JPH0543774B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to a high conductivity aluminum alloy used as a conductive material in various electronic devices, electrical devices, etc. Conventional technology Pure aluminum-based high conductivity aluminum alloys for electrical conductivity are generally specified in JIS H4180.
1060 alloy and 1070 alloy specified by JIS H4000 are widely used. According to the JIS H4180 standard, 1060 alloy has an alloy component content of 0.25% Si (wt
%, hereinafter the same) or less, Fe0.35% or less, Cu0.05% or less, Mn0.03% or less, Mg0.03% or less, Zn0.05% or less, Ti0.03% or less, and 1070 alloy is
According to the JIS H4000 standard, the alloy component content is
Si0.20% or less, Fe0.25% or less, Cu0.04% or less,
Mn 0.03% or less, Mg 0.03% or less, Zn 0.04% or less,
Ti is defined as 0.03% or less. By the way, high conductivity aluminum alloys for electrical conductivity are generally required to have a conductivity of 61% or more in terms of IACS% (hereinafter all conductivities are expressed in IACS%). It is known that the electrical conductivity of an aluminum alloy increases if the content of impurities contained therein is reduced.
In actual conductive aluminum alloys, especially
It is cast using high-purity electrical aluminum ingots containing extremely small amounts of Cu, Mn, Ti, and V, reducing the content of impurity elements in the alloy, and reducing the amount of Fe.
The amount of Si is also regulated, generally around 0.05% Si and 0.10% Fe.
We have obtained a material with a conductivity of 61.0% or more. Problems to be Solved by the Invention As mentioned above, it is possible to obtain an aluminum alloy with high conductivity by reducing the content of impurity elements such as Cu, Mn, Ti, and V as well as the content of Fe and Si as much as possible. If you try to reduce these amounts blindly, even if the conductivity increases, you will end up increasing the cost due to problems such as the cost of the metal and the melting furnace. This invention was made against the background of the above circumstances, and aims to provide an aluminum alloy that can reliably obtain high electrical conductivity of 61% or more without unnecessarily increasing costs. It is something. Means for Solving the Problems The inventors of the present invention have repeatedly studied in detail the relationship between electrical conductivity and the composition and structure of aluminum alloys, and found that instead of simply reducing the amount of impurities,
The inventors have discovered that a high conductivity material with a conductivity of 61% or more can be obtained by controlling the amount of Fe solid solution and the amount of Si solid solution in the alloy to below specific values, respectively, leading to the creation of this invention. That is, the conductive aluminum alloy of the present invention contains 0.04 to 0.70 wt% of Fe and 0.04 to 0.25 wt% of Si, and limits unavoidable impurities to 0.02 wt% or less for each element and 0.05 wt% or less in total. , the remainder is Al, and the solid solution amount of Fe is
The amount of solid solution of Si is 400 ppm or less. Effect The electrical conductivity of an aluminum alloy with a small content of impurity elements depends on the amount of Fe dissolved in the matrix (solid solution Fe amount) and the amount of Si dissolved in the matrix (solid solution amount). The amount of solute Si has a large influence, and the amount of solute Fe has a particularly large effect. solid solution
When compared with the same amount of solid solution, Si does not have as great an effect on conductivity as solid solution Fe, but Si has a higher solid solubility than Fe, and Si dissolved in solid solution in actual alloys is Since the amount of Si in solid solution is much larger than the amount of Fe in solid solution, quantitative fluctuations are large, and therefore the amount of Si in solid solution ultimately has a large effect on conductivity. The inventors investigated the effects of the amount of solid solute Fe and Si on conductivity, and found that even if the total amount of Fe, total Si, and other impurities in the alloy are regulated to a considerable extent, The amount of solid solute Fe is
It has been found that if the amount of Si in solid solution exceeds 100 ppm or the amount of solid solution Si exceeds 400 ppm, it is difficult to stably obtain a material with a conductivity of 61% or more. And conversely Fe
Even if the total amount of Si and the total amount of Si are large to some extent, solid solution
Fe content is 100ppm or less and solid solution Si content is 400ppm
It has been found that a material with a conductivity of 61% or more can be stably obtained if the following conditions are used. Therefore, in this invention, the amount of solid solution Fe is 100 ppm or less, and the amount of solid solution Si is
It was decided to limit the amount to 400ppm or less. Further, in the aluminum alloy of the present invention, the total amount of Fe, the total amount of Si, and the amount of unavoidable impurity elements are also specified, and the reasons for these limitations will be explained below. Fe: Setting the amount of Fe to less than 0.04% causes a significant increase in cost. Furthermore, if the amount of Fe exceeds 0.7%, depending on the casting method, the amount of forced solid solution of Fe will be significantly large.
