CN104561691B - High-plasticity cast aluminum alloy and pressure casting preparation method thereof - Google Patents

Abstract

The invention discloses a high-plasticity cast aluminum alloy and a pressure casting preparation method thereof, belonging to the technical fields of metal materials and metallurgy. The high-plasticity cast aluminum alloy comprises the following components in percentage by weight: 7.5-14.5% of Si, 0.5-0.8% of Mg, 0.2-0.5% of Mn, 0.1-0.4% of Ti, 0.01-1.5% of RE, 0.6-1.3% of Fe, at most 100 ppm of P, 100-600 ppm of Sr and the balance of Al. The RE is one or more of Gd, Y, Nd, Sm, Er, Yb and La. After the high-plasticity cast aluminum alloy is subjected to pressure casting, the elongation percentage delta of the alloy is greater than or equal to 20%. The alloy has the advantages of excellent casting performance and low cost. The method has the advantages of simple technique, high production efficiency and obvious progress, and widens the application range of the Al-Si cast aluminum alloy.

Description

High plasticity casting aluminum alloy and pressure casting preparation method thereof

technical field

The invention relates to a casting aluminum alloy and a preparation method thereof, in particular to a high-plasticity casting aluminum alloy and a pressure casting preparation method thereof, belonging to the field of metal materials and metallurgy.

Background technique

As a traditional metal material, cast aluminum alloy is widely used in aviation, aerospace, automobile, machinery and other industries due to its low density and high specific strength. With the development of modern industry and new casting technologies, the demand for cast aluminum alloys, such as cast aluminum alloys with high strength, high plasticity, excellent wear resistance and corrosion resistance, is increasing. After decades of development, high-strength aluminum alloys have formed a complete series, with stable performance and increasingly perfect production methods, becoming an indispensable alloy system in the field of materials. However, the current high-strength cast aluminum alloys have low plasticity and generally cannot withstand large deformations, which limits their applications. Many important parts that require high plasticity are mostly made of wrought aluminum alloy. However, although wrought aluminum alloy has ideal high plasticity, its processing process requires high equipment and tooling molds, and there are many processes, so the production cycle is long and the cost is high. In contrast, cast aluminum alloy has many advantages such as low price, isotropic casting structure, easy to produce parts with complex shapes, and can be produced in a single piece or in large quantities. Therefore, it has become the current development trend in this field to develop cast aluminum alloys that can replace part of the deformed aluminum alloys and have high plasticity, standardize the casting molding process, shorten the production cycle, and reduce manufacturing costs.

Chinese patent CN85102364AA discloses a silicon-manganese-tellurium high-plasticity casting aluminum alloy, which contains 5.5-9.5% Si, 0.2-0.8% Mn, 0.1-0.2% Ti, 0.001-0.2% Te, 0.1-0.2% Sb , the balance is Al, and the elongation is about 16%. However, while the plasticity of the alloy is improved, the strength of the alloy decreases sharply, and its performance cannot meet the needs of current industrial production. In Chinese patent CN101248200A, a cast aluminum alloy is disclosed, the composition content of which is 2.5-3.3% Si, 0.2-0.7% Mg, Fe<0.18%, Mn<0.5, Ti<0.1, Sr<0.03, others<0.1 , the balance being Al. The alloy has an elongation rate of 13% in the as-cast state, and after T6 heat treatment, the elongation rate is only 5%, which is far from meeting the application requirements of high plasticity casting aluminum alloy castings. In addition, due to the low amount of Si in the alloy and the small amount of eutectic crystals in the structure, the alloy has a high forming temperature and a large gas absorption tendency, and there are unavoidable casting defects such as pores, shrinkage cavities and shrinkage porosity, and it is difficult to obtain high-density castings , so formability (casting performance) is poor. In the Chinese patent CN103305730A, a new type of Al-Si-Mg-Cu-Sr casting alloy is disclosed, whose composition content is 11.0-12.0% Si, 0.30-0.50% Cu, 0.35-0.55% Mg, 0.01-0.02% Sr , Mn≤0.35%, Zn≤0.20%, Fe≤0.40%, Ti≤0.10%, Ni≤0.10%, Pb≤0.10%, Sn≤0.10%, Cr≤0.10%, others ≤0.6%, the balance is Al . The as-cast tensile strength of the alloy is between 245 and 275 MPa, and the elongation is between 5 and 8%. However, the Cu element added in the Al-Si alloy will increase the hot cracking and corrosion tendency of the alloy and reduce the casting performance, thus limiting the application range of the alloy in industry.

