High-yield-ratio 6056 aluminum alloy rod and preparation method thereof

Abstract

The invention provides a high-yield-ratio 6056 aluminum alloy rod and a preparation method thereof, and belongs to the technical field of aluminum alloy. The 6056 aluminum alloy rod with the high yield ratio, provided by the invention, comprises the following chemical components in percentage by mass: 1.0 to 1.5 percent of Si, 0.10 to 0.25 percent of Fe, 0.75 to 0.85 percent of Cu, 0.55 to 0.65 percent of Mn, 0.9 to 1.2 percent of Mg, less than 0.05 percent of Cr, 0.2 to 0.25 percent of Zn, 0.03 to 0.05 percent of Ti, less than 0.002 percent of Sr, 0.001 to 0.005 percent of B, 0.11 to 0.17 percent of Zr, 0.1 to 0.2 percent of rare earth and the balance of Al. The ratio of Si to Mg is greater than or equal to 1.2. By regulating and controlling the contents of Si, Mg, Cu, Zn, Mn and Fe, the Si / Mg ratio is strictly controlled, and the yield ratio of the aluminum alloy can be increased in cooperation with rare earth.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloys, and in particular relates to a high yield ratio 6056 aluminum alloy rod and a preparation method thereof. Background Art

[0002] With the continuous advancement of automobile lightweighting, aluminum alloy materials have been widely used in the field of automobile manufacturing. However, connection technology has always been regarded as the key technology for the effective promotion of automobile lightweighting. Due to the inconsistency between the thermal expansion coefficients of steel bolts and aluminum alloy parts, when the temperature changes, additional stress will be generated in the threaded connection pair, which will increase the creep risk of aluminum alloy and reduce the reliability of bolt connections. Therefore, the research and development of high-strength aluminum alloy bolts has become a hot spot in the field of aluminum alloy processing at home and abroad. 6056 aluminum alloy is a heat-treatable and strengthened aluminum alloy. After T6 treatment, the alloy has high strength, and its weldability, corrosion resistance and cutting performance are better than 7050 and 2024 aluminum alloys. It is very suitable for the preparation of aluminum alloy bolts.

[0003] At present, the chemical composition of 6056 aluminum alloy includes Si 0.7-1.2%, Fe < 0.25%, Cu 0.65-0.85%, Mn 0.55-0.65%, Mg 0.6-1.0%, Cr < 0.05%, Zn 0.15-0.25%, Ti < 0.05%, Sr < 0.002%, B < 0.005%, Zr 0.11-0.17% and the balance Al by mass percentage, but the yield strength ratio and elongation of 6056 aluminum alloy are low. Therefore, how to improve the yield strength ratio and elongation of aluminum alloy has become a technical problem to be solved in this field. Summary of the invention

[0004] The object of the present invention is to provide a 6056 aluminum alloy rod with a high yield strength ratio and a preparation method thereof. The aluminum alloy prepared by the preparation method provided by the present invention has a high yield strength ratio and elongation.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a 6056 aluminum alloy rod with a high yield ratio, wherein the chemical composition comprises, by mass percentage, 1.0-1.5% of Si, 0.10-0.25% of Fe, 0.75-0.85% of Cu, 0.55-0.65% of Mn, 0.9-1.2% of Mg, less than 0.05% of Cr, 0.2-0.25% of Zn, 0.03-0.05% of Ti, less than 0.002% of Sr, 0.001-0.005% of B, 0.11-0.17% of Zr, 0.1-0.2% of rare earth and the balance of Al;

[0007] The Si / Mg≥1.2.

[0008] Preferably, the chemical composition includes, by mass percentage, Si 1.1-1.4%, Fe 0.13-0.20%, Cu0.78-0.84%, Mn 0.58-0.62%, Mg 0.92-1.1%, Cr≤0.04%, Zn 0.21-0.24%, Ti0.03-0.04%, Sr≤0.001%, B 0.002-0.004%, Zr 0.12-0.15%, rare earth 0.12-0.18% and the balance Al.

[0009] Preferably, the chemical composition includes, by mass percentage, Si 1.12-1.3%, Fe 0.15-0.18%, Cu 0.80-0.82%, Mn 0.59-0.60%, Mg 0.98-1.0%, Cr 0.01-0.02%, Zn 0.22-0.23%, Ti 0.03-0.04%, Sr 0.001%, B 0.002-0.003%, Zr 0.13-0.14%, rare earth 0.14-0.16% and the balance Al.

[0010] Preferably, the Si / Mg is 1.21-2.

[0011] The present invention also provides a method for preparing the high yield ratio 6056 aluminum alloy rod described in the above technical solution, comprising the following steps:

[0012] (1) mixing aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy, and sequentially performing smelting and primary refining to obtain a melt;

[0013] (2) mixing the melt obtained in step (1), the magnesium ingot and the aluminum rare earth master alloy, and performing secondary refining to obtain a composite melt;

[0014] (3) mixing the composite melt obtained in step (2) with an aluminum-titanium-boron master alloy, performing grain refinement, and obtaining an aluminum alloy melt;

[0015] (4) The aluminum alloy melt obtained in step (3) is continuously cast and rolled to obtain a 6056 aluminum alloy rod with a high yield ratio.

[0016] Preferably, the smelting temperature in step (1) is 780-800° C., and the smelting time is 60-120 min.

[0017] Preferably, the temperature of the primary refining in step (1) is 780-800° C., and the time of the primary refining is 40-50 min.

[0018] Preferably, the primary refining in step (1) is performed using nitrogen and a particle refining agent.

[0019] Preferably, the pressure of the nitrogen is 0.2-0.25 MPa.

[0020] Preferably, the temperature of the secondary refining in step (2) is 780-800° C., and the time of the secondary refining is 20-30 min.

