High-formability heat shield aluminum plate and preparation method thereof

Abstract

The invention provides a high-formability heat shield aluminum plate and a preparation method thereof, the grain size of the high-formability heat shield aluminum plate is 50-80m, second-phase particles are spherical, and the size of the second-phase particles is 50-100nm. By controlling the cast rolling-cold rolling process and the homogenizing annealing process of the aluminum plate, the morphology of hard and brittle iron-rich phase particles is changed from a lath shape to a spherical shape, spherical second-phase particles can hinder grain boundary migration, grain recrystallization in the homogenizing annealing process is better inhibited, the microscopic structure of the aluminum plate is fully improved, and the tensile strength of the material is improved. And the processing performance of the material can be improved while the processing flow is shortened through the large-rolling-reduction rolling processing mode, and the requirement of an automobile main engine plant for the high-formability aluminum plate is met.

Description

Technical Field

[0001] The invention belongs to the field of metallurgy and chemical industry, and further belongs to the field of aluminum plate and strip production, and specifically relates to a high-formability heat-insulating cover aluminum plate and a preparation method thereof. Background Art

[0002] The engine is the heart of the car, and its normal operation is crucial to the safety and stability of the entire vehicle. The heat shield located above the car engine mainly reduces the heat and radiation transfer, and isolates the excess heat in the engine. At the same time, in order to prevent the excess heat from causing aging and damage to the circuits and electrical components, heat insulation devices are installed on both sides of the engine and above the exhaust pipe. The design of the engine heat shield requires that the weight of the heat shield be reduced as much as possible while meeting the high heat insulation performance, so as to reduce the load and fuel consumption of the entire vehicle. Therefore, the 1235 aluminum alloy with low production cost has become the preferred material. Summary of the invention

[0003] The first object of the present invention is to provide a high-formability heat shield aluminum plate; the second object is to provide a method for preparing the high-formability heat shield aluminum plate.

[0004] The first object of the present invention is achieved in that the grain size of the high-formability heat shield aluminum plate is 50-80 μm, and the second phase particles are spherical with a size of 50-100 nm.

[0005] The second object of the present invention is achieved by comprising batching, smelting, refining and post-processing steps, specifically comprising: A. Ingredients: Ingredients shall be prepared according to the following mass percentages: aluminum (Al) ≥ 99.35%, iron (Fe) + silicon (Si) ≤ 0.65%, copper (Cu) ≤ 0.05%, manganese (Mn) ≤ 0.05%, magnesium (Mg) ≤ 0.05%, zinc (Zn) ≤ 0.05%, titanium (Ti) ≤ 0.06%; B. Smelting: alloy the electrolytic aluminum liquid directly, control the aluminum liquid temperature at 800-860℃, add other alloy elements according to the ingredient list in step A to obtain melt a, and the smelting and holding time is 20-30min; C. Refining: controlling the temperature of the molten aluminum a at 720-760°C for refining to obtain the refined aluminum molten aluminum b; D. Post-processing: The refined aluminum melt b is subjected to casting, cold rolling and annealing to obtain the target high-formability heat shield aluminum plate.

[0006] The specific operations are as follows: (1) Ingredients: The ingredients shall be prepared according to the following mass percentages: aluminum (Al) ≥ 99.35%, iron (Fe) + silicon (Si) ≤ 0.65%, copper (Cu) ≤ 0.05%, manganese (Mn) ≤ 0.05%, magnesium (Mg) ≤ 0.05%, zinc (Zn) ≤ 0.05%, titanium (Ti) ≤ 0.06%.

[0007] (2) Melting: Use electrolytic aluminum liquid to directly carry out alloying production, control the aluminum liquid temperature at 800~860℃, and add other alloy elements according to the ingredient list. The melting and holding time is 20~30min.

[0008] (3) Refining: Use a refining agent for refining, and the refining temperature is controlled at 720~760℃. The refining agent used is composed of the following components by weight: 40~60 parts of potassium chloride, 10~20 parts of sodium fluorosilicate, 10~20 parts of cryolite, 2~5 parts of potassium nitrate, 2~5 parts of calcium fluoride, and 2~5 parts of calcium silicate. The refining agent is evenly sprayed into the aluminum melt with argon gas to produce loose gray-white scum. After standing for 20~30 minutes, the scum is scraped off to obtain a clean melt.

