Fabrication process of high-precision aluminum alloy round bars with composite layers to improve weldability

Abstract

This invention discloses a manufacturing process for high-precision aluminum alloy round bars with a composite layer that improves weldability, comprising the following steps: S1. Forward extrusion of an aluminum tube to improve the weldability of the aluminum alloy mandrel as a composite layer sleeve; S2. Cutting the composite layer sleeve into short pieces; S3. Peeling the aluminum alloy mandrel; S4. Heating the composite layer sleeve and then hot-fitting it into the aluminum alloy mandrel to form a bar stock; S5. Reverse extrusion of the bar stock into a billet; S6. Removing the head and tail of the billet and blanking; S7. Drawing the billet into a precision-drawn bar; S8. Straightening the precision-drawn bar; S9. Cutting the precision-drawn bar to the required length; S10. Cleaning away residual drawing oil from the surface of the precision-drawn bar; S11. Heat-treating the precision-drawn bar to obtain the finished aluminum alloy round bar. This invention, by employing a specific manufacturing process, combines an aluminum tube with good weldability with an aluminum bar with good machinability, resulting in an aluminum alloy round bar that not only has excellent machinability but also improved weldability.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy bar technology, and specifically to a process for preparing high-precision aluminum alloy round bars with a composite layer that improves weldability. Background Technology

[0002] Aluminum (Al) is a light metal whose compounds are widely distributed in nature. The Earth's crust contains approximately 40 to 50 billion tons of aluminum, ranking third after oxygen and silicon, and is the largest category of metals.

[0003] Aluminum possesses unique chemical and physical properties, being not only lightweight and strong but also exhibiting excellent ductility, electrical conductivity, thermal conductivity, heat resistance, and resistance to nuclear radiation. It is a crucial raw material for national economic development. The development of the three major industries—aviation, construction, and automobiles—demands materials with the unique properties of aluminum and its alloys.

[0004] Aluminum bars are a type of aluminum product. Based on their shape, aluminum bars can be categorized into: round aluminum alloy bars, square aluminum alloy bars, hexagonal aluminum alloy bars, trapezoidal aluminum alloy bars, etc. Based on the different metallic elements they contain, aluminum bars can be roughly divided into eight main categories:

[0005] The 1000 series aluminum rods have the highest aluminum content among all series, with a purity exceeding 99.00%. Because they do not contain other alloying elements, the production process is relatively simple, and the price is relatively low, making them the most commonly used series in conventional industries.

[0006] The 2000 series aluminum rods are characterized by their high hardness, with copper content being the highest, at approximately 3-5%. 2000 series aluminum rods are classified as aerospace-grade aluminum and are not commonly used in conventional industrial applications.

[0007] The 3000 series aluminum rods are mainly composed of manganese, with a content between 1.0% and 1.5%, making them a series with good rust prevention properties.

[0008] 4000 series aluminum rods belong to a series with high silicon content, typically between 4.5% and 6.0%. They are used in building materials, mechanical parts, forging materials, and welding materials. They have a low melting point and good corrosion resistance. Product description: They have heat resistance and wear resistance.

[0009] 5000 series aluminum rods are a commonly used series of alloy aluminum rods. The main element is magnesium, with a magnesium content between 3-5%, and it can also be called an aluminum-magnesium alloy. Its main characteristics are low density, high tensile strength, and high elongation. For the same area, aluminum-magnesium alloys weigh less than other series and are widely used in conventional industries.

[0010] The 6000 series aluminum rods mainly contain magnesium and silicon, thus combining the advantages of the 4000 and 5000 series. They are suitable for applications requiring high resistance to corrosion and oxidation, have good usability, are easy to coat, and are easy to process.

[0011] 7000 series aluminum rods also belong to the aerospace series. They are aluminum-magnesium-zinc-copper alloys, heat-treatable alloys, and belong to the category of ultra-hard aluminum alloys with good wear resistance.

[0012] The most commonly used aluminum rod in the 8000 series is 8011, which belongs to other series and is mostly used for aluminum foil. It is not commonly used in the production of aluminum rods.

[0013] Different series of aluminum rods have different grades. In actual use, due to their own characteristics, different grades of aluminum rods have the following problems: some grades of aluminum rods have good machinability, but cannot meet welding requirements; some grades of aluminum rods have good welding performance, but cannot meet machining requirements. Summary of the Invention

[0014] The technical problem to be solved by the present invention is to provide a preparation process for a high-precision aluminum alloy round bar with a composite layer that improves welding performance, which can improve the welding performance of the outer surface of the aluminum bar with good machinability.