[0021] The invention provides a 6056 aluminum alloy rod with a high yield ratio. The chemical composition comprises, by mass percentage, 1.0-1.5% of Si, 0.10-0.25% of Fe, 0.75-0.85% of Cu, 0.55-0.65% of Mn, 0.9-1.2% of Mg, less than 0.05% of Cr, 0.2-0.25% of Zn, 0.03-0.05% of Ti, less than 0.002% of Sr, 0.001-0.005% of B, 0.11-0.17% of Zr, 0.1-0.2% of rare earth and the balance of Al; the Si / Mg ratio is greater than or equal to 1.2. The present invention can improve the yield strength ratio and elongation of aluminum alloy by regulating the content range of main added elements (Si, Mg, Cu, Zn, Mn) and trace impurity elements (Fe), strictly controlling the Si / Mg ratio, and combining rare earth; adding B and Ti can refine the grains of aluminum alloy, thereby further improving the yield strength ratio and elongation of aluminum alloy. Experimental results show that the tensile strength of the 6056 aluminum alloy rod provided by the present invention is 290-310MPa, the yield strength is 240-260MPa, the elongation is ≥14%, and the yield strength ratio is above 80%. DETAILED DESCRIPTION

[0022] The invention provides a 6056 aluminum alloy rod with a high yield ratio, wherein the chemical composition comprises, by mass percentage, 1.0-1.5% of Si, 0.10-0.25% of Fe, 0.75-0.85% of Cu, 0.55-0.65% of Mn, 0.9-1.2% of Mg, less than 0.05% of Cr, 0.2-0.25% of Zn, 0.03-0.05% of Ti, less than 0.002% of Sr, 0.001-0.005% of B, 0.11-0.17% of Zr, 0.1-0.2% of rare earth and the balance of Al;

[0023] The Si / Mg≥1.2.

[0024] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention includes Si 1.0-1.5%. As an embodiment, the mass content of Si can be 1.08-1.4%, or 1.12-1.3%. In the present invention, the Si can improve the strength and hardness of the aluminum alloy.

[0025] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Fe0.10-0.25%. As an embodiment, the mass content of Fe can be 0.11-0.24%, or 0.13-0.18%. In the present invention, Fe is an impurity element, and the yield ratio and elongation of the aluminum alloy can be improved by limiting its content within the above range.

[0026] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Cu0.75-0.85%. As an embodiment, the mass content of Cu can be 0.76-0.84%, or 0.80-0.82%. In the present invention, Cu can form a solid solution in the aluminum alloy, and improve the strength and hardness of the aluminum alloy through the solid solution strengthening mechanism; by limiting the mass content of Cu to the above range, the yield ratio and elongation of the aluminum alloy can be improved.

[0027] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Mn 0.55-0.65%. As an embodiment, the mass content of Mn can be 0.56-0.64%, or 0.59-0.60%. In the present invention, the Mn can form a solid solution in the aluminum alloy, and improve the strength and hardness of the aluminum alloy through the solid solution strengthening mechanism; by limiting the mass content of Mn to the above range, the yield ratio and elongation of the aluminum alloy can be improved.

[0028] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Mg 0.9-1.2%. As an embodiment, the mass content of Mg can be 0.92-1.1%, or 0.98-1.0%. In the present invention, the Mg can form a solid solution in the aluminum alloy, and improve the strength and hardness of the aluminum alloy through the solid solution strengthening mechanism; by limiting the mass content of Mg to the above range, the yield ratio and elongation of the aluminum alloy can be improved.

[0029] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Cr < 0.05%. As an embodiment, the mass content of Cr can be ≤ 0.04%, and can also be 0.01-0.03%. In the present invention, the yield ratio and elongation of the aluminum alloy can be improved by limiting the content of Cr to the above range.

[0030] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes 0.2-0.25% Zn. As an embodiment, the mass content of Zn can be 0.21-0.24%, or 0.22-0.23%. In the present invention, the Zn can form a solid solution in the aluminum alloy, and improve the strength and hardness of the aluminum alloy through the solid solution strengthening mechanism; by limiting the mass content of Zn to the above range, the yield ratio and elongation of the aluminum alloy can be improved.

[0031] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Ti0.03-0.05%. As an embodiment, the mass content of the Ti can be 0.03-0.04%. In the present invention, the Ti can refine the grains of the aluminum alloy, thereby further improving the yield ratio and elongation of the aluminum alloy.

[0032] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Sr < 0.002%. As an embodiment, the mass content of Sr can be ≤ 0.001%, and can also be 0.001%. In the present invention, the yield ratio and elongation of the aluminum alloy can be improved by limiting the content of Sr to the above range.

[0033] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes B 0.001-0.005%. As an embodiment, the mass content of B can be 0.002-0.004%, or 0.002-0.003%. In the present invention, B can refine the grains of the aluminum alloy, thereby further improving the yield ratio and elongation of the aluminum alloy.

[0034] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes Zr 0.11-0.17%. As an embodiment, the mass content of Zr can be 0.12-0.16%, or 0.13-0.14%. In the present invention, Zr acts as an effective grain refiner to promote grain refinement of the aluminum alloy during solidification, thereby improving the strength and hardness of the aluminum alloy.

[0035] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes 0.1-0.2% rare earth. As an embodiment, the mass content of the rare earth can be 0.11-0.18%, or 0.13-0.16%. In the present invention, the rare earth can increase the elongation of the aluminum alloy rod and improve its plasticity.

[0036] In the present invention, the rare earth includes at least one of La and Ce.

[0037] In terms of mass percentage, the chemical composition of the high yield ratio 6056 aluminum alloy rod provided by the present invention also includes a balance of Al. In the present invention, the Al is a matrix element.

[0038] In the present invention, the Si / Mg is ≥ 1.2, preferably 1.21 to 2, and more preferably 1.21 to 1.25. In the present invention, the yield ratio and elongation of the aluminum alloy can be improved by limiting the Si / Mg ratio to the above range.

[0039] The present invention can improve the yield ratio and elongation of the aluminum alloy by regulating the content range of the main added elements (Si, Mg, Cu, Zn, Mn) and the trace impurity elements (Fe), strictly controlling the Si / Mg ratio, and combining rare earths; at the same time, adding B and Ti can refine the grains of the aluminum alloy, thereby further improving the yield ratio of the aluminum alloy.

[0040] The present invention also provides a method for preparing the high yield ratio 6056 aluminum alloy rod described in the above technical solution, comprising the following steps:

[0041] (1) mixing aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy, and sequentially performing smelting and primary refining to obtain a melt;

[0042] (2) mixing the melt obtained in step (1), the magnesium ingot and the aluminum rare earth master alloy, and performing secondary refining to obtain a composite melt;

[0043] (3) mixing the composite melt obtained in step (2) with an aluminum-titanium-boron master alloy, performing grain refinement, and obtaining an aluminum alloy melt;

[0044] (4) The aluminum alloy melt obtained in step (3) is continuously cast and rolled to obtain a 6056 aluminum alloy rod with a high yield ratio.

