JP6084083B2 - Aluminum alloy material for bus bar, and laser welded body of bus bar and other member using the aluminum alloy material - Google Patents

Description

  The present invention is, for example, an aluminum alloy material for a bus bar for electrically connecting a battery or an electric device in a movable body such as an electric vehicle, a hybrid vehicle, or a railway vehicle, or stationary industrial equipment such as a switchboard or a power storage system, In addition, the present invention relates to a laser welded body of a bus bar and other members using the same.

  In general, copper (Cu) alloys are mainly used for bus bars for connecting batteries and electrical equipment because of the balance between conductivity and strength, but cost reduction (Cu is more expensive than aluminum (Al) as raw material costs) In recent years, attempts to replace the bus bar material made of Cu with Al or an Al alloy have become active.

  The problem in replacing the bus bar material from Cu to Al is that the material properties such as strength and conductivity and the electrical bondability between the bus bar materials, or the electrical connection between the bus bar material and the battery or electrical equipment. Bondability (contact resistance, etc.). With regard to the joining of these bus bar materials, bolt fastening has heretofore been the mainstream, but in recent years, laser welding has been frequently used due to the fact that the contact resistance of Al is higher than that of Cu.

  Patent Document 1 proposes a method in which an Al alloy with a limited amount of additive elements Fe and Si is applied to a bus bar material, and the bus bar material is joined by laser welding. However, an Al alloy with a small amount of additive elements cannot ensure a sufficient base material strength. Therefore, there is a possibility that it may be improperly deformed due to handling during product assembly or vibration during use as a product, and there is a problem that the range of application as a bus bar is limited. In addition, the JIS standard 1000 series, 3000 series, 5000 series and 6000 series aluminum alloys are mainly used as the joining material of the bus bar material, but particularly when laser welding is performed with the 5000 series or 6000 series, cracking occurs. There was a problem that often occurred.

JP 2011-171080 A

  The present invention is an aluminum alloy material for a bus bar for connecting a battery or an electric device, which is excellent in strength, conductivity and laser weldability, and a bus bar using the same and other members. The purpose is to provide a laser welded body.

  As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by strictly adjusting the Fe content in the aluminum alloy for busbars and the surface density of the Al—Fe intermetallic compound. The present invention has been completed.

The present invention according to claim 1 includes Fe: 0.70 to 2.50 mass%, consists of the balance Al and inevitable impurities, has a conductivity of 55.0% IACS or more, and corresponds to a circle in the metal structure An aluminum alloy material for busbars characterized by the presence of 14000 / mm ² or more of an Al—Fe-based intermetallic compound having a diameter of 1 to 3 μm.

  According to a second aspect of the present invention, in the first aspect of the present invention, in the first aspect, the aluminum alloy is Ti: 0.005 to 0.30 mass% alone, or B: 0.0001 to 0.05 mass% and C: 0. Further, at least one of 0.0001 to 0.002 mass% was further contained.

  The present invention is as follows. In claim 3, the aluminum alloy material for bus bars is tempered to H1X or H2X with X being an integer of 1 to 9, and has a tensile strength of 100 to 210 MPa.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the aluminum alloy material for bus bars has a tensile strength of 80 MPa or more when tempered to O material.

  The present invention is the laser welded body of the bus bar using the aluminum alloy material according to any one of claims 1 to 4 and another member.

  According to the present invention, an aluminum alloy material for a bus bar excellent in strength, electrical conductivity, and laser weldability, and a laser welded body of a bus bar using the same and other members can be obtained.

  The aluminum alloy material for busbars according to the present invention has a predetermined Al alloy composition and electrical conductivity, and an Al-Fe-based intermetallic compound having an equivalent circle diameter of 1 to 3 μm is present in the metal structure at a predetermined surface density. To do. These will be described in detail below.

