A composite tailor-welding method for improving the yield of an aluminum-silicon coated plate integrated door ring

Abstract

The application discloses a composite tailor-welding method for improving the yield of an aluminum-silicon coated plate integrated door ring, and belongs to the technical field of tailor-welding methods.The method comprises the following steps: preparing a plurality of door ring blanking pieces, all of which are aluminum-silicon coated plate materials; and connecting the blanking pieces into an integrated door ring by tailor-welding, wherein the connection mode between one blanking piece and the adjacent two sides is lap joint, the lap joint strength at the two places is realized by resistance spot welding, the other connections are butt joints, and the strength is realized by laser tailor-welding, the laser tailor-welding adopts a micro-sphere reinforced welding wire, and the preparation method of one of raw materials of the micro-sphere reinforced welding wire, porous micro-sphere composite metal powder, is modifying camphor by using cation starch modified kaolin and sodium lignosulfonate, and mixing the camphor with Al-Si-Sr alloy micro-sphere powder to form pores.Through the above method, the yield of the aluminum-silicon coated plate integrated door ring is improved.

Description

Technical Field

[0001] This invention relates to the field of welding methods, specifically to a composite welding method for improving the yield of integrated door rings made of aluminum-silicon coated panels. Background Technology

[0002] Aluminum-silicon coated hot-formed steel is widely used in automotive safety structural components, such as A-pillars, B-pillars, and door rings, due to its excellent high-temperature oxidation resistance and high strength achieved after quenching. Integrated door rings, as complex structural components that integrate multiple parts into one unit, can significantly improve vehicle body rigidity and collision safety, representing an important direction for the development of automotive lightweighting technology.

[0003] Existing technologies have made many improvements to the welding methods for door knockers. For example, Chinese patent CN111496380B discloses a welding manufacturing method for thin aluminum-silicon coated steel plates and a manufacturing method for door knockers. Step 1: The thickness of the coating on the thin aluminum-silicon coated steel plate is measured. Steel plates with a coating thickness between 8-13 micrometers are designated as Class A plates, those with a coating thickness between 13-20 micrometers are designated as Class B plates, and those with a coating thickness between 20-25 micrometers are designated as Class C plates. Step 2: For Class A plates, laser welding is used; for Class B plates... For Class C plates, direct filler wire welding is used; for Class C plates, indirect filler wire welding is used. The invention also relates to a method for manufacturing a door ring, which includes the following steps: Step 1: Using the above-mentioned method for welding thin aluminum-silicon coated steel plates, multiple thin aluminum-silicon coated steel plates are welded together to form a door ring material; Step 2: The door ring material is placed in a heating furnace and heated to 880-950°C, held for 150-500 seconds, and then stamped; Step 3: Excess material is removed by laser cutting; this method improves welding efficiency while ensuring welding quality.

[0004] However, the above-mentioned inventions and prior art have the following shortcomings: In the current technology, laser welding of door rings uses a process of single-sided welding with or without filler wire to splice multiple pieces together. This method leads to higher overall costs. In the above-mentioned invention, laser welding is used to weld the pieces with the coating removed in advance. However, after the weld shrinkage accumulates, this method will result in a large gap at the last interface, which is prone to welding quality problems and is not conducive to the subsequent assembly and structural safety of the door ring. Furthermore, the scrap sensitivity of the integrated door ring structure is very high because it is not just one of the welded plates that is scrapped, but the entire structure. Therefore, the cost of loss is also high.

[0005] Based on this, the present invention designs a composite welding method to improve the yield of integrated door rings with aluminum-silicon coated plates in order to solve the above problems. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a composite welding method to improve the yield of integrated door rings with aluminum-silicon coated plates.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A composite welding method for improving the yield of integrated door rings with aluminum-silicon coated panels includes the following steps:

[0009] 1. Select a suitable aluminum-silicon coated board;

[0010] 2. Cut the aluminum-silicon coated board from step one into the required size;

[0011] 3. The cut pieces from step 2 are spliced ​​together on the welding fixture platform. The pieces spliced ​​in this step do not include the threshold and the overlapping pieces at both ends of the threshold.

[0012] IV. Adjust the parameters of the laser welding equipment and perform laser welding on the part that was spliced ​​in step three. The gap at the laser welding joint is connected by filler wire welding. The welding wire used is microsphere reinforced welding wire. After the laser welding is completed, sub-assembly A is obtained.

[0013] 5. Transfer sub-assembly A to the resistance spot welding fixture;

[0014] 6. The door sill is spliced ​​to the sub-assembly by the overlapping material at both ends of the door sill; the splicing method is overlapping.