[0045] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0046] The invention mixes aluminum liquid, aluminum silicon master alloy, aluminum copper master alloy, manganese agent, aluminum zinc master alloy and aluminum zirconium master alloy, and sequentially performs smelting and primary refining to obtain a melt.

[0047] In the present invention, the temperature of the aluminum liquid is preferably 780-800°C.

[0048] The present invention has no special limitation on the aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy, and raw materials familiar to those skilled in the art may be used.

[0049] The present invention has no special limitation on the ratio of the aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy, and the ratio can be selected according to the chemical composition of the required aluminum alloy.

[0050] The present invention has no special limitation on the operation of mixing the aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy, and the technical scheme for preparing the mixed material well known to those skilled in the art can be adopted.

[0051] In the present invention, the smelting temperature is preferably 780-800°C; the smelting time is preferably 60-120 min. As an embodiment, the smelting temperature can be 785-790°C; the smelting time can be 70-110 min, or 80-100 min. The present invention limits the smelting temperature and time within the above ranges to make the smelting more uniform.

[0052] In the present invention, the smelting is preferably carried out under stirring conditions. The present invention has no special limitation on the stirring operation, and the operation well known to those skilled in the art can be adopted. The present invention can ensure uniform composition of the melt by stirring during smelting.

[0053] In the present invention, the temperature of the first refining is preferably 780-800°C; the time of the first refining is preferably 40-50 minutes. As an embodiment, the temperature of the first refining can be 786-790°C; the time of the first refining can be 44-48 minutes.

[0054] In the present invention, the primary refining is preferably performed by nitrogen and a particle refining agent; the pressure of the nitrogen is preferably 0.2-0.25 MPa. The present invention has no particular limitation on the type of the particle refining agent, and any refining agent known to those skilled in the art can be used.

[0055] In the present invention, the amount of the particle refining agent is preferably 3-5wt‰ of the mass of the melt obtained by mixing aluminum liquid, aluminum silicon master alloy, aluminum copper master alloy, manganese agent, aluminum zinc master alloy and aluminum zirconium master alloy.

[0056] As an embodiment, the pressure of the nitrogen can be 0.22-0.24 MPa; the amount of the particle refining agent can be 4wt‰ of the mass of the melt obtained by mixing aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy.

[0057] After the primary refining is completed, the present invention preferably performs slagging and standing in sequence on the product obtained from the primary refining to obtain a melt.

[0058] The present invention has no particular limitation on the slag removal operation, and operations well known to those skilled in the art may be adopted.

[0059] In the present invention, the standing time is preferably 20 to 30 minutes. As an embodiment, the standing time can be 24 to 28 minutes. In the present invention, standing can make inclusions in the melt gradually float to the surface of the melt, thereby improving the purity and quality of the aluminum alloy.

[0060] After obtaining the melt, the present invention mixes the melt, a magnesium ingot and an aluminum rare earth master alloy, and performs secondary refining to obtain a composite melt.

[0061] The present invention has no special limitation on the types of the magnesium ingot and the aluminum rare earth master alloy, and raw materials well known to those skilled in the art may be used.

[0062] The present invention has no special limitation on the usage of the magnesium ingot and the aluminum rare earth master alloy, and the usage can be adjusted according to the actual chemical composition of the aluminum alloy.

[0063] The present invention has no special limitation on the operation of mixing the melt, the magnesium ingot and the aluminum rare earth master alloy, and the technical scheme for preparing the mixed material well known to those skilled in the art can be adopted.

[0064] In the present invention, the temperature of the secondary refining is preferably 780-800°C; the time of the secondary refining is preferably 20-30 minutes. As an embodiment, the temperature of the secondary refining can be 781-790°C; the time of the secondary refining can be 24-28 minutes.

[0065] In the present invention, the secondary refining is preferably nitrogen refining; the pressure of the nitrogen is preferably 0.2-0.25 MPa. As an embodiment, the pressure of the nitrogen can be 0.22-0.24 MPa.

[0066] After the secondary refining is completed, the present invention preferably performs slagging and standing in sequence on the product obtained by the secondary refining to obtain a composite melt.

[0067] The present invention has no particular limitation on the slag removal operation, and operations well known to those skilled in the art may be adopted.

[0068] In the present invention, the standing time is preferably 20 to 30 minutes. As an embodiment, the standing time can be 24 to 28 minutes. In the present invention, standing can make inclusions in the melt gradually float to the surface of the melt, thereby improving the purity and quality of the aluminum alloy.

[0069] After obtaining the composite melt, the present invention mixes the composite melt with an aluminum-titanium-boron master alloy to perform grain refinement to obtain an aluminum alloy melt. In the present invention, the aluminum-titanium-boron master alloy is a grain refiner that can refine the crystalline structure and improve the density and uniformity of the structure.

[0070] In the present invention, the aluminum-titanium-boron master alloy is preferably A1-5Ti-1B; the mass of the aluminum-titanium-boron master alloy is preferably 0.3-0.4% of the mass of the composite melt.

[0071] In the present invention, the temperature of the grain refinement is preferably 700-750°C; the time of the grain refinement is preferably 1-12 minutes. In the present invention, limiting the temperature and time of the grain refinement within the above ranges can further improve the effect of the grain refinement.

[0072] As an embodiment, the grain refining temperature may be 710°C, 720°C, 730°C, 740°C or 745°C; the grain refining time may be 5 min, 6 min, 8 min, 10 min or 11 min.

[0073] After the grain refinement is completed, the present invention preferably performs online degassing filtration on the product obtained by the grain refinement to obtain an aluminum alloy melt.

[0074] In the present invention, the online degassing filtration is preferably a double-stage filtration. The present invention has no special limitation on the operation of the double-stage filtration, and the hydrogen content in the melt can be controlled to be below 0.15 mL / 100 g by using the operation well known to those skilled in the art.