1. Al alloy composition The aluminum alloy material for bus bars according to the present invention contains Fe: 0.70 to 2.50 mass% (hereinafter, simply referred to as “%”) as an essential element, and consists of the balance Al and inevitable impurities. Further, as a selective additive element, Ti: 0.005 to 0.30 mass% alone or at least B: 0.0001 to 0.05 mass% and C: 0.0001 to 0.002 mass% One may be further contained.

Fe: 0.70 to 2.50%
Since Fe hardly dissolves in the material, it has little influence on the decrease in conductivity due to the solid solution, and is an essential element that contributes to strengthening and weldability by dispersion as an Al—Fe intermetallic compound. If the Fe content is less than 0.70%, sufficient base material strength cannot be obtained. On the other hand, if it exceeds 2.50%, a coarse Al—Fe-based intermetallic compound is formed, which makes processing difficult. The preferable content of Fe is 0.80 to 1.50%.

Ti: 0.005 to 0.30%, B: 0.0001 to 0.050, C: 0.0001 to 0.002%
Ti is dissolved in the matrix to improve the strength, and is distributed in a layered manner to exhibit the effect of preventing the progress of corrosion in the thickness direction. Further, TiB _{2 made of} Ti and B and TiC made of Ti and C act as a material for refining the ingot structure. In the present invention, Ti: 0.005 to 0.30 mass% alone, or B: 0.0001 to 0.05 mass% and C: 0.0001 to 0.002 mass% as selective additive elements. It is preferable to further contain at least one of the above. If Ti is less than 0.005%, the above effect cannot be obtained sufficiently, and if it exceeds 0.30%, sufficient conductivity cannot be obtained. If B is less than 0.0001%, the effect of the refining material may not be sufficiently obtained, and if it exceeds 0.050%, the laser absorptivity is caused by coarse aggregates of Ti-B compounds (eg, TiB ₂ ). An increase occurs, the penetration depth and beat width become non-uniform, and the stability of laser weldability deteriorates. Further, if C is less than 0.0001%, a sufficient effect of refining may not be obtained, and if it exceeds 0.002%, a coarse agglomerate of a Ti—C compound (for example, TiC) causes laser weldability. The stability of the deteriorated. In addition, the more preferable range of the said content of Ti, B, and C is Ti: 0.01-0.1%, B: 0.0005-0.005%, C: 0.0005-0.001%. is there.

  Si, Mn, Cu, and Mg will be described as inevitable impurities in the Al alloy. First, Si is a typical unavoidable impurity contained in an Al alloy because it is contained in an aluminum ingot. It is preferable to limit the amount of Si to 0.3% or less, preferably 0.1% or less. If the Si content exceeds 0.3%, a compound with Fe is likely to be formed, and a coarse crystallized product is likely to be produced, resulting in a decrease in workability. Moreover, since Si inhibits weldability, it is inappropriate to contain more than 0.3%.

Since Mn is dissolved in a large amount in the Al alloy and lowers the electrical conductivity, it is preferably regulated to 0.05% or less, preferably 0.01% or less. When Cu and Mg are in the Al alloy and are dissolved, the conductivity is lowered. Furthermore, Mg is contained in the Al alloy and inhibits weldability, and Cu lowers the corrosion resistance. Therefore, Cu and Mg are preferably regulated to 0.05% or less, preferably 0.01% or less, respectively.

  In the present invention, impurities other than Si, Mn, Cu and Mg may be further contained in an amount of 0.15% or less as a whole.

2. Conductivity The bus bar material is required to have high conductivity. In the present invention, the electrical conductivity of the aluminum alloy material for bus bars is specified to be 55.0% IACS or more. If the IACS is less than 55.0%, the conductivity required as a bus bar material becomes insufficient, and a failure that increases power loss occurs. The upper limit of the conductivity is not particularly specified, but the upper limit is naturally determined by the material. In the present invention, the upper limit is 61.0% IACS.