It becomes difficult to regulate the amount of solid solution Fe to 100 ppm or less. Therefore, the total amount of Fe was set within the range of 0.04 to 0.7%. Si: Setting the amount of Si to less than 0.04% causes a significant cost increase, as in the case of Fe. On the other hand, if the amount of Si exceeds 0.25%, it becomes difficult to suppress the amount of solid solution Si to 400 ppm or less. Therefore, the total amount of Si is 0.04 ~
It was set within the range of 0.25%. Unavoidable impurities: In ordinary aluminum alloys, Mn,
Ti, Cr, V, Zr, Mg, Cu, etc. are included as unavoidable impurities, but if the individual content of any impurity element exceeds 0.02% or the total content exceeds 0.05%, the above-mentioned Even if the amount of solid solution Fe and the amount of solid solution Si are regulated to 100 ppm or less and 400 ppm or less, respectively, it will be difficult to obtain a conductivity of 61% or more. Therefore, unavoidable impurity elements are regulated to 0.02% or less for each, and 0.05% or less in total. Among various unavoidable impurity elements, especially Mn,
Ti, Cr, V, and Zr have a negative effect on conductivity, so
It is desirable that each of these be 0.01% or less. As described above, in the aluminum alloy of the present invention, the amount of solute Fe is 100 ppm or less, and the amount of solute Si is less than 100 ppm.
By regulating the content of unavoidable impurity elements to 400ppm or less, and regulating the content of unavoidable impurity elements as described above,
It has become possible to stably obtain materials with electrical conductivity of 61% or higher. Specific explanation for carrying out the invention Basically, the aluminum alloy of the present invention has a solid solute Fe amount and a solid solute Si amount of 100 ppm or less, respectively.
It is important that it is regulated to 400ppm or less,
The amount of solid solute Fe can be determined by the analysis method shown in Figure 1, and the amount of solid solution Si can be determined by the amount of residual Si determined by the analysis method shown in Figure 2. It can be obtained by subtracting it from the total amount of Si. Next, a method for manufacturing the conductive aluminum alloy of the present invention will be explained. As mentioned above, in the conductive aluminum alloy of this invention, the amount of solid solution Fe and Si in the alloy is regulated, and therefore, the manufacturing method also requires measures to control the amount of solid solution. It is necessary to take measures. Therefore, basically, prior to hot rolling, an alloy ingot with the above-mentioned composition is heated at 300 to 550℃ for 0.5 to 24 hours, and after hot rolling, the processing rate is
After 50% or more cold working (cold rolling or wire drawing, etc.), final annealing is performed at 220 to 330°C.
It is desirable to apply a method of heating for 0.5 to 24 hours. Alternatively, prior to hot rolling an alloy ingot having the above composition, heat it at 300 to 550°C for 0.5 to 24 hours in the same manner as described above, and after hot rolling, the processing rate is 30.
% or more and intermediate annealing for 0.5 to 24 hours at 220 to 330°C are repeated once or twice, and then final cold working is performed to a processing rate of 50% or more,
Thereafter, as final annealing, it is desirable to apply a method of heating at 220 to 330° C. for 0.5 to 24 hours in the same manner as described above. These manufacturing methods will be explained in more detail below. First, as mentioned above, Fe0.04~0.70%, Si0.04~
A molten aluminum alloy containing 0.25% and other unavoidable impurities of 0.02% or less for each element and 0.05% or less in total is cast in a conventional manner to create an ingot. Here, conventional methods include continuous casting using the Properch method, continuous casting and rolling method, etc.
