CN107208196A - Aluminium diecasting alloy and the aluminum alloy die casting for having used the alloy - Google Patents

Abstract

Aluminium diecasting alloy and the aluminum alloy die casting with the alloy die cast with the castability equal with ADC12 and with high-yield strength and high ductility is provided.That is, aluminium diecasting alloy of the invention is characterised by, contains Si：More than 6.00 weight % and less than 6.50 weight %, Mg：0.10~0.50 weight %, Fe：Below 0.30 weight %, Mn：0.30~0.60 weight %, Cr：0.10~0.30 weight %, surplus includes Al and inevitable impurity.

Description

Aluminum alloy for die casting and aluminum alloy die casting using the same

technical field

The present invention relates to an aluminum alloy for die-casting with improved yield strength and ductility, and an aluminum alloy die-cast product using the alloy.

Background technique

Aluminum alloys are lightweight and have excellent formability and mass productivity, so they are widely used as raw materials for components in automobiles, industrial machinery, aircraft, home electric appliances, and various other fields.

Among them, in automotive applications, a large number of components using aluminum alloys are used for the purpose of reducing the weight of the vehicle body. A condition in which the required mechanical properties of these parts cannot be met.

Therefore, as one of the technologies for solving such problems, for example, in the following patent document 1, as a material suitable for components requiring large elongation such as a disc wheel of an automobile, it is disclosed that silicon containing 5.0 to 11.0%, 0.2 An aluminum alloy for casting with up to 0.8% magnesium, 0.3 to 1.5% chromium and less than 1.2% iron, and high elongation.

According to this technique, an aluminum alloy for casting that contains iron as an impurity but has high elongation can be provided.

prior art literature

patent documents

Patent Document 1: JP-A-52-126609

Contents of the invention

The problem to be solved by the invention

However, it is uncertain whether the above prior art can be applied to parts requiring higher elongation and high yield strength (such as engine mounts, etc.), and it is difficult to say that there is die casting applicability for mass production of thin parts such as engine mounts.

Therefore, the main object of the present invention is to provide castability equivalent to ADC12 (hereinafter simply referred to as "ADC12"), which is an Al-Si-Cu alloy for die-casting specified in Japanese Industrial Standard JIS H5302, while having high yield strength and high Ductile aluminum alloy for die-casting, and aluminum alloy die-casting parts die-cast from the alloy.

means to solve the problem

The first invention of the present invention is an aluminum alloy for die casting, characterized in that "Contains Si: more than 6.00% by weight and less than 6.50% by weight, Mg: 0.10 to 0.50% by weight, Fe: 0.30% by weight or less, Mn: 0.30 to 0.60% by weight, Cr: 0.10 to 0.30% by weight, and the balance contains Al and unavoidable impurities”.

In this invention, Si is mainly contained more than 6.00% by weight and less than 6.50% by weight to minimize the decrease in elongation while maintaining the fluidity at the time of die casting, and in addition, the content ratio of Fe that will have a significant influence on the elongation of the alloy Suppressed to 0.30% by weight or less, while containing 0.30 to 0.60% by weight of Mn, which has an effect of improving the anti-adhesion during die-casting and the elongation of the alloy, it is possible to obtain an alloy that has die-casting applicability in parallel with ADC12 , while having a yield strength comparable to ADC12 and extremely high elongation compared to ADC12.

As described above, in the present invention, an aluminum alloy ingot for die-casting that is excellent in mechanical properties, especially elongation (ductility) and yield strength in addition to die-casting castability can be produced safely and easily by containing only five element components in predetermined ratios .

In addition, in the aluminum alloy for die castings of this invention, it is preferable to add 30-200 ppm of at least one kind selected from Na, Sr, and Ca, and to add 0.05-0.20 weight% of Sb. By doing so, the particles of eutectic Si can be made finer, and the toughness and strength of the aluminum alloy can be further improved.

In addition, it is also preferable to add 0.05 to 0.30% by weight of Ti and to add 1 to 50 ppm of B. By doing so, even when the amount of Si is extremely small or when a casting method with a slow cooling rate is used, the grains of the aluminum alloy can be refined, and as a result, the elongation of the aluminum alloy can be improved.

