CN116445757A - Aluminum alloy rod and preparation method thereof - Google Patents
Aluminum alloy rod and preparation method thereof Download PDFInfo
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- CN116445757A CN116445757A CN202310443391.3A CN202310443391A CN116445757A CN 116445757 A CN116445757 A CN 116445757A CN 202310443391 A CN202310443391 A CN 202310443391A CN 116445757 A CN116445757 A CN 116445757A
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- 229910000838 Al alloy Inorganic materials 0.000 title claims abstract description 203
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- 238000005096 rolling process Methods 0.000 claims abstract description 64
- 238000009749 continuous casting Methods 0.000 claims abstract description 62
- 239000000956 alloy Substances 0.000 claims abstract description 58
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 57
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 47
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 47
- 239000013078 crystal Substances 0.000 claims abstract description 40
- 239000011777 magnesium Substances 0.000 claims abstract description 37
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 23
- 238000005266 casting Methods 0.000 claims abstract description 21
- 239000007788 liquid Substances 0.000 claims abstract description 21
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 13
- SNAAJJQQZSMGQD-UHFFFAOYSA-N aluminum magnesium Chemical compound [Mg].[Al] SNAAJJQQZSMGQD-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000007789 gas Substances 0.000 claims description 58
- 238000001816 cooling Methods 0.000 claims description 54
- 239000000498 cooling water Substances 0.000 claims description 51
- 230000001681 protective effect Effects 0.000 claims description 37
- 238000003756 stirring Methods 0.000 claims description 31
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 30
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 27
- 239000001257 hydrogen Substances 0.000 claims description 27
- 229910052739 hydrogen Inorganic materials 0.000 claims description 27
- 230000009471 action Effects 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 21
- 238000007872 degassing Methods 0.000 claims description 19
- 229910052786 argon Inorganic materials 0.000 claims description 18
- 229910018134 Al-Mg Inorganic materials 0.000 claims description 14
- 229910018467 Al—Mg Inorganic materials 0.000 claims description 14
- 238000004458 analytical method Methods 0.000 claims description 13
- 230000008018 melting Effects 0.000 claims description 13
- 238000002844 melting Methods 0.000 claims description 13
- 239000000919 ceramic Substances 0.000 claims description 10
- 238000001914 filtration Methods 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 239000000155 melt Substances 0.000 claims description 10
- 238000007670 refining Methods 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000002893 slag Substances 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 6
- 239000000460 chlorine Substances 0.000 claims description 5
- 229910052801 chlorine Inorganic materials 0.000 claims description 5
- QQHSIRTYSFLSRM-UHFFFAOYSA-N alumanylidynechromium Chemical compound [Al].[Cr] QQHSIRTYSFLSRM-UHFFFAOYSA-N 0.000 claims description 4
- 238000000746 purification Methods 0.000 claims description 4
- 229910018167 Al—Be Inorganic materials 0.000 claims description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 2
- 238000005070 sampling Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 6
- 238000005204 segregation Methods 0.000 abstract description 5
- 238000005491 wire drawing Methods 0.000 abstract description 3
- 238000004321 preservation Methods 0.000 description 31
- 238000003466 welding Methods 0.000 description 16
- 230000008569 process Effects 0.000 description 14
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 13
- 238000007664 blowing Methods 0.000 description 13
- 229910052802 copper Inorganic materials 0.000 description 13
- 239000010949 copper Substances 0.000 description 13
- 238000003723 Smelting Methods 0.000 description 10
- 230000006911 nucleation Effects 0.000 description 10
- 238000010899 nucleation Methods 0.000 description 10
- 239000000839 emulsion Substances 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 238000002425 crystallisation Methods 0.000 description 7
- 230000008025 crystallization Effects 0.000 description 7
- 238000005275 alloying Methods 0.000 description 6
- 238000010008 shearing Methods 0.000 description 6
- 238000013459 approach Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000011010 flushing procedure Methods 0.000 description 4
- 238000001953 recrystallisation Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 238000005461 lubrication Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 238000005482 strain hardening Methods 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000009991 scouring Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/026—Alloys based on aluminium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/16—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section
- B21B1/18—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section in a continuous process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/466—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a non-continuous process, i.e. the cast being cut before rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/003—Rolling non-ferrous metals immediately subsequent to continuous casting, i.e. in-line rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
- B22D11/003—Aluminium alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
- B22D11/225—Controlling or regulating processes or operations for cooling cast stock or mould for secondary cooling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/28—Selection of soldering or welding materials proper with the principal constituent melting at less than 950 degrees C
- B23K35/286—Al as the principal constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/40—Making wire or rods for soldering or welding
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
- C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B2003/001—Aluminium or its alloys
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses an aluminum alloy rod and a preparation method thereof. The aluminum alloy rod is prepared by continuous casting and rolling, and during casting, magnesium element is added in a form of intermediate alloy, and the mass percentage of magnesium in the added aluminum-magnesium intermediate alloy is 38-40.5%; the aluminum alloy rod has an equiaxial crystal structure, a tensile strength of 290-305 MPa and an elongation of 22-24%, and has good mechanical properties. S1, adding intermediate alloy into aluminum liquid to obtain aluminum alloy melt; s2, purifying the aluminum alloy melt, and then analyzing and adjusting components; s3, pouring the aluminum alloy melt meeting the component requirements into a rotary continuous casting machine to be continuously solidified into an aluminum alloy wire ingot; s4, continuously rolling the aluminum alloy wire ingot into an aluminum alloy rod with the diameter of 6.0-9.5 mm, wherein the preparation method can reduce the component segregation of the aluminum alloy wire ingot, improve the uniformity of continuous casting tissues and the quality of the continuous casting wire ingot, and provide high-performance aluminum alloy rod materials for high-quality wire drawing.
Description
Technical Field
The invention relates to the technical field of materials, in particular to an aluminum alloy rod and a preparation method thereof.
Background
The 5356 aluminum alloy is a high-magnesium Al-Mg aluminum alloy with the magnesium content of 4.5-5.5% (the magnesium content is higher than 3 percent to form a high-magnesium aluminum alloy), has better plasticity, fracture toughness, corrosion resistance, plastic workability and weldability, has better compatibility with most aluminum-based alloys, and is widely used as an aluminum alloy welding material.