It also means DC casting of billets and slabs. In such an ingot, the amount of solid solution of Fe is at least
It exceeds 300 ppm, and most of the added amount of Si is in solid solution. Naturally, conductivity is low at such a level of Fe and Si solid solution amounts, so the solid solution Fe and Si are precipitated in the post-casting process to reduce these solid solution amounts. It is necessary to do so. The first step for this purpose is heating and hot rolling of the ingot. In other words, the ingot is heated in the temperature range of 300 to 550℃ prior to hot rolling.
This is carried out under conditions of holding for 0.5 to 24 hours, and then hot rolling is carried out. However, this heating may be performed as a soaking treatment or as a heat treatment immediately before hot rolling. In other words, the ingot is 300 ~
After soaking at 550°C for 0.5 to 24 hours, the ingot may be reheated to that temperature range and subjected to hot rolling, or the ingot may be heated at 300 to 550°C for 0.5 to 24 hours and then rolled as is. It may also be subjected to hot rolling. As mentioned above, heat before hot rolling to 300~550℃
The reason for setting the time to 0.5 to 24 hours is as follows. In other words, since the precipitation of Fe is maximum in the range of 300 to 550℃, heating in that temperature range
The amount of solid solution of Fe can be reduced. 300 here
If the temperature is below 550°C, precipitation of Fe will be insufficient and the amount of solid solution cannot be reduced sufficiently, while if it exceeds 550°C, Fe will be re-dissolved and the amount of solid solution will increase. In addition, although Si does not precipitate as metallic Si at the ingot stage, solid solution Si migrates into Al-Fe crystals by heating at a temperature within the range of 300 to 550°C, resulting in αAlFeSi, βAlFeSi, and Al ₃ Fe
(Si), and the precipitates also become αAlFeSi, etc., so that Fe precipitation and Si precipitation coexist. Here, below 300℃, the precipitation of Si is insufficient;
If the temperature exceeds 550°C, Si in the crystallized material will migrate back into the matrix, and the amount of Si solid solution in the matrix will increase. Note that if the ingot heating time is less than 0.5 hours, the effect of precipitating Fe and Si will not be sufficiently obtained.
On the other hand, heating for a long time exceeding 24 hours only unnecessarily increases costs. Therefore, the ingot heating conditions are 300-550°C for 0.5-24 hours. Of course, it is difficult to reduce the amount of solid solute Fe and Si to the target level only through the steps of ingot heating and hot rolling as described above, but the above conditions must be met before the subsequent treatment. By heat treatment at
Unless the solid solution levels of Fe and Si are lowered to appropriate levels, it will be difficult to lower them to the final target level. After hot rolling, cold working such as cold rolling and cold drawing is performed, and then final annealing is performed. In this case, the cold working is performed at a processing rate of 50% or more, and the final annealing is performed at 220 to 330°C. Heat for 0.5 to 24 hours at a temperature within the range of . These cold rolling and final annealing conditions are also important for promoting the precipitation of Fe and Si and reducing the amount of solid solution thereof. In other words, dislocations are important as precipitation sites for Fe and Si;
Increasing the dislocation density contributes to the precipitation of Fe and Si. Therefore, by increasing the degree of cold working and increasing the dislocation density, Fe,
It is possible to increase the amount of Si precipitated and reduce the amount of solid solution Fe and the amount of solid solution Si to the target level. In the final annealing after cold working, Fe and Si precipitate as AlFeSi precipitates, and Si also precipitates as metal Si. Here, if the cold working rate is less than 50%, the increase in dislocation density is insufficient, and the subsequent final annealing is sufficient.