[0075] As an implementation manner, the mesh size of the first filter during the double-stage filtration may be 30 meshes; the mesh size of the second filter during the double-stage filtration may be 40 meshes.

[0076] After obtaining the aluminum alloy melt, the present invention continuously casts and rolls the aluminum alloy melt to obtain a high yield ratio 6056 aluminum alloy rod.

[0077] In the present invention, the temperature of the continuous casting is preferably 720-750°C; the speed of the continuous casting is preferably 6.3-8.2 m / min. In the present invention, the aluminum alloy melt flows into the intermediate ladle and enters the crystallization wheel to continuously cast the alloy billet. The aluminum alloy melt is subjected to the extremely strong cooling effect of the crystallization wheel wall, and a solid shell is formed on the surface of the aluminum alloy melt entering the crystallization wheel. The part of the aluminum alloy melt that has solidified and crystallized on the crystallization wheel rotates 180° with the wheel and continuously leaves the crystallization wheel in the form of ingots. In the process of converting the aluminum alloy melt into ingots, the aluminum alloy melt releases a large amount of latent heat, and the heat is quickly taken away by the cooling water sprayed on the crystallization wheel and the steel belt covering the crystallization wheel.

[0078] As an implementation mode, the continuous casting temperature may be 730-740° C.; the continuous casting speed may be 6.5-8.1 m / min, or 7.0-7.5 m / min.

[0079] In the present invention, the continuous casting is preferably wheel-type continuous casting.

[0080] As an embodiment, the aluminum alloy melt may be introduced into the crystallization tank of the wheel-type continuous casting through a tundish.

[0081] In the present invention, the cooling method of the crystallizer during continuous casting is preferably cooling water spraying; the area where the cooling water is sprayed preferably includes the outer side of the steel belt of the crystallization tank, the arc surface of the crystallization wheel on both sides of the crystallization tank, and the inner peripheral wall of the wheel body of the crystallization wheel. The partitioned water distribution of the present invention is conducive to controlling the crystallization and temperature of the aluminum alloy billet, realizing sequential solidification and crystallization, improving the billet structure, reducing casting defects such as looseness and shrinkage, and improving the performance of the aluminum alloy.

[0082] In the present invention, the cooling water spraying area on the outside of the steel strip of the crystallization tank preferably includes outer zone 1, outer zone 2 and outer zone 3; the outer side of the steel strip of the crystallization tank is preferably divided into 4 equal zones along the length direction, and the first three zones along the flow direction of the aluminum alloy melt are preferably the outer zone 1, outer zone 2 and outer zone 3, respectively.

[0083] In the present invention, the flow rate of the spray cooling water in the outer zone 1 is preferably 40-50 L / min; the flow rate of the spray cooling water in the outer zone 2 is preferably 30-40 L / min; the flow rate of the spray cooling water in the outer zone 3 is preferably 20-30 L / min. As an embodiment, the flow rate of the spray cooling water in the outer zone 1 can be 45-48 L / min; the flow rate of the spray cooling water in the outer zone 2 can be 35-38 L / min; the flow rate of the spray cooling water in the outer zone 3 can be 25-26 L / min. The present invention sets the cooling water spray area outside the steel strip of the crystallization tank and the flow rate of the spray cooling water in each area to the above range, which can be more conducive to the cooling and casting of the alloy melt.

[0084] In the present invention, the cooling water spraying area of ​​the arc surface of the crystallization wheel on both sides of the crystallization groove preferably includes two side zones 1 and two side zones 2; the arc surface on both sides of the crystallization wheel is preferably composed of the arc surface corresponding to every 90° radius of the aluminum alloy melt entering the position as a two side zone, and along the flow direction of the aluminum alloy melt, it is sequentially divided into the two side zones 1 and two side zones 2.

[0085] In the present invention, the flow rate of the spray cooling water in the zone 1 on both sides is preferably 40-50 L / min; the flow rate of the spray cooling water in the zone 2 on both sides is preferably 40-50 L / min. As an embodiment, the flow rate of the spray cooling water in the zone 1 on both sides can be 45-47 L / min; the flow rate of the spray cooling water in the zone 2 on both sides can be 45-47 L / min. The present invention sets the cooling water spray area of ​​the crystallization wheel arc surface on both sides of the crystallization tank and the flow rate of the spray cooling water in each area to the above range, which can be more conducive to the cooling and casting of the alloy melt.

[0086] In the present invention, the cooling water spraying area of ​​the inner peripheral wall of the wheel body of the crystallization wheel preferably includes inner zone 1, inner zone 2 and inner zone 3; the arc-shaped area corresponding to every 45° radius of the inner peripheral wall of the wheel body of the crystallization wheel from the entry position of the aluminum alloy melt is preferably the inner area, and along the flow direction of the aluminum alloy melt are the inner zone 1, inner zone 2 and inner zone 3 in sequence.

[0087] In the present invention, the flow rate of the spray cooling water in the inner zone 1 is preferably 50-60 L / min; the flow rate of the spray cooling water in the inner zone 2 is preferably 40-50 L / min; the flow rate of the spray cooling water in the inner zone 3 is preferably 30-40 L / min. As an embodiment, the flow rate of the spray cooling water in the inner zone 1 can be 45-52 L / min; the flow rate of the spray cooling water in the inner zone 2 can be 35-42 L / min; the flow rate of the spray cooling water in the inner zone 3 can be 25-32 L / min. The present invention sets the cooling water spray area of ​​the inner peripheral wall of the wheel body of the crystallization wheel and the flow rate of the spray cooling water in each area to the above range, which can be more conducive to the cooling and casting of the alloy melt.

[0088] In the present invention, the cooling water temperature of the continuous casting is preferably 20-35° C. As an embodiment, the cooling water temperature may be 25-32° C. The present invention limits the cooling water temperature to the above range so that the crystallization wheel has a better cooling capacity, which is beneficial to the continuous casting.

[0089] In the present invention, the billet discharge temperature of the continuous casting is preferably 420-430° C. As an embodiment, the billet discharge temperature may be 421-425° C. The present invention limits the billet discharge temperature of the continuous casting to the above range, which is conducive to the stable crystallization and forming of the billet, and the billet discharge is smooth and not broken, which lays a good foundation for providing billets with stable organization and temperature for subsequent rough rolling and finishing rolling.