[0015] 7. Perform resistance spot welding on the overlapped materials to obtain the composite welded aluminum-silicon coated plate integrated door ring.

[0016] The microsphere-reinforced welding wire is prepared from the following raw materials: pure aluminum ingots, aluminum-silicon alloys, porous microsphere composite metal powders, aluminum-manganese alloys, aluminum-copper alloys, and zinc-aluminum alloys.

[0017] The preparation method of the porous microsphere composite metal powder is as follows:

[0018] (1) Modified camphor was obtained by using cationic starch-modified kaolin and sodium lignosulfonate to modify camphor into modified camphor pore-forming agent powder.

[0019] (2) Si, Sr and Al are melted into an alloy liquid in a vacuum induction melting furnace, and Al-Si-Sr alloy microsphere powder is prepared by tight coupling gas atomization technology;

[0020] (3) The Al-Si-Sr alloy microsphere powder and the modified camphor pore-forming agent are mixed evenly in a three-dimensional mixer at a volume ratio of 70-80:8-15;

[0021] (4) The uniformly mixed powder is then loaded into a mold and hot-extruded at 130-150℃ and 200-400MPa to form a billet;

[0022] (5) The billet is first treated at 180-280℃ for 1-2 hours, and then treated at 580-680℃ for 2-4 hours. After the heat treatment is completed, it is crushed and vibrated to obtain porous microsphere composite metal powder.

[0023] Furthermore, in step two, laser cutting is used to cut the shape.

[0024] In step three, the tooling uses a three-point positioning design for positioning the material pieces. Each material piece is equipped with a permanent magnet or electromagnet on the positioning block below it. The contact surfaces are all in a horizontal plane. The laser head is located above the stepped surface. This process is single-sided welding and double-sided forming.

[0025] In step four, before welding, a laser gun or lidar should be used to locate the welding area and mark it to ensure that the laser head does not deviate from the correct trajectory.

[0026] In step five, the movement process utilizes an end effector to ensure that the sub-assembly is not twisted;

[0027] In step six, the two overlaps are on the laser welding plane side, i.e., the non-step side, with an overlap length of 16-20mm;

[0028] In the resistance spot welding of step seven, medium-frequency DC is used for resistance spot welding at the lap joint.

[0029] Furthermore, the microsphere-reinforced welding wire is prepared from 500-600 parts of pure aluminum ingot, 200-250 parts of aluminum-silicon alloy, 10-20 parts of porous microsphere composite metal powder, 10-15 parts of aluminum-manganese alloy, 5-8 parts of aluminum-copper alloy and 3-5 parts of zinc-aluminum alloy.

[0030] The aluminum-silicon alloy is ZL102 aluminum alloy, the aluminum-copper alloy is ZL202 aluminum alloy, and the zinc-aluminum alloy is Zn-22Al alloy.

[0031] Furthermore, the specific process of step (1) of the porous microsphere composite metal powder is as follows:

[0032] Camphor is ground into camphor powder with a particle size of 10-50 micrometers;

[0033] Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A.

[0034] The mass of kaolin modified with cationic starch is 5-10% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 3-5% of the total mass of camphor powder.

[0035] Mixed solution A is added to camphor powder stirred at high speed by spraying to ensure uniform coating, and then vacuum dried at 40-50℃ to obtain modified camphor pore-forming agent powder.

[0036] Furthermore, the specific process of step (2) of the porous microsphere composite metal powder is as follows:

[0037] Weigh out 10-20% Si and 1-3% Sr by weight percentage, with the balance being Al;

[0038] The above-mentioned Si, Sr and Al are melted into an alloy liquid in a vacuum induction melting furnace. The alloy liquid is then flowed out through a guide tube using a tight-coupled gas atomization technology. It is broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder. Powder with a size of 45-150 micrometers is screened out for later use.

[0039] Furthermore, the specific process of step (3) of the porous microsphere composite metal powder is as follows:

[0040] Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 70-80:8-15 and mechanically stirred at low speed for 2-4 hours under an inert atmosphere.

[0041] To better achieve the objectives of this invention, this invention also provides a composite welding method for improving the yield of integrated door rings with aluminum-silicon coated plates, applied to the welding of integrated double door rings and ring-shaped closed splicing structures.

[0042] To better achieve the objectives of this invention, this invention also provides a composite welding method for preparing an integrated door ring that improves the yield of integrated door rings made from aluminum-silicon coated plates.

