JP4707413B2 - Continuously cast aluminum alloy ingot and method for producing the same - Google Patents

Description

  The present invention relates to an aluminum alloy ingot as a material that matches the physical properties of an aluminum alloy cast product produced by die casting, and a method for producing the ingot by continuous casting. Specifically, an Al-Si-Cu-Mg-based aluminum alloy ingot as a material that conforms to the physical properties of an Al-Si-Cu-Mg-based aluminum alloy cast manufactured by die casting and can be easily machined, and The present invention relates to a method for producing the ingot.

Al-Si-Cu-Mg aluminum alloy die castings are mainly used for automobile parts such as cylinder blocks, which are the main parts of automobile engines. Typical aluminum alloys used in these castings are ADC12 and ADC10.
In the initial prototype test stage in the development of die casting products, die casting molds are usually used. However, it takes cost and time to manufacture molds, and it is necessary to create molds for every design change. And problems that resulted in increased time. In addition, die-cast products were expensive and could not be used in the case of products using a small amount.
Such a problem can be solved if a prototype test product can be manufactured by cutting an ingot of a material, but a commercially available general material has the same characteristics as a die cast product by cutting. In addition, it was not suitable for producing a prototype test product with few internal defects. Therefore, there is a demand for an aluminum alloy as a material that can produce a prototype equivalent to a die cast product by cutting.

  An object of the present invention is to provide Al-Si-Cu-Mg-based aluminum as a material that can be machined and adapted to the desired physical properties of an Al-Si-Cu-Mg-based aluminum alloy cast product manufactured by die casting. An object is to provide an alloy ingot and a method for producing the ingot.

  The inventors of the present invention have prepared an Al-Si-Cu-Mg alloy having a predetermined composition from an aluminum alloy ingot having the characteristics of a conventional die cast product, that is, 0.2% proof stress and thermal conductivity, and capable of being cut. The present inventors have found that an aluminum alloy block can be produced by continuous casting and the ingot can be heat-treated under predetermined conditions, and the present invention has been achieved.

That is, the first gist of the present invention, Si: 8.0~11.0wt%, Cu: 2.5~4.5wt%, Mg: 0.2~0.6wt%, Mn: 0.1~ 0.5 wt%, Fe ≦ 0.25 wt%, Cr: 0.02 to 0.20 wt%, Ti: 0.02 to 0.20 wt%, and V: 0.02 to 0.20 wt% An ingot by continuous casting of an alloy containing one or two or more elements, and the balance aluminum and inevitable impurities, the 0.2% proof stress is 145 to 170 MPa, and the thermal conductivity The ingot having a temperature of 110 to 125 W / m · ° C. is subjected to solution heat treatment at a temperature of 400 to 500 ° C. and a heat treatment time of 4 hours or more, and then subjected to an aging heat treatment at a temperature of 200 to 260 ° C. and a heat treatment time of 3 to 7 hours. continuous casting the aluminum case, characterized in that obtained by It exists in a gold ingot.

The second gist of the present invention is as follows: Si: 8.0 to 11.0 wt%, Cu: 2.5 to 4.5 wt%, Mg: 0.2 to 0.6 wt%, Mn: 0.1 to 0. 5 wt%, Fe ≦ 0.25 wt%, and Cr: 0.02 to 0.20 wt%, Ti: 0.02 to 0.20 wt%, and V: 0.02 to 0.20 wt% It contains one or more elements, a slab by continuous casting of an alloy and the balance aluminum and unavoidable impurities, the 0.2% proof stress 145～170MPa, and thermal conductivity of 110 An ingot having a temperature of 400 to 500 ° C. and a heat treatment time of 4 hours or more is subjected to a solution heat treatment at a temperature of 200 to 260 ° C. and a heat treatment time of 3 to 7 hours. Exists in the manufacturing method of continuous cast aluminum alloy ingot .