In recent years, the fields of aerospace, high-speed rail and the like in China are developed at a high speed, the lightweight aluminum alloy is greatly concerned and applied in the fields, and the demand of aluminum alloy welding wires is also increased. These fields have high requirements for aluminum alloy welding wires, and are required to meet the requirements of containing [ H ]]Less than or equal to 0.12ml/100g Al. The 5356 aluminum alloy system has a high magnesium content, and is likely to undergo segregation during production, resulting in uneven composition. In addition, mg at the smelting temperature (above 700 ℃) can be mixed with O in furnace gas 2 、N 2 Steam (H) 2 O) and CO 2 The gases react, causing severe oxidation and burn-out of Mg. Meanwhile, the hydrogen absorption amount of Mg can reach 92.5 times of that of aluminum, and the hydrogen absorption of the melt leads to high hydrogen content in the prepared aluminum alloy.
The defects of the aluminum alloy finally lead to high hydrogen content, more oxidized slag inclusion and large component deviation in the prepared aluminum alloy welding wire, so that the final aluminum alloy product has poor performance. At present, continuous casting and rolling equipment and production technology of high-end high-magnesium aluminum alloy welding rods are always mastered in the world and other internationally known welding wire manufacturers, and more than 90% of domestic high-end high-magnesium five-system aluminum alloy welding rods depend on import, so that the development of the fields of aerospace, high-speed rail and the like is severely limited.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to solve the problem of high hydrogen content in the existing Al-Mg aluminum alloy welding wire, and provides an aluminum alloy rod and a preparation method thereof, wherein the inside of the aluminum alloy rod is of an equiaxed crystal structure, the hydrogen content is 0.09-0.12 ml/100g Al, and the use requirements of the fields of high-speed rail, aerospace and the like can be met.
In order to solve the technical problems, the invention adopts the following technical scheme:
the aluminum alloy rod is prepared by continuous casting and rolling, wherein magnesium element is added in a form of intermediate alloy during casting, and the mass percentage of magnesium in the added aluminum-magnesium intermediate alloy is 38-40.5%; the inside of the aluminum alloy rod is an equiaxial crystal structure, the tensile strength is 290-305 MPa, and the elongation is 22-24%.
Further, the hydrogen content of the aluminum alloy rod is 0.09 to 0.12ml/100g Al.
The invention also provides a preparation method of the aluminum alloy rod, which comprises the following steps,
s1, adding Al-Cr, al-Mn and Al-10% Ti intermediate alloy into molten aluminum under the action of first protective gas; after all melting, adding an Al-Mg intermediate alloy under the action of a first protective gas and stirring, adding an Al-Be intermediate alloy after the Al-Mg intermediate alloy is completely melted, and stirring uniformly to obtain an aluminum alloy melt; the stirring is preferably electromagnetic stirring. When a traditional stirring rod or the like is used for stirring, the requirement on the melting point and the components of the material for preparing the stirring rod is higher, otherwise, the stirring rod is easy to melt in an aluminum melt, and more impurities are introduced. The above problems can be avoided by using electromagnetic stirring.
S2, after component analysis and adjustment are carried out on the aluminum alloy melt, refining is carried out on the aluminum alloy melt under the action of a second protective gas; under the protection of a third protective gas, standing the refined aluminum alloy melt for 25-30 min;
s3, under the protection of a third protective gas, horizontally pouring the aluminum alloy melt after standing into a rotary continuous casting machine through an upper ladle and a middle ladle, and continuously solidifying the aluminum alloy melt into an aluminum alloy wire ingot under the sectional cooling of a four-side cooling system with sectional flow control;
s4, performing 7-15 passes on the aluminum alloy wire ingot prepared under the protection of the third protective gas, and continuously rolling to obtain an aluminum alloy rod with the diameter of 6.0-9.5 mm, namely the aluminum alloy rod.
Preferably, in the step S1, the aluminum liquid is obtained by melting an aluminum ingot in a smelting furnace, heating the aluminum ingot to 720-740 ℃, and then guiding the aluminum ingot into a heat preservation furnace from the smelting furnace through a diversion launder; the Al-Cr, al-Mn and Al-10% Ti intermediate alloy are added into a diversion trench and flow into a holding furnace along with molten aluminum.
Preferably, in step S1, the Al-Mg intermediate alloy is added into the aluminum liquid in 2-3 batches, and after the Al-Mg intermediate alloy added in the previous batch is completely melted and uniformly stirred, the next batch is added until the Al-Mg intermediate alloy is added.
Preferably, in the step S1, the first protection gas is argon, the pressure is 0.2-0.45 MPa, and the flow is 2.0-4.5L/min; the second protective gas is a mixed gas consisting of 94-97% of argon and 3-6% of chlorine, the pressure is 0.4-0.8 MPa, and the flow is 4.0-8.5L/min; the third protective gas is argon, the pressure is 0.2-0.3 MPa, and the flow is 2.0-3.5L/min.
Preferably, in step S2, the component analysis is performed by sampling at the side, center and 1/2 center of the melt for rapid component analysis; the purification treatment comprises degassing, impurity removal, slag skimming and covering.
Preferably, in the step S3, the sectional cooling of the cooling system with the sectional flow control is divided into four areas, wherein the flow rate of cooling water in the first area is 6-12T/h, the flow rate of cooling water in the second area is 4-8T/h, the flow rate of cooling water in the third area is 10-18T/h, and the flow rate of cooling water in the fourth area is 6-12T/h; the water pressure of the inner cooling water, the outer cooling water, the inner cooling water and the outer cooling water of the cooling system is 0.2-0.4 MPa. The method comprises the steps of adopting a primary forced cooling (corresponding to a first-area cooling water flow of 6-12T/h) +a secondary weak cooling (corresponding to a second-area cooling water flow of 4-8T/h) +a tertiary strong cooling (corresponding to a third-area cooling water flow of 10-18T/h) +a quaternary temperature-regulating cooling process (corresponding to a fourth-area cooling water flow of 6-12T/h.) at a horizontal pouring inlet, forming a primary shell and a liquid wedge of small and thinned equiaxed crystals through primary strong cooling at the pouring inlet, forming columnar crystals produced on an outer arc downward and an inner arc line at a place with small top easily, enabling the liquid viscosity of high-magnesium Al-Mg to be large, enabling the broken grains to serve as new nucleation points under the opposite flushing action of continuously poured high-temperature aluminum alloy melt, improving the breakage rate of columnar crystals through secondary weak cooling, enabling the rate of columnar crystals to be larger than the growth rate, and enabling the columnar crystals to be converted into small and equiaxed crystals.