[0090] The present invention controls the cooling intensity and billet discharge temperature of the billet by regulating the flow rates of inner cooling water, outer cooling water and cooling water on both sides as well as the flow rates of cooling water in each zone, thereby improving the density of the crystal structure and achieving continuous billet casting without breakage.

[0091] In the present invention, the billet obtained by continuous casting is preferably preheated before continuous rolling; the preheating temperature is preferably 490-510° C., more preferably 498-505° C. The present invention preheats the billet to 490-510° C. before rolling, which can soften and recrystallize, is conducive to rolling and prevents billet breakage or blockage during the rolling process.

[0092] In the present invention, the continuous rolling preferably includes rough rolling and finish rolling performed sequentially.

[0093] In the present invention, the number of passes of the rough rolling is preferably 3 to 5; the total deformation of the rough rolling is preferably 60 to 70%; the number of passes of the finish rolling is preferably 7 to 9; the total deformation of the finish rolling is preferably 70 to 80%; the speed of the finish rolling is preferably 200 to 300 m / min. The present invention has no special limitation on the deformation of the rough rolling and finish rolling passes, as long as the total deformation meets the above requirements.

[0094] As an implementation mode, the number of rough rolling passes may be 3 to 4 passes; the total deformation of the rough rolling may be 64 to 68%; the number of finish rolling passes may be 8 to 9 passes; the total deformation of the finish rolling may be 74 to 78%; and the finish rolling speed may be 220 to 280 m / min.

[0095] In the present invention, the temperature of the emulsion used in the continuous rolling is preferably 30-50°C; the mass concentration of the emulsion is preferably 12-15%; the total pressure of the emulsion is 0.02-0.1MPa. As an embodiment, the temperature of the emulsion can be 35-45°C; the mass concentration of the emulsion can be 12-13%. The present invention does not specifically limit the type of the emulsion, and an emulsion well known to those skilled in the art can be used. The present invention can avoid too low a temperature by limiting the temperature of the emulsion within the above range, which will increase the hardness of the rolled material, which is not conducive to the smoothness of rolling, and the product strength will be too high. If the temperature is too high, the temperature of the rolled material cannot be effectively taken away, resulting in cracking and the risk of sticking to the roller; limiting the concentration of the emulsion within the above range can avoid too low a concentration, less heat taken away, less lubrication, rough product surface, too high a concentration, excessive lubrication, and easy slipping during the rolling process.

[0096] The present invention has no particular limitation on the amount of the emulsion, and the amount can be determined based on common sense.

[0097] The present invention controls the finishing rolling torque by regulating the concentration and temperature of the emulsion, matching the appropriate rolling temperature (preheating temperature) and the finishing rolling speed, and realizes continuous rolling of the aluminum alloy without breakage and surface cracks.

[0098] In the present invention, the aluminum alloy has a tensile strength of 290-310 MPa, a yield strength of 240-260 MPa, an elongation of ≥14%, and a yield strength ratio of more than 80%.

[0099] In the present invention, the aluminum alloy is preferably in the shape of a rod; the diameter of the rod is preferably 1 to 3 mm, more preferably 2 mm.

[0100] The preparation method provided by the invention can improve the composition uniformity of the aluminum alloy.

[0101] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0102] Example 1

[0103] The chemical composition of 6056 aluminum alloy is Si 1.12%, Fe 0.13%, Cu 0.84%, Mn 0.60%, Mg 0.92%, Cr 0.04%, Zn 0.24%, Ti 0.04%, Sr 0.001%, B 0.003%, Zr 0.13%, La 0.13% and the balance Al by mass percentage;

[0104] The Si / Mg is 1.21;

[0105] The preparation method of the 6056 aluminum alloy rod is as follows:

[0106] (1) Aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy are mixed, and then smelted at 800° C. for 120 minutes under stirring conditions, and then refined once at 785° C. for 40 minutes using nitrogen and chloride salt refining agent, and then slag is removed and allowed to stand for 20 minutes to obtain a melt; wherein the pressure of the nitrogen is 0.2 MPa; the chloride salt refining agent is 4wt‰ of the mass of the melt obtained by mixing the aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy;

[0107] (2) mixing the melt obtained in step (1), the magnesium ingot and the aluminum rare earth master alloy, and then performing secondary refining at 781° C. for 20 min using nitrogen, and then skimming the slag, and then standing for 20 min to obtain a composite melt; wherein the pressure of the nitrogen is 0.2 MPa;

[0108] (3) mixing the composite melt obtained in step (2) with 0.35% by mass of Al-5Ti-1B of the composite melt, performing grain refinement in a 745°C online degassing front chute for 5 min, and then performing online degassing filtration using bipolar filtration to make the hydrogen content of the melt 0.149 mL / 100 g, thereby obtaining an aluminum alloy melt; wherein the mesh size of the first filter during the two-stage filtration is 30 mesh; and the mesh size of the second filter during the two-stage filtration is 40 mesh;

[0109] (4) continuously casting and rolling the aluminum alloy melt obtained in step (3) to obtain an aluminum alloy rod with a diameter of 12 mm;

[0110] Among them, the continuous casting temperature is 730℃; the continuous casting speed is 7.3m / min; the continuous casting cooling water temperature is 28℃;

[0111] The continuous casting is wheel-type continuous casting; the aluminum alloy melt is introduced into the crystallization tank of the wheel-type continuous casting through the intermediate ladle;

[0112] The cooling method of the crystallizer during continuous casting is cooling water spraying; the cooling water spraying area is the outer side of the steel belt of the crystallization tank, the arc surface of the crystallization wheel on both sides of the crystallization tank, and the inner peripheral wall of the crystallization wheel;

[0113] The cooling water spraying area outside the steel strip of the crystallization tank is outer zone 1, outer zone 2 and outer zone 3; the outer side of the steel strip of the crystallization tank is equally divided into 4 areas along the length direction, and the first three areas along the flow direction of the aluminum alloy melt are the outer zone 1, outer zone 2 and outer zone 3;

[0114] The flow rate of spray cooling water in outer zone 1 is 45L / min; the flow rate of spray cooling water in outer zone 2 is 35L / min; the flow rate of spray cooling water in outer zone 3 is 25L / min;

