Aluminum alloy for blow molding mold and preparation method thereof, blow molding mold

Abstract

The present invention discloses an aluminum alloy for a blow mold, a preparation method thereof, and a blow mold, relating to the technical field of aluminum alloys. Specifically, the aluminum alloy for the blow mold comprises the following components by weight: Si 0.4% to 0.9%, Mg 0.6% to 1.2%, Cu 0.15% to 1.0%, Mn 0.05% to 0.8%, Fe 0% to 0.2%, Zn 0% to 0.1%, Cr 0.01% to 0.35%, and Ti 0.01% to 0.1%, with the remainder being Al and unavoidable impurities, with the impurity content being ≤0.15%. The total content of Si, Mg, Cu, Mn, Fe, Zn, Cr, Ti, and impurities is ≤4%. Implementation of the present invention yields an aluminum alloy with high thermal conductivity, high hardness, and high strength, extending the service life of injection molds based on the aluminum alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an aluminum alloy for a blow molding mold, a preparation method thereof, and the blow molding mold. Background Art

[0002] Blow molding, as a plastics processing method, is widely used in the manufacture of hollow containers. The process involves extruding or injection molding a thermoplastic resin into a tubular plastic parison, heating it to a softened state, and placing it in an open mold. Immediately after the mold is closed, compressed air is introduced into the parison to form and cool the plastic parison, resulting in a hollow product. Materials commonly used include aluminum alloys, steel, and copper-based alloys. Steel, a common material for blow molding molds, offers high hardness, wear resistance, and toughness, but its thermal conductivity is poor, requiring a high cooling system. Copper-beryllium alloys are commonly used, offering high thermal conductivity and corrosion resistance, but beryllium is a harmful element and can be harmful to the human body. Aluminum alloys offer significant advantages over steel and copper-based alloys, including high specific strength, excellent machinability, and a clean, pollution-free design. However, they suffer from low hardness, wear, and a shorter service life.

[0003] On the other hand, most of the current aluminum alloy blow molding molds are made by casting process, which has relatively low hardness and poor toughness. In addition, its surface segregation layer is thick, which has poor wear resistance and short service life. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an aluminum alloy for blow molding and a preparation method thereof, which has good thermal conductivity, good machining performance, high hardness, and the obtained blow molding has a long service life.

[0005] Another technical problem to be solved by the present invention is to provide a blow molding mold.

[0006] Another technical problem to be solved by the present invention is to provide application of the above-mentioned blow molding die in injection molding of PE products.

[0007] In order to solve the above technical problems, the present invention provides an aluminum alloy for a blow mold, which includes the following components in weight percentage:

[0008] Si 0.4% to 0.9%, Mg 0.6% to 1.2%, Cu 0.15% to 1.0%, Mn 0.05% to 0.8%, Fe 0.05% to 0.2%, Zn 0% to 0.1%, Cr 0.01% to 0.35%, Ti 0.01% to 0.1%, the rest are Al and unavoidable impurities, the impurity content is ≤ 0.15%;

[0009] Among them, the total content of Si, Mg, Cu, Mn, Fe, Zn, Cr, Ti and impurities is ≤4%.

[0010] As an improvement of the above technical solution, the weight ratio of Mg to Si is 1.45 to 1.65.

[0011] As an improvement of the above technical solution, 0.5%≤Mn+Cr+Ti≤0.8%.

[0012] As an improvement of the above technical solution, the thickness of the aluminum alloy is ≥140 mm, its thermal conductivity is ≥165 W / (m·K), and its hardness is ≥100 HB.

[0013] As an improvement of the above technical solution, the aluminum alloy has a tensile strength of ≥300 MPa, a yield strength of ≥280 MPa, and an elongation of ≥10%.

