DE102018001585A1 - Rib material made of aluminum alloy for heat exchangers - Google Patents

Abstract

It is intended that a heat exchanger fin material made of an aluminum alloy, in which deformation of the fin material is reduced and which has excellent sag resistance in a range of 400 ° C to 580 ° C, is equal to or lower than a temperature at which a filler alloy is used The finned material made of an aluminum alloy for heat exchangers contains 1.0 to 2.0 mass% of Mn, 0.7 to 1.4 mass% of Si, and 0.05 to 0 , 3 mass% Fe and one or more species of 0.05 to 0.3 mass% Zr, 0.05 to 0.3 mass% Cr and 0.05 to 0.3 mass% V wherein the balance is Al and unavoidable impurities, wherein the number density of intermetallic compounds having a circle equivalent diameter of 0.025 to 0.4 μm before soldering heat is 3.0 x 10 particles / mm or more, the amount of Mn in solid solution 0.3 mass% or less and the respective amount of Zr, Cr and V in solid solution is 0.1 mass% or less, and the recrystallization completion temperature during a temperature rise at the time of soldering heating is 450 ° C or less.

Description

The present invention relates to a fin material made of an aluminum alloy for heat exchangers, which is preferably used as a fin material for heat exchangers, e.g. Radiator, heater cores, condenser and intercooler, is used.

An aluminum alloy has a low weight and excellent strength, and further has excellent heat conductivity, and thus has been preferred in materials for heat exchangers such as heat exchangers. Condenser, radiator, heater cores and intercooler used.

Such heat exchangers are conventionally assembled with other members by brazing a rib of aluminum formed in a corrugated shape by corrugating. As a fin material made of an aluminum alloy, pure aluminum-based alloys having excellent heat conductivity, such as aluminum oxide, have been generally used. JIS 1050 alloys, and Al-Mn-based alloys having excellent strength and buckling resistance, e.g. JIS 3003 alloys, used. Moreover, a technique for preventing corrosion of a pipe of a heat exchanger by electrochemically reducing the potential of a fin material for preferentially corroding the fin material by a sacrificial anode effect has been generally used.

In recent years, there is an increasing demand for size reduction, weight reduction and performance improvement for heat exchangers. Along with this need, it was also necessary to reduce the thickness of a fin material made of an aluminum alloy. In order to realize such a reduction in thickness, higher strength is required to prevent deformation and buckling of a fin material during a manufacturing process of a heat exchanger.

For example, Patent Document 1 describes a method for producing a material that enhances coarsening of recrystallized grains after soldering heating to improve the high temperature buckling resistance.

[Patent Document 1] Japanese Patent Publication No. H02-115336-A

If a fin material is bent and deformed before reaching a temperature of about 550 to 580 ° C, which is a temperature at which a filler alloy begins to melt, it may result in a lack of bonding of the fin and other elements. Therefore, in a high-temperature region at the time of soldering heating, a heat resistance (buckling resistance) that does not cause buckling and deformation in the rib is required.

Although, according to Patent Document 1, the coarsening of recrystallized grains after soldering heating is enhanced, only a slight effect on the deformation suppression of the fin material is achieved before a temperature at which a filler alloy melts at the time of soldering, because the size of crystallized grains affects the kink resistance of the fin only after the filler alloy has melted at a temperature of about 600 ° C.

Accordingly, it is an object of the present invention to provide a heat exchanger fin material made of an aluminum alloy in which deformation of the fin material is suppressed and which has excellent sag resistance in a range of 400 ° C to 580 ° C, equal to or lower than a temperature in which a filler alloy melts at the time of soldering.

The present inventors have intensively studied to solve the above-mentioned problem and found that a fin material made of an aluminum alloy for heat exchangers which can solve the above problem by using an aluminum alloy material having a specific component and by setting a homogenization treatment condition, a hot rolling condition, a tempering condition and a cold rolling condition, and obtaining a preferable distribution of intermetallic compounds and the amount of a solid solution.

That is, the present invention provides (1) a fin material made of an aluminum alloy for heat exchangers comprising 1.0 to 2.0 mass% of Mn, 0.7 to 1.4 mass% of Si and 0.05 to 0.3 mass% Fe and one or more species of 0.05 to 0.3 mass% Zr, 0.05 to 0.3 mass% Cr and 0.05 to 0, Contains 3 mass% V, the remainder being Al and unavoidable impurities, wherein
the number density of intermetallic compounds having a circle equivalent diameter of 0.025 to 0.4 μm before soldering heating is 3.0 x 10 ⁶ particles / mm ² or more,
the amount of Mn in solid solution is 0.3 mass% or less and the respective amount of Zr, Cr and V in solid solution is 0.1 mass% or less, and
the recrystallization completion temperature during a temperature rise at the time of soldering heating is 450 ° C or less.