[0043] Compared with the prior art, the beneficial effects of this invention are as follows: the final process of resistance spot welding avoids the difficulties of laser welding caused by the accumulation of gaps. Resistance welding is not as strict as laser welding in terms of the positional deviation between two workpieces, which is generally greater than or equal to 1.0 mm. By using lap resistance spot welding to splice the last piece of the door ring, the highest yield rate can be ensured. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0045] Figure 1This is a schematic diagram of the structure of the sheet material formed after the aluminum-silicon coated plate is cut and shaped in this invention;

[0046] Figure 2 This is a schematic diagram of the structure of sub-assembly A after laser welding according to the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of the resistance spot-welded door ring assembly of the present invention;

[0048] Figure 4 This is a schematic diagram of the tensile test conducted in the experimental example of the present invention.

[0049] Figure 5 A summary diagram of the weld hardness test results for this invention;

[0050] Figure 6 This invention provides a process flow for a composite welding method to improve the yield of integrated door rings with aluminum-silicon coated panels. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] Example 1: A composite welding method for improving the yield of integrated door rings with aluminum-silicon coated panels, specifically including the following steps:

[0053] (I) Preparation of porous microsphere composite metal powder

[0054] Step 1: Preparation of cationic starch-modified kaolin

[0055] Prepare a 5% cationic starch aqueous suspension and stir continuously in an 85°C water bath for 30 minutes to obtain a gelatinized cationic starch solution.

[0056] Kaolin was dispersed in deionized water to obtain a 15% kaolin slurry. The slurry was stirred at high speed to ensure full dispersion, and the pH was adjusted to 8.

[0057] The gelatinized cationic starch solution was slowly added dropwise to the kaolin slurry, and the mixture was continuously mechanically stirred at 70°C for 60 minutes. After the reaction was completed, the kaolin was obtained by washing, drying, crushing and sieving.

[0058] Step 2: Preparation of modified camphor pore-forming agent

[0059] Camphor is ground into camphor powder with a particle size of 10 micrometers;

[0060] Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A.

[0061] The mass of kaolin modified with cationic starch is 5% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 5% of the total mass of camphor powder.

[0062] Mixed solution A was added to camphor powder by spraying to ensure uniform coating, and then vacuum dried at 10°C to obtain modified camphor pore-forming agent powder.

[0063] Step 3: Alloy smelting and microsphere forming treatment

[0064] Weigh out 10% Si and 3% Sr by weight, with the balance being Al.

[0065] The Si, Sr and Al were melted into an alloy liquid in a vacuum induction melting furnace. The alloy liquid was then flowed out through a guide tube using a tight-coupled gas atomization technology. It was broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder with high sphericity and controllable particle size distribution. Powder with a particle size of 45 micrometers was screened out for later use.

[0066] Step 4: Mixing and Billet Preparation

[0067] Mixing: Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 70:8 and mechanically stirred at low speed for 2 hours under an inert atmosphere.

[0068] Hot extrusion: The uniformly mixed powder is then loaded into a mold and hot extruded at 130°C and 400 MPa. This process causes the alloy microspheres to undergo plastic deformation, bond tightly together, and uniformly extrudes and fills the contact points between and inside the spheres with softened camphor pore-forming agent, forming a billet.

[0069] Step 5: Removal of pore-forming agent and formation of porous microspheres

[0070] The billet was first treated at 180℃ for 2 hours, then at 580℃ for 4 hours. After heat treatment, it was lightly crushed by a jaw crusher and a double roll crusher, and then obtained by vibrating sieve to obtain porous microsphere composite metal powder.

[0071] (II) Preparation of microsphere-reinforced welding wire

[0072] Add 500 parts of pure aluminum ingots, 250 parts of aluminum-silicon alloy (ZL102 aluminum alloy), 10 parts of porous microsphere composite metal powder, 15 parts of aluminum-manganese alloy, 5 parts of aluminum-copper alloy (ZL202 aluminum alloy) and 5 parts of zinc-aluminum alloy (Zn-22Al alloy) to a melting furnace and heat to melt to obtain composite aluminum liquid.

[0073] After refining and ultrasonically degassing the composite filtrate, it is continuously cast and extruded. The wire rod blank extruded by continuous casting and extrusion is cooled and wound into a coil. Then, the wire rod blank is continuously drawn using a wire drawing machine to obtain a wire blank with a diameter of 4.5 mm. After intermediate annealing, the wire blank is drawn to near the finished product size and then processed through two consecutive peeling processes to produce a finished welding wire with a diameter of 2.0 mm.