Precipitation of Fe and Si cannot be planned. Also, the final annealing temperature is
Below 220℃, precipitation of Fe and Si is insufficient,
In particular, the precipitation of Fe becomes insufficient, and on the other hand, even if the temperature exceeds 330°C, the precipitation of Fe and Si is insufficient, and in particular, Si begins to dissolve into solid solution again, making it impossible to achieve a reduction in the amount of solid solution. If the final annealing time is less than 0.5 hours, Fe as described above,
Si is not sufficiently precipitated, and on the other hand, heating for a long time exceeding 24 hours only unnecessarily increases costs. Therefore, the processing rate of cold working is
50% or more, final annealing conditions are 220~330℃ x 0.5~
It was set as 24 hours. Note that the heating rate in the final annealing is preferably slow, and it is usually desirable to set the temperature increase rate to 100° C./hr or less. In addition, in order to further promote the precipitation of Fe and Si, primary cold working and intermediate annealing are performed once after hot rolling.
After doing this twice or repeating these two or more times,
Final cold working may be performed, followed by final annealing. In this case, it is preferable that the primary cold working is performed at a working rate of 30% or more, and the intermediate annealing is performed at 220 to 330°C for 0.5 to 24 hours. In this case as well, the final cold working is at least 50% as in the previous case, and the final annealing is also at 220~220%.
The temperature may be set at 330°C for 0.5 to 24 hours. By repeating the increase in dislocation rate through cold working and the precipitation of Fe and Si through annealing in the above temperature range,
It becomes possible to sufficiently reduce the amount of solid solution of Fe and Si. Example An alloy having the composition shown in alloy codes 1 and 2 in Table 1 was cast into a slab with a thickness of 500 mm and a width of 1200 mm using the DC casting method, and the slab was heated under the ingot heating conditions shown in Table 2. Then, it was hot-rolled according to a conventional method to obtain a hot-rolled sheet with a thickness of 4 mm. Then, the hot-rolled plate is
Cold rolling-final annealing or 1 as shown in the table
The treatment was performed according to the steps of next cold rolling - intermediate annealing - final cold rolling - final annealing. The amount of Fe solid solution and the amount of Si solid solution in the plate after final annealing was investigated using the method described above, and the electrical conductivity was also investigated. The results are also shown in Table 2.

【table】

[Table] In Table 2, condition codes A to C are those in which the amount of solid solution of Fe and the amount of solid solution of Si were made different by changing the manufacturing conditions for Alloy 1 with the same component composition, but condition code C In contrast, in condition codes A and B, the amount of Fe solid solution and the amount of Si solid solution were The dissolved amounts were below the upper limits of this invention, 100 ppm and 400 ppm, respectively, and a conductivity of 61% or more could be secured. Furthermore, condition codes D and E are obtained by changing the manufacturing conditions for Alloy 2 to make the solid solution amounts of Fe and Si different; in this case as well, in condition code E, the solid solution amounts of Fe and Si are the same as those of the present invention. On the other hand, in condition code D, the amount of Fe solid solution and the amount of Si solid solution were below 100 ppm and 400 ppm, respectively, and a conductivity of 61% or more could be secured. Effects of the Invention The conductive aluminum alloy of the present invention has the ability to reduce Fe by regulating the solid solution amount of Fe to 100 ppm or less and by regulating the solid solution amount of Si to 400 ppm or less.
A high conductivity of 61% or more can be reliably obtained without drastically reducing the total Si content or the total content of other impurity elements. Therefore, by using the conductive aluminum alloy of the present invention, a material with high conductivity can be obtained without unnecessarily increasing costs.

[Brief explanation of drawings]

Figure 1 is a flowchart showing the analytical method for measuring the amount of solid solution of Fe in aluminum alloy, and Figure 2 is a flow chart showing the amount of solid solution of Fe in aluminum alloy.
This is a flowchart showing an analysis method for measuring the amount of residual Si after removing Si.

Claims (1)

[Claims] 1 Contains 0.04 to 0.70 wt% of Fe, 0.04 to 0.25 wt% of Si, controls unavoidable impurities to 0.02 wt% or less for each element, and 0.05 wt% or less in total, and the remainder is Al. Moreover, the solid solution amount of Fe is
An aluminum alloy for conductive use, characterized by having a solid solution amount of Si of 400 ppm or less.