Method for producing an al-mg alloy wire for fasteners

Abstract

This invention relates to a method for preparing Al-Mg alloy wire for fasteners, specifically a method for manufacturing aluminum alloy wire for fasteners. The invention aims to solve the technical problems of achieving uniform microstructure and properties and controlling the stability of high-precision surface quality in the industrial-scale batch production of Al-Mg alloy wire. Currently, the tensile strength of imported Al-Mg alloy wire on the market is 305 MPa to 358 MPa, while the tensile strength of the Al-Mg alloy wire prepared by this invention is 320 MPa to 354 MPa, comparable to imported materials. This allows the Al-Mg alloy wire to not only meet the design and material selection requirements for blind rivets but also facilitate its widespread use in the connection of other aerospace and rail transportation structural components. The Al-Mg alloy wire prepared by this invention is used in blind rivets.

Description

Technical Field

[0001] This invention relates to the field of a method for manufacturing Al-Mg alloy wire for fasteners. Background Technology

[0002] Currently, Al-Mg alloy wire is mainly used in low- to mid-range solid rivets in the domestic fastener industry. To address the production bottlenecks in Al-Mg alloy wire manufacturing technology (industrialized batch production microstructure and performance uniformity and high-precision surface quality stability control technology), it is necessary to conduct domestic research and development and application studies on Al-Mg alloy wire for fasteners. This will improve the maturity of Al-Mg alloy wire manufacturing technology and its stable batch production capability, enabling Al-Mg alloy wire to not only meet the design and material selection requirements of blind rivets but also facilitate its widespread use in the connection of other aerospace and rail transportation structural components. Summary of the Invention

[0003] The present invention aims to solve the technical problems of difficulty in controlling the uniformity of microstructure and properties and the stability of high-precision surface quality in the industrial batch production of existing Al-Mg alloy wires, and provides a method for preparing Al-Mg alloy wires for fasteners.

[0004] The method for preparing the Al-Mg alloy wire for fasteners of the present invention is as follows:

[0005] 1. The Al-Mg alloy ingot is extruded, straightened and sawn to obtain Al-Mg alloy extruded bars;

[0006] 2. The Al-Mg alloy extruded bar prepared in step 1 is rolled by hot continuous rolling to obtain a large hot rolled coil.

[0007] 3. Anneal the large hot-rolled coil obtained in step 2 at a temperature of 350℃~420℃ for 2h~6h, and air cool after taking it out of the furnace.

[0008] 4. The hot-rolled coil after annealing in step 3 is cold-rolled to a predetermined diameter wire, and then annealed at a temperature of 350℃~420℃ for 2h~6h. After exiting the furnace, it is air-cooled to obtain cold-rolled coil wire.

[0009] 5. The cold-rolled coiled wire obtained in step 4 is drawn into finished diameter wire through multiple drawing passes. Annealing is required before each drawing pass. The annealing temperature is 350℃~420℃, and the holding time is 2h~6h. After exiting the furnace, it is air-cooled.

[0010] 6. The finished diameter wire obtained in step 5 is subjected to finished product annealing at a temperature of 100℃~300℃ for 2h~6h. After being taken out of the furnace, it is air-cooled to obtain an Al-Mg alloy wire for fasteners.

[0011] The preparation method of the Al-Mg alloy ingot in step one of this invention is carried out according to the following steps (this is a conventional technique):

[0012] A. According to the mass percentage of each element: Mg 4.5%~5.6%, Mn 0.05%~0.20%, Cr 0.05%~0.20%, Ti 0.005%~0.04%, Si <0.3%, Fe <0.4%, with the balance being Al, weigh out pure aluminum ingots, pure magnesium ingots, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-titanium-boron wire grain refiner; wherein, the aluminum-manganese master alloy is an Al-10%Mn alloy, the aluminum-chromium master alloy is an Al-3%Cr alloy, the aluminum-titanium master alloy is an Al-5%Ti alloy, and the aluminum-titanium-boron wire grain refiner is an Al-5%Ti-1%B alloy;

