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 preparation method of the 6056 aluminum alloy rod with the high yield ratio comprises the following steps that aluminum alloy melt is subjected to continuous casting and continuous rolling, and cast-rolled aluminum alloy is obtained; the cast-rolled aluminum alloy is sequentially subjected to primary homogeneous heat treatment and primary drawing, and a drawn aluminum alloy is obtained; and the drawn aluminum alloy is sequentially subjected to secondary homogeneous heat treatment and secondary drawing, and the 6056 aluminum alloy rod with the high yield ratio is obtained. Continuous casting and continuous rolling are adopted, and rapid cooling and continuous deformation in the process are beneficial to eliminating segregation and coarse grains in an as-cast structure, so that the microstructure is more uniform, the anisotropy of the aluminum alloy can be reduced, and the overall performance of the aluminum alloy is improved; and then repeated homogeneous heat treatment and drawing are adopted, so that the components of the aluminum alloy are more uniform, the structure is further refined, and the yield ratio of the aluminum alloy is increased.

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 alloys 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 alloys 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 production method of 6056 aluminum alloy rod mainly adopts smelting and casting aluminum alloy round ingots, and then processes them into 6056 aluminum alloy rods through heat treatment and extrusion process. The process steps are: alloy smelting, round ingot casting, round ingot sawing, round ingot car, round ingot heat treatment, round ingot extrusion, extruded rod heat treatment, but the yield strength ratio of the prepared aluminum alloy is relatively poor. Therefore, how to improve the yield strength ratio of aluminum alloy has become a technical problem that needs to be solved urgently 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 6056 aluminum alloy rod prepared by the preparation method provided by the present invention has a high yield strength ratio.

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

[0006] The present invention provides a method for preparing a 6056 aluminum alloy rod with a high yield ratio, comprising the following steps:

[0007] (1) continuously casting and rolling the aluminum alloy melt to obtain a cast-rolled aluminum alloy;

[0008] (2) subjecting the cast-rolled aluminum alloy obtained in step (1) to a homogenization heat treatment and a drawing in sequence to obtain a drawn aluminum alloy;

[0009] (3) The drawn aluminum alloy obtained in step (2) is subjected to secondary homogenization heat treatment and secondary drawing in sequence to obtain a high yield strength ratio 6056 aluminum alloy rod.

[0010] Preferably, in step (1), the continuous casting temperature is 720-750° C., and the continuous casting speed is 6.3-8.2 m / min.

[0011] Preferably, the temperature of the cooling water during continuous casting and rolling in step (1) is 20-35°C.

[0012] Preferably, the continuous rolling in step (1) includes rough rolling and finish rolling performed sequentially.

[0013] Preferably, the holding temperatures of the first homogenization heat treatment in step (2) and the second homogenization heat treatment in step (3) are independently 540-560° C., and the holding times of the first homogenization heat treatment and the second homogenization heat treatment are independently 12-20 h.

[0014] Preferably, the cooling method of the primary homogenization heat treatment in step (2) and the secondary homogenization heat treatment in step (3) is furnace cooling.

[0015] Preferably, the cooling rate of the furnace cooling is 10-30° C. / h.

[0016] Preferably, the number of drawing passes in step (2) is 3 to 4 times, and the total deformation amount of one drawing is 45 to 55%.

[0017] Preferably, the number of secondary drawing passes in step (3) is 1 to 2 times, and the total deformation of the secondary drawing is 10 to 15%.

[0018] The present invention also provides a high yield-to-strength ratio 6056 aluminum alloy rod prepared by the preparation method described in the above technical solution.