Preferably, in the step S3, the aluminum alloy melt after the purification treatment enters an online degassing and ceramic filtering system through a discharge launder and then flows into an upper casting ladle; the method also comprises the step of adding an Al-Ti-B wire refiner into the discharge launder.
Compared with the prior art, the invention has the following advantages:
1. the aluminum alloy rod provided by the invention is internally provided with equiaxed crystals with the average grain size of 18-22 um. The tensile strength of the aluminum alloy rod reaches 290-305 MPa, the elongation is 22-24%, the hydrogen content is 0.09-0.12 ml/100g Al, the aluminum alloy rod has good mechanical properties, meets the quality requirements of high-performance aluminum alloy rods, and can be used in the fields of aerospace and high-speed rails.
2. According to the preparation method of the aluminum alloy rod, the magnesium element is added in the form of the intermediate alloy during casting, and the mass percentage of magnesium in the added aluminum-magnesium intermediate alloy is 38-40.5%, so that the density of the magnesium-aluminum intermediate alloy is greater than or equal to the density (2.3 g/cm) of an aluminum melt 3 ) The magnesium-aluminum intermediate alloy can suspend or sink into the aluminum melt, so that O in furnace gas in a hearth and when magnesium ingots are directly added into the aluminum alloy melt as furnace charges at present are avoided 2 、N 2 Steam (H) 2 O) and CO 2 The gas reacts to cause the problems of serious oxidation and burning loss of Mg, thereby improving the utilization rate of the Mg, reducing the fluctuation of the content of the Mg in the melt and reducing the hydrogen content in the aluminum alloy. By the precise water distribution cooling process of the segments during casting, the equiaxed crystal structure with the average grain size of 120-140 um of the cross section of the continuous casting wire ingot is obtained, the equiaxed crystallization of the aluminum alloy wire ingot structure is basically realized, the component segregation is reduced, and the continuous casting is improvedUniformity of texture and strand quality. The large deformation continuous casting and rolling control forming process is adopted, so that the high magnesium aluminum alloy welding screw rod is ensured to continuously form the aluminum alloy welding screw rod with the average grain size of 18-22 mu m of the disc weight of 2.0-2.5T/disc at high temperature (the rolling temperature is 420-460 ℃ and the final rolling temperature is 320-360 ℃). The method realizes dynamic recrystallization control Wen Lianga in the full continuous casting process, refines the structure of the alloy rod, reduces the component segregation of the aluminum alloy wire ingot, improves the uniformity of continuous casting structure and the quality of the continuous casting wire ingot, and provides high-performance aluminum alloy raw material rod for high-quality wire drawing.
Drawings
Fig. 1 is a process flow chart of the preparation method provided by the invention.
FIG. 2 is a schematic diagram of an apparatus used in the preparation method provided by the present invention; the aluminum melting furnace 1, the heat preservation furnace 2, the diversion trench 3, the online degassing device 4, the ceramic filtering device 5, the pouring system 6, the continuous casting machine 7, the approach bridge 8, the aluminum alloy wire ingot 9, the scrap shear 10, the planing angle straightener 11, the heating system 12, the front guide wheel 13 of the continuous rolling mill, the continuous rolling mill set 14, the cooling water device 15, the wire winding machine 16 and the aluminum alloy wire rod blank 17.
FIG. 3 is a schematic diagram of a mold of a continuous casting machine in an apparatus used in the preparation method according to the present invention; wherein: the cooling device comprises a crystallization copper wheel 20, a crystallization copper wheel notch 21, a crystallizer inner cooling device 22, a crystallizer outer cooling device 23, a crystallizer outer cooling device 24 and a crystallizer inner cooling device 25.
Fig. 4 is a schematic view of a cooling system of the continuous casting machine.
FIG. 5 is a microstructure chart (OP) of an aluminum alloy wire ingot obtained by continuous casting in examples 1-3 of the present invention; wherein, (a) is the aluminum alloy wire ingot prepared in example 1, (b) is the aluminum alloy wire ingot prepared in example 2, and (c) is the aluminum alloy wire ingot prepared in example 3.
Fig. 6 is a schematic sectional view of a cross section of an aluminum alloy wire ingot prepared in example 2 of the present invention.
Fig. 7 is a microstructure chart (OP) of each section of the cross section of the aluminum alloy wire ingot prepared in example 2 of the present invention.
FIG. 8 shows the microstructure of example 2 of the present invention, wherein a phi 9.5mm aluminum alloy rod is formed by continuous rolling, and the microstructure is rolled from a casting blank to a finished rod for 0-11 passes.
Fig. 9 shows the mechanical properties of the aluminum alloy bars with different continuous casting and rolling forming finishing temperatures Φ9.5mm 5356 in examples 1-3.
Detailed Description
The aluminum alloy rod provided by the embodiment of the invention is prepared through main procedures of batching, smelting, alloying, melt purification, continuous casting, continuous rolling and the like, and the technological process is shown in figure 1. The structure of the cast aluminum alloy rod is an equiaxed crystal structure, basically realizes equiaxed crystallization of an aluminum alloy wire ingot structure, reduces component segregation, improves the uniformity of a continuous casting structure and the quality of the continuous casting wire ingot, and has good mechanical properties. Meanwhile, the hydrogen content of the aluminum alloy is 0.09-0.12 ml/100g Al, so that the quality of the aluminum alloy is greatly improved, and the use requirements of the fields of aerospace, high-speed rail and the like are met.