[0013] B. Add the pure aluminum ingots, aluminum-manganese master alloy, and aluminum-chromium master alloy weighed in step A to the melting furnace, heat to 700~750℃, melt and stir, remove slag, add pure magnesium ingots, add No. 2 covering agent, melt for 15min~30min, then refine with argon gas until the hydrogen content in 100g of aluminum alloy melt is ≤0.15mL, let stand for 30min to obtain aluminum alloy melt; No. 2 covering agent is No. 2 flux, which is composed of (30%~50%)KCl, (35%~50%)MgCl2 and (3%~10%)BaCl2 by weight percentage; the amount of No. 2 covering agent is 0.1%~0.6% of the total mass of the melt in the melting furnace;

[0014] C. The aluminum alloy melt obtained in step B is filtered sequentially through ceramic filters of 30 ppi and 50 ppi, and then poured into a crystallizer. At the same time, an aluminum-titanium-boron wire grain refiner is inserted into the flow channel and uniformly melted into the aluminum alloy melt. The insertion speed of the aluminum-titanium-boron wire grain refiner is 320 mm / min. Under the conditions of temperature of 700℃~750℃, water pressure of 0.045MPa~0.2MPa and speed of 22mm / min~60mm / min, Al-Mg alloy ingots with a diameter of 420mm or 170mm and a length of 1500mm~5500mm are cast.

[0015] The beneficial effects of this invention are as follows: the tensile strength of imported Al-Mg alloy wires on the market is currently 305MPa~358MPa, while the tensile strength of the Al-Mg alloy wires prepared by this invention is 320MPa~354MPa. Its performance is comparable to that of imported materials, which not only meets the design and material selection requirements of blind rivets for fasteners, but also makes it more conducive to the widespread use of Al-Mg alloy wires in the connection of other aerospace and rail transit structural components.

[0016] The Al-Mg alloy wire prepared by this invention is used for fastener blind rivets. Attached Figure Description

[0017] Figure 1 Macroscopic morphology photograph of the Al-Mg alloy ingot in step one of Experiment 1;

[0018] Figure 2 Macroscopic morphology photograph of the Al-Mg alloy hot-rolled coil prepared in step two of Experiment 1;

[0019] Figure 3 Macroscopic morphology photograph of the Al-Mg alloy wire prepared for Experiment 1. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method is a method for preparing Al-Mg alloy wire for fasteners, and the specific process is as follows:

[0021] 1. The Al-Mg alloy ingot is extruded, straightened and sawn to obtain Al-Mg alloy extruded bars;

[0022] 2. The Al-Mg alloy extruded bar prepared in step 1 is rolled by hot continuous rolling to obtain a large hot rolled coil.

[0023] 3. Anneal the large hot-rolled coil obtained in step 2 at a temperature of 350℃~420℃ for 2h~6h, and air cool after taking it out of the furnace.

[0024] 4. The hot-rolled coil after annealing in step 3 is cold-rolled to a predetermined diameter wire, and then annealed at a temperature of 350℃~420℃ for 2h~6h. After exiting the furnace, it is air-cooled to obtain cold-rolled coil wire.

[0025] 5. The cold-rolled coil obtained in step 4 is drawn through multiple passes to the finished diameter wire. Annealing is required before each drawing pass. The annealing temperature is 350℃~420℃, and the holding time is 2h~6h. After exiting the furnace, it is air-cooled.

[0026] 6. The finished diameter wire obtained in step 5 is subjected to finished product annealing at a temperature of 100℃~300℃ for 2h~6h. After being taken out of the furnace, it is air-cooled to obtain an Al-Mg alloy wire for fasteners.

[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the mass percentage of each element in the Al-Mg alloy ingot in step one is as follows: Mg 4.5%~5.6%, Mn 0.05%~0.2%, Cr 0.05%~0.2%, Ti 0.005%~0.04%, Si < 0.3%, Fe < 0.4%, with the balance being Al. Everything else is the same as in Specific Implementation Method One.

[0028] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: in step one, the extrusion blank size before extrusion is Φ405×(750mm~1100mm), the extrusion temperature is 350℃~450℃, the extrusion speed is 0.8mm / s~1.8mm / s, and the finished bar specifications after sawing are (Φ135mm~Φ155mm)×(3500mm~7000mm). Everything else is the same as in Specific Implementation Method One or Two.

[0029] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the straightening rate of the extruded bar in step one is 0.8% to 3%. Everything else is the same as in Specific Implementation Methods One to Three.