[0019] The present invention provides a method for preparing a 6056 aluminum alloy rod with a high yield ratio, comprising the following steps: continuously casting and rolling an aluminum alloy melt to obtain a cast-rolled aluminum alloy; sequentially performing a homogenization heat treatment and a drawing on the cast-rolled aluminum alloy to obtain a drawn aluminum alloy; sequentially performing a secondary homogenization heat treatment and a secondary drawing on the drawn aluminum alloy to obtain a 6056 aluminum alloy rod with a high yield ratio. The present invention adopts continuous casting and rolling, and rapid cooling and continuous deformation during the process help eliminate segregation and coarse grains in the cast structure, making the microstructure more uniform, reducing the anisotropy of the aluminum alloy, and improving the overall performance of the aluminum alloy; then a primary homogenization heat treatment is performed to make the aluminum alloy composition more uniform, but it will lead to a decrease in tensile strength and yield strength, and then a primary drawing is performed to greatly improve the yield strength and tensile strength, and at this time, the yield strength increase is much greater than the tensile strength, thereby improving the yield ratio; then a secondary homogenization heat treatment is performed to further improve the uniformity of the structure, and finally a secondary drawing is performed to quickly increase the yield strength, thereby further improving the yield ratio. Experimental results show that the high yield strength ratio 6056 aluminum alloy rod prepared by the preparation method provided by the present invention has a yield strength ratio of 85-95%, a tensile strength of 150-190 MPa, a yield strength ≥140 MPa, and an elongation ≥25% (gauge length 50 mm). DETAILED DESCRIPTION

[0020] The present invention provides a method for preparing a 6056 aluminum alloy rod with a high yield ratio, comprising the following steps:

[0021] (1) continuously casting and rolling the aluminum alloy melt to obtain a cast-rolled aluminum alloy;

[0022] (2) subjecting the cast-rolled aluminum alloy obtained in step (1) to a homogenization heat treatment and a drawing in sequence to obtain a drawn aluminum alloy;

[0023] (3) The drawn aluminum alloy obtained in step (2) is subjected to secondary homogenization heat treatment and secondary drawing in sequence to obtain a high yield strength ratio 6056 aluminum alloy rod.

[0024] 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.

[0025] The present invention has no special limitation on the chemical composition of the aluminum alloy, and any aluminum alloy well known to those skilled in the art may be used.

[0026] The present invention continuously casts and rolls the aluminum alloy melt to obtain the cast-rolled aluminum alloy.

[0027] The present invention has no special limitation on the composition of the aluminum alloy melt, and it can be adjusted according to the actual needs of the aluminum alloy.

[0028] In the present invention, the method for preparing the aluminum alloy melt preferably comprises the following steps:

[0029] 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;

[0030] 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;

[0031] 3) The composite melt obtained in step 2) is mixed with an aluminum-titanium-boron master alloy to perform grain refinement to obtain an aluminum alloy melt.

[0032] The present invention preferably 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.

[0033] 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.

[0034] 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.

[0035] In the present invention, the temperature of the aluminum liquid is preferably 780-800°C.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] As an implementation mode, the pressure of the nitrogen can be 0.22-0.24 MPa; the amount of the particle refining agent can be 4-5wt‰ 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] After obtaining the melt, the present invention preferably mixes the melt, a magnesium ingot and an aluminum rare earth master alloy, and performs secondary refining to obtain a composite melt.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] After obtaining the composite melt, the present invention preferably 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] In the present invention, the continuous casting is preferably wheel-type continuous casting.

[0067] As an embodiment, the aluminum alloy melt may be introduced into the crystallization tank of the wheel-type continuous casting through a tundish.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 surface 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 zone, and along the flow direction of the aluminum alloy melt are the inner zone 1, inner zone 2 and inner zone 3 in sequence.

[0074] 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 45-55 L / min; the flow rate of the spray cooling water in the inner zone 2 can be 35-45 L / min; the flow rate of the spray cooling water in the inner zone 3 can be 25-35 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] In the present invention, the continuous rolling preferably includes rough rolling and finish rolling performed sequentially.

[0080] 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.

[0081] 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 65 to 67%; the number of finish rolling passes may be 8 to 9 passes; the total deformation of the finish rolling may be 75 to 78%; and the finish rolling speed may be 250 to 280 m / min.