The apparatus used in the preparation process of the aluminum alloy rod provided in this embodiment is shown in fig. 2. Specifically, firstly, aluminum ingots or return waste materials subjected to component analysis are proportioned, are melted in a vertical aluminum melting furnace 1 under the action of first protective gas and flow into a standing furnace of the vertical aluminum melting furnace, and after the aluminum liquid in the standing furnace reaches the capacity, flow into a heat preservation furnace 2 through a diversion launder 3 connected with the heat preservation furnace 2. Under the action of the first protective gas, the alloying elements Cr, mn and Ti required in the aluminum alloy are added into the diversion trench 3 through the form of the intermediate alloy, and flow into the holding furnace 2 along with the scouring action of the aluminum liquid. The alloy element Mg is directly added into the holding furnace 2 in the form of aluminum-magnesium intermediate alloy, then Al-Be intermediate alloy is added, and the mixture is stirred uniformly. After alloying of the alloy element in the holding furnace 2 is completed, refining, degassing and deslagging are carried out under the protection of the bottom blowing second protective gas, covering is carried out, and then standing is carried out for a period of time under the protection of the third protective gas. The whole process from heat preservation in the heat preservation furnace to continuous casting and rolling is protected by the third protective gas. Under the protection of a third protective gas, the aluminum alloy melt flows into the discharge launder 3 through tilting discharge, and Al-Ti-B refined wires are fed in the discharge launder 3 on line so as to refine continuous casting grains. Then further removes hydrogen and slag by an on-line degassing device 4 and a ceramic filtering device 5. Finally, the aluminum alloy melt is horizontally poured into a continuous casting machine 7 by a semi-automatic horizontal pouring system 6, under the sectional cooling of a four-side cooling system with sectional flow control of the continuous casting machine 7, the solidified aluminum alloy wire ingot 9 is guided into a scrap shear 10 through a bridge approach 8 in sequence, after scrap heads and scraps are sheared off, an angle planing straightener 11 performs ingot angle planing and straightening treatment on the aluminum alloy wire ingot 9, the aluminum alloy wire ingot is heated to a certain temperature under the action of a frequency doubling heating system 12, and enters a continuous rolling unit 14 for multi-pass continuous control rolling under the guiding action of a guide wheel 13 in front of a continuous rolling machine, and an aluminum alloy welding wire rod with a required size is rolled. The wire rod is cooled by a cooling water device 15 connected with the outlet of the rolling mill, and a wire receiving machine 16 performs down swinging wire throwing to form a disc-shaped aluminum alloy wire rod blank 17 with one ingot weight.
When the continuous rolling unit 14 carries out multi-pass continuous control rolling, the rolling temperature of the aluminum alloy wire ingot 9 is 420-460 ℃ and the final rolling temperature is 320-360 ℃. Generally, it is classified into rough rolling, intermediate rolling and finish rolling. Wherein, rough rolling is carried out for 1-4 times, and the deformation is 25-28%; intermediate rolling for 5-8 passes with deformation of 22-24.5%; finish rolling for 8-15 times, and the deformation amount is 20%. And obtaining a final product by adopting 8-15 passes in total. In a specific operation, the rolling reduction and the rolling temperature are determined according to the diameter between the aluminum alloy wire ingot 9 and the aluminum alloy wire rod blank 17. When the rolling temperature is low, the rolling line rod can be cracked due to the fact that the rolling reduction is too large, and the rejection rate is high; however, when the rolling reduction is small, the rolling times are increased, and the preparation time and the cost are increased, so that the aluminum alloy wire rod blank 17 with better quality can be obtained by selecting the rolling parameters, and the production cost and the production time can be simultaneously considered.
Referring to fig. 3, the mold of the continuous casting machine 7 is composed of a crystallized copper wheel 20 and a steel strip wrapped around a notch 21 of the crystallized copper wheel. The crystalline copper wheel 20 is H-shaped, and the notch 21 is trapezoidal. The cooling system of the crystalline copper wheel 20 mainly comprises: an in-mold cooling device 22, an outside-mold cooling device 23, an outside-mold cooling device 24, and an inside-mold cooling device 25 provided around the mold, which spray cooling water to the mold in a circular motion during continuous casting. The water flow of each water spray cooling water nozzle is independently adjustable. Therefore, accurate cooling control can be provided for the continuous casting process of the alloy, and the problem of uneven cooling of the aluminum alloy material caused by the reduction of the heat conductivity coefficient is well solved, so that the quality of casting blank products is improved. The water pressure of water spray in the crystallizer inner cooling device 22, the crystallizer outer cooling device 23, the crystallizer outer cooling device 24 and the crystallizer inner cooling device 25 is 0.2-0.4 MPa. Namely, the water pressure of the inner cooling water sprayed from the inner cooling device 22, the outer cooling water sprayed from the outer cooling device 23, the outer cooling water sprayed from the outer cooling device 24 and the inner cooling water sprayed from the inner cooling device 25 is 0.2-0.4 MPa. Referring to fig. 4, the cooling system of the continuous casting machine 7 is divided into four sections clockwise in the circumferential direction by the diameter of the copper wheel in the vertical direction being 0 ° and 180 °, wherein 0 to 45 ° is one section (section a in fig. 4), 46 to 90 ° is two section (section b in fig. 4), 91 to 135 ° is three section (section c in fig. 4), and 136 to 180 ° is four section (section d in fig. 4). The cooling water flow rate of the first area is 6-12T/h, the second area is 4-8T/h, the third area is 10-18T/h, and the fourth area is 6-12T/h.
Example 1
S1, under the protection of a first protective gas (argon, the pressure is 0.2MPa, the flow is 2.0L/min), 5560kg of industrial pure aluminum (Wt, fe is less than or equal to 0.13 percent, si is less than or equal to 0.08 percent) with the purity of more than 99.7 percent is heated and melted in a double-chamber vertical aluminum melting furnace. When the temperature of the aluminum liquid is 730-735 ℃, the aluminum liquid is led into the heat preservation furnace from the smelting furnace through a diversion trench connected with the smelting furnace and the heat preservation furnace, 66.3kg of Al-10% Cr, al-10% Mn and Al-10% Ti are added into an inlet tundish of the heat preservation furnace, and the aluminum liquid enters the heat preservation furnace for bottom blowing of the first protective gas along with the flushing and stirring of the aluminum alloy melt during the discharging. And after all the aluminum melt flows into the heat preservation furnace from the standing furnace, alloying the aluminum melt. Under the protection of the first protective gas by bottom blowing and the electromagnetic stirring force (stirring current 140A, stirring frequency 1.5Hz and stirring time 30 Min), 890Kg of Al-40% Mg intermediate alloy (5.26% Mg of ingredients) is added. And (5) obtaining an aluminum alloy melt after the alloy elements are completely melted. The temperature of the aluminum alloy melt was raised to 710℃and 7.1kg of Al-5% Be master alloy was added to the aluminum alloy melt.