[0074] (III) Composite welding of aluminum-silicon coated plate integrated door ring

[0075] The process flow diagram for the composite welding of aluminum-silicon coated panels into an integrated door ring is as follows: Figure 6 As shown, the specific steps are as follows:

[0076] Step 1: Prepare materials

[0077] Select an appropriate aluminum-silicon coated board;

[0078] Step 2: Cutting and Shaping

[0079] like Figure 1 As shown, the aluminum-silicon coated plate in step one is cut into pieces of the required size using laser cutting.

[0080] Step 3: One-time splicing

[0081] The cut pieces from step two are spliced ​​together on a welding fixture platform. The pieces spliced ​​in this step do not include the threshold and the overlapping pieces at both ends of the threshold.

[0082] Step 4: Laser Welding

[0083] Adjust the parameters of the laser welding equipment and perform laser welding on the part assembled in step three. The welding wire used is a microsphere-reinforced welding wire. After laser welding, sub-assembly A is obtained. The structural diagram of sub-assembly A is shown below. Figure 2 As shown;

[0084] Step 5: Sub-assembly transfer

[0085] Transfer sub-assembly A to the resistance spot welding fixture;

[0086] Step Six: Secondary splicing

[0087] like Figure 3As shown, the door sill is spliced ​​to the sub-assembly by the overlapping material pieces at both ends of the door sill. The splicing method is overlapping, and the overlap length is 16mm.

[0088] Step 7: Resistance spot welding

[0089] Resistance spot welding is performed on the materials assembled in step seven. After completion, an integrated door ring with aluminum-silicon coated plate after composite welding is obtained. The prepared product is recorded as sample 1.

[0090] Example 2: A composite welding method for improving the yield of integrated door rings with aluminum-silicon coated panels, specifically including the following steps:

[0091] (I) Preparation of porous microsphere composite metal powder

[0092] Step 1: Preparation of modified camphor pore-forming agent

[0093] Camphor is ground into camphor powder with a particle size of 50 micrometers;

[0094] Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A.

[0095] The mass of kaolin modified with cationic starch is 10% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 3% of the total mass of camphor powder.

[0096] Mixed solution A was added to camphor powder being stirred at high speed using a spray method to ensure uniform coating, and then vacuum dried at 50°C to obtain modified camphor pore-forming agent powder.

[0097] Step 2: Alloy smelting and microsphere forming treatment

[0098] Weigh 20% Si and 1% Sr by weight, with the balance being Al.

[0099] The Si, Sr and Al were melted into an alloy liquid in a vacuum induction melting furnace. The alloy liquid was then flowed out through a guide tube using a tight-coupled gas atomization technology. It was broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder with high sphericity and controllable particle size distribution. Powder with a particle size of 150 micrometers was screened out for later use.

[0100] Step 3: Mixing and billet preparation

[0101] Mixing: Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 80:15 and mechanically stirred at low speed for 4 hours under an inert atmosphere.

[0102] Hot extrusion: The uniformly mixed powder is then loaded into a mold and hot extruded at 150°C and 200 MPa. This process causes the alloy microspheres to undergo plastic deformation, bond tightly together, and uniformly extrudes and fills the contact points between and inside the spheres with softened camphor pore-forming agent, forming a billet.

[0103] Step 4: Removal of pore-forming agent and formation of porous microspheres

[0104] The billet was first treated at 280℃ for 1 hour, then at 580℃ for 2 hours. After heat treatment, it was lightly crushed by a jaw crusher and a double roll crusher, and then obtained by vibrating sieve to obtain porous microsphere composite metal powder.

[0105] (II) Preparation of microsphere-reinforced welding wire

[0106] Add 600 parts of pure aluminum ingots, 200 parts of aluminum-silicon alloy (ZL102 aluminum alloy), 20 parts of porous microsphere composite metal powder, 10 parts of aluminum-manganese alloy, 8 parts of aluminum-copper alloy (ZL202 aluminum alloy) and 3 parts of zinc-aluminum alloy (Zn-22Al alloy) to a melting furnace and heat to melt to obtain composite aluminum liquid.

[0107] The other steps are the same as in Example 1, and the product obtained is referred to as Sample 2.

[0108] Example 3: A composite welding method for improving the yield of integrated door rings with aluminum-silicon coated panels, specifically including the following steps:

[0109] (I) Preparation of porous microsphere composite metal powder

[0110] Step 1: Preparation of modified camphor pore-forming agent

[0111] Camphor is ground into camphor powder with a particle size of 25 micrometers;

[0112] Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A.