[0082] 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%; and the total pressure of the emulsion is preferably 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%; and the total pressure of the emulsion can be 0.03-0.06MPa. 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 roll; limiting the concentration of the emulsion within the above range can avoid too low a concentration, less heat taken away, less lubrication, and rough product surface, too high a concentration, excessive lubrication, and easy slipping during the rolling process.

[0083] The present invention has no particular limitation on the amount of the emulsion, and the amount can be determined based on common sense.

[0084] The present invention controls the finishing rolling torque by regulating the concentration and temperature of the emulsion, matching the appropriate rolling temperature and finishing rolling speed, and realizing continuous rolling of the aluminum alloy without breakage and surface cracks.

[0085] In the present invention, the tensile strength of the cast-rolled aluminum alloy is 240-280 MPa, the yield strength is 190-205 MPa, and the elongation is ≥13%; after 3-5 days of natural aging, the performance of the cast-rolled aluminum alloy tends to be stable, the tensile strength is 290-310 MPa, the yield strength is 240-260 MPa, and the elongation is ≥14%.

[0086] After obtaining the cast-rolled aluminum alloy, the present invention sequentially performs a homogenization heat treatment and a drawing on the cast-rolled aluminum alloy to obtain a drawn aluminum alloy.

[0087] In the present invention, the holding temperature of the primary homogenization heat treatment is preferably 540-560°C; the holding time of the primary homogenization heat treatment is preferably 12-20 hours. The present invention has no special limitation on the rate of heating to the holding temperature of the primary homogenization heat treatment, and the heating time can be controlled within 1-3.5 hours. The present invention limits the temperature of the primary homogenization heat treatment within the above range to further improve the effect of the homogenization heat treatment.

[0088] As an implementation mode, the holding temperature of the primary homogenization heat treatment may be 545-550° C.; and the holding time of the primary homogenization heat treatment may be 14-16 hours.

[0089] In the present invention, the primary homogenization heat treatment is preferably carried out in a homogenization furnace. The present invention has no particular limitation on the type of the homogenization furnace, and any equipment well known to those skilled in the art can be used.

[0090] In the present invention, the cooling method of the primary homogenization heat treatment is preferably furnace cooling; the cooling rate of the furnace cooling is preferably 10-30°C / h; the terminal temperature of the furnace cooling is preferably ≤50°C. As an embodiment, the cooling rate of the furnace cooling can be 15-25°C / h.

[0091] In the present invention, the number of passes of the drawing is preferably 3 to 4, and the total deformation of the drawing is preferably 45 to 55%. The present invention has no special limitation on the deformation per pass, as long as the total deformation meets the requirements.

[0092] As an embodiment, the total deformation amount of the one-time drawing may be 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53% or 54%.

[0093] After obtaining the drawn aluminum alloy, the present invention sequentially performs secondary homogenization heat treatment and secondary drawing on the drawn aluminum alloy to obtain a high yield strength ratio 6056 aluminum alloy rod.

[0094] In the present invention, the operation of the secondary homogenization heat treatment is preferably the same as the operation of the aforementioned primary homogenization heat treatment, which will not be described in detail herein.

[0095] In the present invention, the number of passes of the secondary drawing is preferably 1 to 2 passes; the total deformation of the secondary drawing is preferably 10 to 15%. The present invention has no special limitation on the deformation per pass, as long as the total deformation meets the requirements.

[0096] As an embodiment, the total deformation amount of the secondary drawing may be 11%, 12%, 13% or 14%.

[0097] In order to control the product specifications (diameter) and performance indicators of the high yield strength ratio aluminum alloy rod, the present invention needs to strictly control the number of secondary drawing passes and deformation after the secondary homogenization heat treatment, that is, the diameter of the aluminum alloy rod after the first drawing (can be multiple passes) meets the reserved drawing deformation (10-15%), and the secondary homogenization is to control the mechanical properties of the aluminum alloy rod before the secondary drawing and further improve the structure, that is, reduce the strength of the aluminum alloy rod after the first drawing, and quickly increase the yield strength through the secondary drawing, thereby improving the yield strength ratio; because the diameter of the aluminum alloy rod cannot accurately guarantee the required reserved drawing deformation before the secondary drawing without the first drawing and continuous casting and rolling, therefore, it is necessary to perform a first homogenization and drawing before the secondary homogenization and drawing.