[0115] The cooling water spraying areas of the arc surface of the crystallization wheel on both sides of the crystallization tank are zone 1 on both sides and zone 2 on both sides; the arc surface corresponding to each 90° fillet of the arc surface on both sides of the crystallization wheel from the aluminum alloy melt entering position is regarded as a two-side area, and along the flow direction of the aluminum alloy melt, it is sequentially the said two-side zone 1 and the two-side zone 2;

[0116] The flow rate of spray cooling water in zone 1 on both sides is 45L / min; the flow rate of spray cooling water in zone 2 on both sides is 45L / min;

[0117] The cooling water spraying area of ​​the inner peripheral wall of the crystal wheel is inner zone 1, inner zone 2 and inner zone 3; the arc area corresponding to each 45° fillet of the inner peripheral wall of the crystal wheel from the position where the aluminum alloy melt enters is the inner zone, and the inner zone 1, inner zone 2 and inner zone 3 are arranged in sequence along the flow direction of the aluminum alloy melt;

[0118] The flow rate of spray cooling water in inner zone 1 is 55L / min; the flow rate of spray cooling water in inner zone 2 is 45L / min; the flow rate of spray cooling water in inner zone 3 is 35L / min;

[0119] The billet temperature of continuous casting is 430°C; the billet obtained by continuous casting is preheated before continuous rolling; the preheating temperature is 500°C;

[0120] The continuous rolling includes rough rolling and finish rolling in sequence; the number of passes of the rough rolling is 4; the total deformation of the rough rolling is 65%; the number of passes of the finish rolling is 8; the total deformation of the finish rolling is 75%; the speed of the finish rolling is 250m / min;

[0121] The temperature of the emulsion used in the continuous rolling is 45°C; the mass concentration of the emulsion is 14%; and the total pressure of the emulsion is 0.06MPa.

[0122] After the 6056 aluminum alloy rod prepared in Example 1 was naturally aged for 5 days, performance tests were performed. The results are shown in Table 1. The test standard is "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3.

[0123] Table 1 Mechanical properties data of 6056 aluminum alloy rod prepared in Example 1 after 5 days of natural aging

[0124] project Tensile strength / MPa Yield strength / MPa Elongation / % Yield strength ratio / % Example 1 296.8 241.6 15.1 81.4

[0125] It can be seen from Table 1 that the 6056 aluminum alloy rod provided by the present invention has a high yield strength ratio.

[0126] Example 2

[0127] The chemical composition of 6056 aluminum alloy is Si 1.5%, Fe 0.24%, Cu 0.76%, Mn 0.64%, Mg 1.20%, Cr 0.03%, Zn 0.2%, Ti 0.05%, Sr 0.001%, B 0.004%, Zr 0.16%, La 0.18% and the balance Al by mass percentage;

[0128] The Si / Mg is 1.25;

[0129] The preparation method of the 6056 aluminum alloy rod is as follows:

[0130] (1) Aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy are mixed, and then smelted at 800° C. for 120 minutes under stirring conditions, and then refined once at 785° C. for 40 minutes using nitrogen and chloride salt refining agent, and then slag is removed and allowed to stand for 20 minutes to obtain a melt; wherein the pressure of the nitrogen is 0.2 MPa; the chloride salt refining agent is 4wt‰ of the mass of the melt obtained by mixing the aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy;

[0131] (2) mixing the melt obtained in step (1), the magnesium ingot and the aluminum rare earth master alloy, and then performing secondary refining at 781° C. for 20 min using nitrogen, and then skimming the slag, and then standing for 20 min to obtain a composite melt; wherein the pressure of the nitrogen is 0.2 MPa;

[0132] (3) mixing the composite melt obtained in step (2) with 0.35% by mass of Al-5Ti-1B of the composite melt, performing grain refinement in a 745° C. online degassing front chute for 6 min, and then performing online degassing filtration using bipolar filtration to make the hydrogen content of the melt 0.149 mL / 100 g, thereby obtaining an aluminum alloy melt; wherein the mesh size of the first filter during the two-stage filtration is 30 mesh; and the mesh size of the second filter during the two-stage filtration is 40 mesh;

[0133] (4) continuously casting and rolling the aluminum alloy melt obtained in step (3) to obtain an aluminum alloy rod with a diameter of 12 mm;

[0134] Among them, the continuous casting temperature is 725℃; the continuous casting speed is 8m / min; the continuous casting cooling water temperature is 30℃;

[0135] The continuous casting is wheel-type continuous casting; the aluminum alloy melt is introduced into the crystallization tank of the wheel-type continuous casting through the intermediate ladle;

[0136] The cooling method of the crystallizer during continuous casting is cooling water spraying; the cooling water spraying area is the outer side of the steel belt of the crystallization tank, the arc surface of the crystallization wheel on both sides of the crystallization tank, and the inner peripheral wall of the crystallization wheel;

[0137] The cooling water spraying area outside the steel strip of the crystallization tank is outer zone 1, outer zone 2 and outer zone 3; the outer side of the steel strip of the crystallization tank is equally divided into 4 areas along the length direction, and the first three areas along the flow direction of the aluminum alloy melt are the outer zone 1, outer zone 2 and outer zone 3;

[0138] The flow rate of spray cooling water in outer zone 1 is 45L / min; the flow rate of spray cooling water in outer zone 2 is 35L / min; the flow rate of spray cooling water in outer zone 3 is 25L / min;

[0139] The cooling water spraying areas of the arc surface of the crystallization wheel on both sides of the crystallization tank are zone 1 on both sides and zone 2 on both sides; the arc surface corresponding to each 90° fillet of the arc surface on both sides of the crystallization wheel from the aluminum alloy melt entering position is regarded as a two-side area, and along the flow direction of the aluminum alloy melt, it is sequentially the said two-side zone 1 and the two-side zone 2;

[0140] The flow rate of spray cooling water in zone 1 on both sides is 45L / min; the flow rate of spray cooling water in zone 2 on both sides is 45L / min;

[0141] The cooling water spraying area of ​​the inner peripheral wall of the crystal wheel is inner zone 1, inner zone 2 and inner zone 3; the arc area corresponding to each 45° fillet of the inner peripheral wall of the crystal wheel from the position where the aluminum alloy melt enters is the inner zone, and the inner zone 1, inner zone 2 and inner zone 3 are arranged in sequence along the flow direction of the aluminum alloy melt;