[0015] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows.

[0016] A manufacturing process for a high-precision aluminum alloy round bar with a composite layer for improving weldability, wherein the aluminum alloy round bar includes an aluminum alloy core rod 1 and an aluminum alloy composite layer 2 laminated on the outside of the aluminum alloy core rod 1 to improve the weldability of the aluminum alloy core rod, and the manufacturing process includes the following steps:

[0017] S1. Forward extrusion is used to improve the welding performance of aluminum alloy mandrels, and aluminum tubes are used as composite layer sleeves;

[0018] S2. Cut the composite layer pipe sleeve into short pieces;

[0019] S3. Peel the aluminum alloy core rod;

[0020] S4. Heat the composite layer sleeve and then heat-fit it into the aluminum alloy mandrel to form a bar stock;

[0021] S5. Extrude the bar stock in reverse to form a billet;

[0022] S6. Remove the head and tail billets before feeding;

[0023] S7. Draw the billet into a precision-drawn bar;

[0024] S8. Straighten the precision drawing bar;

[0025] S9. Cut the precision drawing bar to the required length;

[0026] S10. Clean off any residual drawing oil from the surface of the fine drawing bar;

[0027] S11. The precision-drawn bar is heat-treated to obtain the finished aluminum alloy round bar.

[0028] Preferably, in step S1, an aluminum tube is extruded using a forward extrusion press.

[0029] Preferably, in step S2, the composite layer tube sleeve is cut into a short piece of the bar length required for reverse extrusion in step S5; in step S3, the length of the aluminum alloy mandrel is the bar length required for reverse extrusion in step S5.

[0030] Preferably, in step S4, the composite layer sleeve is heated to 320–380°C.

[0031] Preferably, in step S5, the bar stock is extruded into a billet using a reverse extrusion press, and the extrusion die of the reverse extrusion press is a one-out-one-die.

[0032] Preferably, in step S6, the parts of the billet without the composite layer and the parts with gradually changing composite layer thickness are detected by low magnification using 5% NaOH solution and removed as process waste. The remaining parts are cut to a length suitable for drawing.

[0033] Preferably, the ordinary aging process temperature for heat treatment in step S11 is 175±10℃, and the holding time is 6.5±0.5H.

[0034] Due to the adoption of the above technical solutions, the technical progress achieved by this invention is as follows.

[0035] This invention employs a specific production process to combine aluminum tubes with good weldability with aluminum rods with good machinability, producing an aluminum alloy round rod comprising an aluminum alloy core rod and an aluminum alloy composite layer on the outside of the core rod. This not only gives the produced aluminum alloy round rod good machinability but also improves its weldability. Attached Figure Description

[0036] Figure 1 is a flow chart of the present invention;

[0037] Figure 2 This is a schematic diagram of the aluminum alloy round bar structure of the present invention.

[0038] Among them: 1. Aluminum alloy core rod, 2. Aluminum alloy composite layer. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0040] A process for manufacturing high-precision aluminum alloy round bars with a composite layer that improves weldability, such as... Figure 1 As shown, it includes the following steps:

[0041] S1. Forward extrusion is used to improve the welding performance of aluminum alloy mandrels, and aluminum tubes are used as composite layer sleeves.

[0042] Aluminum tubes are extruded using a forward extrusion press, resulting in aluminum tubes with good weldability.

[0043] S2. Cut the composite layer sleeve into short pieces.

[0044] The composite layer tube sleeve is cut into short pieces of the bar length required for reverse extrusion in step S5.

[0045] S3. Peel the aluminum alloy core rod.

[0046] The aluminum alloy mandrel is a machinable aluminum alloy mandrel, and its length is the length of the bar required for reverse extrusion in step S5.

[0047] S4. Heat the composite layer tube sleeve and then heat-fit it into the aluminum alloy mandrel to form a bar stock.

[0048] S5. Extrude the bar stock in the reverse direction to form a billet.

[0049] The bar stock is extruded into billets using a reverse extrusion press. The extrusion die of the reverse extrusion press must be a single die for each extrusion. The bar temperature, extrusion speed, and cooling method are set according to the desired finished state of the aluminum alloy round bar.

