6111 extruded aluminum alloy sheet stamping forming method

Abstract

The present invention provides a 6111 extruded aluminum alloy plate stamping forming method, comprising: step S1: melting and extruding aluminum plates; step S2: stamping aluminum plates after solution treatment; step S3: artificial aging heat treatment to strengthen the stamped aluminum plates. After adopting the above technical scheme, the forming performance of the aluminum alloy plate is greatly improved, the influence of aging hardening on the forming performance of the aluminum plate is avoided, and the required high-strength performance parts can be obtained. The performance of the aluminum plate reaches tensile strength Rm≥330MPa, yield strength Rp0.2≥280MPa, and elongation A50≥14%. After adopting the above technical scheme, high-strength and low-cost stamped aluminum alloy parts can be obtained, and extruded aluminum plates can replace rolled aluminum plates, providing powerful research results for the application of aluminum alloys in automobile body parts.

Description

Technical Field

[0001] The invention relates to a method for preparing an aluminum alloy plate stamping part, and in particular to a stamping forming process of an extruded aluminum alloy plate. Background Art

[0002] In order to meet the development requirements of lightweight automobiles, more and more lightweight materials are being applied to automobiles, and aluminum alloy plates have the characteristics of low density, light weight, easy processing, corrosion resistance, and aging hardening, and have become the first choice for major automobile manufacturers to replace steel plates to reduce vehicle weight. Due to the different materials of aluminum alloy plates and steel plates, there are large differences in the mechanical properties of aluminum alloy plates and steel plates for car bodies. Therefore, the stamping process design of aluminum alloy body parts cannot be applied to the traditional steel plate stamping forming numerical simulation theory and process design experience or standards. In addition, due to the aging hardening phenomenon of aluminum plates, their material parameters will change with the increase of storage time, resulting in unstable part quality after stamping.

[0003] Process difficulties and common defects of aluminum alloy sheet stamping parts:

[0004] (1) Poor formability: Due to its face-centered cubic crystal structure, the plastic deformation ability of aluminum alloy is quite different from that of steel, so the steel stamping process cannot be directly applied.

[0005] (2) Severe wrinkling tendency: Compared with steel plates, the window between wrinkling and cracking of aluminum alloy plates is narrower and the wrinkling tendency is serious.

[0006] (3) The springback is large and the precision control of parts is difficult. The elastic modulus of aluminum alloy plate is only one-third of that of steel plate, so parts are more likely to rebound.

[0007] (4) Poor edge binding, easy to crack and produce "orange peel" defects.

[0008] (5) The oxide layer on the surface of the sheet is highly sticky, which affects the service life of the mold. The oxide layer on the surface of the aluminum alloy plate has great friction with the mold surface during the sheet drawing process, and is easy to peel off and stick to the mold surface, causing mold damage.

[0009] (6) After trimming, the burrs are large and the debris accumulates seriously, which affects the surface quality of the parts and increases the mold maintenance cost.

[0010] Therefore, how to solve the problems arising from the application of the above-mentioned aluminum alloy plates in automobile bodies is of great significance for achieving automobile lightweighting. Summary of the invention

[0011] In order to overcome the above technical defects, the object of the present invention is to provide a 6111 extruded aluminum alloy plate stamping forming method, comprising:

[0012] Step S1: melting, casting and extruding aluminum plates;

[0013] Step S2: stamping the aluminum plate after solution treatment;

[0014] Step S3: Artificial aging heat treatment to strengthen the stamped aluminum plate.

[0015] Further, in step S1, the molten cast aluminum alloy includes the following components in percentage by mass: 0.762% Si, 0.127% Fe, 0.095% Cu, 0.582% Mg, 0.464% Mn, 0.013% Zn, 0.021% Ti, 0.081% Cr, and the balance is Al.

[0016] Furthermore, in step S1, the aluminum alloy aluminum rod extrusion process parameters are: aluminum rod temperature is 410-430°C, extrusion speed is 2.8-3.2 mm / s (preferably 3.0 mm / s), outlet temperature is 500-520°C (preferably 520°C), and water cooling.