[0113] The mass of kaolin modified with cationic starch is 8% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 4% of the total mass of camphor powder.

[0114] Mixed solution A was added to camphor powder by spraying to ensure uniform coating, and then vacuum dried at 45°C to obtain modified camphor pore-forming agent powder.

[0115] Step 2: Alloy smelting and microsphere forming treatment

[0116] Weigh out 15% Si and 2% Sr by weight, with the balance being Al.

[0117] The Si, Sr and Al were melted into an alloy liquid in a vacuum induction melting furnace. The alloy liquid was then flowed out through a guide tube using a tight-coupled gas atomization technology. It was broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder with high sphericity and controllable particle size distribution. Powder with a particle size of 100 micrometers was screened out for later use.

[0118] Step 3: Mixing and billet preparation

[0119] Mixing: Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 75:9 and mechanically stirred at low speed for 3 hours under an inert atmosphere.

[0120] Hot extrusion: The uniformly mixed powder is then loaded into a mold and hot extruded at 140°C and 300 MPa. This process causes the alloy microspheres to undergo plastic deformation, bond tightly together, and uniformly extrudes and fills the contact points between and inside the spheres with softened camphor pore-forming agent, forming a billet.

[0121] Step 4: Removal of pore-forming agent and formation of porous microspheres

[0122] The billet was first treated at 200℃ for 1.5 hours, then at 650℃ for 3 hours. After heat treatment, it was lightly crushed by a jaw crusher and a double roll crusher, and then obtained by vibrating sieve to obtain porous microsphere composite metal powder.

[0123] (II) Preparation of microsphere-reinforced welding wire

[0124] Add 550 parts of pure aluminum ingots, 220 parts of aluminum-silicon alloy (ZL102 aluminum alloy), 15 parts of porous microsphere composite metal powder, 12 parts of aluminum-manganese alloy, 6 parts of aluminum-copper alloy (ZL202 aluminum alloy) and 4 parts of zinc-aluminum alloy (Zn-22Al alloy) to a melting furnace and heat to melt to obtain composite aluminum liquid.

[0125] The other steps are the same as in Example 1, and the product obtained is designated as Sample 3.

[0126] Example 4: A composite welding method for improving the yield of integrated door rings with aluminum-silicon coated panels, specifically including the following steps:

[0127] (I) Preparation of porous microsphere composite metal powder

[0128] Step 1: Preparation of modified camphor pore-forming agent

[0129] Camphor is ground into camphor powder with a particle size of 20 micrometers;

[0130] Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A.

[0131] The mass of kaolin modified with cationic starch is 6% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 3.5% of the total mass of camphor powder.

[0132] Mixed solution A was added to camphor powder being stirred at high speed using a spray method to ensure uniform coating, and then vacuum dried at 42°C to obtain modified camphor pore-forming agent powder.

[0133] Step 2: Alloy smelting and microsphere forming treatment

[0134] Weigh out 12% Si and 1.5% Sr by weight, with the balance being Al.

[0135] The Si, Sr and Al were melted into an alloy liquid in a vacuum induction melting furnace. The alloy liquid was then flowed out through a guide tube using a tight-coupled gas atomization technology. It was broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder with high sphericity and controllable particle size distribution. Powder with a particle size of 60 micrometers was screened out for later use.

[0136] Step 3: Mixing and billet preparation

[0137] Mixing: Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 72:10 and mechanically stirred at low speed for 2.5 hours under an inert atmosphere.

[0138] Hot extrusion: The uniformly mixed powder is then loaded into a mold and hot extruded at 135°C and 250 MPa. This process causes the alloy microspheres to undergo plastic deformation, bond tightly together, and uniformly extrudes and fills the contact points between and inside the spheres with softened camphor pore-forming agent, forming a billet.

[0139] Step 4: Removal of pore-forming agent and formation of porous microspheres

[0140] The billet was first treated at 200℃ for 1.2 hours, then at 600℃ for 2.5 hours. After heat treatment, it was lightly crushed by a jaw crusher and a double roll crusher, and then obtained by vibrating sieve to obtain porous microsphere composite metal powder.

[0141] (II) Preparation of microsphere-reinforced welding wire

[0142] Add 520 parts of pure aluminum ingots, 210 parts of aluminum-silicon alloy (ZL102 aluminum alloy), 12 parts of porous microsphere composite metal powder, 11 parts of aluminum-manganese alloy, 5.5 parts of aluminum-copper alloy (ZL202 aluminum alloy) and 3.5 parts of zinc-aluminum alloy (Zn-22Al alloy) to a melting furnace and heat to melt to obtain composite aluminum liquid.