The present invention provides (2) a fin material made of an aluminum alloy for heat exchangers (1), which further has one or more kinds of Zn, 0.01 to 0.5 mass% 0.4 mass% of Cu, 0.01 to 0.3 mass% of Mg and 0.05 to 0.3 mass% of Ti.

The present invention provides a fin material made of aluminum alloy for heat exchangers in which deformation of the fin material is suppressed and which has excellent sag resistance in a range of 400 ° C to 580 ° C, which is equal to or lower than a temperature is where a filler alloy melts at the time of soldering.

A fin material made of aluminum alloy for heat exchangers of the present invention contains 1.0 to 2.0 mass% of Mn, 0.7 to 1.4 mass% of Si and 0.05 to 0.3 mass% Fe and one or more species of 0.05 to 0.3 mass% Zr, 0.05 to 0.3 mass% Cr and 0.05 to 0.3 mass% V, wherein the remainder being Al and unavoidable impurities, wherein
the number density of intermetallic compounds having a circle equivalent diameter of 0.025 to 0.4 μm before soldering heating is 3.0 x 10 ⁶ particles / mm ² or more,
the amount of Mn in solid solution is 0.3 mass% or less and the respective amount of Zr, Cr and V in solid solution is 0.1 mass% or less, and
the recrystallization completion temperature during a temperature rise at the time of soldering heating is 450 ° C or less.

The fin material made of an aluminum alloy for heat exchangers of the present invention contains Mn, Si and Fe and one or more kinds of Zr, Cr and V, the balance being Al and unavoidable impurities. The fin material made of an aluminum alloy for heat exchangers of the present invention may contain a total of 0.05 mass% or less and 0.15 mass% or less of unavoidable impurities.

The content of Mn in an aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention is 1.0 to 2.0 mass%, and preferably 1.2 to 1.8 mass%. Mn is an essential element for increasing the strength in a temperature range of 400 ° C to 580 ° C before the filler alloy melts at the time of soldering. Mn, together with Si, produces Al-Mn-Si (Fe) -based intermetallic compounds, contributes to dispersion hardening and improves material strength at a high temperature. If the content of Mn in the aluminum alloy is below the above range, the effects are not sufficiently exerted. When the content of Mn in the aluminum alloy exceeds the above range, coarse intermetallic compounds are produced at the time of casting, the rolling properties are deteriorated, and the production of a sheet material becomes difficult.

The content of Si in the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention is 0.70 to 1.4 mass%, and preferably 0.85 to 1.3 mass%. Si is an essential element for increasing the strength in a temperature range of 400 ° C to 580 ° C before the filler alloy melts at the time of soldering. Si, together with Al, produces Al-Mn-Si (Fe) -based intermetallic compounds, contributes to dispersion hardening and improves material strength at a high temperature. If the content of Si in the aluminum alloy is below the above range, the effects are not sufficiently exerted. When the content of Si in the aluminum alloy exceeds the above range, the amount of Si in solid solution increases and the melting point decreases, and it may be sensitive to melting of a fin material due to excessive solder erosion at the time of soldering heating.

The content of Fe in the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention is 0.05 to 0.3 mass% and preferably more than 0.1 mass% and 0.3 mass% or less. When the content of Fe in an aluminum alloy exceeds the above-mentioned range, a large number of coarse crystallized products (intermetallic compounds) generated at the time of casting are produced, and as a result, precipitation of fine intermetallic compounds is reduced. Accordingly, a desired strength in a temperature range of 400 to 580 ° C can not be obtained and a self-corrosion resistance of the fin material can be deteriorated because the crystallized products (intermetallic compounds) generated at the time of casting become a corrosion starting point. When the content of Fe in an aluminum alloy is less than 0.05 mass%, the amount of Mn in solid solution increases and the melting point decreases, and it may be sensitive to melting of the fin material due to solder erosion at the time of soldering heating , In addition, it causes an increase in cost because a high-purity aluminum metal must be used.

The aluminum alloy of the fin material made of aluminum alloy for heat exchangers of the present invention contains, in addition to Mn, Si and Fe, one or more kinds of Zr, Cr and V.

When the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention comprises Zr, the content of Zr is 0.05 to 0.3 mass%, and preferably 0.1 to 0.2 mass%. Zr is deposited in the form of Al-Zr-based intermetallic compounds and increases the deformation resistance at a high temperature. When the content of Zr is below the above range, such effects can not be obtained. When the content of Zr exceeds the above range, it becomes susceptible to formation of very large intermetallic compounds and the plastic processability is lowered.