[0009] (4) Casting and rolling: The refined aluminum melt is cast and rolled into 7.0±0.3mm aluminum sheet billets. The casting and rolling temperature is 720~740℃ and the casting and rolling rate is 80~100mm / min.

[0010] (5) Cold rolling: The aluminum sheet blank is rolled into an aluminum sheet with a thickness of 2.5±0.3mm by a large reduction in one pass at a rolling speed of 400~500m / min.

[0011] (6) Homogenization annealing: The cold-rolled aluminum sheet is subjected to homogenization annealing at a temperature of 500-520°C for 4 hours.

[0012] Compared with the traditional production method, the present invention changes the particle morphology of the hard and brittle iron-rich phase from lath to spherical by controlling the aluminum plate casting-cold rolling process and homogenization annealing process. The spherical second phase particles can hinder the grain boundary migration, better inhibit the grain recrystallization during the homogenization annealing process, fully improve the microstructure of the aluminum plate, and enhance the tensile strength of the material. The large reduction rolling processing method can shorten the processing flow and improve the processing performance of the material. The grain size of the final finished plate is 50~80μm, the second phase particles are spherical, and the size is 50~100nm; the plate tensile strength is greater than 100.0MPa, and the elongation is greater than 35.0%, which meets the needs of automobile OEMs for high-formability aluminum plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the morphology of the iron-rich phase particles after homogenization annealing in Example 1; Figure 2This is a schematic diagram of the recrystallized grain structure IPF of Example 1. DETAILED DESCRIPTION

[0014] The present invention is further described below in conjunction with the embodiments, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0015] The grain size of the high-formability heat shield aluminum plate of the present invention is 50-80 μm, and the second phase particles are spherical with a size of 50-100 nm.

[0016] The high-formability heat shield aluminum plate has a plate tensile strength greater than 100.00 MPa and an elongation greater than 35.0%.

[0017] The method for preparing the high-formability heat shield aluminum plate of the present invention comprises batching, smelting, refining and post-processing steps, specifically comprising: A. Ingredients: Ingredients shall be prepared according to the following mass percentages: aluminum (Al) ≥ 99.35%, iron (Fe) + silicon (Si) ≤ 0.65%, copper (Cu) ≤ 0.05%, manganese (Mn) ≤ 0.05%, magnesium (Mg) ≤ 0.05%, zinc (Zn) ≤ 0.05%, titanium (Ti) ≤ 0.06%; B. Smelting: alloy the electrolytic aluminum liquid directly, control the aluminum liquid temperature at 800-860℃, add other alloy elements according to the ingredient list in step A to obtain melt a, and the smelting and holding time is 20-30min; C. Refining: controlling the temperature of the molten aluminum a at 720-760°C for refining to obtain the refined aluminum molten aluminum b; D. Post-processing: The refined aluminum melt b is subjected to casting, cold rolling and annealing to obtain the target high-formability heat shield aluminum plate.

[0018] The refining described in step C is to evenly spray the refining agent into the aluminum melt with an inert gas to produce loose gray-white slag. After standing for 20 to 30 minutes, the slag is scraped off to obtain a clean melt, namely the refined aluminum melt b.

[0019] The refining agent is composed of the following components in parts by weight: 40-60 parts of potassium chloride, 10-20 parts of sodium fluorosilicate, 10-20 parts of cryolite, 2-5 parts of potassium nitrate, 2-5 parts of calcium fluoride and 2-5 parts of calcium silicate.

[0020] The casting and rolling described in step D is to cast and roll the refined aluminum melt b into an aluminum plate blank, the casting and rolling temperature is 720~740℃, and the casting and rolling rate is 80~100mm / min.

[0021] The cold rolling described in step D is to roll the aluminum sheet blank obtained after casting into an aluminum sheet strip by a large reduction in one pass, and the rolling speed is 400~500m / min.

[0022] The annealing described in step D is to perform homogenization annealing on the cold-rolled aluminum strip.

[0023] The annealing temperature is 500-520°C.

[0024] The annealing time is 3 to 5 hours.

[0025] The present invention is further described below with specific implementation cases: Example 1 (1) The ingredients are prepared according to the following element ratios: aluminum (Al) 99.37%, silicon (Si) 0.15%, iron (Fe) 0.40%, copper (Cu) 0.02%, manganese (Mn) 0.02%, and titanium (Ti) 0.04%.