[0143] The other steps are the same as in Example 1, and the product obtained is designated as Sample 4.

[0144] Example 5: A composite welding method for improving the yield of integrated door rings with aluminum-silicon coated panels, specifically including the following steps:

[0145] (I) Preparation of porous microsphere composite metal powder

[0146] Step 1: Preparation of modified camphor pore-forming agent

[0147] Camphor is ground into camphor powder with a particle size of 40 micrometers;

[0148] Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A.

[0149] The mass of kaolin modified with cationic starch is 9% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 4.5% of the total mass of camphor powder.

[0150] Mixed solution A was added to camphor powder stirred at high speed by spraying to ensure uniform coating, and then vacuum dried at 48°C to obtain modified camphor pore-forming agent powder.

[0151] Step 2: Alloy smelting and microsphere forming treatment

[0152] Weigh out 18% Si and 2.5% Sr by weight, with the balance being Al.

[0153] The Si, Sr and Al were melted into an alloy liquid in a vacuum induction melting furnace. Using a tight-coupled gas atomization technology, the alloy liquid was flowed out through a guide tube, broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder with high sphericity and controllable particle size distribution. Powder with a particle size of 120 micrometers was screened out for later use.

[0154] Step 3: Mixing and billet preparation

[0155] Mixing: Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 78:10 and mechanically stirred at low speed for 3.5 hours under an inert atmosphere.

[0156] Hot extrusion: The uniformly mixed powder is then loaded into a mold and hot extruded at 145°C and 350 MPa. This process causes the alloy microspheres to undergo plastic deformation, bond tightly together, and uniformly extrudes and fills the contact points between and inside the spheres with softened camphor pore-forming agent, forming a billet.

[0157] Step 4: Removal of pore-forming agent and formation of porous microspheres

[0158] The billet was first treated at 250℃ for 1.75 hours, then at 665℃ for 3.5 hours. After heat treatment, it was lightly crushed by a jaw crusher and a double roll crusher, and then obtained by vibrating sieve to obtain porous microsphere composite metal powder.

[0159] (II) Preparation of microsphere-reinforced welding wire

[0160] Add 580 parts of pure aluminum ingots, 240 parts of aluminum-silicon alloy (ZL102 aluminum alloy), 18 parts of porous microsphere composite metal powder, 14 parts of aluminum-manganese alloy, 7.5 parts of aluminum-copper alloy (ZL202 aluminum alloy) and 4.5 parts of zinc-aluminum alloy (Zn-22Al alloy) to a melting furnace and heat to melt to obtain composite aluminum liquid.

[0161] The other steps are the same as in Example 1, and the product obtained is designated as Sample 5.

[0162] Example 6: In the composite welding of the integrated door ring with aluminum-silicon coated plates in Examples 1-5, the specific parameters are as follows:

[0163] I. The specific parameters involved in steps one through three are as follows:

[0164] 1. Parts appearance: The surface is clean and free of foreign objects, scratches, dents, rust, oil stains, coating peeling, and edge damage;

[0165] 2. The overall flatness of the sheet material is ≤1mm, and the product is free from deformation;

[0166] 3. The welded edges are free from warping and wavy edges, and the edge warping is ≤8% of the plate thickness;

[0167] 4. Straightness requirements for welded edges: The straightness of a single sheet must be less than 0.06mm; the gap between two sheets must be less than 0.1mm.

[0168] 5. Weld position accuracy (ensuring repeatability): ≤0.05mm;

[0169] 6. Contour accuracy (ensuring repeatability): Contour accuracy and positional accuracy relative to the weld ≤ 0.05mm;

[0170] 7. Burr height: Burrs ≤ 6% of plate thickness, but the maximum burr shall not exceed 0.1mm.

[0171] II. The specific parameters for laser welding are as follows:

[0172] 1. Welding wire diameter: 2.0mm;

[0173] 2. Laser power 6 kW, laser spot welding diameter 0.7 mm;

[0174] 3. Welding speed: 3.5-5 m / min, with different segmented speeds and power matching set for each weld.

[0175] 4. The wire feeding speed should be 0.6-2 m / min, and the wire feeding speed should be matched with the welding speed and power.

[0176] 5. The protective gas purity is 99.999% argon; flow control is used, with an argon flow rate of 12-15 liters / minute;

[0177] 6. Take tensile test specimens from the welded door ring sub-assembly using laser cutting, cutting perpendicular to the weld seam, with the weld seam located in the exact center of the specimen.

