JPS6056785B2 - Continuous casting and rolling method for conductive aluminum or aluminum alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing conductive aluminum or aluminum alloy bar material by continuous casting and rolling, and specifically relates to an improvement in the process of continuously rolling the obtained ingot. It is.

Conventionally, conductive aluminum or aluminum alloy rough drawn wires were manufactured by rolling or extrusion methods, but recently there has been a shift to belt-and-wheel continuous casting and rolling methods, which are advantageous in terms of production efficiency and production costs. ing.

In this "belt and wheel type continuous casting and rolling method", the ingot size is small and sufficient processing cannot be performed, so the rough drawn wire has poor ductility compared to the conventional spreading method and extrusion method.

As a result, there are many wire breakages in the wire drawing process after rough wire production, resulting in higher manufacturing costs, which halves the advantage of continuous casting and rolling, which is the reduction in conductor costs due to high efficiency production. Therefore, the present inventors conducted systematic research on a method to improve the above-mentioned drawbacks of continuous casting and rolling and to obtain a rough drawn wire with high ductility at a low processing rate. Knowing that it is possible to reduce
Based on this knowledge, repeated experiments led to the present invention.

In the present invention, when continuously rolling continuously cast aluminum ingots (aluminum ingots and aluminum alloy ingots), the first stage of rolling is performed at 250 to 400°C at 40 to 90°C.
Add 5% area reduction processing, then 0 to 90% area reduction processing at 360 to 50 (generations) as the second stage intermediate heating or rolling, and then 40% area reduction processing after cooling or while adding cooling as the third stage rolling. The present invention provides a method of rolling so that the temperature at the end of rolling is 320° C. or less by adding the above-mentioned area-reducing process.

By using the rough drawn wire obtained by the above method of the present invention, the number of wire breakages after wire drawing is reduced, and the wire performance is also higher than that of the conventional continuous casting and rolling method, extrusion method, or spreading method. It is possible to obtain a conductor that is excellent in strength, ductility, flexibility, and vibration fatigue properties without being inferior in electrical conductivity.

In the method of the present invention, the rolling temperature is 2 as the first stage of rolling.
The reason for specifying that 40 to 95% reduced pressure processing be applied at 50 to 400°C is that the coarse crystallized substances are made fine by the destruction of the casting structure, and by adding processing strain, the next high-temperature rolling process is carried out. This is to promote recrystallization in the process and to obtain a fine recrystallized structure by uniformly and finely dispersing the crystallized substances that become precipitation nuclei when the supersaturated solid solution elements in the impurities precipitate. , thereby improving strength, ductility, and flexibility.

At this time, the rolling temperature is limited to a range of 250 to 400°C because if the rolling temperature is 250°C or lower, there will be little temperature rise due to subsequent heating, and if it is higher than 400°C, there will be less processing strain.

On the other hand, the degree of surface reduction. The reason for limiting the area reduction rate to 40-95% is that when the area reduction degree is less than 40%, the processing strain is small, so the destruction of the cast structure is insufficient, and the effect of refining coarse crystallized substances is small. The precipitation of precipitates also decreases, and when this degree of working is greater than 95%, the effect of refining the precipitates increases. is saturated, and the degree of area reduction per rolling is usually about 10 to 50%, so as the number of rolling increases, extra work is required to maintain the temperature of the rolled material within a predetermined temperature range. This is because heat must be supplied and there are disadvantages. The next second stage of intermediate heating or rolling is 360~5
The reason why the surface area is reduced by 0 to 90% at 00℃ is that the processed structure changed from the casting structure in the first stage becomes a fine recrystallized structure, which improves the ductility and flexibility of the material and also improves the ductility and flexibility of the material in the next low-temperature rolling process. This is to increase the work hardening ability during the process.

At that time, the rolling temperature was specified as 360 to 500℃.
At temperatures below 0°C, when rolling continuously as in the method of the present invention, the heating time is short, so recrystallization is slow and there is little improvement in ductility and flexibility; This is because the recrystallized structure becomes coarse and the strength, ductility, and flexibility decrease, and the solid solubility limit of impurities becomes wider, so the amount of solid solution increases and the electrical conductivity decreases.