Contents of the invention

The present invention aims at the generally low plasticity of cast aluminum alloys existing in the prior art and does not take into account the lack of casting performance of aluminum alloys. On the basis of not reducing the strength and casting performance of the alloy, a high-plasticity casting aluminum alloy and a pressure casting preparation method thereof are provided. By selecting appropriate components and process parameters, the casting aluminum alloy with excellent elongation is prepared.

The purpose of the present invention is achieved through the following technical solutions:

In the first aspect, the present invention provides a high plastic casting aluminum alloy, which includes the following components and weight content: Si 7.5-14.5%, Mg 0.5-0.8%, Mn 0.2-0.5%, Ti 0.1-0.4%, RE 0.01- 1.5%, Fe 0.6～1.3%, P≤100ppm, Sr 100～600ppm, the balance is Al;

Preferably, the RE is one or more of Gd, Y, Nd, Sm, Er, Yb, La.

Preferably, when the RE is one or more of Gd, Er or Yb, the weight content of RE is 0.05-1.0%; the RE is one or more of Y, Nd, Sm or La, The preferred solution of these four rare earth elements is 0.05-0.6%.

Preferably, P is 1-50 ppm.

Preferably, the Si, Mg, Mn, Ti, RE, Fe, P, Sr, Al come from industrial pure aluminum, crystalline silicon, industrial pure magnesium, Al-Mn master alloy, rare earth master alloy, Al-Sr master alloy, Al-P master alloy and Al-Ti-B master alloy.

In a second aspect, the present invention provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, comprising the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt;

In the second step, pressure casting is performed on the aluminum alloy melt to obtain a high plasticity cast aluminum alloy.

Preferably, in the first step, the melting of the alloy includes the following steps:

(1) Preheat industrial pure aluminum, crystalline silicon, industrial pure magnesium, Al-Mn master alloy, rare earth master alloy, Al-Sr master alloy, Al-P master alloy and Al-Ti-B master alloy to 100-200 ℃, keep warm for more than 2 hours;

(2) Smelting Al and Si: Preheat the smelting appliance to 400-500°C, add crystalline silicon at the bottom, cover the crystalline silicon with 40-80% of the total weight of industrial pure aluminum required, and heat up to the melting point of industrial pure aluminum temperature to obtain liquid aluminum; crystalline silicon is melted under the wrapping of liquid aluminum, stirred repeatedly after melting, and then the remaining industrial pure aluminum is added;

(3) Add Mn and RE: Add Al-Mn master alloy and rare earth master alloy to the melt obtained in step (2) under the condition of 720-740°C;

(4) Adding Sr and P: Add Al-Sr master alloy and Al-P master alloy to the melt obtained in step (3) at 730-750°C, let stand for 15-30 minutes and then stir for 3-5 minutes , to make it fully melted;

(5) Adding Ti: at 710-730°C, add Al-Ti-B master alloy to the melt obtained in step (4), stir, and let stand for 3-5 minutes;

(6) Add Mg: under the condition of 700～720 DEG C, add industrial pure magnesium to the melt obtained in step (5), fully melt;

(7) Refining: Add refining agent to the melt obtained in step (6) at 710-740°C, refine for 10-20 minutes, let stand for 15-40 minutes, cool to 660-700°C, skim off the surface floating Slag, that is, aluminum alloy melt.

Preferably, in step (1), the preheating is specifically using an oven.

Preferably, in step (2), the smelter is specifically a crucible; the melting temperature of industrial pure aluminum is about 680° C.; and graphite rods are used for the stirring.

Preferably, in step (7), the refining agent is a commercially available aluminum alloy refining agent or hexachloroethane containing inorganic salts such as sodium salt, potassium salt, fluorine salt, etc. 5% by weight of the alloy.

Preferably, in the second step, in the die casting, the pouring temperature of the aluminum alloy melt is 660-700°C, the injection speed is 0.2-3.0m/s, and the casting mold preheating temperature is 200-300°C.