3. Area density of Al-Fe intermetallic compound The aluminum alloy material for a bus bar according to the present invention has 14000 pieces / mm ² or more of Al-Fe intermetallic compounds having an equivalent circle diameter of 1 to 3 µm in the metal structure. Since the Al—Fe-based intermetallic compound increases the absorption rate of the laser, the penetration depth of the aluminum alloy by the laser is increased. If the surface density is less than 14,000 pieces / mm ² , the laser absorptivity is low and the penetration depth of the aluminum alloy is not sufficient, so that it is difficult to join the bus bar materials. Further, when the surface density is less than 14000 pieces / mm ^2, the solid solution amount of Fe becomes large, and there is a high possibility that the electrical conductivity necessary for the bus bar material is less than 55.0% IACS. The upper limit of the surface density of the intermetallic compound is not particularly specified, but the upper limit is naturally determined by the composition and the manufacturing process. In the present invention, the upper limit is 50000 pieces / mm ² . The Al—Fe-based intermetallic compound refers to an intermetallic compound such as FeAl ₃ , FeAl ₆ , FeAl _m , and FeAlSi.

  Moreover, the equivalent circle diameter of the target Al—Fe-based intermetallic compound is 1 to 3 μm. An Al—Fe-based intermetallic compound having an equivalent circle diameter of less than 1 μm does not adversely affect the required characteristics of the bus bar material. Therefore, those with an equivalent circle diameter of less than 1 μm were excluded. On the other hand, Al—Fe-based intermetallic compounds having an equivalent circle diameter of more than 3 μm have a small contribution to laser weldability, so this is also excluded. The equivalent circle diameter means an equivalent circle diameter.

4). Tempering and tensile strength The aluminum alloy material for bus bars according to the present invention is tempered to H1X or H2X (X is an integer of 1 to 9) and preferably has a tensile strength of 100 to 210 MPa, preferably 130 to 170 MPa. .

  If the tensile strength of the base material is less than 100 MPa, it is not preferable because it may be deformed by vibration during handling during assembly or when used as a product. In addition, when the tensile strength of the base material exceeds 210 MPa, it is not preferable because there is a high possibility of cracking when the bus bar material is bent.

5. Tensile strength when tempered to O material The aluminum alloy material for bus bars according to the present invention preferably has a tensile strength of 80 MPa or more when tempered to O material. In the welded part and the heat-affected part in the vicinity thereof, strengthening due to processing strain disappears or decreases. Therefore, by setting the tensile strength when the tempering is O material to 80 MPa or more, a minimum strength can be secured in the welded portion as a structural material. The upper limit of the tensile strength when the material is O is not particularly specified, but the upper limit is naturally determined by the composition and the manufacturing process. In the present invention, the upper limit is 170 MPa.

6). Manufacturing method The aluminum alloy material for bus bars according to the present invention is manufactured through a casting process, a homogenizing process, a chamfering process, a hot heating preheating process, a hot rolling process, a cold rolling process, and an annealing process.

6-1. Casting process An ingot is produced by a casting process using a molten aluminum alloy adjusted to a predetermined composition. In order to achieve an electrical conductivity of 55.0% IACS or more, it is preferable to use a semi-continuous casting method (DC method) as a casting method. When an ingot is manufactured by the continuous casting method (CC method), the Fe solid solution amount becomes large and the prescribed conductivity may not be obtained.

6-2. Homogenization process The ingot produced by the casting process is subjected to a homogenization process. As the homogenization treatment conditions, heating is performed at a temperature of 520 to 620 ° C. for 4 to 10 hours, and then the cooling rate from 500 ° C. to 400 ° C. is set to 50 ° C./hour or less, preferably 30 ° C./hour or less. Thereby, the surface density of the Al—Fe-based intermetallic compound having an equivalent circle diameter of 1 to 3 μm can be set to 14000 pieces / m ² or more. When the homogenization treatment temperature is less than 520 ° C. or the heating time is less than 4 hours, the Al—Fe intermetallic compound cannot be sufficiently precipitated. On the other hand, if the homogenization temperature exceeds 620 ° C., the ingot may be melted, which is not preferable. Moreover, when heating time exceeds 10 hours, there is no problem in material characteristics, but productivity is impaired. Further, if the cooling rate exceeds 50 ° C. / time, the surface density of the Al-Fe intermetallic compound is likely to fall below 14,000 pieces / ^{m 2.}