In addition, the degree of area reduction is defined as 0 to 90% in this article, but 0% area reduction means that only intermediate heating is performed without rolling, and in this case, the degree of area reduction is 0% to 90%. Following rolling, in the second stage intermediate heating is performed at 360 to 500°C, and then the third stage of rolling begins. As mentioned above, this second stage is to advance recrystallization in order to improve the ductility and flexibility of the wire, and the recrystallization progresses sufficiently through rolling in the first stage and intermediate heating in the second stage. However, if recrystallization is not sufficient or to obtain an even finer recrystallized structure, high-temperature rolling may be used instead of the above intermediate heating. It is necessary to do this.

That is, by applying hot working at a temperature of 360 to 500°C, a rough drawn wire with excellent saw layer ductility, flexibility, and strength can be obtained through a repeated process of processing strain and recrystallization. At that time, even if the degree of area reduction was increased to more than 90%, no improvement effect was observed for the improvement of the above properties, and the rolling temperature was increased from 360 to 360%.
In order to maintain the temperature at 500°C, extra heat must be supplied, which is not advantageous from an economic standpoint. Next, in the third stage of rolling, after or while cooling, an area reduction process of 40% or more is applied so that the temperature at the end of rolling is 320°C or less, in order to increase strength through work hardening. This is because if the degree of area reduction is less than 40% or if the temperature at the end of rolling is higher than 320°C, work hardening will decrease and the strength will decrease. The rough drawn wire manufactured according to the method of the present invention has excellent strength, ductility, and malleability, and therefore has fewer wire breaks during the subsequent wire drawing process, and has fine precipitates, so it It is possible to obtain a wire with high work hardening ability and excellent strength, ductility, flexibility, and vibration fatigue properties.

In the practice of the present invention, in order to more effectively improve the strength, ductility, flexibility, and vibration fatigue characteristics of the conductor, the first stage of rolling is performed at a temperature of 280 to 340°C to reduce the area by 50 to 80%. Adding 400 to 470 ℃ in the second step
It is more preferable to apply an area reduction process of 30 to 80% at a temperature of 30 to 80 degrees, and further to add an area reduction process of 45% or more at a rolling end temperature of 300° C. or less in the third stage of rolling.

The present invention will be explained in detail below using examples.

Examples 1 to 5 Ordinary electrical aluminum ingot (FeO.l6wt%,
SiO. 13.5 to 8.07177 from an ingot with a cross-sectional area of 2000i according to the invention after melting of O7Wt%)! φ
Rough wires were manufactured under various rolling conditions.

In addition, when manufacturing these rough drawn wires, a rolling machine divided into two or more and a cooling or heating device installed before, before, and between these rolling machines are used, and the type of coolant (
The rolling temperature was controlled by adjusting the amount of liquid (with different cooling capacity) or the amount of liquid. The rolling conditions at this time are shown in Table 1. For comparison, the rolls produced outside the range of rolling conditions specified in the present invention are also listed as Comparative Examples 6 to 11.

As Comparative Examples 12 to 14, rough drawn wires were manufactured using the same electrical aluminum ingots by the conventional continuous casting and rolling method of the Properch type, rolling method, and extrusion method. The manufacturing conditions at this time are as follows. Comparative Example 12: Properch-type continuous casting and rolling method ingot: Electrical aluminum ingot cross-sectional area: 2000
i Rolling start temperature: 450°C Rolling end temperature: 200°C Rough line dimension: 9.5wnφ Comparative example 13: Rolling method ingot: Electrical aluminum ingot cross-sectional area: 2000wd! t Ingot reheating conditions: 450°C for 2 hours Rolling start temperature: 440°C Rolling end temperature: 180°C Rough line dimensions: 12w! nφ Comparative Example 14: Extrusion method ingot: Electrical aluminum ingot 1 Ingot cross-sectional area: 1962.5Tr! 1t Ingot reheating conditions: 450℃ for 2 hours Rough drawing wire size: 9.5 wmφ The number of wire breaks during wire drawing in Table 2 is 4.
．． It is expressed as the number of wire breaks per 10 tons of wire drawn when wire is drawn to 0Tfrfnφ.

The torsion value was expressed as the number of twists required to twist in one direction at a gauge distance of 5 mm of the rough wire diameter until the wire broke.