S2, after uniformly stirring the aluminum alloy melt, carrying out stokehold rapid analysis on the aluminum alloy melt, carrying out component adjustment on the aluminum alloy melt according to the rapid stokehold analysis result, and then blowing in a second protective gas (94% Ar+6% Cl) from the bottom of the heat preservation furnace 2 The pressure of the mixed gas is 0.4MPa, the flow is 6.0L/min), the melt is subjected to refining steps such as degassing, impurity removal, slag skimming and the like, and the refining time of the bottom blowing mixed gas is 20min until the component requirement is met. At this time, the second shielding gas is closed, the aluminum alloy melt is kept at 700 ℃, the third shielding gas (argon, the pressure is 0.25MPa, the flow is 2.8/min) is introduced, the micro-positive pressure of the argon in the furnace is kept, the air is prevented from reacting with Mg element added into the heat preservation furnace, and the aluminum alloy melt is kept stand for 20min.
S3, keeping the third protective gas continuously blown in, tilting and releasing the aluminum alloy melt after standing from the heat preservation furnace by means of a releasing chute, and realizing on-line wire feeding (Al-5% Ti-1% B aluminum alloy wire rod with phi 9.5) in the releasing chute, wherein the wire feeding speed is 8.2m/min. The aluminum alloy melt after the online wire feeding flows through an online degassing and ceramic filtering system connected at the back through a discharge groove, wherein the online degassing pressure is 0.2MPa and 4L/min. After degassing outside the furnace and ceramic filtering, the aluminum alloy melt flows through an upper casting ladle, continuous hydrogen measurement treatment is carried out on the upper casting ladle, a middle casting ladle is carried out, and finally the aluminum alloy melt is horizontally cast into a continuous casting machine through a lower casting ladle. The temperature of the lower ladle of the aluminum alloy melt poured into the continuous casting machine is 680 ℃. The aluminum alloy melt flows into a cavity formed by a copper wheel notch of a continuous casting machine with the rotating speed of 12RPM and a steel belt, the cooling water pressure of cooling water in a pouring system, cooling water outside, cooling water inside and cooling water outside is 0.28MPA, and the flow of each section of cooling water is as follows: 1 zone 6T/h, two zones 4T/h, three zones 10T/h, four zones 6T/h. Continuously and continuously solidifying the aluminum alloy wire ingots to obtain the aluminum alloy wire ingots with the temperature of 390 ℃, continuously removing the solidified wire ingots by a wire ingot shaver in a continuous casting machine, and realizing the continuous separation of the aluminum alloy wire ingots and the continuous casting crystalline copper wheel.
S4, continuously separating the continuous casting aluminum alloy wire ingot from the crystallization wheel, passing through a curve ingot approach bridge, shearing off waste materials about 1m of the wire ingot stub by a head shearing machine under the action of traction before the continuous casting continuous rolling machine is driven, and continuously measuring hydrogen by an HDA on-line hydrogen meter in the process to obtain the hydrogen content of 0.09-0.10 ml/100g Al. The aluminum alloy wire ingot is straightened by a straightening machine and is continuously heated by a frequency doubling heater, under the action of an active feeding system, the aluminum alloy wire ingot is fed into a continuous rolling machine at 430 ℃, under the lubrication and cooling actions of a continuous casting machine emulsion with the emulsion flow of 50T/h, the pressure of 0.30MPa and the concentration of 9%, the aluminum alloy wire ingot is rolled into an aluminum alloy welding screw rod with the diameter of 9.5mm by 11 passes, and the final rolling temperature of the aluminum alloy welding screw rod is 360 ℃. Wherein, rough rolling is carried out for 1-4 times, and the deformation is 25-28%; intermediate rolling for 5-7 times, deformation of 22-24.5%, finish rolling for 8-11 times and deformation of 20%. The chemical compositions of the aluminum alloy rods prepared in the embodiment are shown in table 1, and the mechanical properties are shown in fig. 6.
Example 2
S1, under the protection of a first protective gas (argon, the pressure is 0.2MPa, the flow is 2.0L/min), 5565kg of industrial pure aluminum (Wt, fe is less than or equal to 0.13 percent, si is less than or equal to 0.08 percent) with the purity of more than 99.7 percent is heated and melted in a double-chamber vertical aluminum melting furnace. When the temperature of the aluminum liquid is 730-735 ℃, the aluminum liquid is led into the heat preservation furnace from the smelting furnace through a diversion trench connected with the smelting furnace and the heat preservation furnace, 66.4kg of Al-10% Cr, al-10% Mn and Al-10% Ti are added into an inlet tundish of the heat preservation furnace, and the aluminum liquid enters the heat preservation furnace for bottom blowing of the first protective gas along with the flushing and stirring of the aluminum alloy melt during the discharging. And after all the aluminum melt flows into the heat preservation furnace from the standing furnace, alloying the aluminum melt. Under the protection of the first protective gas by bottom blowing and the electromagnetic stirring force (stirring current 170A, stirring frequency 2.0Hz and stirring time 22 Min), 890Kg of Al-40% Mg intermediate alloy (5.26% Mg of ingredients) is added. And (5) obtaining an aluminum alloy melt after the alloy elements are completely melted. The temperature of the aluminum alloy melt was raised to 720℃and 7.1kg of Al-5% Be master alloy was added to the aluminum alloy melt.
S2, after uniformly stirring the aluminum alloy melt, carrying out stokehold rapid analysis on the aluminum alloy melt, carrying out component adjustment on the aluminum alloy melt according to the rapid stokehold analysis result, and then blowing in a second protective gas (94% Ar+6% Cl) from the bottom of the heat preservation furnace 2 The pressure of the mixed gas is 0.5MPa, the flow is 7.0L/min), the melt is subjected to refining steps such as degassing, impurity removal, slag skimming and the like,refining the bottom-blown mixed gas for 25min until the composition requirement is met. At this time, the second shielding gas is closed, the aluminum alloy melt is kept at 710 ℃, the third shielding gas (argon, the pressure is 0.2MPa, the flow is 2.0L/min) is introduced, the micro-positive pressure of the argon in the furnace is kept, the air is prevented from reacting with Mg element added into the heat preservation furnace, and the aluminum alloy melt is kept stand for 25min.