[0014] Accordingly, the present invention also discloses a method for preparing an aluminum alloy for use in a blow molding mold, comprising the following steps:

[0015] (1) Prepare raw materials in proportion; the raw material formula in weight percentage is as follows:

[0016] Si 0.4% to 0.9%, Mg 0.6% to 1.2%, Cu 0.15% to 1.0%, Mn 0.05% to 0.8%, Fe 0% to 0.2%, Zn 0% to 0.1%, Cr 0.01% to 0.35%, Ti 0.01% to 0.1%, the rest are Al and unavoidable impurities, the impurity content is ≤ 0.15%;

[0017] (2) melting and casting the raw materials to obtain ingots;

[0018] (3) homogenizing the ingot;

[0019] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0020] (5) straightening the aluminum alloy blank;

[0021] (6) subjecting the straightened aluminum alloy billet to aging treatment to obtain the aluminum alloy billet; wherein the aging treatment is a double-stage aging treatment, wherein the first-stage aging treatment temperature is 160° C. to 180° C., and the treatment time is 3 h to 10 h; and the second-stage aging treatment temperature is 200° C. to 210° C., and the treatment time is 0.5 h to 1 h.

[0022] As an improvement of the above technical solution, in step (3), the homogenization treatment is a two-stage homogenization treatment; wherein, the temperature of the first-stage homogenization treatment is 480°C to 500°C, and the treatment time is 2h to 5h; the temperature of the second-stage homogenization treatment is 560°C to 570°C, and the treatment time is 5h to 18h; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0023] As an improvement of the above technical solution, in step (4), the extrusion ratio is 10 to 50, and the extrusion outlet temperature is 520° C. to 560° C.

[0024] Correspondingly, the present invention also discloses a blow molding mold, which is obtained by machining the above-mentioned aluminum alloy; the machining includes cutting processing.

[0025] Correspondingly, the present invention also discloses the application of the above-mentioned blow molding mold in the injection molding of PE products.

[0026] The implementation of the present invention has the following beneficial effects:

[0027] The aluminum alloy for blow molds of the present invention has excellent machining properties through the synergy of various strengthening elements in the formula, so that it can be used to form blow molds using extrusion and machining processes. At the same time, the aluminum alloy in the present invention has high thermal conductivity and hardness, and the injection molds obtained by using it have high hardness and long service life. Specifically, the aluminum alloy in the present invention can be used to prepare rough blanks with a thickness of ≥140mm, which are suitable for subsequent processing of molds using machining processes; at the same time, the aluminum alloy in the present invention has a thermal conductivity of ≥165W / (m·K), a hardness of ≥60HB, a tensile strength of ≥300MPa, a yield strength of ≥280MPa, and an elongation of ≥10%, which effectively extends the service life of the injection mold. Specifically, the injection mold prepared based on the aluminum alloy of the present invention can have a service life of more than 2.5 million times, which is 25% to 30% longer than the service life of conventional cast aluminum alloy blow molds. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below in conjunction with specific implementation methods.

[0029] The present invention discloses an aluminum alloy for a blow mold, comprising the following components in percentage by weight:

[0030] Si 0.4%~0.9%, Mg 0.6%~1.2%, Cu 0.15%~1.0%, Mn 0.05%~0.8%, Fe0%~0.2%, Zn 0%~0.1%, Cr 0.01%~0.35%, Ti 0.01%~0.1%, and the rest are Al and unavoidable impurities, and the impurity content is ≤0.15%.

[0031] Among them, the total content of Si, Mg, Cu, Mn, Fe, Zn, Cr, Ti and impurities is ≤4%. By controlling the total content of strengthening elements, the aluminum alloy can have good mechanical properties while reducing the adverse effects of strengthening on thermal conductivity, maintaining a thermal conductivity coefficient of ≥165W / (m·K).

[0032] Among them, Mg and Si are the main strengthening elements, which can form Mg2Si phase and improve the mechanical properties of aluminum alloys. Specifically, the Si content in the aluminum alloy is 0.4wt% to 0.9wt%, and exemplarily 0.5wt%, 0.6wt%, 0.7wt% or 0.8wt%, but not limited thereto. The Mg content in the aluminum alloy is 0.6wt% to 1.2wt%, and exemplarily 0.7wt%, 0.9wt%, 1wt%, 1.1wt% or 1.15wt%, but not limited thereto.

[0033] Preferably, in one embodiment of the present invention, Mg / Si (weight ratio) is controlled to be 1.45 to 1.65, that is, Si is in an excess state, and the excess silicon can improve the processing performance of the aluminum alloy to a certain extent. It should be noted that since the blow mold needs to withstand a certain pressure, it has a certain wall thickness. In particular, the present invention adopts the extrusion-machining process to produce the blow mold, which inevitably means that an aluminum alloy blank with a higher wall thickness (thickness ≥ 50 mm) must be formed for machining. However, the molding difficulty of the aluminum alloy blank with a large wall thickness is high, and the subsequent machining is also easy to deform, and the dimensional accuracy is low. For this reason, in the present invention, by controlling Mg / Si, the extrusion performance and machining performance of the aluminum alloy are improved to a certain extent.

