JPS623228B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing Al--Mg--Si based aluminum alloy conductors, and more specifically, the present invention relates to a method for producing Al--Mg--Si based aluminum alloy conductors, and more specifically, the present invention relates to a method for producing Al--Mg--Si based aluminum alloy conductors, and more specifically, a high conductivity, high The present invention relates to a method of manufacturing a strong aluminum alloy conductor. Demand for Al-Mg-Si alloys as conductive materials has increased rapidly in recent years, and this alloy is commonly known as No. A series of steps are required: processing, solution treatment, aging, expansion and contraction, and stabilization treatment, and there was a problem in that the production cost was high, especially since there were many heat treatment steps. On the other hand, instead of the rolling method in which the cast ingot is reheated and hot rolled as described above, a continuous casting and rolling method has recently been adopted to improve productivity. However, even in this method, a heat treatment process is required to subject the rough drawn wire after rolling to solution treatment, aging, wire drawing, and stabilization treatment, and a sufficient reduction in manufacturing costs cannot be expected. Therefore, as a measure to omit the solution treatment process,
A method has been proposed in which quenching is performed during the process of rolling an ingot using a continuous rolling mill to produce a rough wire while minimizing the precipitation of Mg and Si that are forcibly dissolved during casting. However, with this method, the Mg ₂ Si crystallized in a non-equilibrium state during casting is carried over to the rough drawing line as it is, and even if the cooling rate during rolling is increased, the Mg 2 Si crystallized around the crystallized material due to processing strain during rolling. ₂ Si condenses, which causes problems such as unstable properties compared to aluminum alloy conductors that have been hot-rolled and then solution-treated using conventional methods. The present invention has been developed based on various studies in view of the above, and has been developed by appropriately selecting the amounts of Mg and Si added to Al--Mg--Si alloys, and by making them coexist with Fe and Cu. It is possible to provide a high-strength aluminum alloy conductor with reduced manufacturing costs, and to obtain a conductor with excellent conductivity and strength by specifying the rolling temperature, etc. as manufacturing conditions when continuously casting and rolling the above alloy. This is what led to the discovery of the method of the present invention. That is, in the present invention, Mg0.3-1.0wt%, Si0.3-0.8wt%
%, Fe0.15~0.50wt%, Cu0.005~0.1wt%, balance
The alloy consisting of Al and its impurities is made into a conductor with excellent performance by continuous casting and rolling without undergoing solution treatment or aging treatment.The reason why the composition of the alloy was limited as described above is as follows. This is due to Mg and Si are elements for improving strength, and if the added amounts of both Mg and Si are less than 0.3% each, the effect will be small and the strength of the obtained conductor will be low. Also Mg
If more than 1.0% and 0.8% of Si are added, the electrical conductivity will decrease and the amount of Mg and Si precipitated in the ingot will increase, making it impossible to obtain the effect of solution treatment and greatly reducing fatigue strength. Because it does. On the other hand, Fe is an element that improves strength without significantly lowering electrical conductivity, and there is little decrease in elongation due to improvement in strength. If Fe is less than 0.15%, it has little effect on improving strength, and even if it is added more than 0.50%, no further strength improvement effect is observed, and the conductivity and elongation also decrease, resulting in the formation of coarse crystallized substances during casting. This is due to the fact that the fatigue resistance properties deteriorate significantly. Like Fe, Cu is added to improve strength; if it is less than 0.005%, no effect will be observed, and if it is more than 0.1%, fatigue resistance, ductility, and corrosion resistance will deteriorate. The present invention provides hot rolling at 400 to 550°C when continuously rolling an ingot that is continuously obtained when producing an aluminum alloy conductor using an alloy defined in the above composition range by a continuous casting and rolling method. After reducing the area by 40% or more, the aluminum is rapidly cooled to 370℃ or less, and then warm rolled from 370 to 200℃ to reduce the area by 20% or more so that the temperature at the end of rolling is 300 to 160℃. Regarding the manufacturing method of alloy conductors, the reason why the rolling temperature etc. are specified as mentioned above during continuous casting is as follows. First, when continuously rolling the ingot obtained continuously, reducing the area by 40% or more by hot rolling at 400 to 550℃ is because crystallization occurs in a non-equilibrium state during solidification.
This is to make Mg ₂ Si a solution and to prevent precipitation during rolling. In other words, if the rolling temperature is less than 400℃,
Since Mg ₂ Si will precipitate, the rolling temperature should be 400°C or higher, preferably 450°C or higher, and more preferably 500°C or higher.
Rolling at 550°C prevents precipitation during rolling, and also enables solutionization of Mg ₂ Si crystallized during solidification. However, when the temperature is higher than 550°C, although solutionization of Mg ₂ Si is advantageous, cracking of the ingot tends to occur during rolling, making it impossible to obtain a high-quality rolled material. Also, reducing the area by more than 40% destroys the casting structure and reduces Mg in the ingot.
This is to finely disperse crystallized substances such as Si and Fe to create a homogeneous rolling structure, and thereby to easily dissolve the Mg ₂ Si crystallized substances during rolling. To achieve this, it is necessary to reduce the surface area by more than 40%.
If it is less than 40%, the working degree will be insufficient for homogenizing the rolling structure and solutionizing Mg ₂ Si. Next, this is rapidly cooled to below 370℃ to prevent coarse Mg ₂ Si phase from precipitating in the subsequent rolling process and reducing the strength;
Mg ₂ Si phase precipitates, reducing the strength and fatigue resistance of the conductor. 370 in the next 370-200℃ warm rolling process
The process of reducing the surface area by 20 to 95% from a temperature of ~200℃ so that the temperature at the end of rolling is 300 to 160℃ is as follows.
This is to obtain excellent performance in both electrical conductivity and tensile strength by uniformly precipitating a fine Mg ₂ Si phase during rolling and utilizing the precipitation effect. Further, if the rolling is carried out at a rolling end temperature of 250 to 160°C, a processing effect is added and a product with even higher strength can be obtained.
The reason why the area is reduced by 20 to 95% is to generate a large number of dislocations during rolling and to uniformly precipitate a large amount of fine Mg ₂ Si phase. If this is less than 20%, the precipitation is insufficient. , more than 95%, coarse precipitates will be formed. Also, in the above, the temperature at the start of rolling was set at 370-200℃ and the temperature at the end of rolling was set at 300-160℃.
This is to precipitate the Mg ₂ Si phase, and if the starting temperature is higher than 370℃ or the rolling end temperature is 300℃.
When the temperature is higher than ℃, the Mg ₂ Si phase becomes coarse. Furthermore, when the rolling start temperature is lower than 200°C or when the rolling end temperature is lower than 160°C, precipitation of the Mg ₂ Si phase is insufficient and no precipitation effect appears. As described above, when an Al--Mg--Si alloy conductor is manufactured by the method of the present invention, the heat treatment and aging steps are omitted compared to the conventional method, so the manufacturing cost is reduced, and the conductor has high strength and high conductivity. can be obtained. In carrying out the present invention, among the rolling conditions after continuous casting, after 60-90% area reduction processing at 500-550℃, 320-
It is advantageous to reduce the surface area by 40% or more at 250°C because it can provide even better performance. Next, the present invention will be explained in more detail with reference to Examples. Example Melting 99.70% electrical aluminum ingot,
In addition, Al-25%Si master alloy, Al-6%Fe master alloy,
After melting Al-Mg-Si alloys of various compositions using Al-50% Cu master alloy and Mg units, they are cast into a cross-sectional area of 2000 mm ² using a belt-and-wheel type continuous casting machine.
of ingots were continuously cast. When this ingot is continuously rolled, a continuous rolling mill equipped with a heating and cooling device between each rolling stand and capable of freely controlling the rolling temperature is used to roll the ingot under various temperature conditions to produce rough wire. Performance was measured immediately after rolling without aging at room temperature. Table 1 shows the chemical composition and rolling conditions, and Table 2 shows the tensile strength, elongation, and electrical conductivity of the rough wire.