6-3. Chamfering process and preheating process The ingot is subjected to a chamfering process before or after the homogenization treatment process to perform chamfering to remove the surface portion. When the chamfering step is performed before the homogenization treatment step, the homogenization treatment step can also serve as a preheating step for hot rolling. In this case, the hot-rolling step may be started immediately without passing through the preheating step for hot rolling after the chamfered ingot is held at the homogenization temperature for a predetermined time and then cooled to a predetermined temperature. Well, or within the range of the starting temperature of the hot rolling process and a temperature higher by 40 ° C., the hot rolling process is started after the preliminary heating process for hot rolling for 0.5 to 4 hours. Also good.

  In the case of performing the chamfering process after the homogenization treatment process, it is necessary to perform a preheating process for hot rolling after the chamfering. In this preheating step, the chamfered ingot is heated for 0.5 to 4 hours within a range of the start temperature of the hot rolling step and a temperature 40 ° C. higher than that.

  Regardless of whether the chamfering process is performed before or after the homogenization process, if the temperature of the preheating process exceeds the above range, a longer time is required to adjust to the hot rolling start temperature. Thus, productivity is impaired, and when the temperature is less than the above range, the hot rolling start temperature is not reached, which is inefficient. Further, if the preheating time is less than 0.5 hours, the entire slab cannot be heated sufficiently, so that stable hot rolling becomes difficult, and if it exceeds 4 hours, there is no problem in material properties, but productivity is impaired.

6-4. Hot rolling step The ingot temperature at the start of the hot rolling step is not particularly limited, but is preferably 350 to 520 ° C in order to perform efficient hot rolling. If this temperature is less than 350 ° C., stable hot rolling becomes difficult, and if it exceeds 520 ° C., the recrystallized grains in the hot rolling become coarse, which may cause poor appearance. In addition, when an aluminum alloy plate having a thickness of 2 mm or more is used as a bus bar material, an aluminum alloy plate (tempered H112 material or O material) after the hot rolling step is used without going through the cold rolling step described later. It is preferably used as a bus bar material.

6-5. Cold rolling step and annealing step By rolling the rolled material to the cold rolling step after the hot rolling step, it is possible to roll to a predetermined plate thickness. In particular, when the product plate thickness is less than 2 mm, it is preferable to go through a cold rolling process. Further, an annealing step may be provided during the cold rolling step or after the cold rolling step. Instead of this, an annealing step may be provided without providing the cold rolling step after the hot rolling step. Cold rolling conditions and annealing conditions are not particularly limited, and may be appropriately determined by considering the balance between the two according to the required strength and formability of the product. In the intermediate annealing or the final annealing for obtaining the O material, in order to obtain a uniform recrystallized structure, a condition of holding at 350 to 500 ° C. for 0.5 to 8 hours using a batch annealing furnace is suitable. This annealing may be performed using a continuous annealing line that is rapidly heated and cooled in some cases, but in that case, after the material temperature has reached a predetermined annealing temperature set in a suitable range of 370 to 520 ° C. The holding time is preferably 0 seconds (immediate cooling without holding) to 60 seconds. In addition, final annealing for obtaining the H2X material may be performed by appropriately selecting the conditions in order to achieve the required degree of recovery, but it is 0.5 to 8 at 150 to 280 ° C. using a batch annealing furnace. A range of conditions for holding time is preferred. However, if the total rolling reduction ratio of cold rolling without intermediate annealing or the rolling reduction ratio of cold rolling after intermediate annealing with intermediate annealing is 70% or more, it is hardened and the bendability deteriorates. Therefore, it is preferable to make it less than 70%.