As shown in Table 2, Examples 1 to 5 produced according to the method of the present invention have high tensile strength and high elongation. Also, the twist value is 3
The number of wire breakages when wire is drawn to a diameter of 4.0 or more is also small, which is five times or more.

On the other hand, in Comparative Example 6, the temperature in the first stage of rolling was too high, and in Comparative Example 7, the degree of area reduction was low, and the tensile strength and elongation were low.

In Comparative Example 8, the temperature in the second stage was low, so the tensile strength was high, but the elongation was low and the number of wire breaks was high, and Comparative Example 9
Since the rolling temperature is too high, impurity re-solid solution phenomenon occurs, resulting in low electrical conductivity. In Comparative Examples 10 and 11, the tensile strength was low because the degree of area reduction or the rolling temperature in the third stage of rolling was not appropriate. Moreover, the wires of Comparative Examples 12 to 14 are inferior to the wires of the present invention in terms of strength or elongation, and are also worse in terms of twist value and number of wire breaks.

Next, Table 3 shows the properties when these rough drawn wires were drawn to 4.0 WrInφ.

The fatigue strength was determined to be 1C using a Nakamura rotary bending fatigue tester.
The fatigue strength was determined up to f' times.The repeated bending test was performed by holding the test piece between rounded metal fittings of the same diameter and bending it alternately in opposite directions for 90 degrees and from a vertical position for 900 degrees. Do this once, then return to the original position and do this twice.

Next, 900 bends were repeated three times in the opposite direction, and the number of bends until breakage was measured in the same manner. Third
Examples 1 to 1 produced according to the method of the present invention as shown in the table
It can be seen that No. 5 has high tensile strength, elongation, and fatigue strength, can be repeatedly bent many times, and is excellent in flexibility.

On the other hand, Comparative Examples 6 to 11 have low tensile strength and elongation, and are inferior to Examples 1 to 5 in terms of flexibility.
Nos. 2 to 14 are inferior to those obtained by the method of the present invention in each performance.

Examples 15 and 16 This example is an example in which 500 lining metals were manufactured, in which iron and magnesium were added to electrical aluminum ingots using N-6% Fe master alloy and magnesium alone. .8
A rough drawn wire was produced by melting a Wt%Mg-0.5Wt%Fe alloy according to the method of the present invention (Example 1\16).

For comparison, cases in which rough wires were manufactured by the conventional method are also shown as Comparative Examples 17 and 18. The manufacturing conditions at this time are shown in Table 4. These rough lines and this 4. 『φ
The performance is shown in Table 5 (rough drawing performance) and Table 6. (Wire performance) Comparative Examples 19 to 21 also show cases in which wires were manufactured under the same conditions as the aluminum rough drawn wire described above by conventional continuous casting and rolling methods, rolling methods, and pressing methods.

From this, Examples 15 and 16 are Comparative Examples 17, 18 and 19.
, 2 to 21 are found to be superior in terms of tensile strength, elongation, fatigue strength, and flexibility.

As described above, by manufacturing according to the method of the present invention, it has superior strength, ductility, flexibility, and vibration fatigue properties compared to products manufactured by conventional continuous casting and rolling methods, rolling methods, and extrusion methods. conductors can be provided.

Claims (1)

[Scope of Claims] 1. When producing a bar material of conductive aluminum or aluminum alloy by continuous casting and rolling, in the first stage of rolling, the area is reduced by 40 to 95% at 250 to 400°C, After that, it is heated to 360-500℃ in the second stage of intermediate heating, and then the area is reduced by 40% or more after or while cooling in the third stage of rolling, so that the temperature at the end of rolling is 320℃ or less. 1. A continuous casting and rolling method for conductive aluminum or aluminum alloy, characterized by rolling it so that the aluminum or aluminum alloy is rolled. 2. When producing conductive aluminum or aluminum alloy bar materials by continuous casting and rolling, the first stage of rolling involves 40 to 95% reduction in area at 250 to 400°C, followed by the second stage of rolling. At 360-500℃, the area is reduced by 90% or less, and then in the third stage of rolling, after or while cooling, the area is reduced by 40% or more so that the temperature at the end of rolling is 320℃ or less. 1. A continuous casting and rolling method for conductive aluminum or aluminum alloy, characterized by rolling the aluminum or aluminum alloy.