[0030] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the preparation method of the large hot-rolled coil in step two is carried out according to the following steps:

[0031] A. Heat the Al-Mg alloy extruded bar prepared in step one in an electric furnace. When the metal temperature reaches 450℃~550℃, take it out of the furnace and hot roll it into a large hot-rolled coil of the predetermined specifications.

[0032] B. The prepared hot-rolled coil is hot-rolled until the metal temperature reaches 450℃~550℃, and then hot-rolled to the predetermined specifications. Other aspects are the same as in any of the specific implementation methods one to four.

[0033] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the specifications of the hot-rolled coil obtained in step two are controlled based on the diameter, state, and total cold deformation rate of the finished wire. Everything else is the same as in Specific Implementation Methods One to Five.

[0034] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: during the cold deformation processing of the finished diameter wire obtained in steps four and five, the total cold deformation rate is controlled at 65% to 95%; the single-pass cold deformation rate in step five is controlled at 25% to 50%. Everything else is the same as in Specific Implementation Methods One to Six.

[0035] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the Al-Mg alloy wire prepared in step six is ​​used in a fastener, specifically a blind rivet. Otherwise, it is the same as Specific Implementation Methods One to Seven.

[0036] The invention was verified using the following experiments:

[0037] Experiment 1: This experiment demonstrates a method for preparing Al-Mg alloy wire for fasteners. The specific process is as follows:

[0038] 1. Take an Al-Mg alloy ingot with dimensions of Φ405×950mm (see...) Figure 1 The material is then extruded, straightened, and sawn to obtain Φ145×6000mm extruded bars.

[0039] 2. The Al-Mg alloy extruded bars with specifications of Φ145×6000mm prepared in step one are rolled using hot continuous rolling to obtain large hot-rolled coils weighing over 200Kg (see...). Figure 2 );

[0040] 3. Anneal the hot-rolled coil obtained in step 2 at a temperature of 350℃ for 4 hours, and then air-cool it after it is taken out of the furnace.

[0041] 4. The hot-rolled coil obtained in step 3 is cold-rolled to a predetermined diameter wire, and then annealed at 350°C for 4 hours. After being taken out of the furnace, it is air-cooled to obtain cold-rolled coil wire.

[0042] 5. The cold-rolled coil obtained in step 4 is drawn into finished diameter wire through multiple drawing passes. Intermediate annealing is required before each drawing pass. The annealing temperature is 350℃ and the holding time is 4 hours. After exiting the furnace, it is air-cooled.

[0043] VI. The finished diameter wire obtained in step 5 is subjected to finished product annealing at a temperature of 200℃ for 4 hours. After removal from the furnace, it is air-cooled to obtain an Al-Mg alloy wire for fasteners (see...). Figure 3 ).

[0044] The preparation method of Al-Mg alloy ingot in step one is carried out according to the following steps:

[0045] A. Weigh out pure aluminum ingots, pure magnesium ingots, aluminum-manganese master alloys, aluminum-chromium master alloys, and aluminum-titanium-boron wire grain refiners according to the following mass percentages: Mg 5%, Mn 0.1%, Cr 0.1%, Ti 0.02%, Si < 0.3%, Fe < 0.4%, with the balance being Al. The aluminum-manganese master alloy is an Al-10%Mn alloy, the aluminum-chromium master alloy is an Al-3%Cr alloy, the aluminum-titanium master alloy is an Al-5%Ti alloy, and the aluminum-titanium-boron wire grain refiner is an Al-5%Ti-1%B alloy.

[0046] B. Add the pure aluminum ingots, aluminum-manganese master alloy, and aluminum-chromium master alloy weighed in step A to the melting furnace, heat to 750℃, melt and stir, remove slag, add pure magnesium ingots, add No. 2 covering agent, melt for 30 minutes, then refine with argon gas until the hydrogen content in 100 grams of aluminum alloy melt is ≤0.15mL, let stand for 30 minutes to obtain aluminum alloy melt; No. 2 covering agent is No. 2 flux, which is composed of 40% KCl, 50% MgCl2 and 10% BaCl2 by weight percentage; the amount of No. 2 covering agent is 0.3% of the total mass of the melt in the melting furnace;

[0047] C. The aluminum alloy melt obtained in step B is filtered sequentially through ceramic filters of 30 ppi and 50 ppi, and then poured into a crystallizer. At the same time, an aluminum-titanium-boron wire grain refiner is inserted into the flow channel and uniformly melted into the aluminum alloy melt. The insertion speed of the aluminum-titanium-boron wire grain refiner is 320 mm / min. Under the conditions of temperature of 750℃, water pressure of 0.1 MPa and speed of 50 mm / min, an Al-Mg alloy ingot with a diameter of 420 mm and a length of 5500 mm is cast.