[0142] The flow rate of spray cooling water in inner zone 1 is 55L / min; the flow rate of spray cooling water in inner zone 2 is 45L / min; the flow rate of spray cooling water in inner zone 3 is 35L / min;

[0143] The billet temperature of continuous casting is 430°C; the billet obtained by continuous casting is preheated before continuous rolling; the preheating temperature is 500°C;

[0144] The continuous rolling includes rough rolling and finish rolling in sequence; the number of passes of the rough rolling is 4; the total deformation of the rough rolling is 65%; the number of passes of the finish rolling is 8; the total deformation of the finish rolling is 75%; the speed of the finish rolling is 250m / min;

[0145] The temperature of the emulsion used in the continuous rolling is 45°C; the mass concentration of the emulsion is 14%; and the total pressure of the emulsion is 0.06MPa.

[0146] After the 6056 aluminum alloy rod prepared in Example 2 was naturally aged for 5 days, performance tests were performed according to "Bare Wire Test Method Part 3: Tensile Test" (GB / T 4909.3). The results are shown in Table 2.

[0147] Table 2 Mechanical properties data of 6056 aluminum alloy rod prepared in Example 2 after 5 days of natural aging

[0148] project Tensile strength / MPa Yield strength / MPa Elongation / % Yield strength ratio / % Example 2 305.6 254.6 14.1 83.3

[0149] It can be seen from Table 2 that the 6056 aluminum alloy rod provided by the present invention has a high yield strength ratio.

[0150] Example 3

[0151] The chemical composition of 6056 aluminum alloy is Si 1.08%, Fe 0.11%, Cu 0.80%, Mn 0.56%, Mg 0.90%, Cr 0.01%, Zn 0.22%, Ti 0.03%, Sr 0.001%, B 0.001%, Zr 0.11%, La 0.11% and the balance Al by mass percentage;

[0152] The Si / Mg is 1.2;

[0153] The preparation method of the 6056 aluminum alloy rod is as follows:

[0154] (1) Aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy are mixed, and then smelted at 800° C. for 120 minutes under stirring conditions, and then refined once at 785° C. for 40 minutes using nitrogen and chloride salt refining agent, and then slag is removed and allowed to stand for 20 minutes to obtain a melt; wherein the pressure of the nitrogen is 0.2 MPa; the chloride salt refining agent is 4wt‰ of the mass of the melt obtained by mixing the aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy;

[0155] (2) mixing the melt obtained in step (1), the magnesium ingot and the aluminum rare earth master alloy, and then performing secondary refining at 781° C. for 20 min using nitrogen, and then skimming the slag, and then standing for 20 min to obtain a composite melt; wherein the pressure of the nitrogen is 0.2 MPa;

[0156] (3) mixing the composite melt obtained in step (2) with 0.35% by mass of Al-5Ti-1B of the composite melt, performing grain refinement in a 745° C. online degassing front chute for 7 min, and then performing online degassing filtration using bipolar filtration to make the hydrogen content of the melt 0.140 mL / 100 g, thereby obtaining an aluminum alloy melt; wherein the mesh size of the first filter during the two-stage filtration is 30 mesh; and the mesh size of the second filter during the two-stage filtration is 40 mesh;

[0157] (4) continuously casting and rolling the aluminum alloy melt obtained in step (3) to obtain an aluminum alloy rod with a diameter of 12 mm;

[0158] Among them, the continuous casting temperature is 740℃; the continuous casting speed is 7m / min; the continuous casting cooling water temperature is 32℃;

[0159] The continuous casting is wheel-type continuous casting; the aluminum alloy melt is introduced into the crystallization tank of the wheel-type continuous casting through the intermediate ladle;

[0160] The cooling method of the crystallizer during continuous casting is cooling water spraying; the cooling water spraying area is the outer side of the steel belt of the crystallization tank, the arc surface of the crystallization wheel on both sides of the crystallization tank, and the inner peripheral wall of the crystallization wheel;

[0161] The cooling water spraying area outside the steel strip of the crystallization tank is outer zone 1, outer zone 2 and outer zone 3; the outer side of the steel strip of the crystallization tank is equally divided into 4 areas along the length direction, and the first three areas along the flow direction of the aluminum alloy melt are the outer zone 1, outer zone 2 and outer zone 3;

[0162] The flow rate of spray cooling water in outer zone 1 is 48L / min; the flow rate of spray cooling water in outer zone 2 is 38L / min; the flow rate of spray cooling water in outer zone 3 is 26L / min;

[0163] The cooling water spraying areas of the arc surface of the crystallization wheel on both sides of the crystallization tank are zone 1 on both sides and zone 2 on both sides; the arc surface corresponding to each 90° fillet of the arc surface on both sides of the crystallization wheel from the aluminum alloy melt entering position is regarded as a two-side area, and along the flow direction of the aluminum alloy melt, it is sequentially the said two-side zone 1 and the two-side zone 2;

[0164] The flow rate of spray cooling water in zone 1 on both sides is 47 / min; the flow rate of spray cooling water in zone 2 on both sides is 47L / min;

[0165] The cooling water spraying area of ​​the inner peripheral wall of the crystal wheel is inner zone 1, inner zone 2 and inner zone 3; the arc area corresponding to each 45° fillet of the inner peripheral wall of the crystal wheel from the position where the aluminum alloy melt enters is the inner zone, and the inner zone 1, inner zone 2 and inner zone 3 are arranged in sequence along the flow direction of the aluminum alloy melt;

[0166] The flow rate of spray cooling water in inner zone 1 is 52L / min; the flow rate of spray cooling water in inner zone 2 is 42L / min; the flow rate of spray cooling water in inner zone 3 is 32L / min;

[0167] The billet temperature of continuous casting is 430°C; the billet obtained by continuous casting is preheated before continuous rolling; the preheating temperature is 495°C;

[0168] The continuous rolling includes rough rolling and finish rolling in sequence; the number of passes of the rough rolling is 4; the total deformation of the rough rolling is 65%; the number of passes of the finish rolling is 9; the total deformation of the finish rolling is 77%; the speed of the finish rolling is 270m / min;

[0169] The temperature of the emulsion used in the continuous rolling is 45°C; the mass concentration of the emulsion is 14%; and the total pressure of the emulsion is 0.06MPa.