[0178] 7. Place the sample in the furnace and heat it at 950 degrees for 4 minutes. Then quench it within 7 seconds using a flat mold with water channels inside. Cool for 10 seconds with a water temperature of 15 degrees. The tensile test requires that the fracture occurs in the base material, which means that the strength of the weld must be at least higher than that of the base material on one side.

[0179] 8. Weld hardness sampling: Cut samples perpendicular to the weld direction. Along the neutral layer of the thin plate in the joint section, starting from one side of the base material and ending at the other side, perform hardness tests at equal intervals of 0.2 mm. There should be at least 3 test points on each side of the base material.

[0180] III. The specific parameters for resistance spot welding are as follows:

[0181] 1. The resistance spot welding power supply uses medium-frequency DC, with an electrode diameter of 16mm; the upsetting force (clamping force of the upper and lower electrodes) is 4500 Newtons; the current is 8000 Amps.

[0182] 2. The base plate thickness (GMT) is taken as the threshold plate thickness, which is generally designed to be 1 mm, i.e., GMT = 1 mm; the solder joint spacing is 20 mm.

[0183] 3. Conduct a tearing and breakage test. Calculate the average melt core diameter according to the melt core calculation formula. Based on GMT=1mm, the melt core size is 4mm. Generally, the melt core shape is elliptical after tearing. To evaluate the melt core, first measure the values ​​dp1 and dp2 in the two directions of the major and minor axes, then add them together and divide by 2. Use this result to evaluate the melt core size, i.e., (dp1+dp2) / 2=4mm.

[0184] Comparative Example 1: Compared with Example 3, porous microsphere composite metal powder was not added during the preparation of the microsphere-reinforced welding wire.

[0185] The other steps are the same as in Example 3, and the product obtained is designated as Sample 6.

[0186] Comparative Example 2: Compared with Example 3, the difference is that commercially available ER4047 aluminum welding wire was used instead of microsphere reinforced welding wire.

[0187] The other steps are the same as in Example 3, and the product obtained is designated as Sample 7.

[0188] Experimental example:

[0189] (1) The door ring products prepared by the methods in Examples 1-5 were subjected to hardness testing. The results of the hardness testing are as follows: Figure 5 As shown, the average weld hardness of the five groups of products prepared using this method is higher than that of the average hardness of the softer substrate, and does not exceed the average hardness of the harder substrate by more than 50 HIV. This proves that the weld hardness of the integrated door ring prepared using this welding method is qualified, and the yield rate is 100%.

[0190] (2) Tensile tests were conducted on the product samples prepared in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1, and the schematic diagram of the tensile test site is shown in the figure. Figure 4 As shown.

[0191] Table 1 Summary of Tensile Test Results

[0192]

[0193] As shown in Table 1, the fracture locations of samples 1-5 were all in the base material, and the tensile strength was above the required strength. The welding quality of all samples was qualified. The fracture locations of samples 6-7 were all at the weld seam, and the welding quality was poor. That is, if porous microsphere composite metal powder is not added during the preparation of microsphere reinforced welding wire, the tensile test of the prepared product samples will fail and the product yield will decrease. If commercially available ER4047 aluminum welding wire is used instead of microsphere reinforced welding wire, the tensile test of the prepared product samples will fail and the product yield will decrease.

[0194] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite tailor-welding method for improving the yield of an integrated door ring of an aluminum-silicon coated sheet, characterized by, Includes the following steps:

1. Select appropriate aluminum-silicon coated boards; 2. Cut the aluminum-silicon coated board from step one into the required size; 3. The cut pieces from step 2 are spliced ​​together on the welding fixture platform. The pieces spliced ​​in this step do not include the threshold and the overlapping pieces at both ends of the threshold. IV. Adjust the parameters of the laser welding equipment and perform laser welding on the part that was spliced ​​in step three. The gap at the laser welding joint is connected by filler wire welding. The welding wire used is microsphere reinforced welding wire. After the laser welding is completed, sub-assembly A is obtained.

5. Transfer sub-assembly A to the resistance spot welding fixture; 6. The door sill is spliced ​​to the sub-assembly by the overlapping material at both ends of the door sill; the splicing method is overlapping.