  The continuous cast aluminum alloy ingot obtained by the present invention can produce a product having the same physical properties as a die-cast product without performing die-casting. The performance can be grasped by cutting out from the ingot at the early stage of development, and the cost and time for remanufacturing the die casting mold can be saved greatly. . The aluminum alloy ingot of the present invention is a very useful material because it conforms to the physical properties of 0.2% proof stress and thermal conductivity which are important for parts around the engine such as a cylinder block.

Hereinafter, although the structure of this invention is demonstrated in detail, these are representative examples and are not restrict | limited to these. In the present specification,% of the metal element amount unit in the alloy means% by weight.
Conventionally, ADC12, ADC10, or similar Al-Si-Cu-Mg alloys have been used for die cast products that require a certain level of strength, such as cylinder blocks. These alloys have been tested by cutting. It was not suitable for producing works.
The aluminum alloy of the present invention is an aluminum alloy ingot by continuous casting as a material having physical properties equivalent to those of die cast products such as ADC12 and ADC10 and capable of being cut.

  In the present invention, in order to produce an aluminum alloy ingot having physical properties equivalent to those of ADC12, ADC10, etc. by continuous casting, 0.2% proof stress, which is a characteristic required for the alloy, is studied. By setting the amount of Mg, Mn, and Fe within a predetermined range, it is possible to match the 0.2% proof stress to the physical properties of the die cast product, and the thermal conductivity is Ti, Cr, Mn, or V. It has been found that by controlling the content within a small range, it is possible to match the physical properties of a conventional die cast product. Furthermore, when an ingot produced by continuous casting is cut as it is cast, the residual stress is high and distortion occurs. However, it is possible to remove this residual stress by subjecting the ingot to heat treatment under specified conditions. It is known that there is, and the present invention is based on these findings.

The continuous cast aluminum alloy of the present invention is obtained by heat-treating an ingot by continuous casting of an aluminum alloy containing Si, Cu and Mg as main elements, and the aluminum alloy ingot after continuous casting before the heat treatment is Its 0.2% proof stress is 145 to 170 MPa, and its thermal conductivity is 110 to 125 W / m · ° C.
And the aluminum alloy ingot after this continuous casting is Si: 8.0-11.0 wt%, Cu: 2.5-4.5 wt%, Mg: 0.2-0.8 wt%, Mn: 0.00. An alloy composed of 1 to 0.5 wt%, Fe ≦ 0.25 wt%, the balance aluminum and inevitable impurities, Cr: 0.02 to 0.20 wt%, Ti: 0.02 to 0.20 wt%, V: It is made of an alloy containing one or more elements of 0.02 to 0.20 wt%.

In the aluminum alloy of the present invention, Si, Cu. The contents of Mg, Mn, Fe, Ti, Cr, Mn, and V affect the thermal conductivity and strength (0.2% yield strength), but the amount of Fe is reduced compared to conventional ADC12 and ADC10, and Ti The amount of Cr is increasing, and the characteristics of the alloy of the present invention are manifested by the synergistic effect of containing these elements in predetermined amounts.
The Si content is set in the range of 8.0 to 11.0%, preferably 9.0 to 10.0%. If it is less than 8.0%, the thermal conductivity becomes high, and it becomes difficult to adjust the thermal conductivity. Moreover, when it exceeds 11.0%, the toughness as a raw material will fall.

The Cu content is set in the range of 2.5 to 4.5%, preferably 3.0 to 4.0%. If it is less than 2.5%, the thermal conductivity becomes high, and it becomes difficult to adjust the thermal conductivity. Moreover, when it exceeds 4.5%, the toughness as a raw material will fall.
The Mg content is set in the range of 0.2 to 0.8%, preferably 0.4 to 0.6%. If it is less than 0.2%, the thermal conductivity becomes high, and it becomes difficult to adjust the thermal conductivity. Moreover, when it exceeds 0.8%, the toughness as a raw material will fall.

Mn has the effect of improving yield strength by addition, and is added in the range of 0.1 to 0.5%, preferably 0.2 to 0.4%. If it is less than 0.1%, the yield strength improvement effect cannot be obtained. On the other hand, if it exceeds 0.50%, the toughness as a raw material is lowered.
The Fe content is controlled to be Fe ≦ 0.25%, preferably ≦ 0.20% as an impurity. If it exceeds 0.25%, the toughness as a raw material is lowered.