The second invention among the present invention is an aluminum alloy die-casting, characterized in that it is die-cast from the aluminum alloy for die-casting described in the above-mentioned first invention.

Since the aluminum alloy die-casting parts die-cast from the aluminum alloy for die-casting of the present invention can be mass-produced with good castability, and have excellent yield strength and elongation, they are most suitable for structural parts for automobiles, especially engine mounts.

Invention effect

According to the present invention, it is possible to provide an aluminum alloy for die-casting which has castability equivalent to ADC12 and which has both high yield strength and high ductility, and an aluminum alloy die-casting product obtained by die-casting the alloy.

Description of drawings

Fig. 1 is a graph showing the relationship between the amount of Mn and the mechanical properties of the alloy in the aluminum alloys for die casting of Examples and Comparative Examples of the present invention, wherein Fig. 1(a) shows the relationship between the amount of Mn and the elongation of the alloy, the graph 1(b) shows the relationship between the amount of Mn and the 0.2% yield strength of the alloy.

detailed description

Hereinafter, embodiments of the present invention will be described in detail while showing specific examples.

The aluminum alloy for die casting of the present invention (hereinafter sometimes simply referred to as "aluminum alloy") mainly contains more than 6.00% by weight and less than 6.50% by weight of Si (silicon, silicon), 0.10 to 0.50% by weight of Mg (magnesium), and 0.30% by weight % or less of Fe (iron), 0.30 to 0.60% by weight of Mn (manganese), 0.10 to 0.30% by weight of Cr (chromium), and the balance consists of Al (aluminum) and unavoidable impurities. Hereinafter, the characteristics of each element will be described.

Si (silicon; silicon) is an important element that contributes to the improvement of the fluidity when the aluminum alloy is melted, the lowering of the liquidus temperature, and the like, thereby improving the castability.

As described above, the content ratio of Si to the weight of the entire aluminum alloy is preferably in the range of more than 6.00% by weight and less than 6.50% by weight. This is because, when the content ratio of Si is 6.00% by weight or less, the melting temperature and casting temperature of the aluminum alloy become high, and at the same time, the fluidity of the aluminum alloy during melting decreases, so sufficient melt flow cannot be ensured during die casting. On the other hand, when the content of Si exceeds 6.50% by weight, although the fluidity of the melt during die casting can be ensured sufficiently, the elongation of the obtained alloy decreases.

Mg (magnesium) mainly exists in the state of solid solution in the Al base material in the aluminum alloy or as Mg ₂ Si, and it imparts 0.2% yield strength and tensile strength to the aluminum alloy. Components that adversely affect the properties and elongation of the alloy.

As described above, the content ratio of Mg to the weight of the entire aluminum alloy is preferably in the range of 0.10 to 0.50% by weight. The presence of Mg within this range can improve mechanical properties such as yield strength and tensile strength of the aluminum alloy without greatly affecting the castability and elongation of the alloy. In addition, when the compounding ratio of Mg exceeds 0.50 weight%, elongation of an alloy will fall, and the quality of the aluminum alloy die-casting manufactured using such an alloy will deteriorate.

Fe (iron) is known to have an anti-sticking effect during die casting. However, this Fe crystallizes needle-like crystals composed of Al—Si—Fe, significantly reduces the elongation of the aluminum alloy, and makes melting at an appropriate temperature difficult when added in a large amount.

As described above, the content ratio of Fe to the weight of the entire aluminum alloy is preferably 0.30% by weight or less. This is because, when the content ratio of Fe exceeds 0.30% by weight, the above-mentioned anti-adhesion effect becomes sufficient, but the elongation of the alloy is significantly reduced.

Mn (manganese) is mainly used to prevent the aluminum alloy from sticking to the mold during casting.