[0098] In the present invention, the shape of the aluminum alloy is preferably a rod; the diameter of the rod is preferably 7 to 8 mm, more preferably 7.8 mm.

[0099] The 6056 aluminum alloy rod prepared by the preparation method provided by the present invention has high yield strength ratio (85-95%), high strength and toughness (tensile strength of 150-190MPa, yield strength ≥140MPa, elongation ≥25% (gauge length 50mm)), good comprehensive performance, and can meet the processing and use performance requirements of fasteners such as aluminum alloy bolts; the aluminum alloy has good continuity, and the length of a single rod exceeds 5000 meters; the production process is simple, the production cycle is short, and the efficiency is high.

[0100] The present invention also provides a high yield-to-strength ratio 6056 aluminum alloy rod prepared by the preparation method described in the above technical solution.

[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 preparation method of 6056 aluminum alloy rod is:

[0104] (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 100 minutes under stirring conditions, and then refined once at 786° C. for 40 minutes using nitrogen and chloride salt refining agent, and then slag is removed and allowed to stand for 30 minutes to obtain a melt; wherein the nitrogen pressure 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;

[0105] (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, 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;

[0106] (3) subjecting the composite melt obtained in step (2) and 0.3% of the mass of Al-5Ti-1B of the composite melt to grain refinement at 745° C. for 6 min, and then performing online degassing filtration by 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;

[0107] (4) continuously casting and rolling the aluminum alloy melt obtained in step (3) to obtain a cast-rolled aluminum alloy rod with a diameter of 12 mm;

[0108] Among them, the continuous casting temperature is 740℃, the speed is 8.1m / min, and the cooling water temperature is 32℃;

[0109] 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;

[0110] 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;

[0111] The cooling water spraying areas outside the steel strip of the crystallization tank are 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 respectively;

[0112] 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;

[0113] 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;

[0114] 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;

[0115] 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 surface 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;

[0116] 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;

[0117] The billet temperature of continuous casting is 421°C, and the billet is preheated to 498°C before continuous rolling;

[0118] The continuous rolling includes rough rolling and finish rolling in sequence; the number of rough rolling passes is 4; the total deformation of the rough rolling is 67%; the number of finish rolling passes is 8; the total deformation of the finish rolling is 75%; the speed of the finish rolling is 250m / min;

[0119] During continuous rolling, the temperature of the emulsion was 45°C, the mass concentration was 12%, and the total pressure of the emulsion was 0.06MPa.

[0120] (5) placing the cast-rolled aluminum alloy rod obtained in step (4) into a homogenizing furnace, heating the furnace to 550° C. for 3 h and keeping the temperature for 12 h for homogenizing heat treatment, then cooling the furnace to 50° C. for 20 h, and drawing the rod again to obtain a drawn aluminum alloy; wherein the number of drawing passes is 4 and the total deformation is 50%;

[0121] (6) The drawn aluminum alloy prepared in step (5) is placed in a homogenizing furnace, the homogenizing heat treatment operation is repeated once, and then a second drawing is performed to obtain a 6056 aluminum alloy rod; wherein the number of drawing passes is 1 pass, and the total deformation is 12%.

[0122] The chemical composition of the 6056 aluminum alloy prepared in Example 1 is shown in Table 1.

[0123] Table 1 Chemical composition of 6056 aluminum alloy prepared in Example 1

[0124] Element Si Fe Cu Mn Mg Cr Zn Ti Sr B Zr La Al Content / wt% 1.12 0.13 0.84 0.60 0.92 0.04 0.24 0.04 0.001 0.003 0.13 0.12 margin

[0125] After 5 days of natural aging, the cast-rolled aluminum alloy rod in Example 1 was subjected to performance testing. The results are shown in Table 2. The test standard is "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3.