When the amount of rare earth added is different, the rare earth mainly exists in three forms in the aluminum alloy: solid solution in the matrix, segregated in the phase boundary, grain boundary and dendrite boundary, solid solution in the compound or in the form of a compound. After rare earth elements are added to the alloy, the rare earth elements play a role of limited solid solution strengthening and increase the strength. On the other hand, the rare earth elements are extremely chemically active and can be selectively adsorbed on the grain interface of the grown grains to hinder the formation of the grains. Growth and grain refinement improve the mechanical properties of the alloy, especially the plasticity. When the content of rare earth is further increased, the intermetallic compound formed by rare earth and Al, Mg, Si and other elements is dispersed in the matrix, which changes the crack initiation position and propagation path during the fracture process of the alloy, and improves the plasticity of the alloy. The addition of rare earth elements can also improve the casting performance of cast aluminum alloys. This is because Fe is a harmful impurity in aluminum alloys. The crystal structure of most iron-containing phases is very coarse, which directly affects the mechanical properties of the alloy and reduces the fluidity of the alloy. And plasticity, increase the inhomogeneity of structure, adding rare earth, can change the existence form of iron phase, improve the casting performance and plasticity of the alloy. In addition, the modification of primary Si and eutectic Si by P and Sr can effectively improve the plasticity of the alloy.

Compared with the prior art, the present invention has the following beneficial effects:

(1) Rare earth elements are added to the cast aluminum alloy of the present invention. Through composition optimization and adjustment of a series of process parameters, RE-rich intermetallic compounds with fine grains, compactness, uniform composition, and dispersed distribution in the matrix and few and no defects are obtained. The structure can significantly improve its plasticity without reducing the strength of the alloy, and can better meet the service requirements of industrial production;

(2) Compared with the existing Al-Si alloys, the aluminum alloy prepared by extrusion casting according to the composition of the present invention has no obvious reduction in strength at room temperature but a great improvement in plasticity, and the tensile strength at room temperature of the die-casting casting is σ≥ 280MPa, elongation δ ≥ 20%, breaking through the bottleneck of other Al-Si cast aluminum alloys with high strength but low plasticity, and its high strength and elongation can meet the industry's demand for this type of material;

(3) The alloy prepared by the invention has excellent casting performance, low cost, simple process, high production efficiency and remarkable progress, which expands the application range of Al-Si series cast aluminum alloys.

detailed description

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention. Various master alloys and refining agents involved in the present invention are commercially available products.

Example 1

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, this embodiment provides a high plasticity cast aluminum alloy, the composition (weight content) of the aluminum alloy is: 7.5% Si, 0.5% Mg, 0.2% Mn, 0.1% Ti, 0.05% Y, 0.6% Fe , 20ppm P, 100ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 100° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then placed on the surface of the furnace for baking. The baking temperature is 100°C and baked for 1 hour. (2) Preheat the crucible to 400°C, add crystalline silicon at the bottom of the crucible, cover the crystalline silicon with 2/3 of the amount of pure aluminum required after drying, together When the temperature rises, pure aluminum melts at around 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 730°C and add Al-Mn master alloy, Al-5Y master alloy, stir to make it melt completely; (4) Add Al-Sr master alloy and Al-P master alloy to 740°C and let stand for 15 minutes; (5) Add Al-Ti-B after cooling to 710°C For the master alloy, stir and let it stand for 3 to 5 minutes; (6) Press the pure magnesium wrapped in aluminum foil into the aluminum alloy liquid with a bell jar at 700°C, stir to make it fully melt; (7) heat up to 720°C Refining, the refining agent is aluminum alloy three-in-one refining agent, the amount of refining agent added is 1% of the total weight of the alloy liquid, and the refining agent wrapped in aluminum foil is pressed into the aluminum liquid with a bell jar to move horizontally and circuitously for about 10 minutes. After the completion, measure the hydrogen content and carry out pre-furnace inspection;

The second step is to stand still at the pouring temperature of 660°C for 20 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 660°C, the mold temperature at 200°C, and the injection speed of 0.2 m/s.

The room temperature tensile strength of the die-cast high-plastic aluminum alloy in this embodiment is 282 MPa, and the elongation is 20.3%.