[0170] After the 6056 aluminum alloy rod prepared in Example 3 was naturally aged for 5 days, a performance test was performed according to "Bare Wire Test Method Part 3: Tensile Test" (GB / T 4909.3). The results are shown in Table 3. The test standard is "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3.

[0171] Table 3 Mechanical properties data of 6056 aluminum alloy rod prepared in Example 3 after 5 days of natural aging

[0172] project Tensile strength / MPa Yield strength / MPa Elongation / % Yield strength ratio / % Example 3 288.2 231.7 15.2 80.4

[0173] It can be seen from Table 3 that the 6056 aluminum alloy rod provided by the present invention has a high yield strength ratio.

[0174] Comparative Example 1

[0175] The chemical composition of the 6056 aluminum alloy is changed on the basis of Example 1, and other conditions remain unchanged, wherein the chemical composition of the 6056 aluminum alloy is Si 1.0%, Fe 0.13%, Cu 0.84%, Mn 0.60%, Mg 0.92%, Cr 0.04%, Zn 0.24%, Ti 0.04%, Sr 0.001%, B 0.003%, Zr 0.13%, La 0.13% and the balance Al in mass percentage;

[0176] The Si / Mg is 1.09.

[0177] After 5 days of natural aging, the 6056 aluminum alloy rod prepared in Comparative Example 1 was subjected to performance testing. The results are shown in Table 4. The test standard is "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3.

[0178] Table 4 Mechanical properties data of 6056 aluminum alloy rod prepared in Comparative Example 1 after 5 days of natural aging

[0179] project Tensile strength / MPa Yield strength / MPa Elongation / % (gauge length 50mm) Yield strength ratio / % Comparative Example 1 297.8 231.3 13.6 77.7

[0180] It can be seen from Table 4 that in Comparative Example 1, Si / Mg is less than 1.2, and the aluminum alloy rod prepared by continuous casting and rolling has a relatively low yield strength and an elongation of less than 14%.

[0181] Comparative Example 2

[0182] The chemical composition of the 6056 aluminum alloy is changed on the basis of Example 1, and other conditions remain unchanged, wherein the chemical composition of the 6056 aluminum alloy is Si 0.7%, Fe 0.13%, Cu 0.84%, Mn 0.60%, Mg 0.92%, Cr 0.04%, Zn 0.24%, Ti 0.04%, Sr 0.001%, B 0.003%, Zr 0.13%, La 0.13% and the balance Al in mass percentage;

[0183] The Si / Mg is 0.76.

[0184] When the aluminum alloy in Comparative Example 2 was subjected to continuous casting and rolling production, the billets were severely fractured and production could not be carried out.

[0185] It can be seen from the above embodiments and comparative examples that the aluminum alloy prepared by the preparation method provided by the present invention has excellent yield strength ratio and elongation.

[0186] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high yield ratio 6056 aluminum alloy rod, the chemical composition of which includes, by mass percentage, Si 1.0-1.5%, Fe 0.10-0.25%, Cu 0.75-0.85%, Mn 0.55-0.65%, Mg 0.9-1.2%, Cr <0.05%, Zn 0.2-0.25%, Ti 0.03-0.05%, Sr <0.002%, B 0.001-0.005%, Zr 0.11-0.17%, rare earth 0.1-0.2% and the balance Al; The Si / Mg≥1.

2.

2. The high yield ratio 6056 aluminum alloy rod according to claim 1, characterized in that: The chemical composition includes, by mass percentage, Si 1.1-1.4%, Fe 0.13-0.20%, Cu 0.78-0.84%, Mn 0.58-0.62%, Mg 0.92-1.1%, Cr≤0.04%, Zn 0.21-0.24%, Ti 0.03-0.04%, Sr≤0.001%, B 0.002-0.004%, Zr 0.12-0.15%, rare earth 0.12-0.18% and the balance Al.

3. The high yield ratio 6056 aluminum alloy rod according to claim 1 or 2, characterized in that: The chemical composition includes, by mass percentage, 1.12-1.3% Si, 0.15-0.18% Fe, 0.80-0.82% Cu, 0.59-0.60% Mn, 0.98-1.0% Mg, 0.01-0.02% Cr, 0.22-0.23% Zn, 0.03-0.04% Ti, 0.001% Sr, 0.002-0.003% B, 0.13-0.14% Zr, 0.14-0.16% rare earth and the balance Al.

4. The high yield ratio 6056 aluminum alloy rod according to claim 1, characterized in that: The Si / Mg is 1.21-2.

5. The method for preparing the high yield ratio 6056 aluminum alloy rod according to any one of claims 1 to 4, comprising the following steps: (1) mixing aluminum liquid, aluminum-silicon master alloy, aluminum-copper master alloy, manganese agent, aluminum-zinc master alloy and aluminum-zirconium master alloy, and sequentially performing smelting and primary refining to obtain a melt; (2) mixing the melt obtained in step (1), the magnesium ingot and the aluminum rare earth master alloy, and performing secondary refining to obtain a composite melt; (3) mixing the composite melt obtained in step (2) with an aluminum-titanium-boron master alloy, performing grain refinement, and obtaining an aluminum alloy melt; (4) The aluminum alloy melt obtained in step (3) is continuously cast and rolled to obtain a 6056 aluminum alloy rod with a high yield ratio.

6. The preparation method according to claim 5, characterized in that: The smelting temperature in step (1) is 780-800° C., and the smelting time is 60-120 min.

7. The preparation method according to claim 5, characterized in that: The temperature of the first refining in the step (1) is 780-800° C., and the time of the first refining is 40-50 minutes.

8. The preparation method according to claim 5 or 7, characterized in that: In the step (1), the primary refining is performed using nitrogen and a particle refining agent.

9. The preparation method according to claim 8, characterized in that: The pressure of the nitrogen is 0.2-0.25 MPa.

10. The preparation method according to claim 5, characterized in that: The temperature of the secondary refining in the step (2) is 780-800° C., and the time of the secondary refining is 20-30 minutes.