S3, keeping the third protective gas continuously blown in, tilting and releasing the aluminum alloy melt after standing from the heat preservation furnace by means of a releasing chute, and realizing on-line wire feeding (Al-5% Ti-1% B aluminum alloy wire rod with phi 9.5) in the releasing chute, wherein the wire feeding speed is 8.2m/min. The aluminum alloy melt after the online wire feeding flows through an online degassing and ceramic filtering system connected at the back through a discharge groove, wherein the online degassing pressure is 0.33MPa,5L/min. After degassing outside the furnace and ceramic filtering, the aluminum alloy melt flows through an upper casting ladle, continuous hydrogen measurement treatment is carried out on the upper casting ladle, a middle casting ladle is carried out, and finally the aluminum alloy melt is horizontally cast into a continuous casting machine through a lower casting ladle. The temperature of the lower ladle of the aluminum alloy melt which is poured into the continuous casting machine is 690 ℃. The aluminum alloy melt flows into a cavity formed by a copper wheel notch of a continuous casting machine with the rotating speed of 12RPM and a steel belt, the cooling water pressure of cooling water in a pouring system, cooling water outside, cooling water inside and cooling water outside is 0.3MPA, and the flow of each section of cooling water is as follows: 1 zone 8T/h, two zones 6T/h, three zones 14T/h, and four zones 8.5T/h. Continuously and continuously solidifying the aluminum alloy wire ingots to form aluminum alloy wire ingots with the temperature of 400 ℃, continuously removing the solidified wire ingots by a wire ingot shaver in a continuous casting machine, and realizing continuous separation of the aluminum alloy wire ingots and the continuous casting crystalline copper wheel.
S4, continuously separating the aluminum alloy wire ingot formed by continuous casting from the crystallization wheel, passing through a curve ingot approach bridge, shearing off waste materials about 1m of wire ingot material head through a shearing machine under the action of traction before the continuous casting and rolling machine is active, continuously measuring hydrogen by using an HDA on-line hydrogen meter in the process, measuring 0.10-0.11 ml/100g Al of hydrogen content, feeding into a straightening machine for straightening, continuously heating by using a double frequency heater, feeding the aluminum alloy wire ingot into the continuous rolling machine at 445 ℃ under the action of an active feeding system, rolling the aluminum alloy wire ingot into an aluminum alloy welding screw rod with the thickness of 9% by using 11 passes under the lubrication and cooling actions of emulsion of a continuous casting machine with the emulsion flow rate of 50T/h, the pressure of 0.4MPa, and the final rolling temperature of 340 ℃. Wherein, rough rolling is carried out for 1-4 times, and the deformation is 25-28%; intermediate rolling for 5-7 times, deformation of 22-24.5%, finish rolling for 8-11 times and deformation of 20%. The chemical composition of the alloy rod is shown in Table 1, and the mechanical properties are shown in FIG. 6.
Example 3
S1, under the protection of a first protective gas (argon, the pressure is 0.2MPa, the flow is 2.0L/min), 5559.5kg of industrial pure aluminum (Wt, fe is less than or equal to 0.13 percent, si is less than or equal to 0.08 percent) with the purity of more than 99.7 percent is heated and melted in a double-chamber vertical aluminum melting furnace. When the temperature of the aluminum liquid is 730-735 ℃, the aluminum liquid is led into the heat preservation furnace from the smelting furnace through a diversion trench connected with the smelting furnace and the heat preservation furnace, 66.8kg of Al-10% Cr, al-10% Mn and Al-10% Ti are added into an inlet tundish of the heat preservation furnace, and the aluminum liquid enters the heat preservation furnace for bottom blowing of the first protective gas along with the flushing and stirring of the aluminum alloy melt during the discharging. And after all the aluminum melt flows into the heat preservation furnace from the standing furnace, alloying the aluminum melt. Under the protection of the first protective gas by bottom blowing and the electromagnetic stirring force (stirring current 200A, stirring frequency 2.5Hz and stirring time 15 Min), 890Kg of Al-40% Mg intermediate alloy (5.26% Mg of ingredients) is added. And (5) obtaining an aluminum alloy melt after the alloy elements are completely melted. The temperature of the aluminum alloy melt was raised to 730℃and 8kg of Al-5% Be master alloy was added to the aluminum alloy melt.
S2, after uniformly stirring the aluminum alloy melt, carrying out stokehold rapid analysis on the aluminum alloy melt, carrying out component adjustment on the aluminum alloy melt according to the rapid stokehold analysis result, and then blowing in a second protective gas (94% Ar+6% Cl) from the bottom of the heat preservation furnace 2 The pressure of the mixed gas is 0.58MPa, the flow is 7.8L/min), the melt is subjected to refining steps such as degassing, impurity removal, slag skimming and the like, and the refining time of the bottom blowing mixed gas is 28min until the component requirement is met. At this time, the second shielding gas is closed, the aluminum alloy melt is kept at 720 ℃, the third shielding gas (argon, the pressure is 0.3MPa, the flow is 3.5L/min) is introduced, the micro-positive pressure of the argon in the furnace is kept, the air is prevented from reacting with Mg element added into the heat preservation furnace, and the aluminum alloy melt is kept stand for 30min.
S3, keeping the third protective gas continuously blown in, tilting and releasing the aluminum alloy melt after standing from the heat preservation furnace by means of a releasing chute, and realizing on-line wire feeding (Al-5% Ti-1% B aluminum alloy wire rod with phi 9.5) in the releasing chute, wherein the wire feeding speed is 8.2m/min. The aluminum alloy melt after the online wire feeding flows through an online degassing and ceramic filtering system connected at the back through a discharge groove, wherein the online degassing pressure is 0.42MPa and 5.8/min. After degassing outside the furnace and ceramic filtering, the aluminum alloy melt flows through an upper casting ladle, continuous hydrogen measurement treatment is carried out on the upper casting ladle, a middle casting ladle is carried out, and finally the aluminum alloy melt is horizontally cast into a continuous casting machine through a lower casting ladle. The temperature of the lower ladle of the aluminum alloy melt poured into the continuous casting machine is 700 ℃. The aluminum alloy melt flows into a cavity formed by a copper wheel notch of a continuous casting machine with the rotating speed of 12RPM and a steel belt, the cooling water pressure of cooling water in a pouring system, outer cooling water, inner cooling water and outer cooling water is 0.4MPA, and the flow of each section of cooling water is as follows: zone 1, 11.5T/h, zone 7.6T/h, zone 17.2T/h, zone four, 10.5T/h. Continuously and continuously solidifying the aluminum alloy wire ingots to form aluminum alloy wire ingots with the temperature of 410 ℃, continuously removing the solidified wire ingots by a wire ingot shaver in a continuous casting machine, and continuously separating the aluminum alloy wire ingots from a continuous casting crystalline copper wheel.
