tape with a thickness of 0.3mm and a width of 7mm, and the filling amount of the welding wire is controlled at 23wt%.

[0174] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a drug core welding wire with a diameter of 1.2mm is obtained;

[0175] Step 5: After the drawing of the drug core welding wire is completed, it is wound on a welding wire reel through a winding machine, and finally sealed in a drug core welding wire vacuum packaging bag for use.

[0176] The method for preparing a near-steel layer welding wire for butt welding of aluminum-steel composite plates comprises the following steps:

[0177] Step 1: The drug powder is weighed according to the mass percentage, i.e. 49% of Zn powder, 34% of Ag powder, 9% of Si powder, and the rest of Fe powder, and the sum of the mass percentages of the above components is 100%.

[0178] The purity of each raw material component of the drug core of the near-steel layer welding wire is ≥99.90%, and the particle size of the drug powder is 100-200 meshes.

[0179] Step 2: The drug powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 190℃, and the holding time is 2.8h 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 2.8h;

[0180] Step 3: Low-carbon steel tape is used as the welding skin, alcohol is used to remove the grease on the surface of the low-carbon steel tape, and the drug powder prepared in step 2 is wrapped in the pure aluminum tape through the drug core welding wire drawing equipment, and the first drawing die hole diameter is 2.6mm; the welding skin of the near-steel layer welding wire is a low-carbon steel tape with a thickness of 0.3mm and a width of 7mm, and the filling amount of the welding wire is controlled at 21wt%.

[0181] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a drug core welding wire with a diameter of 1.2mm is obtained;

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

[0183] Aluminum-steel composite plate butt groove form (such as Figure 1 As shown in the figure, the aluminum-steel composite plate has an asymmetric X-shaped groove, where the steel side groove angle is 55°, the aluminum side groove angle is 55°, no blunt edge is left, and the center position of the steel side groove is 2.9mm below the aluminum-steel composite plate interface.

[0184] The method for butt welding aluminum-steel composite plates using the welding wire near the aluminum layer and the welding wire near the steel layer provided in Example 4 (such as Figure 2 The specific steps are as follows:

[0185] (1) The aluminum-steel composite plate is grooved in the above-mentioned manner, and the gap between the butt test plates is set to 0.9 mm;

[0186] (2) Welding of the steel layer is performed using MAG welding (welding current 210A), welding material is ER50-6 welding wire, and the wire diameter is 1.2 mm;

[0187] (3) The test plate is turned over, and the back side of the steel layer weld is welded with the welding wire near the steel layer of the present invention, using MIG welding (welding current 140A);

[0188] (4) Performing near-aluminum layer welding on the above-mentioned near-steel layer weld, selecting the near-aluminum layer welding wire of the present invention, and adopting MIG welding (welding current 95A);

[0189] (5) Finally, ER1100 welding wire is used to complete the filling and cover welding of the aluminum side. The welding is done by MIG welding (welding current 140A) using a multi-layer and multi-pass welding method.

[0190] The welded aluminum-steel composite plate butt joint was subjected to microstructure observation, tensile strength test, and microhardness test. The results are as follows:

[0191] (1) No defects were found in the welds near the steel layer and the welds near the aluminum layer;

[0192] (2) The tensile strength of the joint is 369 MPa and the elongation is 26.5%;

[0193] (3) The microhardness of the weld near the steel layer is 266HV0.3, and the microhardness of the weld near the aluminum layer is 212HV0.3.

[0194] Example 5

[0195] The specific steps of the method for preparing the near-aluminum layer welding wire for butt welding of aluminum-steel composite plates are as follows:

[0196] Step 1: The powders are weighed according to the mass percentage: Zn powder 41%, Sn powder 21%, Ti powder 6.5%, Mg powder 6.5%, Re powder 1.3%, and the rest is Al powder. The sum of the mass percentages of the above components is 100%.

[0197] The purity of each raw material component constituting the core of the near-aluminum layer welding wire is ≥ 99.90%, and the particle size of the powder is 100-200 mesh.

[0198] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated to 110°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.