Example 2

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, this embodiment provides a high-plasticity casting aluminum alloy, the composition (weight content) of the aluminum alloy is: 8.5% Si, 0.6% Mg, 0.3% Mn, 0.2% Ti, 1.5% Gd, 0.7% Fe , 40ppm P, 200ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then baked on the surface of the furnace at 200°C for 1 hour. (2) Preheat the crucible to 450°C, add crystalline silicon to the bottom of the crucible, cover the crystalline silicon with 2/3 of the amount of pure aluminum required after drying, and When the temperature rises, pure aluminum melts at about 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 720°C and add Al-Mn master alloy, Mg-90Gd master alloy, stir to melt it completely; (4) Add Al-Sr master alloy and Al-P master alloy to 730°C and let it stand for 15 minutes; (5) Add Al-Ti-B after cooling to 720°C For the master alloy, stir and let stand for 3 to 5 minutes; (6) Use a bell jar to press the pure magnesium wrapped in aluminum foil into the aluminum alloy liquid at 710°C, stir to make it fully melt; (7) heat up to 730°C Refining, the refining agent is hexachloroethane, and the amount of refining agent added is 1% of the total weight of the alloy liquid. When refining, use a bell jar to press the refining agent wrapped in aluminum foil into the aluminum liquid and move horizontally. After about 10 minutes of refining, measure Hydrogen content, and pre-furnace inspection;

The second step is to stand still at the pouring temperature of 680°C for 30 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 680°C, the mold temperature at 225°C, and the injection speed at 0.5 m/s.

The room temperature tensile strength of the die-cast high-plastic aluminum alloy in this embodiment is 286 MPa, and the elongation is 20.0%.

Example 3

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, the present invention provides a high plasticity casting aluminum alloy, the composition (weight content) of the aluminum alloy is: 9.5% Si, 0.7% Mg, 0.4% Mn, 0.3% Ti, 0.1% Gd, 0.1% Y, 0.02% Nd, 0.8% Fe, 60ppm P, 300ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then baked on the surface of the furnace at 200°C for 1 hour. (2) Preheat the crucible to 500°C, add crystalline silicon at the bottom of the crucible, and cover 2/3 of the amount of pure aluminum required after drying on the crystalline silicon, together When the temperature rises, pure aluminum melts at around 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 730°C and add Al-Mn master alloy, Mg-90Gd master alloy, Mg-25Y master alloy, Mg-90Nd master alloy, stirring to make it melt completely; (4) heating up to 740°C, adding Al-Sr master alloy and Al-P master alloy, and standing for 15 minutes; ( 5) Cool down to 730°C and add Al-Ti-B master alloy, stir, and let it stand for 3 to 5 minutes; (6) Press the pure magnesium wrapped in aluminum foil into the aluminum alloy liquid with a bell jar at 720°C, stir to make it Fully melted; (7) Refining with aluminum alloy refining agent when the temperature rises to 740 ° C, the amount of refining agent added is 2% of the total weight of the alloy liquid, and the refining agent wrapped in aluminum foil is pressed into the aluminum liquid with a bell jar during refining. Roundabout movement, after about 10 minutes of refining, measure the hydrogen content, and carry out pre-furnace inspection;

The second step is to stand still at a pouring temperature of 700°C for 30 minutes, skim off the surface scum, obtain an aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 700°C, the mold temperature at 250°C, and the injection speed at 1.0 m/s.

The room temperature tensile strength of the die-cast high-plastic aluminum alloy in this embodiment is 286 MPa, and the elongation is 20.2%.

Example 4

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, the present invention provides a high plasticity casting aluminum alloy, the composition (weight content) of the aluminum alloy is: 10.5% Si, 0.8% Mg, 0.5% Mn, 0.4% Ti, 0.2% Gd, 0.3% Y, 0.15% Nd, 0.02% Sm, 0.9% Fe, 80ppm P, 400ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talc powder and 5% water glass with an appropriate amount of water, and then placed on the surface of the furnace for baking. The baking temperature is 220°C and baked for 1 hour. (2) Preheat the crucible to 400°C, add crystalline silicon at the bottom of the crucible, cover the crystalline silicon with 2/3 of the amount of pure aluminum required after drying, together When the temperature rises, pure aluminum melts at about 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 720°C and add Al-Mn master alloy, Mg-90Gd master alloy, Al-5Y master alloy, Mg-90Nd master alloy, Mg-20Sm master alloy, stir to melt completely; (4) heat up to 730°C and add Al-Sr master alloy and Al-P master alloy, Stand still for 15 minutes; (5) Cool down to 710°C and add Al-Ti-B master alloy, stir, and let stand for 3 to 5 minutes; (6) Press pure magnesium wrapped in aluminum foil into aluminum alloy at 700°C (7) Refining when the temperature rises to 710°C, the refining agent is hexachloroethane, the amount of refining agent added is 5% of the total weight of the alloy liquid, and the aluminum foil is wrapped in a bell jar during refining The refining agent is pressed into the molten aluminum and moves horizontally. After about 10 minutes of refining, the hydrogen content is measured and the furnace inspection is carried out;

The second step is to stand still at the pouring temperature of 680°C for 40 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 680°C, the mold temperature at 300°C, and the injection speed at 2.0 m/s.