[0026] (2) Use electrolytic aluminum liquid to directly carry out alloying production, control the aluminum liquid temperature at 800~820℃, and then add other alloying elements according to the ingredient list. The smelting and holding time is 30min.

[0027] (3) Refining is performed at 740-750°C. The refining agent used is composed of the following components by weight: 50 parts of potassium chloride, 20 parts of sodium fluorosilicate, 15 parts of cryolite, 5 parts of potassium nitrate, 5 parts of calcium fluoride, and 5 parts of calcium silicate. After standing for 20 minutes, the scum is scraped off to obtain a clean melt.

[0028] (4) The refined aluminum melt is cast and rolled into 7.0 mm aluminum sheet billets at a casting temperature of 740°C and a casting rate of 100 mm / min.

[0029] (5) Cold rolling: The aluminum sheet blank is rolled into an aluminum sheet strip with a thickness of 2.5 mm in one pass at a rolling speed of 500 m / min.

[0030] (6) Homogenization annealing: The cold-rolled aluminum sheet is subjected to homogenization annealing at 500°C for 4 hours.

[0031] Compared with the traditional production method, the aluminum alloy plate produced by this embodiment changes the morphology of the hard and brittle iron-rich phase particles from lath to spherical by controlling the aluminum plate casting-cold rolling process and the homogenization annealing process. The spherical second phase particles can hinder the grain boundary migration, better inhibit the grain recrystallization during the homogenization annealing process, fully improve the microstructure of the aluminum plate, and enhance the tensile strength of the material. The large reduction rolling processing method can improve the processing performance of the material while shortening the processing flow. The grain size of the final finished plate is 68μm, and the second phase particles are spherical with a size of 74nm; the plate tensile strength is 103.7MPa, and the elongation is 38.2%, which meets the needs of automobile OEMs for high-formability aluminum plates.

[0032] Example 2 (1) The ingredients are prepared according to the following element ratios: aluminum (Al) 99.41%, silicon (Si) 0.30%, iron (Fe) 0.20%, copper (Cu) 0.03%, manganese (Mn) 0.03%, and titanium (Ti) 0.03%.

[0033] (2) Use electrolytic aluminum liquid to directly carry out alloying production, control the aluminum liquid temperature at 850~860℃, and then add other alloying elements according to the ingredient list. The smelting and holding time is 20min.

[0034] (3) Refining is carried out at 720-740°C. The refining agent used is composed of the following components by weight: 40 parts of potassium chloride, 10 parts of sodium fluorosilicate, 10 parts of cryolite, 2 parts of potassium nitrate, 2 parts of calcium fluoride, and 2 parts of calcium silicate. After standing for 30 minutes, the scum is scraped off to obtain a clean melt.

[0035] (4) The refined aluminum melt is cast and rolled into 7.2 mm aluminum sheet billets at a casting temperature of 720°C and a casting rate of 80 mm / min.

[0036] (5) Cold rolling: The aluminum sheet blank is rolled into an aluminum sheet strip with a thickness of 2.8 mm in one pass at a rolling speed of 400 m / min.

[0037] (6) Homogenization annealing: The cold-rolled aluminum sheet is subjected to homogenization annealing at 400°C for 4 hours.

[0038] Compared with the traditional production method, the aluminum alloy sheet produced by this embodiment changes the morphology of the hard and brittle iron-rich phase particles from lath to spherical by controlling the aluminum sheet casting-cold rolling process and homogenization annealing process. The spherical second phase particles can hinder the migration of grain boundaries, better inhibit the recrystallization of grains during the homogenization annealing process, fully improve the microstructure of the aluminum sheet, and enhance the tensile strength of the material. The large reduction rolling processing method can improve the processing performance of the material while shortening the processing flow. The grain size of the final finished sheet is 63μm, and the second phase particles are spherical with a size of 85nm; the sheet has a tensile strength of 103.8MPa and an elongation of 37.3%, which meets the needs of automobile OEMs for high-formability aluminum sheets.

[0039] Example 3 (1) The ingredients are prepared according to the following element ratios: aluminum (Al) 99.39%, silicon (Si) 0.30%, iron (Fe) 0.21%, copper (Cu) 0.03%, manganese (Mn) 0.04%, and titanium (Ti) 0.03%.

[0040] (2) Use electrolytic aluminum liquid to directly carry out alloying production, control the aluminum liquid temperature at 840~850℃, and then add other alloying elements according to the ingredient list. The smelting and holding time is 25min.