[0017] Furthermore, in step S2, the aluminum plate is subjected to a solution treatment, and the parameters of the solution treatment process are: a solution treatment temperature of 490±5° C. and a solution treatment time of 30 minutes.

[0018] Furthermore, in step S2, after the aluminum plate is solid-solutionized, the stamping process is completed within 4 hours (<4h). When the time exceeds 4 hours, the stamped aluminum plate will crack or peel.

[0019] Furthermore, in step S3, the aluminum plate is subjected to artificial aging heat treatment strengthening, the aging process is 180±5°C, and the heat preservation is 6 hours.

[0020] Compared with the prior art, the above technical solution has the following beneficial effects:

[0021] Conventional aluminum alloys used for stamping are all cold-rolled aluminum plates, but this application uses 6111 extruded aluminum plates for solid solution and then stamping to greatly improve the forming performance of aluminum alloy plates, avoid the influence of aging hardening on the forming performance of aluminum plates, and obtain the required high-strength parts. The performance of the aluminum plate reaches tensile strength Rm ≥ 330MPa, yield strength Rp0.2 ≥ 280MPa, and elongation A50 ≥ 14%. After adopting the above technical solution, high-strength and low-cost stamped aluminum alloy parts can be obtained, and extruded aluminum plates can replace rolled aluminum plates, providing powerful research results for the application of aluminum alloys in automobile body parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of the 6111 extruded aluminum alloy plate stamping method of the present application;

[0023] Figure 2A schematic diagram of a typical binary phase diagram with solubility change according to an embodiment of the present application;

[0024] Figure 3 When conducting the Webster hardness test, when the Webster hardness exceeds 6HW, the stamped aluminum plate will crack. DETAILED DESCRIPTION

[0025] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art should understand that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0026] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims. The term "including" and its variations used in this article represent open inclusion, that is, "including but not limited to."

[0027] like Figure 1 As shown, the 6111 extruded aluminum alloy plate stamping forming process method of the present application includes steps S1-S3:

[0028] Step S1: Casting and extruding aluminum sheet

[0029] Aluminum ingots, magnesium ingots, aluminum-silicon master alloys, manganese agents, chromium agents, and aluminum-50 copper master alloys are added to a 30T aluminum smelting furnace; the smelted aluminum liquid includes the following components in percentage: 0.762% Si, 0.127% Fe, 0.095% Cu, 0.582% Mg, 0.464% Mn, 0.013% Zn, 0.021% Ti, 0.081% Cr, and the balance is Al;

[0030] Extrusion process parameter setting

[0031] Aluminum rod heating temperature: 410℃-430℃; (ingot heating temperature during extrusion process)

[0032] Extrusion barrel set temperature: 450℃±10℃; (extrusion barrel set temperature during extrusion process)

[0033] Extrusion rod forward speed: 3.0±0.2mm / s (the extrusion rod forward speed during the extrusion process should be adjusted appropriately to meet the outlet temperature range);

[0034] Outlet temperature (i.e. profile temperature entering quenching system): 500-520℃;

[0035] Cooling method: water cooling;

[0036] Step S2: Stamping aluminum sheet after solution treatment

[0037] Solution treatment refers to a heat treatment process in which the alloy is heated to a high temperature single-phase region and maintained at a constant temperature, so that the excess phase is fully dissolved into the solid solution and then rapidly cooled to obtain a supersaturated solid solution. It is generally a preliminary heat treatment, and its function is to prepare the best conditions for subsequent processing or heat treatment. Solution treatment is to dissolve carbides, γ phases, etc. in the matrix to obtain a uniform supersaturated solid solution, so that fine and evenly distributed carbides and γ strengthening phases can be re-precipitated during aging, while eliminating the stress caused by hot and cold processing to cause the alloy to recrystallize. Secondly, solution treatment is to obtain a suitable grain size to ensure the high temperature creep resistance of the alloy.