[0199] Step 3: Pure aluminum tape is used as the welding skin, and alcohol is used to remove the grease on the surface of the pure aluminum tape. The powder prepared in step 2 is wrapped in the pure aluminum tape through the core wire drawing equipment. The first drawing die has a hole diameter of 2.6 mm. The welding skin of the near-aluminum layer welding wire is pure aluminum tape with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the welding wire is controlled at 20wt%.

[0200] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally a core wire with a diameter of 1.2 mm is obtained.

[0201] Step 5: After the core wire drawing is completed, it is wound on the wire spool by the winding machine and finally sealed in the core wire vacuum packaging bag for use.

[0202] The method for preparing a near-steel layer welding wire for aluminum-steel composite plate butt welding is as follows:

[0203] Step 1: The powders are weighed according to the mass percentage: Zn powder 41%, Ag powder 31%, Si powder 6.5%, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0204] The purity of each raw material component constituting the core of the near-steel layer welding wire is ≥ 99.90%, and the particle size of the powder is 100-200 mesh.

[0205] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated to 155°C for 1.3 hours to remove the crystal water in the powder. The dried powder is placed in a powder mixer for thorough mixing for 1.3 hours.

[0206] Step 3: using low carbon steel strip as the welding skin, using alcohol to remove the grease on the surface of the low carbon steel strip, wrapping the flux powder prepared in step 2 into the pure aluminum strip through the core wire drawing equipment, and the first drawing die hole diameter is 2.6 mm; the welding skin of the near-steel layer welding wire is a low carbon steel strip with a thickness of 0.3 mm and a width of 7 mm, and the filling amount of the welding wire is controlled at 20 wt%.

[0207] Step 4: after the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally a diameter of 1.2 mm of the flux-cored wire is obtained;

[0208] Step 5: after the drawing of the flux-cored wire is completed, the wire is wound on the wire spool through the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0209] The butt joint groove form of the aluminum-steel composite plate is shown as in FIG. 1, and the aluminum-steel composite plate is opened into an asymmetric X-shaped groove, wherein the groove angle of the steel side is 55°, the groove angle of the aluminum side is 65°, no blunt edge is left, and the centering position of the steel side groove is 2.2 mm below the aluminum-steel composite plate interface. Figure 1 The method for butt welding the aluminum-steel composite plate using the near-aluminum layer welding wire and the near-steel layer welding wire provided in Example 5 is shown as in FIG. 2, and the specific steps are as follows:

[0210] Figure 2 (1) the aluminum-steel composite plate is opened into the above groove form, and the gap of the butt joint test plate is set to 0.55 mm;

[0211] (2) the welding of the steel layer is performed, the welding adopts MAG welding (welding current 181 A), the welding material is ER50-6 welding wire, and the diameter of the welding wire is 1.2 mm;

[0212] (3) the test plate is turned over, and the near-steel layer welding wire of the present application is used to weld on the back of the above steel layer weld;

[0213] (4) the near-aluminum layer welding is performed on the above near-steel layer weld, the near-aluminum layer welding wire of the present application is selected, and the welding adopts MIG welding (welding current 82 A);

[0214] (5) finally, the ER1100 welding wire is used to complete the filling and cap welding of the aluminum side, the welding adopts MIG welding (welding current 110 A), and a multi-layer and multi-pass welding mode is adopted.

[0215] The aluminum-steel composite plate butt joint obtained by welding is observed for structure, tested for tensile strength and tested for microhardness, and the results are as follows:

[0216] (1) no defects are found in the near-steel layer weld and the near-aluminum layer weld;

[0217] (2) the tensile strength of the aluminum-steel composite plate butt joint is 340 MPa, and the microhardness of the aluminum-steel composite plate butt joint is 220 HV.

[0218] ​(2) The tensile strength of the joint is 379 MPa, and the elongation is 25.8%;

[0219] (3) The microhardness of the near-steel layer weld is 281HV0.3, and the microhardness of the near-aluminum layer weld is 220HV0.3.