[0034] Among them, Cu can be dissolved in the aluminum alloy matrix and precipitate Al2Cu phase after aging, which improves the mechanical properties of the aluminum alloy such as hardness and tensile strength. However, too much Cu will also reduce the corrosion resistance of the aluminum alloy; in addition, too much Cu will also reduce the machinability of the aluminum alloy. To this end, the Cu content is controlled to be 0.15wt% to 1.0wt%, and illustratively 0.2wt%, 0.4wt%, 0.6wt%, 0.8wt% or 0.9wt% are examples, but are not limited to these. Preferably, the Cu content is 0.4wt% to 0.8wt%.

[0035] Among them, adding Mn and Cr to aluminum alloys can improve the corrosion resistance of aluminum alloys, and can also play a role in refining grains, improving the physical and chemical properties and machining performance of aluminum alloys, but grain refinement will reduce thermal conductivity. Specifically, the Mn content is 0.05wt% to 0.8wt%, and exemplary amounts are 0.07wt%, 0.12wt%, 0.2wt%, 0.3wt%, 0.5wt%, 0.6wt% or 0.72wt%, but are not limited thereto. The Cr content is 0.01wt% to 0.35wt%, and exemplary amounts are 0.05wt%, 0.12wt%, 0.18wt%, 0.23wt%, 0.28wt% or 0.32wt%, but are not limited thereto. Preferably, the Mn content is 0.2wt% to 0.6wt%; the Cr content is 0.05wt% to 0.2wt%.

[0036] Ti can also play a role in grain refinement, and its content is 0.01wt% to 0.1wt%, exemplified by 0.03wt%, 0.05wt%, 0.07wt% or 0.08wt%, but not limited thereto. Preferably, the Ti content is 0.01wt% to 0.05wt%.

[0037] Preferably, in one embodiment of the present invention, the Mn+Cr+Ti content is controlled to be 0.5% ≤ 0.8%. This control not only imparts excellent mechanical and machinability to the aluminum alloy, but also excellent thermal conductivity. Specifically, this control allows for subsequent extrusion of aluminum alloy billets with a thickness of 180 mm or greater, while maintaining a thermal conductivity of 170 W / (m·K) or greater.

[0038] Among them, Fe will form Al8Fe2Si phase in aluminum alloy, which greatly reduces the extrusion performance of aluminum alloy. However, the inventors have shown through experiments that the introduction of a small amount of Fe is conducive to forming a certain roughness on the surface of the blow mold after later machining, thereby effectively improving the exhaust efficiency during the blow molding process. This blow mold is particularly suitable for blow molding of PE materials. Specifically, the Fe content is 0.05wt% to 0.2wt%, exemplified by 0.08wt%, 0.1wt%, 0.13wt%, 0.16wt% or 0.18wt%, but not limited to this. Preferably, the Fe content is 0.05wt% to 0.1wt%.

[0039] In addition, the aluminum alloy of the present invention further contains Zn in an amount of 0 to 0.1 wt %, and inevitable impurities in an amount of ≤ 0.15 wt %.

[0040] Accordingly, the present invention also discloses a method for preparing an aluminum alloy for use in a blow molding mold, comprising the following steps:

[0041] (1) Prepare the raw materials in proportion;

[0042] Specifically, each element can be prepared as a pure phase or alloy phase as raw materials, but is not limited to this. For example, a pure aluminum ingot can be used as the Al source, a high-purity silicon ingot can be used as the Si source, or an aluminum-silicon alloy can be used as both the Al and Si sources. Another example is an Al-20% Mn alloy can be used as both the Al and Mn sources, but is not limited to this.

[0043] (2) melting and casting the raw materials to obtain ingots;

[0044] Specifically, various raw materials are added to a smelting furnace, the smelting temperature is controlled at 720°C to 750°C, and they are stirred thoroughly until melted. Preferably, the raw materials are added sequentially according to the difficulty of melting the metals, and high-purity magnesium is added last. Each raw material is stirred for 10 to 15 minutes between additions to ensure uniform composition and temperature.