[0050] S6. Remove the head and tail billets before feeding.

[0051] Low-magnification detection using 5% NaOH solution identified the parts of the billet without a composite layer at the head and tail, as well as the parts with gradually changing composite layer thickness, which were removed as process waste. The remaining parts were cut to lengths suitable for drawing.

[0052] S7. Draw the billet into a precision drawing bar.

[0053] S8. Straighten the precision drawing bar.

[0054] The straightening machine is used to straighten the precision drawing bar to meet the straightness requirements.

[0055] S9. Cut the precision drawing bar to the required length.

[0056] Use a cutting machine to cut the precision drawing bar to the required length.

[0057] S10. Clean off any residual drawing oil from the surface of the fine drawing rod.

[0058] S11. The precision-drawn bar is heat-treated to obtain the finished aluminum alloy round bar.

[0059] The precision-drawn bars are heat-treated according to the desired finished state of the aluminum alloy round bars.

[0060] S12. Packaging.

[0061] The obtained aluminum alloy round bars are packaged, such as... Figure 2 As shown, the finished aluminum alloy round bar includes an aluminum alloy core rod 1 and an aluminum alloy composite layer 2. The aluminum alloy core rod 1 has good machinability, which can ensure the machinability of the aluminum alloy round bar. The aluminum alloy composite layer 2 is laminated on the outside of the aluminum alloy core rod 1. The aluminum alloy composite layer 2 has good welding performance, thereby improving the welding performance of the aluminum alloy core rod and ensuring that the aluminum alloy round bar has good welding performance.

[0062] The present invention will now be described in further detail with reference to specific embodiments.

[0063] Example 1

[0064] A process for preparing a high-precision aluminum alloy round bar with a composite layer that improves weldability includes the following steps:

[0065] S1. Forward extrusion is used to improve the welding performance of aluminum alloy mandrels, and aluminum tubes are used as composite layer sleeves.

[0066] Aluminum tubes are extruded using a forward extrusion press, resulting in aluminum tubes with good weldability.

[0067] S2. Cut the composite layer sleeve into short pieces.

[0068] The composite layer tube sleeve is cut into short pieces of the bar length required for reverse extrusion in step S5.

[0069] S3. Peel the aluminum alloy core rod.

[0070] The aluminum alloy mandrel is a machinable aluminum alloy mandrel, and its length is the length of the bar required for reverse extrusion in step S5.

[0071] S4. Heat the composite layer sleeve to 320-380℃, and then heat-fit it into an aluminum alloy mandrel to form a bar stock.

[0072] S5. Extrude the bar stock in the reverse direction to form a billet.

[0073] The bar stock is extruded into billets using a reverse extrusion press. The extrusion die of the reverse extrusion press must be a single die for each extrusion. The bar temperature, extrusion speed, and cooling method are set according to the desired finished state of the aluminum alloy round bar.

[0074] S6. Remove the head and tail billets before feeding.

[0075] Low-magnification detection using 5% NaOH solution identified the parts of the billet without a composite layer at the head and tail, as well as the parts with gradually changing composite layer thickness, which were removed as process waste. The remaining parts were cut to lengths suitable for drawing.

[0076] S7. Draw the billet into a precision drawing bar.

[0077] S8. Straighten the precision drawing bar.

[0078] The straightening machine is used to straighten the precision drawing bar to meet the straightness requirements.

[0079] S9. Cut the precision drawing bar to the required length.

[0080] Use a cutting machine to cut the precision drawing bar to the required length.

[0081] S10. Clean off any residual drawing oil from the surface of the fine drawing rod.

[0082] S11. The precision-drawn bar is heat-treated to obtain an aluminum alloy round bar.

[0083] The standard aging process temperature for heat treatment is 175±10℃, and the holding time is 6.5±0.5H.

[0084] S12. Packaging.

[0085] Example 2

[0086] A process for preparing a high-precision aluminum alloy round bar with a composite layer to improve weldability, using 6060 grade aluminum alloy as the core rod and a T5 state composite layer of 4343 grade aluminum alloy with a thickness of 0.15±0.08mm to improve weldability, to obtain an aluminum alloy round bar with a diameter of D12+0.05mm, includes the following steps:

[0087] S1. Use a forward extrusion press to extrude 4343R D201x2.5mm aluminum tube as the composite layer sleeve. The outer diameter is the outer diameter of the bar stock during subsequent reverse extrusion, and the wall thickness of 2.5mm is the thickness corresponding to the composite layer.