7). Shape The aluminum alloy material for bus bars according to the present invention usually has a bar shape with a rectangular cross section. The rod-like thickness is preferably 0.5 to 10 mm. If the thickness is less than 0.5 mm, sufficient electrical conductivity may not be ensured. On the other hand, if it exceeds 10 mm, press formability and bending workability necessary for practical use may not be obtained. In addition, the aluminum alloy material for bus bars according to the present invention may use a hot-rolled plate or a cold-rolled plate depending on its thickness.

8). Laser welded body of bus bar using aluminum alloy material and other member A laser joined body is obtained by laser welding the bus bar using the aluminum alloy material according to the present invention and the other member. As other members, aluminum bus bars and various electric devices are used, bus bars using the aluminum alloy material according to the present invention, bus bars using the aluminum alloy material according to the present invention and other bus bars, or the present invention. It can be set as the joined body of the bus bar and various electric equipment using the aluminum alloy material which concerns. As the laser to be used, either continuous wave or pulse wave may be used. Moreover, it can replace with joining by a laser welding method and can also employ | adopt bolt fastening. Furthermore, even if one side of the bus bar using the aluminum alloy material according to the present invention is joined to another bus bar or an electric device using a laser welding method, the other side is joined to another bus bar or the like using bolting. Good.

  The present invention will be described based on the following examples. In addition, these Examples show one Embodiment of this invention, and this invention is not limited to these.

  The aluminum alloy material samples for bus bars of the present invention and comparative examples were prepared by the following five kinds of manufacturing methods. Manufacturing method (1) and manufacturing method (2) are methods for manufacturing a hot-rolled sheet, in which (1) is tempered with H112 material and (2) is tempered with O material. Manufacturing method (3) and manufacturing method (4) are methods for manufacturing a cold-rolled sheet, (3) is an O material or H2X material, and (4) is an H1X material. In addition, all the manufacturing methods (1)-(4) used the semi-continuous casting method (DC casting method), and produced the sample from the same slab. In the production method (5), a continuous casting method (CC casting method) was used.

(1) DC casting → homogenization treatment → facing → hot rolling (2) DC casting → homogenization treatment → facing → hot rolling → final annealing (3) DC casting → homogenization treatment → facing → hot Rolling → Cold rolling → Final annealing (4) DC casting → (Homogenization treatment) → Face milling → Hot rolling → Cold rolling (→ Intermediate annealing → Cold rolling)
(5) CC casting → homogenization → cold rolling (→ final annealing)

  Aluminum alloy ingots shown in Table 1 were produced by DC casting or CC casting. In Table 1, “-” indicates no addition. Tables 3, 6, 7, and 9 show the production methods of the inventive examples and the comparative examples. In addition, the numbers of the manufacturing methods in these tables are the numbers of the manufacturing methods described above. A casting process, a homogenization process, a chamfering process, a preheating process, a hot rolling process, a cold rolling process, an intermediate annealing process, and a final annealing process were appropriately performed in accordance with required characteristics.

  The electrical conductivity, tensile strength, surface density, bending test, and laser weldability of the Al—Fe intermetallic compound having a circle-equivalent diameter of 1 to 3 μm were evaluated as follows.

1. Conductivity Conductivity (% IACS) was measured by an eddy current method using a sigma tester.

2. Tensile strength Tensile strength was measured by cutting a JIS No. 5 test piece defined in JIS Z 2201 from a sample and performing a tensile test according to JIS Z 2241. Moreover, about H112, H1X material, and H2X material, the tensile strength was similarly measured after giving 400 degreeC * 2 hours annealing to the thing of a tensile test shape.

3. Area density of Al—Fe-based intermetallic compound Distribution state (area density) of Al—Fe-based intermetallic compound having a circle equivalent diameter of 1 to 3 μm present in the metal structure of the sample is measured by an optical microscope. This was obtained by analyzing with image analysis software. Note that Comparative Examples 3 to 6 and 12 to 15 were excluded from the measurement because they contained a large amount of additive elements other than Fe and a large amount of intermetallic compounds other than Al-Fe.