[0220] Example 6

[0221] The specific steps of the method for preparing the near-aluminum layer welding wire for butt welding of aluminum-steel composite plates are as follows:

[0222] Step 1: The powder is weighed according to the mass percentage: Zn powder 42%, Sn powder 21%, Ti powder 6.5%, Mg powder 6.5%, Re powder 1.3%, and the rest is Al powder. The sum of the mass percentages of the above components is 100%.

[0223] The purity of each raw material component constituting the core of the near-aluminum layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 mesh.

[0224] Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated to a temperature of 110°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.

[0225] Step 3: Pure aluminum tape is used as the welding skin, and alcohol is used to remove the grease on the surface of the pure aluminum tape. The powder prepared in step 2 is wrapped in the pure aluminum tape through the wire drawing equipment of the flux-cored wire, and the first drawing die has a hole diameter of 2.6 mm. The welding skin of the near-aluminum layer welding wire is pure aluminum tape with a thickness of 0.3 mm and a width of 7 mm, and the filling amount of the welding wire is controlled at 20wt%.

[0226] Step 4: After the first drawing process is completed, the die hole diameter is gradually reduced, and finally a flux-cored wire with a diameter of 1.2 mm is obtained.

[0227] Step 5: After the drawing of the flux-cored wire 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.

[0228] The specific steps of the method for preparing the near-aluminum layer welding wire for butt welding of aluminum-steel composite plates are as follows:

[0229] Step 1: The powder is weighed according to the mass percentage: Zn powder 42%, Sn powder 21%, Ti powder 6.5%, Mg powder 6.5%, Re powder 1.3%, and the rest is Al powder. The sum of the mass percentages of the above components is 100%.

[0230] The purity of each raw material component constituting the core of the near-aluminum layer welding wire is ≥99.90%, and the particle size of the powder is 100-200 mesh.

[0231] Step 2: The powder weighed in step 1 was placed in a vacuum heating furnace and heated at 155°C for 1.3 hours to remove the crystal water in the powder; the dried powder was placed in a powder mixer and fully mixed for 1.3 hours;

[0232] Step 3: Use low-carbon steel strip as the weld skin, use alcohol to remove grease on the surface of the low-carbon steel strip, and wrap the powder prepared in step 2 in a pure aluminum strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6 mm; the weld skin of the near-steel layer welding wire is a low-carbon steel strip with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the welding wire is controlled at 20 wt%.

[0233] 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;

[0234] 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.

[0235] Aluminum-steel composite plate butt groove form (such as Figure 1 As shown in the figure, the aluminum-steel composite plate has an asymmetric X-shaped groove, where the steel side groove angle is 55° and the aluminum side groove angle is 65°, leaving no blunt edge. The center position of the steel side groove is 2.2mm below the aluminum-steel composite plate interface.

[0236] The method for butt welding aluminum-steel composite plates using the welding wire near the aluminum layer and the welding wire near the steel layer provided in Example 5 (eg Figure 2 The specific steps are as follows:

[0237] (1) The aluminum-steel composite plate is grooved in the above-mentioned manner, and the gap between the butt test plates is set to 0.55 mm;

[0238] (2) Welding of the steel layer was performed using MAG welding (welding current 181A), ER50-6 welding wire as the welding material, and a wire diameter of 1.2 mm;

[0239] (3) The test plate is turned over, and the back side of the steel layer weld is welded with the welding wire near the steel layer of the present invention, using MIG welding (welding current 110A);

[0240] (4) Performing near-aluminum layer welding on the above-mentioned near-steel layer weld, selecting the near-aluminum layer welding wire of the present invention, and adopting MIG welding (welding current 82A);

[0241] (5) Finally, ER1100 welding wire is used to complete the filling and cover welding of the aluminum side. The welding is done by MIG welding (welding current 110A) using a multi-layer and multi-pass welding method.

[0242] The butt joint of the welded aluminum-steel clad plate was observed, tensile strength test and microhardness test, and the results were as follows:

[0243] (1) No defects were found in the near-steel layer weld and the near-aluminum layer weld;

[0244] (2) The tensile strength of the joint was 378 MPa, and the elongation was 25.8%;

[0245] (3) The microhardness of the near-steel layer weld was 282 HV0.3, and the microhardness of the near-aluminum layer weld was 220 HV0.3.