[0038] For most non-ferrous metal alloys, the purpose of solution treatment is to obtain a supersaturated solid solution to prepare the structure for subsequent aging treatment. Figure 2 The figure shows a typical binary phase diagram with solubility changes. The room temperature equilibrium structure of the C1 alloy with n-point composition is α+β two-phase, α is the matrix solid solution, and β is the second phase. After the C1 alloy is heated to Tq and kept warm for a sufficient time, the β phase will dissolve in the matrix to obtain a single-phase α solid solution. If the alloy is quickly cooled from Tq to room temperature, the diffusion and redistribution of the alloying element atoms will not be carried out in time, and the β phase cannot nucleate and grow, and the β phase cannot precipitate in the α phase. At this time, the room temperature structure of the alloy is a single-phase supersaturated solid solution of α with n-point composition (the equilibrium composition of the α phase at room temperature is the b-point composition). This supersaturated solid solution is thermodynamically metastable. At an appropriate temperature, the supersaturated solid solution will undergo precipitation and precipitation, thereby strengthening the alloy. The structure after solution treatment is not necessarily a single-phase supersaturated solid solution. As shown in the figure, the C2 alloy contains β phase at any temperature below the eutectic temperature. When heated to Tq, the structure of the alloy C2 is α phase and β phase of m-point composition. If quenched from Tq, its room temperature structure contains part of β phase in addition to the supersaturated α phase.

[0039] The extruded aluminum alloy plate is subjected to solid solution treatment to avoid the influence of aluminum alloy aging hardening on the forming performance of the aluminum plate. The solid solution treatment process is: solid solution temperature is 490±5℃, solid solution holding time is 30 minutes, and rapid water cooling.

[0040] Test verification: The aluminum alloy after solid solution is tested for Webster hardness. The test shows that when the Webster hardness exceeds 6HW, the stamped aluminum plate will crack, such as Figure 3 And as shown in Table 1.

[0041] Table 1 Hardness change with time after solid solution

[0042] time Release 1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 7 hours hardness 4HW 4HW 5HW 5HW 6HW 6HW 7HW 7HW

[0043] Based on the test hardness test and stamping conditions, in step S2, after the aluminum plate is solid-solutionized, the stamping process is completed within 4 hours, which can effectively avoid cracking and orange peel.

[0044] Step S3: Artificial aging heat treatment to strengthen the stamped aluminum plate

[0045] The aluminum alloy plate is subjected to artificial aging heat treatment and strengthening. The aging process is 180±5°, and the temperature is kept for 6 hours. After being taken out of the furnace, it is cooled naturally. The tensile strength Rm≥330MPa, the yield strength Rp0.2≥280MPa, and the elongation A 50 ≥14% of stamping aluminum alloy workpieces.

[0046] Test verification: Based on the test verification (test instrument: universal tensile machine, national standard implemented: GB / T 228-2002, sample is taken from the middle of the test plate), the measured data comparison is shown in Table 2:

[0047] Table 2 Performance comparison of different grades of aluminum alloys

[0048]

[0049]

[0050] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1.6111 extruded aluminum alloy sheet stamping forming method, characterized in that: include: Step S1: melting, casting and extruding aluminum plates; Step S2: stamping the aluminum plate after solution treatment; Step S3: artificial aging heat treatment to strengthen the stamped aluminum plate; In step S1, the molten aluminum alloy includes the following components in percentage by mass: 0.762% Si, 0.127% Fe, 0.095% Cu, 0.582% Mg, 0.464% Mn, 0.013% Zn, 0.021% Ti, 0.081% Cr, and the balance is Al; In step S1, the aluminum alloy aluminum rod extrusion process parameters are: aluminum rod temperature is 410-430°C, extrusion speed is 2.8-3.2 mm / s, outlet temperature is 500-520°C, and water cooling; In step S2, the aluminum plate is subjected to a solution treatment, and the parameters of the solution treatment process are: a solution temperature of 490±5° C. and a solution time of 30 minutes; In step S2, after the aluminum plate is solid-solutionized, the stamping process is completed within 4 hours; In step S3, the aluminum plate is subjected to artificial aging heat treatment strengthening, the aging process is 180±5°C, and the temperature is kept for 6 hours.

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