[0045] Slag removal is also carried out during the smelting process. Slag removal is divided into primary and secondary slag removal. The primary slag removal is carried out before adding high-purity magnesium, and the secondary slag removal is carried out after adding high-purity magnesium. The slag removal temperature is controlled at 720℃~750℃. Slag removal is carried out using a slag removal vehicle. Before slag removal, a slag removal agent is sprinkled into the molten aluminum to completely separate the slag and aluminum. An iron rake is used to remove slag and other impurities on the surface of the molten aluminum, and to ensure that as little molten aluminum as possible is removed.

[0046] After the second slag removal, the slag is refined. Specifically, the refining temperature is 710°C to 730°C, the refining time is 15 minutes to 20 minutes, and high-purity argon is introduced during the refining process. After the refining is completed, the slag is allowed to stand for 0.8 hours to 1.5 hours.

[0047] Specifically, the alloy melt is cast after being allowed to rest. Aluminum-titanium-boron wire is evenly fed into the casting process using a wire feeder to refine the grain size. Simultaneously, online degassing and filtration purification equipment are used to produce a pure, impurity-free melt. The casting speed is 60-70 mm / min, and the casting temperature is 675-695°C.

[0048] (3) homogenizing the ingot;

[0049] The homogenization temperature is 480-600°C and the treatment time is 5-24 hours. After the homogenization, water mist and strong wind are used for cooling. Preferably, in one embodiment of the present invention, a two-stage homogenization process is adopted, wherein the temperature of the first stage homogenization process is 480-500°C and the treatment time is 2-5 hours; the temperature of the second stage homogenization process is 560-570°C and the treatment time is 5-18 hours; after the homogenization process is completed, water mist and strong wind are used for cooling.

[0050] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0051] The extrusion ratio is 10 to 50, the extrusion outlet temperature is 520°C to 560°C, and the extrusion speed is 8 to 20 m / min. After extrusion, the product is quenched online and cooled by spraying water.

[0052] (5) straightening the aluminum alloy blank;

[0053] Among them, the straightening amount is 1% to 3%.

[0054] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0055] The aging treatment is a two-stage process, with the first stage at 160°C to 180°C for 3 to 10 hours, and the second stage at 200°C to 210°C for 0.5 to 1 hour. This two-stage process effectively strengthens thick aluminum alloy billets and imparts them with higher mechanical strength.

[0056] Specifically, the aluminum alloy obtained by the above formula and preparation method has a thermal conductivity of ≥165W / (m·K), a hardness of ≥100HB, a tensile strength of ≥300MPa, a yield strength of ≥280MPa, and an elongation of ≥10%.

[0057] The above-mentioned aluminum alloy can be used to prepare blow molds. Specifically, the aluminum alloy can be processed by machining to obtain a blow mold. The machining process includes but is not limited to cutting (turning, milling) and wire cutting. The blow mold prepared using the aluminum alloy of the present invention not only has a long service life of more than 2.5 million times, but also has a suitable surface roughness, which can greatly improve the exhaust during the blow molding process of PE products, increase their cooling rate and cooling uniformity, and thus improve the various performance properties of PE products.

[0058] The present invention will be described below with specific embodiments:

[0059] Example 1

[0060] This embodiment provides an aluminum alloy for a blow mold, and its formula is as follows:

[0061] Si 0.44%, Mg 0.8%, Cu 0.27%, Mn 0.7%, Fe 0.15%, Zn 0.05%, Cr 0.22%, Ti 0.08%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0062] The preparation method comprises the following steps:

[0063] (1) Prepare the raw materials in proportion;

[0064] (2) melting and casting the raw materials to obtain ingots;

[0065] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0066] (3) homogenizing the ingot;

[0067] The homogenization temperature is 500°C and the treatment time is 20 hours. After the homogenization is completed, water mist and strong wind are used for cooling.

[0068] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0069] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 8 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0070] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 150 mm.