7. Perform resistance spot welding on the overlapped materials to obtain the composite welded aluminum-silicon coated plate integrated door ring. The microsphere-reinforced welding wire is prepared from the following raw materials: pure aluminum ingots, aluminum-silicon alloys, porous microsphere composite metal powders, aluminum-manganese alloys, aluminum-copper alloys, and zinc-aluminum alloys. The preparation method of the porous microsphere composite metal powder is as follows: (1) Modified camphor was obtained by using cationic starch-modified kaolin and sodium lignosulfonate to modify camphor into modified camphor pore-forming agent powder. (2) Si, Sr and Al are melted into an alloy liquid in a vacuum induction melting furnace, and Al-Si-Sr alloy microsphere powder is prepared by tight coupling gas atomization technology; (3) The Al-Si-Sr alloy microsphere powder and the modified camphor pore-forming agent are mixed evenly in a three-dimensional mixer at a volume ratio of 70-80:8-15; (4) The uniformly mixed powder is then loaded into a mold and hot-extruded at 130-150℃ and 200-400MPa to form a billet; (5) The billet is first treated at 180-280℃ for 1-2 hours, and then treated at 580-680℃ for 2-4 hours. After the heat treatment is completed, it is crushed and vibrated to obtain porous microsphere composite metal powder.

2. The composite welding method for improving the yield of integrated door rings with aluminum-silicon coated plates according to claim 1, characterized in that: In step two, laser cutting is used to cut the shape. In step three, the tooling uses a three-point positioning design for positioning the material pieces. Each material piece is equipped with a permanent magnet or electromagnet on the positioning block below it. The contact surfaces are all in a horizontal plane. The laser head is located above the stepped surface. This process is single-sided welding and double-sided forming. In step four, before welding, a laser gun or lidar should be used to locate the welding area and mark it to ensure that the laser head does not deviate from the correct trajectory. In step five, the movement process utilizes an end effector to ensure that the sub-assembly is not twisted; In step six, the two overlaps are on the laser welding plane side, i.e., the non-step side, with an overlap length of 16-20mm; In the resistance spot welding of step seven, medium-frequency DC is used for resistance spot welding at the lap joint.

3. The composite welding method for improving the yield of integrated door rings with aluminum-silicon coated plates according to claim 2, characterized in that, The microsphere-reinforced welding wire is prepared from 500-600 parts of pure aluminum ingot, 200-250 parts of aluminum-silicon alloy, 10-20 parts of porous microsphere composite metal powder, 10-15 parts of aluminum-manganese alloy, 5-8 parts of aluminum-copper alloy and 3-5 parts of zinc-aluminum alloy. The aluminum-silicon alloy is ZL102 aluminum alloy, the aluminum-copper alloy is ZL202 aluminum alloy, and the zinc-aluminum alloy is Zn-22Al alloy.

4. The method of claim 3, wherein the method is characterized by: The specific process of step (1) of porous microsphere composite metal powder is as follows: Camphor is ground into camphor powder with a particle size of 10-50 micrometers; Cationic starch-modified kaolin was dissolved in deionized water, and sodium lignosulfonate was added and stirred until completely dissolved to obtain mixed solution A. The mass of kaolin modified with cationic starch is 5-10% of the total mass of camphor powder, and the mass of sodium lignosulfonate is 3-5% of the total mass of camphor powder. Mixed solution A is added to camphor powder stirred at high speed by spraying to ensure uniform coating, and then vacuum dried at 40-50℃ to obtain modified camphor pore-forming agent powder.

5. The composite welding method for improving the yield of integrated door rings with aluminum-silicon coated plates according to claim 4, characterized in that, The specific process of step (2) of porous microsphere composite metal powder is as follows: Weigh out 10-20% Si and 1-3% Sr by weight percentage, with the balance being Al; The above-mentioned Si, Sr and Al are melted into an alloy liquid in a vacuum induction melting furnace. The alloy liquid is then flowed out through a guide tube using a tight-coupled gas atomization technology. It is broken up by a high-speed inert gas and rapidly cooled to form Al-Si-Sr alloy microsphere powder. Powder with a size of 45-150 micrometers is screened out for later use.

6. The composite welding method for improving the yield of integrated door rings with aluminum-silicon coated plates according to claim 5, characterized in that, The specific process of step (3) of porous microsphere composite metal powder is as follows: Al-Si-Sr alloy microsphere powder and modified camphor pore-forming agent were placed in a three-dimensional mixer at a volume ratio of 70-80:8-15 and mechanically stirred at low speed for 2-4 hours under an inert atmosphere.

7. The application of a composite welding method for improving the yield of integrated door rings with aluminum-silicon coated plates according to any one of claims 1-6 in welding integrated double door rings and those with a ring-shaped closed splicing structure.

8. An integrated door ring prepared by a composite welding method according to any one of claims 1-6 to improve the yield of integrated door rings with aluminum-silicon coated plates.

Images