As described above, the compounding ratio of Mn to the weight of the entire aluminum alloy is preferably in the range of 0.30 to 0.60% by weight, more preferably in the range of 0.40 to 0.60% by weight. This is because, when the compounding ratio of Mn is less than 0.30% by weight, adhesion occurs between the aluminum alloy and the mold when die-casting the aluminum alloy. On the other hand, when the compounding ratio of Mn exceeds 0.60% by weight, In this case, although the problem of sticking does not occur during die casting, the elongation of the alloy decreases.

In addition, in the aluminum alloy of the present invention, the compounding ratio of Mn is allowed to be up to 0.6% by weight with respect to the weight of the entire alloy as described above, so Al-Mn-based scrap with a high Mn content such as recycled aluminum cans can be used as Part of the alloy raw material.

Cr (chromium) exists mainly in a molten state when the aluminum alloy is molten, and in a solid solution state in the Al phase or in a crystallized state as an Al-Si-Cr phase or an Al-Si-Cr-Fe phase when it is solid , used to prevent the aluminum alloy from sticking to the mold during die casting.

As described above, the compounding ratio of Cr to the weight of the entire aluminum alloy is preferably in the range of 0.10 to 0.30% by weight. This is because, when the blending ratio of Cr is less than 0.10% by weight, adhesion occurs between the aluminum alloy and the die when the aluminum alloy is die-cast, and on the other hand, when the blending ratio of Cr exceeds 0.30% by weight Under this condition, although the adhesion is eliminated during die casting, the elongation of the aluminum alloy drops sharply.

When the content ratios of Si, Mg, Fe, Mn, and Cr are adjusted according to the above content ratios, an aluminum alloy base metal for die casting can be obtained that has castability equivalent to ADC12, high yield strength, and high ductility.

Here, in the above-mentioned aluminum alloy for die casting in the as-cast state, the elongation (elongation at break) is preferably 11% or more, and the 0.2% yield strength is preferably 125 MPa or more. This is because an aluminum alloy for die-casting having such mechanical properties is particularly suitable as a die-casting material for an automobile engine mount.

In addition, at least one selected from Na (sodium), Sr (strontium), Ca (calcium), and Sb (antimony) may be added as an improvement treatment material in addition to the above-mentioned respective element components. By adding such a modified material, the particles of eutectic Si can be made finer, and the toughness and strength of the aluminum alloy can be further improved.

Here, the addition ratio of the modifying material to the weight of the entire aluminum alloy is preferably 30 to 200 ppm when the modifying material is Na, Sr, and Ca, and 0.05 to 0.20 wt% in the case of Sb. scope. This is because, when the addition ratio of the reforming material is less than 30 ppm (less than 0.05% by weight in the case of Sb), it is difficult to refine the grains of eutectic Si in the aluminum alloy. When the addition ratio exceeds 200 ppm (more than 0.20% by weight in the case of Sb), the particles of eutectic Si in the aluminum alloy are sufficiently refined, and even if the addition amount is increased above that, the addition effect does not improve.

In addition, at least one of Ti (titanium) and B (boron) may be added instead of or together with the above-mentioned modified treatment material. By adding at least one of Ti and B in this way, the crystal grains of the aluminum alloy are refined, and the elongation of the alloy can be improved. It should be noted that such an effect becomes remarkable when the amount of Si is particularly small or when a casting method with a slow cooling rate is used.

The addition ratio of Ti and B to the weight of the entire aluminum alloy is preferably in the range of 0.05 to 0.30% by weight in the case of Ti, and preferably in the range of 1 to 50 ppm in the case of B. This is because, when the addition ratio of Ti is less than 0.05% by weight or the addition ratio of B is less than 1ppm, it is difficult to refine the grains in the aluminum alloy. On the other hand, when the addition ratio of Ti exceeds 0.30% by weight When the addition ratio of B is less than or greater than 50 ppm, the crystal grains in the aluminum alloy are sufficiently refined, and even if the addition amount is increased above that, the addition effect does not improve.