[0126] Table 2 Mechanical properties data of the cast-rolled aluminum alloy rod in Example 1 after 5 days of natural aging

[0127]

[0128]

[0129] The 6056 aluminum alloy rod prepared in Example 1 was subjected to performance testing. The results are shown in Table 3. The test standard is "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3.

[0130] Table 3 Mechanical properties data of 6056 aluminum alloy rod prepared in Example 1

[0131] project Tensile strength / MPa Yield strength / MPa Elongation / % (gauge length 50mm) Yield strength ratio / % Example 1 166.8 145 25.7 86.9

[0132] It can be seen from Table 3 that the 6056 aluminum alloy rod prepared by the present invention has a tensile strength of 166.8 MPa, a yield strength of 145 MPa, an elongation of 25.7%, and a yield strength ratio of 86.9%.

[0133] Example 2

[0134] The preparation method of 6056 aluminum alloy rod is:

[0135] (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. under stirring conditions for 70 minutes, and then refined once at 786° C. for 50 minutes using nitrogen and chloride salt refining agent, and then slag is removed and allowed to stand for 30 minutes to obtain a melt; wherein the nitrogen pressure is 0.25 MPa; the chloride salt refining agent is 5wt‰ 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;

[0136] (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 30 min using nitrogen, then skimming the slag, and then standing for 30 min to obtain a composite melt; wherein the pressure of the nitrogen is 0.25 MPa;

[0137] (3) subjecting the composite melt obtained in step (2) and 0.3% of the mass of Al-5Ti-1B of the composite melt to grain refinement at 745° C. for 6 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;

[0138] (4) continuously casting and rolling the aluminum alloy melt obtained in step (3) to obtain a cast-rolled aluminum alloy rod with a diameter of 12 mm;

[0139] Among them, the continuous casting temperature is 740℃, the speed is 8.1m / min, and the cooling water temperature is 32℃;

[0140] 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;

[0141] 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;

[0142] The cooling water spraying areas outside the steel strip of the crystallization tank are 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 respectively;

[0143] The flow rate of spray cooling water in outer zone 1 is 50L / min; the flow rate of spray cooling water in outer zone 2 is 40L / min; the flow rate of spray cooling water in outer zone 3 is 30L / min;

[0144] The cooling water spraying areas of the arc surface of the crystallization wheel on both sides of the crystallization tank are two-side zone 1 and two-side zone 2; the arc surface on both sides of the crystallization wheel corresponding to the arc surface of each 90° fillet at the position where the aluminum alloy melt enters is regarded as a two-side zone, and along the flow direction of the aluminum alloy melt, it is sequentially the two-side zone 1 and the two-side zone 2;

[0145] The flow rate of spray cooling water in zone 1 on both sides is 40L / min; the flow rate of spray cooling water in zone 2 on both sides is 40L / min;

[0146] 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 surface 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;

[0147] The flow rate of spray cooling water in inner zone 1 is 60L / min; the flow rate of spray cooling water in inner zone 2 is 50L / min; the flow rate of spray cooling water in inner zone 3 is 40L / min;

[0148] The billet temperature of continuous casting is 420℃, and the billet is preheated to 490℃ before continuous rolling;

[0149] 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 280m / min;

[0150] During continuous rolling, the temperature of the emulsion was 45°C, the mass concentration was 12%, and the total pressure of the emulsion was 0.05 MPa.

[0151] (5) placing the cast-rolled aluminum alloy rod obtained in step (4) into a homogenizing furnace, heating the furnace to 550° C. for 3 h and keeping the temperature for 12 h for a homogenizing heat treatment, then cooling the furnace to 50° C. for 20 h, and then drawing the rod to obtain a drawn aluminum alloy, wherein the number of drawing passes is 3 and the total deformation is 53%;

[0152] (6) The drawn aluminum alloy prepared in step (5) is placed in a homogenizing furnace, and the homogenizing heat treatment operation is repeated once, and then a second drawing is performed to obtain a 6056 aluminum alloy rod, wherein the number of drawing passes is 1 and the total deformation is 14%.