4). Bending test The bending test was performed by the V block method prescribed | regulated to JISZ2248. The R of the metal fittings was ½ of the plate thickness, and the angle of the V block was 90 °. What checked the crack visually was "x" (failed), and what was not able to be confirmed was set as "(circle)" (passed).

4). Laser weldability 4-1. Penetration depth Laser irradiation was continuously moved over a length of 100 mm on the sample surface, and the penetration depth in the irradiated portion was measured. The laser irradiation conditions are as follows: laser output is 2000 W, welding speed is 15 m / min, condensing diameter is 0.3 mmφ, continuous wave (CW: Continuous Wave), and termination processing is performed to reduce the output stepwise at the termination part. There wasn't. The cross section was observed with an optical microscope at three places (interval of 15 mm) of the total irradiation length, and the maximum value of the penetration depth in each cross section was measured. And it was set as the penetration depth with these arithmetic mean values. Those having a penetration depth of 1 mm or more were judged as “◯” (passed), and those less than 1 mm were judged as “x” (failed).

4-2. Weldability The weldability was evaluated by laser welding a sample, which is a material to be evaluated, with a counterpart material. The sample and the mating member were processed into a strip shape having a width of 30 mm and a length of 100 mm, the sample and the mating material were attached to each other along the width direction, and laser welding was performed over the entire length in the width direction. As the counterpart material, representative aluminum JIS alloys 1100, 3003, 5454, and 6061 (each of the alloys c, d, e, and f shown in Table 1 were rolled to the same thickness as the sample, Used). In addition to these, weldability was also evaluated between samples that were evaluation target materials. The welding conditions were a laser output of 2000 W, a welding speed of 5 m / min, a focused diameter of 0.3 mmφ, and a continuous wave (PW: Pulse Wave). In the pulse waveform, the On time was 2 msec and the Off time was 15 msec. Weldability was evaluated as follows. First, the surface of the welded portion was visually observed to check for the presence or absence of cracks on the surface of the joint. Furthermore, the cross section was observed with the optical microscope about five places (space | interval is 5 mm) of all the welding lengths, and the presence or absence of the crack in each junction cross section was investigated. In both surface observation and cross-sectional observation, no crack was generated, and “O” (passed), and one or both of the cracks were evaluated as “X” (failed).

  The evaluation results are shown in Tables 2, 4, 5, and 8. Table 2 shows tempering materials that are O materials by the manufacturing method shown in Table 3. Tables 4 and 5 show tempering H1X and H2X by the manufacturing methods shown in Tables 6 and 7, respectively. Further, Table 8 shows tempered H112 material or O material by the manufacturing method shown in Table 9. As shown in Tables 2, 4, and 8, in Examples 1 to 43 of the present invention, all evaluations were acceptable in order to satisfy the scope of the present invention.

  On the other hand, as shown in Tables 2, 5, and 8, in Comparative Examples 1 to 21, since the scope of the present invention was not satisfied, at least one of the evaluations failed.

  In Comparative Examples 1, 10, and 20, since the Fe content exceeded the upper limit, a coarse Al—Fe-based intermetallic compound was formed, the conductivity was low, and cracks occurred during the bending test.

  In Comparative Examples 2, 11, and 21, since the Fe content was less than the lower limit, the surface density of the Al—Fe-based intermetallic compound having an equivalent circle diameter of 1 to 3 μm was small. Furthermore, the penetration depth at the time of welding was unacceptable, and cracks occurred when the mating materials were 5454 and 6061 in butt welding.

  In Comparative Examples 3 and 12, it is estimated that the Fe content of the JIS 1100 alloy is less than the lower limit value, and the surface density of the Al—Fe intermetallic compound having an equivalent circle diameter of 1 to 3 μm is small. As a result, the penetration depth during welding was unacceptable. Furthermore, cracks occurred in butt welding.