The room temperature tensile strength of the die-cast high plasticity aluminum alloy in this embodiment is 287Mpa, and the elongation is 20.5%.

Example 5

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, this embodiment provides a high plasticity cast aluminum alloy, the composition (weight content) of the aluminum alloy is: 10.5% Si, 0.8% Mg, 0.5% Mn, 0.4% Ti, 0.1% Gd, 0.1% Y , 0.05% Nd, 0.2% Sm, 0.1% Er, 1.0% Fe, 90ppm P, 500ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then baked on the surface of the furnace at 200°C for 1 hour. (2) Preheat the crucible to 420°C, add crystalline silicon at the bottom of the crucible, cover the crystalline silicon with 2/3 of the amount of pure aluminum required after drying, together When the temperature rises, pure aluminum melts at about 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 720°C and add Al-Mn master alloy, Mg-90Gd master alloy, Al-5Y master alloy, Mg-90Nd master alloy, Mg-20Sm master alloy, Al-20Er master alloy, stirring to make it completely melted; (4) heating up to 730°C and adding Al-Sr master alloy and Al-P master alloy, let it stand for 15 minutes; (5) Cool down to 710°C and add Al-Ti-B master alloy, stir, let stand for 3 to 5 minutes; (6) Wrap aluminum foil with a bell jar at 700°C Press pure magnesium into the aluminum alloy liquid, stir to make it fully melt; (7) Refining with aluminum alloy refining agent when the temperature rises to 710°C, the amount of refining agent added is 2% of the total weight of the alloy liquid, and a bell jar is used for refining Press the refining agent wrapped in aluminum foil into the molten aluminum and move horizontally, measure the hydrogen content after refining for about 10 minutes, and conduct pre-furnace inspection;

The second step is to stand still at the pouring temperature of 690°C for 20 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 690°C, the mold temperature at 200°C, and the injection speed at 3.0 m/s.

The room temperature tensile strength of the die-cast high-plastic aluminum alloy in this embodiment is 281 MPa, and the elongation is 20.3%.

Example 6

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, the present invention provides a high plasticity casting aluminum alloy, the composition (weight content) of the aluminum alloy is: 11.5% Si, 0.6% Mg, 0.3% Mn, 0.2% Ti, 0.05% Gd, 0.1% Y, 0.05% Nd, 0.02% Sm, 0.7% Er, 0.02% La, 1.3% Fe, 100ppm P, 600ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then placed on the surface of the furnace for baking. The baking temperature is 240°C and baked for 1 hour. (2) Preheat the crucible to 430°C, add crystalline silicon at the bottom of the crucible, cover the crystalline silicon with 2/3 of the amount of pure aluminum required after drying, together When the temperature rises, pure aluminum melts at around 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 730°C and add Al-Mn master alloy, Mg-90Gd master alloy, Al-5Y master alloy, Mg-90Nd master alloy, Mg-20Sm master alloy, Al-20Er master alloy, Al-20La master alloy, stir to melt completely; (4) heat up to 740°C and add Al-Sr master alloy and Al-P master alloy, let stand for 15 minutes; (5) Cool down to 720°C and add Al-Ti-B master alloy, stir, let stand for 3 to 5 minutes; (6) Use at 710°C The bell jar presses the pure magnesium wrapped in aluminum foil into the aluminum alloy liquid, and stirs to make it fully melted; (7) Refining is carried out when the temperature is raised to 720°C, and the refining agent is hexachloroethane, and the amount of the refining agent added is the total weight of the alloy liquid When refining, use a bell jar to press the refining agent wrapped in aluminum foil into the molten aluminum and move horizontally. After about 10 minutes of refining, measure the hydrogen content and carry out pre-furnace inspection;

The second step is to stand still at the pouring temperature of 670°C for 30 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 670°C, the mold temperature at 200°C, and the injection speed at 1.0 m/s.

The room temperature tensile strength of the die-cast high-plastic aluminum alloy in this embodiment is 284 MPa, and the elongation is 20.4%.