[0153] The chemical composition of the 6056 aluminum alloy prepared in Example 2 is shown in Table 4.

[0154] Table 4 Chemical composition of 6056 aluminum alloy prepared in Example 2

[0155] Element Si Fe Cu Mn Mg Cr Zn Ti Sr B Zr La Al Content / wt% 1.41 0.13 0.84 0.60 1.13 0.04 0.24 0.04 0.001 0.003 0.13 0.12 margin

[0156] After the cast-rolled aluminum alloy rod in Example 2 was naturally aged for 5 days, performance tests were performed according to "Bare Wire Test Methods Part 3: Tensile Test" GB / T 4909.3. The results are shown in Table 5.

[0157] Table 5 Mechanical properties data of the cast-rolled aluminum alloy rod in Example 2 after 5 days of natural aging

[0158]

[0159]

[0160] The 6056 aluminum alloy rod prepared in Example 2 was subjected to performance testing according to "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3. The results are shown in Table 6.

[0161] Table 6 Mechanical properties data of 6056 aluminum alloy rod prepared in Example 2

[0162] project Tensile strength / MPa Yield strength / MPa Elongation / % (gauge length 50mm) Yield strength ratio / % Example 2 175.8 161.6 25.1 91.9

[0163] It can be seen from Table 6 that the 6056 aluminum alloy rod prepared by the present invention has a tensile strength of 175.8 MPa, a yield strength of 161.6 MPa, an elongation of 25.1%, and a yield strength ratio of 91.9%.

[0164] Example 3

[0165] The preparation method of 6056 aluminum alloy rod is:

[0166] (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 786° C. for 50 minutes using nitrogen and chloride salt refining agent, and then slag is removed and allowed to stand for 30 minutes to obtain a melt; wherein the nitrogen pressure is 0.2 MPa; the chloride salt refining agent is 3wt‰ 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;

[0167] (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 30 min using nitrogen, then skimming the slag, and then standing for 20 min to obtain a composite melt; wherein the pressure of the nitrogen is 0.25 MPa;

[0168] (3) subjecting the composite melt obtained in step (2) and 0.3% of the mass of Al-5Ti-1B of the composite melt to grain refinement at 745° C. for 6 min, and then performing online degassing filtration by 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;

[0169] (4) continuously casting and rolling the aluminum alloy melt obtained in step (3) to obtain a cast-rolled aluminum alloy rod with a diameter of 12 mm;

[0170] Among them, the continuous casting temperature is 740℃, the speed is 8.1m / min, and the cooling water temperature is 32℃;

[0171] 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;

[0172] 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;

[0173] The cooling water spraying areas outside the steel strip of the crystallization tank are 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 respectively;

[0174] The flow rate of spray cooling water in outer zone 1 is 40L / min; the flow rate of spray cooling water in outer zone 2 is 30L / min; the flow rate of spray cooling water in outer zone 3 is 20L / min;

[0175] The cooling water spraying areas of the arc surface of the crystallization wheel on both sides of the crystallization tank are two-side zone 1 and two-side zone 2; the arc surface on both sides of the crystallization wheel corresponding to the arc surface of each 90° fillet at the position where the aluminum alloy melt enters is regarded as a two-side zone, and along the flow direction of the aluminum alloy melt, it is sequentially the two-side zone 1 and the two-side zone 2;

[0176] The flow rate of spray cooling water in zone 1 on both sides is 50L / min; the flow rate of spray cooling water in zone 2 on both sides is 50L / min;

[0177] 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 surface 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;

[0178] The flow rate of spray cooling water in inner zone 1 is 50L / min; the flow rate of spray cooling water in inner zone 2 is 40L / min; the flow rate of spray cooling water in inner zone 3 is 30L / min;

[0179] The billet temperature of continuous casting is 430℃, and the billet is preheated to 510℃ before continuous rolling;

[0180] The continuous rolling includes rough rolling and finish rolling in sequence; the number of passes of the rough rolling is 5; the total deformation of the rough rolling is 70%; the number of passes of the finish rolling is 9; the total deformation of the finish rolling is 80%; the speed of the finish rolling is 250m / min;

[0181] During continuous rolling, the temperature of the emulsion was 45°C, the mass concentration was 12%, and the total pressure of the emulsion was 0.03 MPa.