Claims

1. Aluminum-steel composite plate butt welding material, characterized in that: Including welding materials for near aluminum layer and near steel layer; The welding material for the near-aluminum layer is a near-aluminum layer welding wire, including a flux core and a welding skin, wherein the flux core is composed of the following components by mass percentage: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder, and the sum of the mass percentages of the above components is 100%; The welding material used for the near-steel layer is the near-steel layer welding wire, including the flux core and the welding cover, wherein the flux core is composed of the following components by mass percentage: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest is Fe powder, and the sum of the mass percentages of the above components is 100%; The welding wire of the near-aluminum layer is made of pure aluminum strip with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the welding wire is controlled at 20 wt% to 25 wt%; The weld skin of the near-steel layer welding wire is a low-carbon steel strip with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the welding wire is controlled at 20 wt% to 22 wt%.

2. The aluminum-steel composite plate butt welding material according to claim 1, characterized in that: The purity of each raw material component constituting the flux core in the near-aluminum layer welding wire is ≥99.90%, and the particle size of the flux powder is 100-200 meshes.

3. The aluminum-steel composite plate butt welding material according to claim 1, characterized in that: The purity of each raw material component constituting the flux core in the near-steel layer welding wire is ≥99.90%, and the particle size of the flux powder is 100-200 meshes.

4. The aluminum-steel composite plate butt welding material according to claim 1, characterized in that: The specific steps of the method for preparing the near-aluminum layer welding wire are as follows: Step 1: Weigh the powders by mass percentage: Zn powder 40-50%, Sn powder 20-25%, Ti powder 5-10%, Mg powder 5-10%, Re powder 1-3%, and the rest is Al powder; Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 100°C to 150°C for 1 hour to 2 hours to remove the crystal water in the powder; the dried powder is placed in a powder mixer and fully mixed for 1 hour to 2 hours; Step 3: Use pure aluminum strip as welding skin, remove grease from the surface of the pure aluminum strip with alcohol, and wrap the powder prepared in step 2 inside the pure aluminum strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6mm; the filling amount of welding wire is controlled at 20wt%~25wt%; 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.

5. The aluminum-steel composite plate butt welding material according to claim 1, characterized in that: The specific steps of the method for preparing the near-steel layer welding wire are as follows: Step 1: Weigh the powders by mass percentage: Zn powder 40-50%, Ag powder 30-35%, Si powder 5-10%, and the rest Fe powder; Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace and heated at a temperature of 150°C to 200°C for 1 hour to 3 hours to remove the crystal water in the powder; the dried powder is placed in a powder mixer and fully mixed for 1 hour to 3 hours; Step 3: Use a low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in step 2 in a pure aluminum strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6mm; the filling amount of welding wire is controlled at 20wt%~22wt%; 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 method for butt welding of aluminum-steel composite plates, characterized in that: The aluminum-steel composite plate butt welding material according to claim 1 is used to weld the aluminum-steel composite plate, and the specific steps are as follows: (1) Make a welding groove on the aluminum-steel composite plate and set the gap between the butt test plates to 0.5mm~1mm; (2) Welding the steel layer using MAG welding, with a welding current of 180A to 220A, and ER50-6 welding wire as the welding material, with a wire diameter of 1.2mm; (3) Turn the test plate over and perform welding on the back of the steel layer weld using the near-steel layer welding wire described in claim 1, using MIG welding with a welding current of 100A to 150A; (4) Performing near-aluminum layer welding on the above-mentioned near-steel layer weld, selecting and using the near-aluminum layer welding wire described in claim 1, and using MIG welding with a welding current of 80A to 100A; (5) Finally, ER1100 welding wire is used to complete the filling and cover welding of the aluminum side. MIG welding is used, and the welding current is 100~150A; a multi-layer and multi-pass welding method is adopted.

7. The aluminum-steel composite plate butt welding method according to claim 6, characterized in that: The aluminum-steel composite plate has an asymmetric X-shaped groove, where the steel side groove angle is 50±5° and the aluminum side groove angle is 60±5°, leaving no blunt edge, and the center position of the steel side groove is 2mm~3mm below the aluminum-steel composite plate interface.

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