S4, continuously separating the aluminum alloy wire ingot formed by continuous casting from the crystallization wheel, passing through a curve ingot approach bridge, shearing off waste materials about 1m of wire ingot material head through a shearing machine under the action of traction before the continuous casting and rolling machine is active, continuously measuring hydrogen by using an HDA on-line hydrogen meter in the process, measuring 0.11-0.115 ml/100g Al of hydrogen content, feeding into a straightening machine for straightening, continuously heating by using a double frequency heater, feeding the aluminum alloy wire ingot into the continuous rolling machine at the temperature of 455 ℃ under the action of an active feeding system, rolling the aluminum alloy wire ingot into an aluminum alloy welding screw rod with the thickness of 9% by using 11 passes under the lubrication and cooling actions of emulsion of a continuous casting machine with the emulsion flow rate of 50T/h, the pressure of 0.45MPa, and the final rolling temperature of 320 ℃ of the aluminum alloy welding screw rod. Wherein, rough rolling is carried out for 1-4 times, and the deformation is 25-28%; intermediate rolling for 5-7 times, deformation of 22-24.5%, finish rolling for 8-11 times and deformation of 20%. The chemical compositions of the alloy rods are shown in Table 1, and the mechanical properties of the alloy rods are shown in FIG. 6.
Table 1 chemical composition table of aluminum alloy rods prepared in examples 1 to 3
As can be seen from Table 1, the prepared aluminum alloy rod has higher magnesium content, solves the problem of production of high-Mg aluminum alloy according to the following table, and the prepared aluminum alloy rod has hydrogen content of 0.10-0.12 ml/100g Al, so that the use requirements of aerospace and high-speed rail fields can be met. The main reason why the Mg content and the hydrogen content in the aluminum alloy rods prepared in examples 1 to 3 were high is: the invention applies the bottom blowing shielding gas and the electromagnetic stirring to the same heat preservation furnace, thereby realizing the low-frequency electromagnetic stirring which protects and does not damage the oxide film on the surface of the melt. Example 1 gives the alloy with the highest Mg content, example 3 with the lowest Mg content and example 1 with the lowest H content, and example 3 with the highest H content, mainly because the finishing temperature of example 3 is higher than that of example 1, the finishing temperature is increased, the capacity employed needs to be increased synchronously with the casting temperature, and thus the burning loss of Mg metal and the tendency of the melt to absorb hydrogen are increased.
An optical microscopic view of the aluminum alloy wire ingot obtained by continuous casting in examples 1 to 3 is shown in fig. 5, wherein (a) is the aluminum alloy wire ingot prepared in example 1, (b) is the aluminum alloy wire ingot prepared in example 2, and (c) is the aluminum alloy wire ingot prepared in example 3. As can be seen from fig. 5, the structure of the continuous casting alloy is equiaxed, and its average grain size is 120um, instead of the conventional dendrite structure. The three-layer structure of the conventional continuous casting wire ingot is changed, and the uniformity of the structure is greatly improved. The microstructure of the wire rod prepared in example 2 is shown in fig. 6 and 7. Fig. 6 is a schematic view showing a sectional view of a wire ingot, and fig. 7 is a microstructure view of 1 to 9 parts. As can be seen from fig. 6 and 7, the cross-sectional structure of the continuous casting 5356 aluminum alloy wire ingot is unevenly distributed with equiaxed crystals, the distribution of the crystal grains is small in external crystal grains, large in middle crystal grains and the largest in core crystal grains. The grains at the positions of the wire ingot cross sections 1, 3, 7 and 9 are smaller, and the average grain diameters are respectively 100um, 98.6um, 101um and 108um; the grains at the intermediate positions 2, 4, 6 and 8 were 160um, 138 um, 136 um and 158 um, respectively, with larger grains. The average grain size of the core position 5 was 198 μm at the maximum. The crystal grains of the 5356 aluminum alloy wire ingot formed by continuous casting are basically equiaxed crystals. This is mainly: (1) adopting a primary forced cooling (corresponding to a first-region cooling water flow of 6-12T/h) +a secondary weak cooling (corresponding to a second-region cooling water flow of 4-8T/h) +a tertiary strong cooling (corresponding to a third-region cooling water flow of 10-18T/h) +a quaternary temperature-regulating cooling process (corresponding to a fourth-region cooling water flow of 6-12T/h.) at a horizontal pouring inlet, forming a primary shell and a liquid wedge of small and thinned equiaxed crystals through primary strong cooling at the pouring inlet, forming columnar crystals produced on an outer arc downward and an inner arc at a place with small top easily, breaking the liquid viscosity of high-magnesium Al-Mg under the scouring action of a continuously poured high-temperature aluminum alloy melt, taking the broken grains as new nucleation points, and carrying out secondary weak cooling, increasing the breaking rate of columnar crystals, so that the rate of nucleation of the crystal grains is larger than the growing rate, the columnar crystals start to be converted into tiny equiaxed crystals, (2) adding alloy elements and grain refiners of heterogeneous nucleation such as Cr, mn, al-Ti-B and the like, increasing the nucleation rate, (3) but increasing the cooling rate, wherein the rate of nucleation of the crystal grains is larger than the growing rate of the crystal grains, reducing cooling by two areas, increasing the solidification temperature interval of 5356 aluminum alloy, increasing the breaking trend, accelerating the breaking of columnar crystals, leading more columnar crystals to be broken, greatly increasing the nucleation rate, leading more columnar crystals to start to be converted into equiaxed crystals, (4) bending liquid cavities, accelerating homogenization and dispersion of nucleation in melt, but having low heat conductivity of high magnesium alloy and low heat transfer capability, the alloy is not cooled uniformly in the solidification process, the temperature of the center of the solidified cross section of the wire ingot is high, the temperature of the edge is low, and as a result, the crystal grains at the middle core are larger.