[0182] (5) placing the cast-rolled aluminum alloy rod obtained in step (4) into a homogenizing furnace, heating the furnace for 3 hours to 550° C. and keeping the temperature for 12 hours to perform a homogenizing heat treatment, then cooling the furnace to 50° C. for 20 hours, and then drawing the rod to obtain a drawn aluminum alloy, wherein the number of drawing passes is 4 and the total deformation is 50%;

[0183] (6) The drawn aluminum alloy prepared in step (5) is placed in a homogenizing furnace, and the homogenizing heat treatment operation is repeated once, and then a second drawing is performed to obtain a 6056 aluminum alloy rod, wherein the number of drawing passes is 2 and the total deformation is 13%.

[0184] The chemical composition of the 6056 aluminum alloy prepared in Example 3 is shown in Table 7.

[0185] Table 7 Chemical composition of 6056 aluminum alloy prepared in Example 3

[0186] Element Si Fe Cu Mn Mg Cr Zn Ti Sr B Zr La Al Content / wt% 1.12 0.13 0.84 0.60 0.92 0.04 0.24 0.04 0.001 0.003 0.13 0.12 margin

[0187] After the cast-rolled aluminum alloy rod in Example 3 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 8.

[0188] Table 8 Mechanical properties data of the cast-rolled aluminum alloy rod in Example 3 after 5 days of natural aging

[0189]

[0190]

[0191] The 6056 aluminum alloy rod prepared in Example 3 was subjected to performance testing according to "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3. The results are shown in Table 9.

[0192] Table 9 Mechanical properties data of 6056 aluminum alloy rod prepared in Example 3

[0193] project Tensile strength / MPa Yield strength / MPa Elongation / % (gauge length 50mm) Yield strength ratio / % Example 3 163.4 141 25.9 86.3

[0194] It can be seen from Table 9 that the 6056 aluminum alloy rod prepared by the present invention has a tensile strength of 163.4 MPa, a yield strength of 141 MPa, an elongation of 25.9%, and a yield strength ratio of 86.3%.

[0195] Comparative Example 1

[0196] On the basis of Example 1, the temperature of the first homogenization heat treatment and the second homogenization heat treatment was changed to 500° C., and other conditions remained unchanged.

[0197] The 6056 aluminum alloy rod prepared in Comparative Example 1 was subjected to performance testing according to "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3, and the results are shown in Table 10.

[0198] Table 10 Mechanical properties data of 6056 aluminum alloy rod prepared in Comparative Example 1

[0199] project Tensile strength / MPa Yield strength / MPa Elongation / % (gauge length 50mm) Yield strength ratio / % Comparative Example 1 204.3 141.8 11 69.4

[0200] It can be seen from Table 10 that the tensile strength of the 6056 aluminum alloy rod prepared in Comparative Example 1 is high, the elongation is low, and the yield strength ratio is low, which does not meet the requirements, indicating that changing the insulation temperature of the primary homogenization heat treatment and the secondary homogenization heat treatment will affect the yield strength ratio of the aluminum alloy, resulting in a significant decrease in the yield strength ratio.

[0201] Comparative Example 2

[0202] On the basis of Example 1, the flow rate of cooling water sprayed on 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 was changed, and other conditions remained unchanged;

[0203] The flow rate of spray cooling water in outer zone 1 is 30L / min; the flow rate of spray cooling water in outer zone 2 is 25L / min; the flow rate of spray cooling water in outer zone 3 is 15L / min;

[0204] The flow rate of spray cooling water in zone 1 on both sides is 30L / min; the flow rate of spray cooling water in zone 2 on both sides is 30L / min;

[0205] The flow rate of spray cooling water in inner zone 1 is 35L / min; the flow rate of spray cooling water in inner zone 2 is 30L / min; the flow rate of spray cooling water in inner zone 3 is 25L / min.