  Si, Cu. An alloy ingot having a 0.2% proof stress equivalent to ADC12 and ADC10 can be produced by continuous casting of aluminum containing Mg, Mn, and Fe in the above-mentioned range, but the thermal conductivity is higher than that of die cast products. Tend to be higher. In order to control and match the thermal conductivity corresponding to ADC12 and ADC10, a small amount of one or more of Cr, Ti and V is contained. These elements have a large effect of lowering the thermal conductivity when added in a small amount, and if the content is 0.20% or less, which is the upper limit value of each predetermined amount, the 0.2% proof stress, which is a physical property of the material, is achieved. Does not affect.

  If any of these elements exceeds 0.20%, the amount of crystallized substances increases and the toughness as a raw material decreases. On the other hand, if the content is less than 0.02%, the thermal conductivity is higher than that of the die cast products of ADC12 and ADC10. For this reason, at least one of Cr, Ti, and V is contained, and the content is set in the range of 0.02 to 0.20%, preferably 0.10 to 0.15%.

    Said Si, Cu. The continuously cast aluminum alloy ingot containing Mg, Mn, Fe and at least one selected from Ti, Cr, Mn, and V in a predetermined range has a 0.2% proof stress of 145 to 170 MPa. And the thermal conductivity is 110 to 125 W / m · ° C. The 0.2% proof stress of the ingot corresponds to 0.2% proof stress ± 10 MPa of the conventional ADC12 and ADC10, and the thermal conductivity is comparable to the thermal conductivity ± 5 W / m · ° C. of the ADC12 and ADC10.

When the aluminum alloy ingot produced by the continuous casting is cut as it is cast, the residual stress is high and distortion occurs, and the dimensional accuracy cannot be maintained. Therefore, in the present invention, the continuously cast aluminum alloy ingot is subjected to heat treatment to remove residual stress and prevent occurrence of distortion.
In order to prevent the occurrence of distortion, the aluminum casting alloy is subjected to solution heat treatment at a temperature of 400 to 500 ° C. and a heat treatment time of 4 hours or more, and then an aging heat treatment at a temperature of 200 to 260 ° C. and a heat treatment time of 3 to 7 hours. Is suitable.

The solution heat treatment temperature is usually 400 to 500 ° C. If the temperature is less than 400 ° C, the 0.2% proof stress is lower than that of the ADC12 and ADC10 die cast products, and if it exceeds 500 ° C, burning occurs and the 0.2% proof stress is achieved. Is lower than ADC12 and ADC10 die-cast products. A preferable solution heat treatment temperature is 430 to 470 ° C.
The solution heat treatment time is 4 hours or more, preferably 5 to 7 hours, and if it is less than 4 hours, the residual stress is not sufficiently removed and distortion after cutting occurs.

The aging heat treatment temperature is usually 200 to 260 ° C, preferably 220 to 240 ° C. If the temperature is less than 200 ° C., the residual stress is not sufficiently removed, and distortion occurs after cutting. If the temperature exceeds 260 ° C., the 0.2% proof stress is lower than that of the ADC12 and ADC10 die cast products.
The aging heat treatment time is usually 3 to 7 hours, preferably 4 to 6 hours, and in less than 3 hours, the 0.2% proof stress is lower than that of the ADC12 and ADC10 die cast products. Moreover, when it exceeds 7 hours, overaging will advance and 0.2% yield strength will fall below ADC12 and ADC10 die-cast castings.

  The aluminum alloy of the present invention may contain 0.20% or less of Sb and 0.02% or less of Sr in order to control the ingot structure as long as the physical properties are not impaired in addition to the above elements. Further, 0.01% or less of Be may be included to suppress the formation of a molten oxide film during casting.