Example 2 continuous Rolling to form a microstructure of phi 9.5mm aluminum alloy rod formed in 11 passes from a finished rod of a continuous casting wire ingot as shown in fig. 8, 0 to 11 correspond to rolling passes, respectively, as can be seen from fig. 8, the microstructure of phi 9.5mm aluminum alloy rod prepared by the present invention in 0 to 11 th passes from a cast blank to a finished rod, has an equiaxed structure with an average grain diameter of 160um of the wire ingot to 20um of the finished rod. The main reasons for the presence of equiaxed crystal structure are: (1) The structure inheritance, or similar deformation theory, that is, the structure of the alloy wire ingot is equiaxed crystal, increases the trend of the deformed structure equiaxed crystal. (2) The high-temperature continuous thermal deformation improves the dynamic recrystalization rate of alloy crystal grains and the trend of growth trend. (3) 5356 aluminum alloy has low heat transfer speed, small heat dissipation of rolled piece, small heat dissipation at edge part and high deformation temperature of rolled piece. (4) The emulsion has high concentration, small cooling capacity and high deformation temperature of the rolled piece. Therefore, on the basis of the wire ingot equiaxed crystal, the dynamic recrystallization nucleation rate is high, the energy requirement for recrystallization growth is small, the heat transfer of 5356 alloy is small, the concentration of emulsion is high, the cooling capacity is low, and sufficient driving energy is provided for the dynamic recrystallization nucleation and growth of a rolled piece, so that the rolling process realizes the rolling of the congruent axial crystal, but the specific surface area of the rolled piece is increased, the temperature is reduced, the growth driving force is reduced, and the crystal grains of the rolled piece are reduced along with the increase of the rolling pass.
Fig. 9 shows the mechanical properties of the aluminum alloy bars with different continuous casting and rolling forming finishing temperatures Φ9.5mm 5356 in examples 1-3. As can be seen from fig. 9, the elongation of the 5356 aluminum alloy increases with an increase in the finishing temperature, and the tensile strength decreases with an increase in the finishing temperature. When the finishing temperature is below 320 ℃, the strength exceeds 310MPA but the elongation is below 22%. As a raw material rod for wire drawing, the alloy composition is high, the cold working process is fast in work hardening, and the requirement of the subsequent cold working stretch forming cannot be well met. When the final rolling temperature reaches 320-360 ℃, the strength of the alloy rod is reduced to 290-305 MPA, the elongation reaches 22-24%, and the cold processing performance of the alloy rod is improved.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (9)
1. The aluminum alloy rod is characterized in that the aluminum alloy rod is prepared by continuous casting and rolling, magnesium element is added in a form of intermediate alloy during casting, and the mass percentage of magnesium in the added aluminum-magnesium intermediate alloy is 38-40.5%; the inside of the aluminum alloy rod is an equiaxial crystal structure, the tensile strength is 290-305 MPa, and the elongation is 22-24%.
2. The aluminum alloy rod as claimed in claim 1, wherein the hydrogen content of the aluminum alloy rod is 0.09 to 0.12ml/100g Al.
3. A preparation method of an aluminum alloy rod is characterized by comprising the following steps,
s1, adding Al-Cr, al-Mn and Al-10% Ti intermediate alloy into molten aluminum under the action of first protective gas; after all melting, adding an Al-Mg intermediate alloy under the action of a first protective gas and stirring, adding an Al-Be intermediate alloy after the Al-Mg intermediate alloy is completely melted, and stirring uniformly to obtain an aluminum alloy melt;
s2, after component analysis and adjustment are carried out on the aluminum alloy melt, refining is carried out on the aluminum alloy melt under the action of a second protective gas; under the protection of a third protective gas, standing and preserving heat of the refined aluminum alloy melt;
s3, under the protection of a third protective gas, horizontally pouring the aluminum alloy melt after standing into a rotary continuous casting machine through an upper ladle and a middle ladle, and continuously solidifying the aluminum alloy melt into an aluminum alloy wire ingot under the sectional cooling of a cooling system with sectional flow control;
s4, under the protection of a third protective gas, the aluminum alloy wire ingot is subjected to 7-15 passes and is continuously rolled into an aluminum alloy rod with the diameter of 6.0-9.5 mm, and the aluminum alloy rod is the aluminum alloy rod in claim 1.
4. The method for producing an aluminum alloy rod according to claim 3, wherein in step S1, the aluminum liquid is obtained by melting an aluminum ingot in a melting furnace and heating the molten aluminum to 720 to 740 ℃, and then introducing the molten aluminum into a holding furnace from the melting furnace through a diversion trench; the Al-Cr, al-Mn and Al-10% Ti intermediate alloy are added into a diversion trench and flow into a holding furnace along with molten aluminum.
5. The method for preparing an aluminum alloy rod according to claim 3, wherein in the step S1, the Al-Mg intermediate alloy is added into the aluminum liquid in 2-3 batches, and after the Al-Mg intermediate alloy added in the previous batch is completely melted and uniformly stirred, the next batch is added until the Al-Mg intermediate alloy is added.
6. The method of manufacturing an aluminum alloy rod according to claim 3, wherein in the step S1, the first shielding gas is argon, the pressure is 0.2-0.45 MPa, and the flow is 2.0-4.5L/min; the second protective gas is a mixed gas consisting of 94-97% of argon and 3-6% of chlorine, the pressure is 0.4-0.8 MPa, and the flow is 4.0-8.5L/min; the third protective gas is argon, the pressure is 0.2-0.3 MPa, and the flow is 2.0-3.5L/min.
7. The method of manufacturing an aluminum alloy rod according to claim 3, wherein in the step S2, the component analysis is a rapid component analysis performed by sampling at the side portion of the melt, the center of the melt, and 1/2 center; the purification treatment comprises degassing, impurity removal, slag skimming and covering.
8. The method of manufacturing an aluminum alloy rod according to claim 3, wherein in step S3, the sectional cooling of the cooling system with the sectional flow control is divided into four areas, wherein the cooling water flow rate of the first area is 6-12T/h, the cooling water flow rate of the second area is 4-8T/h, the cooling water flow rate of the third area is 10-18T/h, and the cooling water flow rate of the fourth area is 6-12T/h; the water pressure of the inner cooling water, the outer cooling water, the inner cooling water and the outer cooling water of the cooling system is 0.2-0.4 MPa.
9. The method for manufacturing an aluminum alloy rod according to claim 3, wherein in the step S3, the purified aluminum alloy melt flows into an on-line degassing and ceramic filtering system through a discharge launder and then flows into an upper ladle; the method also comprises the step of adding Al-Ti-B wires into the discharge launder.
Priority Applications (1)
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