[0206] After the cast-rolled aluminum alloy rod in Comparative 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 11.

[0207] Table 11 Mechanical properties data of the cast-rolled aluminum alloy rod in comparative example 2 after 5 days of natural aging

[0208] project Tensile strength / MPa Yield strength / MPa Elongation / % Yield strength ratio / % Comparative Example 2 328.8 250.5 10.1 76.2

[0209] It can be seen from Table 11 that the tensile strength of the cast-rolled aluminum alloy prepared in Comparative Example 2 is relatively high, the yield strength ratio is relatively low, and the elongation is relatively low, which indicates that changing the cooling water flow rate in each zone will affect the yield strength ratio of the cast-rolled aluminum alloy. It also proves that the flow rate of the spray cooling water of the present invention can improve the yield strength ratio of the cast-rolled aluminum alloy.

[0210] The 6056 aluminum alloy rod prepared in Comparative Example 2 was subjected to performance testing according to "Bare Wire Test Method Part 3: Tensile Test" GB / T 4909.3. The results are shown in Table 12.

[0211] Table 12 Mechanical properties data of 6056 aluminum alloy rod prepared in Comparative Example 2

[0212] project Tensile strength / MPa Yield strength / MPa Elongation / % (gauge length 50mm) Yield strength ratio / % Comparative Example 2 190.3 128.8 12.5 67.7

[0213] It can be seen from Table 12 that the 6056 aluminum alloy rod prepared in Comparative Example 2 has low yield strength, low elongation, and low yield strength ratio, which indicates that changing the cooling water flow rate in each zone will affect the yield strength ratio of the aluminum alloy, and also proves that the flow rate of the spray cooling water of the present invention can improve the yield strength ratio of the aluminum alloy.

[0214] It can be seen from the above embodiments and comparative examples that the high yield ratio 6056 aluminum alloy rod prepared by the preparation method provided by the present invention has a high yield ratio.

[0215] 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 method for preparing a high yield ratio 6056 aluminum alloy rod, comprising the following steps: (1) continuously casting and rolling the aluminum alloy melt to obtain a cast-rolled aluminum alloy; (2) subjecting the cast-rolled aluminum alloy obtained in step (1) to a homogenization heat treatment and a drawing in sequence to obtain a drawn aluminum alloy; (3) The drawn aluminum alloy obtained in step (2) is subjected to secondary homogenization heat treatment and secondary drawing in sequence to obtain a high yield strength ratio 6056 aluminum alloy rod.

2. The preparation method according to claim 1, characterized in that: In the step (1), the continuous casting temperature is 720-750° C., and the continuous casting speed is 6.3-8.2 m / min.

3. The preparation method according to claim 1, characterized in that: The temperature of the cooling water for continuous casting in step (1) is 20-35°C.

4. The preparation method according to claim 1, characterized in that: The continuous rolling in step (1) includes rough rolling and finish rolling performed sequentially.

5. The preparation method according to claim 1, characterized in that: The holding temperatures of the first homogenization heat treatment in step (2) and the second homogenization heat treatment in step (3) are independently 540-560° C., and the holding times of the first homogenization heat treatment and the second homogenization heat treatment are independently 12-20 hours.

6. The preparation method according to claim 1, characterized in that: The cooling method of the first homogenization heat treatment in step (2) and the second homogenization heat treatment in step (3) is furnace cooling.

7. The preparation method according to claim 6, characterized in that: The cooling rate of the furnace cooling is 10-30°C / h.

8. The preparation method according to claim 1, characterized in that: The number of drawing passes in step (2) is 3 to 4 times, and the total deformation amount of one drawing is 45 to 55%.

9. The preparation method according to claim 1, characterized in that: The number of secondary drawing passes in step (3) is 1 to 2 times, and the total deformation of the secondary drawing is 10 to 15%.

10. A 6056 aluminum alloy rod with high yield strength ratio prepared by the preparation method according to any one of claims 1 to 9.