Examples The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples unless it exceeds the gist.
Example An ingot was produced by continuous casting using an aluminum alloy (alloys No. 1 to 4) having the composition described in Table 1 below and a general material (commercial product: 5000 series). Continuous casting was carried out with a slab shape having a cross section of 150 × 300 mm. Moreover, as the aluminum for adjusting the alloy, 99.8% purity aluminum was used.
In order to show the target standard, ADC12 and ADC10 were used to manufacture a die cast product (target example).

The 0.2% proof stress, elongation and electrical conductivity of the ingot and die cast product obtained by continuous casting were measured and evaluated. Thermal conductivity shows the value converted from the measured conductivity value. These results are summarized in Table 1.
The 0.2% proof stress and elongation test were performed according to JIS Z2241, and the conductivity measurement was performed using an eddy current conductivity measuring device.

As is apparent from Table 1, the commercially available 5000 series general material of the comparative example has a 0.2% yield strength lower than that of the target example, and has a higher elongation and thermal conductivity.
Alloy No. of Comparative Example 1, the 0.2% yield strength is lower than the target example, and the thermal conductivity is high. In addition, Alloy No. In 2, the thermal conductivity is higher than the target example.
Example alloy no. 3 is ADC10 and No.3. 4 shows the physical property value equivalent to ADC12. This means that, according to the present invention, ADC10 and ADC12, which are targeted for tensile strength and 0.2% proof stress, respectively, have 0.2% proof stress ± 10 MPa and thermal conductivity within the range of ± 5 W / m · ° C. Indicates that control is possible.

Example alloy Nos. The ingot produced by the continuous casting of No. 4 was subjected to solution heat treatment at 460 ° C. for 6 hours, and then subjected to aging heat treatment at 230 ° C. for 5 hours. The amount of strain was measured for the ingot (No. 6) subjected to heat treatment and the ingot (No. 5) not subjected to heat treatment, and the results are shown in Table 2. The effect of removing the residual stress by the heat treatment was evaluated by measuring the amount of strain generated by the residual stress and comparing the amount.
As is apparent from Table 2, Comparative Example No. in which no heat treatment was performed. In Example No. 5 where heat treatment was performed on In No. 6, the residual stress is removed, and the amount of distortion is reduced to 1/20. Thereby, favorable dimensional accuracy can be ensured without generating distortion at the time of cutting.

Claims (2)

Si: 8.0 to 11.0 wt%, Cu: 2.5 to 4.5 wt%, Mg: 0.2 to 0.6 wt%, Mn: 0.1 to 0.5 wt%, Fe ≦ 0.25 wt % containing further Cr: 0.02~0.20wt%, Ti: 0.02~0.20wt %, and V: 1 or two or more elements of the 0.02～0.20Wt% Ingot by continuous casting of an alloy composed of the balance aluminum and inevitable impurities , the 0.2% proof stress is 145 to 170 MPa, and the thermal conductivity is 110 to 125 W / m · ° C. The ingot was obtained by subjecting the ingot to solution heat treatment at a temperature of 400 to 500 ° C. and a heat treatment time of 4 hours or more, and then performing an aging heat treatment at a temperature of 200 to 260 ° C. and a heat treatment time of 3 to 7 hours. Cast aluminum alloy ingot. Si: 8.0 to 11.0 wt%, Cu: 2.5 to 4.5 wt%, Mg: 0.2 to 0.6 wt%, Mn: 0.1 to 0.5 wt%, Fe ≦ 0.25 wt % containing further Cr: 0.02~0.20wt%, Ti: 0.02~0.20wt %, and V: 1 or two or more elements of the 0.02～0.20Wt% Ingot by continuous casting of an alloy composed of the balance aluminum and inevitable impurities , the 0.2% proof stress is 145 to 170 MPa, and the thermal conductivity is 110 to 125 W / m · ° C. A continuous cast aluminum alloy ingot characterized by subjecting an ingot to solution heat treatment at a temperature of 400 to 500 ° C. and a heat treatment time of 4 hours or more, and then performing an aging heat treatment at a temperature of 200 to 260 ° C. and a heat treatment time of 3 to 7 hours. Manufacturing method.