  In Comparative Examples 4 and 13, it is estimated that the Fe content of the JIS3003 alloy is less than the lower limit, and the surface density of the Al—Fe intermetallic compound having an equivalent circle diameter of 1 to 3 μm is small. The penetration depth at the time of welding is good due to the presence of many intermetallic compounds other than Al-Fe, but the Mn and Cu contents exceeded the upper limit, so the conductivity is low and the counterpart in butt welding Cracks occurred when the material was other than the same type.

  In Comparative Examples 5 and 14, it is estimated that the Fe content of the JIS5454 alloy is less than the lower limit, and the surface density of the Al—Fe intermetallic compound having an equivalent circle diameter of 1 to 3 μm is small. The penetration depth at the time of welding is good due to the presence of many intermetallic compounds other than Al-Fe, but the Mn and Mg contents exceeded the upper limit, so the conductivity is low, and cracks occur in butt welding. There has occurred. In Comparative Example 14, cracks occurred during the bending test.

  In Comparative Examples 6 and 15, it is estimated that the Fe content of the JIS6061 alloy is less than the lower limit, and the surface density of the Al—Fe intermetallic compound having an equivalent circle diameter of 1 to 3 μm is small. As for the penetration depth at the time of welding, it is good because there are many intermetallic compounds other than the Al-Fe system, but the content of Si, Mn, Cu and Mg exceeds the upper limit, so the conductivity is low, Cracks occurred during butt welding. In Comparative Example 15, cracks occurred during the bending test.

  In Comparative Examples 7 and 16, the homogenization temperature after casting was as low as 480 ° C., and the treatment time was as short as 2 hours. Furthermore, the cooling rate was too high. As a result, the surface density of the Al—Fe intermetallic compound having an equivalent circle diameter of 1 to 3 μm was small, and the penetration depth during welding was unacceptable. In Comparative Example 16, the conductivity was lowered due to the influence of strong processing.

  In Comparative Example 8, since the cooling rate from 500 ° C. to 400 ° C. after the homogenization treatment was increased to 100 ° C./hour, the compound was not sufficiently precipitated, and the surface density of the Al—Fe-based intermetallic compound was decreased. It was. As a result, the penetration depth during welding was also unacceptable. Moreover, since the homogenization process was not performed in Comparative Example 17, one of the precipitation steps of the intermetallic compound was eliminated, and the surface density of the Al—Fe-based intermetallic compound was reduced. As a result, the penetration depth during welding was unacceptable.

  In Comparative Examples 9 and 19, since it was produced by continuous casting (CC method), a large amount of Fe was dissolved, and the surface density of the Al—Fe intermetallic compound having an equivalent circle diameter of 1 to 3 μm was small. As a result, the conductivity was lowered.

  In Comparative Example 18, since the tensile strength exceeded 210 MPa by strong processing, a crack was generated in the bending test, which was unacceptable.

  The aluminum alloy material for busbars according to the present invention and the laser welded body of this and other members have characteristics excellent in conductivity, strength and laser weldability.

Claims (5)

Fe: 0.70 to 2.50 mass%, consisting of the balance Al and inevitable impurities, having an electric conductivity of 55.0% IACS or more, and having an equivalent circle diameter of 1 to 3 μm in the metal structure An aluminum alloy material for a bus bar, characterized in that 14000 / mm ² or more intermetallic compounds are present.   The aluminum alloy material is Ti: 0.005-0.30 mass% alone, or at least one of B: 0.0001-0.05 mass% and C: 0.0001-0.002 mass%. Furthermore, the aluminum alloy material for bus bars of Claim 1 which contains.   The aluminum alloy material for bus bars according to claim 1, wherein X is an integer of 1 to 9 and is tempered to H1X or H2X and has a tensile strength of 100 to 210 MPa.   The aluminum alloy material for bus bars according to any one of claims 1 to 3, wherein the aluminum alloy material is tempered into an O material and has a tensile strength of 80 MPa or more.   A laser welded body of a bus bar using the aluminum alloy material according to any one of claims 1 to 4 and another member.