Example 7

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, the present invention provides a high plasticity casting aluminum alloy, the composition (weight content) of the aluminum alloy is: 13.5% Si, 0.6% Mg, 0.3% Mn, 0.2% Ti, 0.05% Gd, 0.05% Y, 0.02% Nd, 0.02% Sm, 0.1% Er, 0.6% La, 0.1% Yb, 1.2% Fe, 10ppm P, 200ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then baked on the surface of the furnace at 200°C for 1 hour. (2) Preheat the crucible to 440°C, add crystalline silicon at the bottom of the crucible, and cover 2/3 of the amount of pure aluminum required after drying on the crystalline silicon, together When the temperature rises, pure aluminum melts at around 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 730°C and add Al-Mn master alloy, Mg-90Gd master alloy, Al-5Y master alloy, Mg-90Nd master alloy, Mg-20Sm master alloy, Al-20Er master alloy, Al-20La master alloy, Al-10Yb master alloy, stir to melt completely; (4 ) heating up to 740°C, adding Al-Sr master alloy and Al-P master alloy, and standing for 15 minutes; (5) cooling down to 720°C, adding Al-Ti-B master alloy, stirring, and standing for 3 to 5 minutes; (6) ) at 710°C, use a bell jar to press pure magnesium wrapped in aluminum foil into the aluminum alloy liquid, and stir to make it fully melt; 3% of the total weight of the liquid. When refining, use a bell jar to press the refining agent wrapped in aluminum foil into the aluminum liquid to move horizontally. After about 10 minutes of refining, measure the hydrogen content and carry out pre-furnace inspection;

The second step is to stand still at the pouring temperature of 690°C for 30 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 690°C, the mold temperature at 200°C, and the injection speed at 1.5 m/s.

The room temperature tensile strength of the die-cast high plastic aluminum alloy in this embodiment is 287Mpa, and the elongation is 20.1%.

Example 8

This embodiment relates to a high plasticity casting aluminum alloy and a preparation method thereof by pressure casting.

In the first aspect, the present invention provides a high plasticity casting aluminum alloy, the composition (weight content) of the aluminum alloy is: 14.5% Si, 0.6% Mg, 0.3% Mn, 0.2% Ti, 0.05% Gd, 0.05% Y, 0.02% Nd, 0.02% Sm, 0.1% Er, 0.02% La, 0.7% Yb, 1.1% Fe, 10ppm P, 200ppm Sr, other unavoidable impurities are less than 0.2%, and the rest is Al.

In the second aspect, this embodiment provides a method for preparing the high-plastic cast aluminum alloy by pressure casting, which includes the following steps:

The first step is to smelt the alloy to obtain an aluminum alloy melt; wherein, the specific steps of the process of smelting the alloy are: (1) Preheat the smelting raw material in an oven to 200° C. The bell jar and other surfaces are cleaned and derusted and coated with paint. The paint is made of 25% talcum powder and 5% water glass with an appropriate amount of water, and then baked on the surface of the furnace at 200°C for 1 hour. (2) Preheat the crucible to 400°C, add crystalline silicon at the bottom of the crucible, cover the crystalline silicon with 2/3 of the amount of pure aluminum required after drying, together When the temperature rises, pure aluminum melts at around 680°C, and silicon slowly melts under the wrapping of molten aluminum. After melting, stir repeatedly with a graphite rod, and then add the remaining pure aluminum; (3) Cool down to 730°C and add Al-Mn master alloy, Mg-90Gd master alloy, Al-5Y master alloy, Mg-90Nd master alloy, Mg-20Sm master alloy, Al-20Er master alloy, Al-20La master alloy, Al-10Yb master alloy, stir to melt completely; (4 ) heating up to 740°C, adding Al-Sr master alloy and Al-P master alloy, and standing for 15 minutes; (5) cooling down to 720°C, adding Al-Ti-B master alloy, stirring, and standing for 3 to 5 minutes; (6) ) at 710°C, use a bell jar to press pure magnesium wrapped in aluminum foil into the aluminum alloy liquid, stir to make it fully melt; (7) refine when the temperature rises to 720°C, the refining agent is hexachloroethane, The amount is 3% of the total weight of the alloy liquid. During refining, use a bell jar to press the refining agent wrapped in aluminum foil into the aluminum liquid and move horizontally. After about 10 minutes of refining, measure the hydrogen content and carry out pre-furnace inspection;

The second step is to stand still at the pouring temperature of 690°C for 30 minutes, skim off the surface scum, obtain the aluminum alloy melt, and prepare for pouring; keep the temperature of the aluminum alloy melt at 690°C, the mold temperature at 200°C, and the injection speed at 2.5 m/s.