[0071] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0072] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0073] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0074] Example 2

[0075] This embodiment provides an aluminum alloy for a blow mold, and its formula is as follows:

[0076] Si 0.52%, Mg 0.72%, Cu 0.27%, Mn 0.7%, Fe 0.15%, Zn 0.05%, Cr 0.22%, Ti 0.08%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0077] The preparation method comprises the following steps:

[0078] (1) Prepare the raw materials in proportion;

[0079] (2) melting and casting the raw materials to obtain ingots;

[0080] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0081] (3) homogenizing the ingot;

[0082] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0083] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0084] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 8.5 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0085] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 150 mm.

[0086] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0087] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0088] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0089] Example 3

[0090] This embodiment provides an aluminum alloy for a blow mold, and its formula is as follows:

[0091] Si 0.49%, Mg 0.75%, Cu 0.5%, Mn 0.57%, Fe 0.08%, Zn 0.08%, Cr 0.19%, Ti 0.05%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0092] The preparation method comprises the following steps:

[0093] (1) Prepare the raw materials in proportion;

[0094] (2) melting and casting the raw materials to obtain ingots;

[0095] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0096] (3) homogenizing the ingot;

[0097] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0098] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0099] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 12 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0100] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 150 mm.

[0101] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0102] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0103] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0104] Example 4

[0105] This embodiment provides an aluminum alloy for a blow mold, and its formula is as follows:

[0106] Si 0.49%, Mg 0.75%, Cu 0.8%, Mn 0.33%, Fe 0.1%, Zn 0.08%, Cr 0.12%, Ti 0.04%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0107] The preparation method comprises the following steps:

[0108] (1) Prepare the raw materials in proportion;

[0109] (2) melting and casting the raw materials to obtain ingots;

[0110] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0111] (3) homogenizing the ingot;

[0112] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0113] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0114] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 10 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0115] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 150 mm.

[0116] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0117] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0118] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0119] Example 5

[0120] This embodiment provides an aluminum alloy for a blow mold, and its formula is as follows:

[0121] Si 0.49%, Mg 0.75%, Cu 0.6%, Mn 0.47%, Fe 0.08%, Zn 0.08%, Cr 0.19%, Ti 0.05%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0122] The preparation method comprises the following steps:

[0123] (1) Prepare the raw materials in proportion;

[0124] (2) melting and casting the raw materials to obtain ingots;

[0125] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0126] (3) homogenizing the ingot;

[0127] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0128] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0129] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 15 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0130] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 200 mm.

[0131] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0132] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0133] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0134] Example 6

[0135] This embodiment provides an aluminum alloy for a blow mold, and its formula is as follows:

[0136] Si 0.49%, Mg 0.75%, Cu 0.6%, Mn 0.47%, Fe 0.08%, Zn 0.08%, Cr 0.19%, Ti 0.05%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0137] The preparation method comprises the following steps:

[0138] (1) Prepare the raw materials in proportion;

[0139] (2) melting and casting the raw materials to obtain ingots;

[0140] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0141] (3) homogenizing the ingot;

[0142] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0143] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0144] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 13 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0145] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 200 mm.

[0146] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0147] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0148] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0149] Comparative Example 1

[0150] This comparative example provides an aluminum alloy, the formula of which is as follows:

[0151] Si 0.72%, Mg 1.18%, Cu 0.85%, Mn 0.7%, Fe 0.15%, Zn 0.05%, Cr 0.32%, Ti 0.06%, the rest are Al and unavoidable impurities, the impurity content is 0.1%;

[0152] The preparation method comprises the following steps:

[0153] (1) Prepare the raw materials in proportion;

[0154] (2) melting and casting the raw materials to obtain ingots;

[0155] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0156] (3) homogenizing the ingot;

[0157] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0158] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0159] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 8.5 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0160] The aluminum alloy blank obtained by extrusion is a semi-circular rod with a thickness (ie, diameter) of 100 mm (a diameter of 140 mm cannot be extruded).

[0161] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0162] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0163] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0164] Comparative Example 2

[0165] This comparative example provides an aluminum alloy, the formula of which is as follows:

[0166] Si 0.85%, Mg 1.3%, Cu 0.9%, Mn 0.52%, Fe 0.1%, Zn 0.08%, Cr 0.22%, Ti 0.05%, the rest are Al and unavoidable impurities, the impurity content is 0.15%;

[0167] The preparation method comprises the following steps:

[0168] (1) Prepare the raw materials in proportion;

[0169] (2) melting and casting the raw materials to obtain ingots;

[0170] The smelting temperature was 740°C. Two slag removal processes were performed during the smelting process, with the slag removal temperature controlled at 730°C. After slag removal, the steel was refined at 720°C for 15 minutes, with high-purity argon gas introduced during the refining process. After refining, the steel was allowed to stand for 1 hour.