[0048] The Al-Mg alloy wire prepared in step six is ​​used in fasteners such as blind rivets.

[0049] The finished Al-Mg alloy wire prepared in step six has a diameter of Φ4.7mm.

[0050] The Al-Mg alloy wire prepared by this invention has a tensile strength of 320MPa~354MPa. Compared with the tensile strength of imported Al-Mg alloy wire currently on the market, which is 305MPa~358MPa, its performance is comparable to that of imported materials. This makes the Al-Mg alloy wire not only meet the design and material selection requirements for blind rivets for fasteners, but also more conducive to the promotion and use of Al-Mg alloy wire in the connection of other aerospace and rail transportation structural components.

Claims

1. A method for preparing Al-Mg alloy wire for fasteners, characterized in that... The preparation process of Al-Mg alloy wire for fasteners is as follows:

1. The Al-Mg alloy ingot is extruded, straightened and sawn to obtain Al-Mg alloy extruded bars; The mass percentage of each element in the Al-Mg alloy ingot mentioned in step one is as follows: Mg 4.5%~5.6%, Mn 0.05%~0.2%, Cr 0.05%~0.2%, Ti 0.005%~0.04%, Si <0.3%, Fe <0.4%, with the balance being Al; In step one, the extrusion blank size before extrusion is Φ405×(750mm~1100mm) billet, the extrusion temperature is 350℃~450℃, the extrusion speed is 0.8mm / s~1.8mm / s, and the Al-Mg alloy extruded bar obtained by sawing has the specifications of (Φ135mm~Φ155mm)×(3500mm~7000mm); 2. The Al-Mg alloy extruded bar prepared in step 1 is rolled by hot continuous rolling to obtain a large hot-rolled coil.

3. Anneal the large hot-rolled coil obtained in step 2 at a temperature of 350℃~420℃ for 2h~6h, and air cool after taking it out of the furnace.

4. The hot-rolled coil after annealing in step 3 is cold-rolled to a predetermined diameter wire, and then annealed at a temperature of 350℃~420℃ for 2h~6h. After exiting the furnace, it is air-cooled to obtain cold-rolled coil wire.

5. The cold-rolled coil obtained in step 4 is drawn through multiple passes to the finished diameter wire. Annealing is required before each drawing pass. The annealing temperature is 350℃~420℃, and the holding time is 2h~6h. After exiting the furnace, it is air-cooled. During the cold deformation processing of the finished wire obtained in steps four and five, the total cold deformation rate is controlled between 65% and 95%; the single-pass cold deformation rate in step five is controlled between 25% and 50%.

6. The finished diameter wire obtained in step 5 is subjected to finished product annealing at a temperature of 100℃~300℃ for 2h~6h. After being taken out of the furnace, it is air-cooled to obtain an Al-Mg alloy wire for fasteners. The tensile strength of the Al-Mg alloy wire is 320MPa~354MPa. The prepared Al-Mg alloy wire is used in fastener blind rivets.

2. The method for preparing Al-Mg alloy wire for fasteners according to claim 1, characterized in that... In step one, the straightening rate of the extruded bar is 0.8% to 3%.

3. The method for preparing Al-Mg alloy wire for fasteners according to claim 1, characterized in that... The preparation method of the large-coil reheated and finished coil in step two is carried out according to the following steps: A. Heat the Al-Mg alloy extruded bar prepared in step one in an electric furnace. When the metal temperature reaches 450℃~550℃, take it out of the furnace and hot roll it into a large hot-rolled coil of the predetermined specifications. B. The prepared hot-rolled coil is hot-rolled until the metal temperature reaches 450℃~550℃. The hot-rolled coil is then rolled to the predetermined specifications.

4. The method for preparing Al-Mg alloy wire for fasteners according to claim 1, characterized in that... The specifications of the large hot-rolled coils obtained in step two are controlled based on the diameter, condition, and total cold deformation rate of the finished wire rod.

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