[0041] (3) Refining is performed at 730-750°C. The refining agent used is composed of the following components by weight: 60 parts of potassium chloride, 20 parts of sodium fluorosilicate, 20 parts of cryolite, 5 parts of potassium nitrate, 5 parts of calcium fluoride, and 5 parts of calcium silicate. After standing for 25 minutes, the scum is scraped off to obtain a clean melt.

[0042] (4) The refined aluminum melt is cast and rolled into 6.8 mm aluminum sheet billets at a casting temperature of 730°C and a casting rate of 90 mm / min.

[0043] (5) Cold rolling: The aluminum sheet blank is rolled into an aluminum sheet strip with a thickness of 2.3 mm in one pass at a rolling speed of 450 m / min.

[0044] (6) Homogenization annealing: The cold-rolled aluminum sheet is subjected to homogenization annealing at 450°C for 4 hours.

[0045] Compared with the traditional production method, the aluminum alloy sheet produced by this embodiment changes the morphology of the hard and brittle iron-rich phase particles from lath to spherical by controlling the aluminum sheet casting-cold rolling process and the homogenization annealing process. The spherical second phase particles can hinder the migration of grain boundaries, better inhibit the recrystallization of grains during the homogenization annealing process, fully improve the microstructure of the aluminum sheet, and enhance the tensile strength of the material. The large reduction rolling processing method can improve the processing performance of the material while shortening the processing flow. The grain size of the final finished sheet is 70μm, and the second phase particles are spherical with a size of 75nm; the sheet has a tensile strength of 104.2MPa and an elongation of 39.1%, which meets the needs of automobile OEMs for high-formability aluminum sheets.

[0046] Example 4 (1) The ingredients are prepared according to the following element ratios: aluminum (Al) 99.42%, silicon (Si) 0.27%, iron (Fe) 0.25%, copper (Cu) 0.02%, manganese (Mn) 0.02%, and titanium (Ti) 0.02%.

[0047] (2) Use electrolytic aluminum liquid to directly carry out alloying production, control the aluminum liquid temperature at 830~850℃, and then add other alloying elements according to the ingredient list. The smelting and holding time is 26min.

[0048] (3) Refining is performed at 740-760°C, and the refining agent used is composed of the following components by weight: 45 parts of potassium chloride, 16 parts of sodium fluorosilicate, 12 parts of cryolite, 3 parts of potassium nitrate, 3 parts of calcium fluoride, and 3 parts of calcium silicate. After standing for 26 minutes, the scum is scraped off to obtain a clean melt.

[0049] (4) The refined aluminum melt is cast and rolled into 7.1 mm aluminum sheet billets at a casting temperature of 730°C and a casting rate of 95 mm / min.

[0050] (5) Cold rolling: The aluminum sheet blank is rolled into an aluminum sheet strip with a thickness of 2.7 mm in one pass at a rolling speed of 480 m / min.

[0051] (6) Homogenization annealing: The cold-rolled aluminum sheet is subjected to homogenization annealing at a temperature of 450°C for 5 h.

[0052] Compared with the traditional production method, the aluminum alloy plate produced by this embodiment changes the morphology of the hard and brittle iron-rich phase particles from lath to spherical by controlling the aluminum plate casting-cold rolling process and the homogenization annealing process. The spherical second phase particles can hinder the migration of grain boundaries, better inhibit the recrystallization of grains during the homogenization annealing process, fully improve the microstructure of the aluminum plate, and enhance the tensile strength of the material. The large reduction rolling processing method can improve the processing performance of the material while shortening the processing flow. The grain size of the final finished plate is 67μm, and the second phase particles are spherical with a size of 88nm; the tensile strength of the plate is >102.8MPa, and the elongation is 37.6%, which meets the needs of automobile OEMs for high-formability aluminum plates.

[0053] Example 5 (1) The ingredients are prepared according to the following element ratios: aluminum (Al) 99.38%, silicon (Si) 0.25%, iron (Fe) 0.29%, copper (Cu) 0.02%, manganese (Mn) 0.04%, and titanium (Ti) 0.02%.

[0054] (2) Use electrolytic aluminum liquid to directly carry out alloying production, control the aluminum liquid temperature at 835~850℃, and then add other alloying elements according to the ingredient list. The smelting and holding time is 24min.