【table】

【table】

【table】

[Table] Examples 1 to 10 were manufactured according to the method of the present invention, and the electrical conductivity was 53% IACS or higher, and the tensile strength was 21 Kg/
Excellent performance can be obtained with mm ² or more and elongation of 7% or more. Next, as comparative examples, Nos. 11 to 26 have compositions and manufacturing conditions different from those of the present invention. Nos. 11 to 18 have rolling conditions within the range specified in the present invention, but have different alloy compositions, and Nos. 11 to 14 have Mg, Si,
Due to the lack of Fe and Cu, the conductivity is high but the tensile strength is low, and Nos. 15 to 18 have low conductivity due to excess of each element. Further, although the compositions of Nos. 19 to 26 are within the range specified by the present invention, it is not possible to obtain conductors with excellent conductivity and tensile strength because the rolling conditions such as rolling temperature and processing rate are different. In addition, rough drawn wires were manufactured using conventional continuous casting and rolling methods, rolling methods, and extrusion methods. In the conventional continuous casting and rolling method, rolling of an ingot with a cross-sectional area of 2000 mm ² was started at 450°C, the area was reduced by 94.3% without intermediate heating, and then rolling was finished at 200°C. As for the rolling method, a 50 x 50 x 500 mm ingot is heated at 450°C for 2 hours and then hot rolled to 95.4%.
In the case of the extrusion method, an ingot with a cross-sectional area of 962.5 mm ² was heated at 450° C. for 2 hours and then hot extruded to reduce the area by 94.2%. These are shown in Tables 1 and 2 as Nos. 27 to 30. Sample No. 27 was heated at 520℃ for 2 hours according to the conventional manufacturing method.
No. 30 shows what was water-cooled after time solution treatment. As shown in Table 2, all of the products manufactured by the conventional method have low strength, and the solution-treated No. 30 has an electrical conductivity of 49.5% IACS and a tensile strength of 18.9 kg/kg even after aging at room temperature for about 7 days. mm ² and lower than those shown in Example Nos. 1 to 10. As described above, by manufacturing an alloy within the composition range specified by the present invention according to the conditions specified by the method of the present invention, a conductor with even better strength and electrical conductivity can be obtained.

Claims (1)

[Claims] 1 Mg0.3~1.0wt%, Si0.3~0.8wt%, Fe0.15~
When an alloy consisting of 0.50 wt% Cu, 0.005 to 0.1 wt% Cu, residual Al and its impurities is continuously cast, and the resulting ingot is subsequently rolled, 40% reduction is achieved by hot rolling at 400 to 550°C. After the above surface reduction processing, it is rapidly cooled to below 370℃,
Producing Al--Mg--Si based alloy conductor by continuous casting and rolling method by continuing warm rolling from 370 to 200°C to reduce the area by 20% or more so that the temperature at the end of rolling is 300 to 160°C. A method for producing an aluminum alloy conductor characterized by: 2 When the obtained ingot is subsequently rolled, 400
370 after being hot rolled at ~550℃ to reduce the area by more than 40%
Rapid cooling to below ℃, followed by warm rolling from 370 to 200℃ to reduce the area by 20 to 95% until the temperature at the end of rolling reaches 300℃.
The method for manufacturing an aluminum alloy conductor according to claim 1, wherein the temperature is 160°C.