[0171] (3) homogenizing the ingot;

[0172] Among them, the homogenization treatment is a two-stage homogenization treatment; among them, the temperature of the first-stage homogenization treatment is 480°C, and the treatment time is 4 hours; the temperature of the second-stage homogenization treatment is 565°C, and the treatment time is 10 hours; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

[0173] (4) extruding the homogenized ingot to obtain an aluminum alloy blank;

[0174] The extrusion ratio is 30, the extrusion outlet temperature is 540°C, and the extrusion speed is 9 m / min. After extrusion, the product is quenched online and cooled by water spray.

[0175] The aluminum alloy blank obtained by extrusion is a semi-circular bar with a thickness (ie, diameter) of 120 mm (a diameter of 140 mm cannot be extruded).

[0176] (5) Straightening the aluminum alloy blank; wherein the straightening amount is 1.5%.

[0177] (6) subjecting the straightened aluminum alloy blank to aging treatment to obtain;

[0178] Among them, the aging treatment is a double-stage aging treatment, the first-stage aging treatment temperature is 170°C, and the treatment time is 5h; the second-stage aging treatment temperature is 200°C, and the treatment time is 0.8h.

[0179] The aluminum alloys obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were tested, and the specific results are shown in the following table:

[0180]

[0181] The above is a preferred embodiment of the 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 principles of the invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum alloy for a plastic blow molding mold, characterized in that: The following steps are involved: (1) Prepare the raw materials in proportion; the raw material formula in weight percentage is as follows: Si 0.4%~0.9%, Mg 0.6%~1.2%, Cu 0.4%~0.8%, Mn 0.2%~0.6%, Fe 0.05%~0.1%, Zn 0%~0.1%, Cr 0.01%~0.35%, Ti 0.01%~0.1%, the rest is Al and unavoidable impurities, the impurity content is ≤0.15%; of which the total content of Si, Mg, Cu, Mn, Fe, Zn, Cr, Ti and impurities is ≤4%; 0.5%≤Mn+Cr+Ti≤0.8%; the weight ratio of Mg to Si is 1.45~1.65; (2) Melting and casting the raw materials to obtain ingots; (3) homogenizing the ingot; (4) Extruding the homogenized ingot to obtain an aluminum alloy blank; (5) Straightening the aluminum alloy blank; (6) subjecting the straightened aluminum alloy billet to aging treatment, wherein the aging treatment is a two-stage aging treatment, wherein the first-stage aging treatment temperature is 160°C to 180°C, and the treatment time is 3h to 10h; the second-stage aging treatment temperature is 200°C to 210°C, and the treatment time is 0.5h to 1h; The thickness of the aluminum alloy used for plastic blow molding molds is ≥130mm, its thermal conductivity is ≥165W / (m·K), and its hardness is ≥100HB.

2. The method for preparing an aluminum alloy for a plastic blow mold according to claim 1, wherein: The aluminum alloy has a tensile strength of ≥300 MPa, a yield strength of ≥280 MPa, and an elongation of ≥10%.

3. The method for preparing an aluminum alloy for a plastic blow molding mold according to claim 1, wherein: In step (3), the homogenization treatment is a two-stage homogenization treatment; wherein, the temperature of the first-stage homogenization treatment is 480°C~500°C, and the treatment time is 2h~5h; the temperature of the second-stage homogenization treatment is 560°C~570°C, and the treatment time is 5h~18h; after the homogenization treatment is completed, water mist and strong wind are used for cooling.

4. The method for preparing an aluminum alloy for a plastic blow molding mold according to claim 1, wherein: In step (4), the extrusion ratio is 10-50, and the extrusion outlet temperature is 520°C-560°C.

5. A plastic blow molding mold, characterized in that: The aluminum alloy prepared by the method for preparing an aluminum alloy for a plastic blow mold according to any one of claims 1 to 4 is machined; the machining includes cutting.

6. Use of the plastic blow molding die as claimed in claim 5 in injection molding of PE products.

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