[0088] S2. Cut the composite sleeve to the length of bar stock required for reverse extrusion.

[0089] S3. Peel the surface of the 6060 aluminum alloy mandrel. The diameter of the 6060 aluminum alloy mandrel after peeling is 196.2 + 0.2 mm. The length of the 6060 aluminum alloy mandrel is the length of the bar required for reverse extrusion.

[0090] S4. Heat the composite layer sleeve to 350°C, and then heat-fit a 6060 aluminum alloy mandrel to form a bar stock.

[0091] S5. The bar stock is extruded into a D13 billet using a reverse extrusion press. The extrusion die of the reverse extrusion press must be a single die for each extrusion. Since the finished aluminum alloy round bar is in T5 condition, the bar temperature is 460℃, the extrusion speed is 0.9mm / s, and strong air cooling is used.

[0092] S6. Using a 5% NaOH solution, low-magnification detection is performed to identify the parts of the billet without a composite layer and the parts with gradually changing composite layer thickness, which are then removed as process waste. The remaining parts are cut to a length suitable for drawing. At this point, the composite layer thickness of the billet is approximately 0.12–0.26 mm.

[0093] S7. Draw the billet of D13 into a precision-drawn bar of D12+0.05mm. At this time, the composite layer thickness of the precision-drawn bar is about 0.15±0.05mm.

[0094] S8. Use a straightening machine to straighten the precision drawing bar to meet the straightness requirements.

[0095] S9. Use a cutting machine to cut the precision drawing bar to the required length.

[0096] S10. Clean off any residual drawing oil from the surface of the fine drawing rod.

[0097] S11. The precision-drawn bar is heat-treated to obtain the finished aluminum alloy round bar.

[0098] Since the finished aluminum alloy round bar is in T5 condition, the ordinary aging process temperature for heat treatment is 180℃ and the holding time is 6.5H.

[0099] S12. Packaging.

[0100] The measured properties of the resulting aluminum alloy round bars are as follows:

[0101]

Claims

1. A manufacturing process for a high-precision aluminum alloy round bar with a composite layer that improves weldability, characterized in that: The aluminum alloy round bar includes an aluminum alloy core rod (1) and an aluminum alloy composite layer (2) laminated on the outside of the aluminum alloy core rod (1) to improve the welding performance of the aluminum alloy core rod. Its preparation process includes the following steps: S1. Forward extrusion is used to improve the welding performance of aluminum alloy mandrels, and aluminum tubes are used as composite layer sleeves; S2. Cut the composite layer pipe sleeve into short pieces; S3. Peel the aluminum alloy core rod; S4. Heat the composite layer sleeve to 320~380℃, and then heat-fit the aluminum alloy mandrel to form a bar stock; S5. Extrude the bar stock in reverse to form a billet; S6. Remove the head and tail billets before feeding; In step S6, the parts of the billet without composite layer and the parts with gradually changing composite layer thickness are detected by low magnification using 5% NaOH solution and removed as process waste. The remaining part is cut into lengths suitable for drawing. S7. Draw the billet into a precision-drawn bar; S8. Straighten the precision drawing bar; S9. Cut the precision drawing bar to the required length; S10. Clean off any residual drawing oil from the surface of the fine drawing bar; S11. The precision-drawn bar is heat-treated to obtain the finished aluminum alloy round bar; The conventional aging process temperature for heat treatment in step S11 is 175±10℃, and the holding time is 6.5±0.5H.

2. The manufacturing process of a high-precision aluminum alloy round bar with a composite layer for improving weldability according to claim 1, characterized in that: In step S1, an aluminum tube is extruded using a forward extrusion press.

3. The manufacturing process of a high-precision aluminum alloy round bar with a composite layer for improving weldability according to claim 1, characterized in that: In step S2, the composite layer tube sleeve is cut into a short piece of the bar length required for reverse extrusion in step S5; in step S3, the length of the aluminum alloy mandrel is the bar length required for reverse extrusion in step S5.

4. The manufacturing process of a high-precision aluminum alloy round bar with a composite layer for improving weldability according to claim 1, characterized in that: In step S5, the bar stock is extruded into a billet using a reverse extrusion press. The extrusion die of the reverse extrusion press is a one-out-one-die.

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