When producing the aluminum alloy for die casting of the present invention, first, a raw material containing the respective element components of Al, Si, Mg, Fe, Mn, and Cr in the aforementioned predetermined proportions is prepared. Next, these raw materials are put into a melting furnace such as a closed melting furnace or a melting furnace with a forehearth to melt them. If necessary, refining treatments such as dehydrogenation treatment and inclusion removal treatment are applied to the metal solution of the aluminum alloy which is the molten raw material. Then, the molten metal of the aluminum alloy is formed into an alloy base metal ingot or the like by flowing the refined molten metal into a predetermined mold or the like and solidifying it.

In addition, after an aluminum alloy die-casting is cast using the aluminum alloy for die-casting of the present invention, solution treatment, aging treatment, and the like are performed as necessary. By performing solution treatment, aging treatment, etc. on the aluminum alloy die casting in this way, the mechanical properties of the aluminum alloy die casting can be improved.

Example

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to an Example.

In addition, each mechanical characteristic (tensile strength, elongation, 0.2% yield strength) in the predetermined Example and a comparative example was measured by the following method. That is, using a common die-casting machine (manufactured by Toshiba Machinery Co., Ltd., DC135EL) with a clamping force of 135 tons, die-casting was performed at an injection speed of 1.0 m/sec and a casting pressure of 60 MPa, and an ASTM (American Society for Testing and Material) was produced. ) standard as the reference round bar specimen. Then, the tensile strength, elongation (elongation at break), and 0.2% yield of the round bar specimen in the as-cast state were measured using a universal testing machine (AG-IS 100 kN) manufactured by Shimadzu Corporation. strength.

In addition, for component analysis of the die-casting round bar sample pieces, a solid-state emission spectrometer (Thermo Scientific (registered trademark) ARL 4460) manufactured by Thermophysics Corporation was used.

Furthermore, as the castability evaluation of each alloy, the fluidity of the molten metal at the time of die casting and the presence or absence of adhesion to the mold (adhesion resistance) were visually observed, and ○ (good) and △ (acceptable) were evaluated. , × (impossible) three grades for evaluation.

Table 1 shows the elemental composition, mechanical properties, and die-casting applicability of Examples 1 and 2 and Comparative Examples 1 to 3 of the aluminum alloys that are the object of the present invention. In addition, Comparative Example 1 corresponds to ADC12 widely used as an aluminum alloy for die casting.

Table 1

The element composition of table 1-(1) embodiment and comparative example

Table 1-(2) Physical property measurement results and castability evaluation results of Examples and Comparative Examples

According to Table 1, when comparing Examples 1 and 2, which are the alloys of the present invention, and Comparative Example 1 corresponding to ADC12, it is found that although both have the same castability (i.e., die-casting applicability), Examples 1 and 2 The elongation of the alloy is significantly higher than that of Comparative Example 1 corresponding to ADC12.

In addition, when comparing Examples 1 and 2 and Comparative Examples 2 and 3 in which only the content ratio of Mn is different, as shown in FIG. In Examples 1 and 2 of the above Mn, sticking during die casting can be effectively prevented, and the elongation and 0.2% yield strength of the alloy are improved.

Claims (6)

1. An aluminum alloy for die casting, characterized by containing Si: more than 6.00% by weight and less than 6.50% by weight, Mg: 0.10 to 0.50% by weight, Fe: 0.30% by weight or less, Mn: 0.30 to 0.60% by weight, Cr: 0.10 ~0.30% by weight, the balance contains Al and unavoidable impurities. 2. The aluminum alloy for die casting according to claim 1, wherein at least one selected from Na, Sr, and Ca is added at 30 to 200 ppm. 3. The aluminum alloy for die casting according to claim 1 or 2, wherein 0.05 to 0.20% by weight of Sb is added. 4. The aluminum alloy for die casting according to any one of claims 1 to 3, characterized in that 0.05 to 0.30% by weight of Ti is added. 5. The aluminum alloy for die casting according to any one of claims 1 to 4, characterized in that 1 to 50 ppm of B is added. 6. An aluminum alloy die-casting part, characterized in that it is formed by die-casting the aluminum alloy for die-casting according to any one of claims 1 to 5.