[0055] (3) Refining was performed at 725-740°C, and the refining agent used was composed of the following components by weight: 54 parts of potassium chloride, 14 parts of sodium fluorosilicate, 16 parts of cryolite, 3 parts of potassium nitrate, 4 parts of calcium fluoride, and 3 parts of calcium silicate. After standing for 23 minutes, the scum was scraped off to obtain a clean melt.

[0056] (4) The refined aluminum melt is cast and rolled into 7.3 mm aluminum sheet billets at a casting temperature of 740°C and a casting rate of 85 mm / min.

[0057] (5) Cold rolling: The aluminum sheet blank is rolled into an aluminum sheet strip with a thickness of 2.6 mm in one pass at a rolling speed of 480 m / min.

[0058] (6) Homogenization annealing: The cold-rolled aluminum sheet is subjected to homogenization annealing at 430°C for 3h.

[0059] Compared with the traditional production method, the aluminum alloy sheet produced by this embodiment changes the morphology of the hard and brittle iron-rich phase particles from lath to spherical by controlling the aluminum sheet casting-cold rolling process and homogenization annealing process. The spherical second phase particles can hinder the grain boundary migration, better inhibit the grain recrystallization during the homogenization annealing process, fully improve the microstructure of the aluminum sheet, and enhance the tensile strength of the material. The large reduction rolling processing method can improve the processing performance of the material while shortening the processing flow. The grain size of the final finished sheet is 52μm, and the second phase particles are spherical with a size of 55nm; the sheet has a tensile strength of 103.2MPa and an elongation of 38.4%, which meets the needs of automobile OEMs for high-formability aluminum sheets.

Claims

1. A high-formability heat shield aluminum plate, characterized in that: The grain size of the high-formability heat shield aluminum plate is 50-80 μm, and the second phase particles are spherical with a size of 50-100 nm.

2. The high formability heat shield aluminum plate according to claim 1, characterized in that: The high-formability heat shield aluminum plate has a plate tensile strength greater than 100.00 MPa and an elongation greater than 35.0%.

3. A method for preparing a high-formability heat shield aluminum plate according to claim 1 or 2, characterized in that: It includes batching, smelting, refining and post-processing steps, including: A. Ingredients: Ingredients shall be prepared according to the following mass percentages: aluminum (Al) ≥ 99.35%, iron (Fe) + silicon (Si) ≤ 0.65%, copper (Cu) ≤ 0.05%, manganese (Mn) ≤ 0.05%, magnesium (Mg) ≤ 0.05%, zinc (Zn) ≤ 0.05%, titanium (Ti) ≤ 0.06%; B. Smelting: The electrolytic aluminum liquid is directly alloyed, the aluminum liquid temperature is controlled at 800-860°C, and other alloy elements are added according to the ingredient list of step A to obtain melt a. The smelting and heat preservation time is 20-30 minutes; C. Refining: controlling the temperature of the molten aluminum a at 720-760°C for refining to obtain the refined aluminum molten aluminum b; D. Post-processing: The refined aluminum melt b is subjected to casting, cold rolling and annealing to obtain the target high-formability heat shield aluminum plate.

4. The preparation method according to claim 3, characterized in that: The refining described in step C is to evenly spray the refining agent into the aluminum melt with an inert gas to produce loose gray-white slag. After standing for 20 to 30 minutes, the slag is scraped off to obtain a clean melt, namely the refined aluminum melt b.

5. The preparation method according to claim 3 or 4, characterized in that: The refining agent is composed of the following components in parts by weight: 40-60 parts of potassium chloride, 10-20 parts of sodium fluorosilicate, 10-20 parts of cryolite, 2-5 parts of potassium nitrate, 2-5 parts of calcium fluoride and 2-5 parts of calcium silicate.

6. The preparation method according to claim 3, characterized in that: The casting and rolling described in step D is to cast and roll the refined aluminum melt b into an aluminum plate blank, the casting and rolling temperature is 720~740℃, and the casting and rolling rate is 80~100mm / min.

7. The preparation method according to claim 3, characterized in that: The cold rolling described in step D is to roll the aluminum sheet blank obtained after casting into an aluminum sheet strip by a large reduction in one pass, and the rolling speed is 400~500m / min.

8. The preparation method according to claim 3, characterized in that: The annealing described in step D is to perform homogenization annealing on the cold-rolled aluminum strip.

9. The preparation method according to claim 8, characterized in that: The annealing temperature is 500-520°C.

10. The preparation method according to claim 8, characterized in that: The annealing time is 3 to 5 hours.

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