The room temperature tensile strength of the cast high plastic aluminum alloy in this embodiment is 284Mpa, and the elongation is 20.6%.

In summary, the present invention obtains an aluminum alloy with both alloy strength and plasticity through the optimization of alloy components and preparation methods. Compared with the prior art, it has significant progress and substantive features, as shown in Table 1 below. .

Table 1 is the room temperature performance comparison between the cast aluminum alloy of the present invention and the existing cast aluminum-silicon alloy under pressure casting conditions

Alloy code (heat treatment state) Tensile strength (MPa) Elongation (%) CN103146962A patent (F) ≥225 ≥6 CN103898376A Patent (F) ≥280 5～12 ZL107A(T5) 420～470 4～6 YL112(F) ≥330 ≥3 A380(T5) ≥310 ≥3.2 Invention patent (T5) ≥280 ≥20

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (5)

1. a kind of high plasticity alloy cast aluminum compression casting preparation method it is characterised in that described preparation method include following Step:

The first step, molten alloy, obtain aluminium alloy melt；

Second step, carries out compression casting to described aluminium alloy melt, obtains final product high plasticity alloy cast aluminum；Wherein, described high-ductility Cast aluminium alloy gold includes component and weight content is as follows: si 7.5～14.5%, mg 0.5～0.8%, mn 0.2～0.5%, Ti 0.1～0.4%, re 0.01～1.5%, fe 0.6～1.3%, p≤100ppm, sr 100～600ppm, balance of al；

In the first step, described molten alloy comprises the steps:

(1) by commercial-purity aluminium, silicon metal, pure magnesium, al-mn intermediate alloy, rare earth intermediate alloy, al-sr intermediate alloy, Al-p intermediate alloy and al-ti-b intermediate alloy are preheated to 100～200 DEG C, are incubated more than 2 hours；

(2) melting al, si: preheating melting utensil, to 400～500 DEG C, adds silicon metal in its bottom, covers on silicon metal The 40～80% of required commercial-purity aluminium gross weight, are warming up to the temperature of commercial-purity aluminium fusing, obtain aluminium liquid；Silicon metal is in the bag of aluminium liquid Wrap up in lower fusing, repeatedly stir after fusing, add remaining commercial-purity aluminium；

(3) mn, re are added: under the conditions of 720～740 DEG C, add in al-mn intermediate alloy, rare earth in step (2) gained liquation Between alloy；

(4) sr, p are added: under the conditions of 730～750 DEG C, add in al-sr intermediate alloy and al-p in step (3) gained liquation Between alloy, standing after 15～30 minutes stirring 3～5 minutes so as to abundant melt；

(5) add ti: under the conditions of 710～730 DEG C, in step (4) gained liquation, add al-ti-b intermediate alloy, stir, quiet Put 3～5 minutes；

(6) add mg: under the conditions of 700～720 DEG C, add pure magnesium in step (5) gained liquation, fully melt；

(7) refine: under the conditions of 710～740 DEG C, the addition refining agent in step (6) gained liquation, refine 10～20 minutes, Standing 15～40 minutes, is cooled to 660～700 DEG C, skims surface scum, obtain final product aluminium alloy melt.

2. the compression casting preparation method of high plasticity alloy cast aluminum according to claim 1 is it is characterised in that step (1), in, described preheating specially adopts baking oven.

3. the compression casting preparation method of high plasticity alloy cast aluminum according to claim 1 is it is characterised in that step (2), in, described smelting device is specially crucible；Described stirring adopts graphite rod.

4. the compression casting preparation method of high plasticity alloy cast aluminum according to claim 1 is it is characterised in that step (7), in, described refining agent is that conventional commercial contains sodium salt, potassium salt, the aluminum refining agent of villiaumite inorganic salt or hexachlorethane.

5. the compression casting preparation method of high plasticity alloy cast aluminum according to claim 1 is it is characterised in that second step In, in described compression casting, the pouring temperature of aluminium alloy melt is 660～700 DEG C, and injection speed is 0.2～3.0m/s, casting Mold preheating temperature is 200～300 DEG C.