When the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention comprises Cr, the content of Cr is 0.05 to 0.3 mass%, and preferably 0.1 to 0.2 mass%. Cr is precipitated in the form of Al-Cr-based intermetallic compounds and improves the deformation resistance at a high temperature. If the content of Cr is below the above range, such effects can not be obtained. When the content of Cr exceeds the above range, it becomes susceptible to formation of very large intermetallic compounds and the plastic processability is lowered.

When the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention includes V, the content of V is 0.05 to 0.3 mass%, and preferably 0.1 to 0.2 mass%. V is precipitated in the form of Al-V based intermetallic compounds and improves the deformation resistance at a high temperature. If the content of V is below the above range, such effects can not be obtained. When the content of V exceeds the above range, it becomes susceptible to formation of very large intermetallic compounds and the plastic processability is lowered.

In the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention, the amount of Mn in solid solution is 0.3 mass% or less, and the respective amount of Zr, Cr and V in solid solution is zero , 1 mass% or less. When the amount of Mn in solid solution exceeds 0.3 mass%, the recrystallization due to precipitation of intermetallic compounds during soldering heating is retarded and this leads to a deterioration in sag resistance. When the amount of Zr in solid solution exceeds 0.1 mass%, recrystallization due to precipitation of Al-Zr-based intermetallic compounds during soldering heating is retarded, resulting in deterioration of sag resistance. When the amount of Cr in solid solution exceeds 0.1 mass%, recrystallization due to precipitation of Al-Cr-based intermetallic compounds during soldering heating is retarded, resulting in deterioration of sag resistance. When the amount of V in solid solution exceeds 0.1 mass%, recrystallization due to precipitation of Al-V-based intermetallic compounds during soldering heating is retarded, resulting in deterioration of sag resistance. "The respective amount of Zr, Cr and V in solid solution is 0.1 mass% or less" indicates that: when the aluminum alloy according to the fin material made of aluminum alloy is used for heat exchangers of the present invention by Zr, Cr and V only Zr contains, the amount of Zr in solid solution is 0.1 mass% or less, when the aluminum alloy of Zr, Cr and V contains only Cr, the amount of Cr in solid solution is 0.1 mass% or less, when the aluminum alloy of Zr, Cr and V contains only V, the amount of solid solution V is 0.1 mass% or less, when the aluminum alloy of Zr, Cr and V contains Zr and Cr, the amount of Zr is more solid Solution is 0.1 mass% or less and the amount of Cr in solid solution is 0.1 mass% or less, when the aluminum alloy of Zr, Cr and V contains Zr and V, the amount of Zr in solid solution is 0 Is 1 mass% or less and the amount of solid solution V is 0.1 mass% or less, when the aluminum alloy of Zr, Cr and V contains Cr and V, the amount of Cr in solid solution is 0.1 Mass% or less and the amount of V in solid solution is 0.1 mass% or less when the aluminum alloy is used g of Zr, Cr and V Zr, Cr and V, the amount of Zr in solid solution is 0.1 mass% or less, the amount of Cr in solid solution is 0.1 mass% or less and the amount of V in solid solution is 0.1 mass% or less.

The aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention may further contain one or more species of 0.5 to 4.0 mass% Zn, 0.01 to 0.4 mass%. Cu, 0.01 to 0.3 mass% Mg and 0.05 to 0.3 mass% Ti.

The aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention may further contain 0.5 to 4.0 mass% of Zn. Zn provides a sacrificial anode effect by reducing the potential of the fin material. When the content of Zn in the aluminum alloy is below the above range, the effects are not sufficiently exerted. If the content of Zn exceeds the above range, the self-corrosion resistance of the fin material may be deteriorated.

The aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention may further contain 0.01 to 0.40 mass% of Cu. Cu has the function of increasing the strength of the fin material at a high temperature by solid solution strengthening. If the content of Cu in the aluminum alloy is below the above range, the effects are not sufficiently exerted. When the content of Cu exceeds the above-mentioned range, the potential of the fin material becomes high and the sacrificial anode effect can be deteriorated.

The aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention may further contain 0.01 to 0.30 mass% of Mg. Mg has a function to increase the strength of the fin material at a high temperature by solid-solution hardening. If the content of Mg is below 0.01 mass%, the effects are not sufficiently exerted. When the content of Mg is over 0.30 mass%, solder failure may occur due to a reaction with a flux.

The aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention may further contain 0.05 to 0.30 mass% of Ti, and preferably 0.1 to 0.2 mass% of Ti. Ti increases the strength by solid solution hardening. If the content of Ti in the aluminum alloy is below the above range, such effects may not be obtained. When the content of Ti exceeds the above-mentioned range, the aluminum alloy becomes susceptible to the formation of very large intermetallic compounds and the plastic workability is deteriorated.

In the aluminum alloy according to the fin material made of an aluminum alloy, for heat exchangers of the present invention, the number density of intermetallic compounds having a circle equivalent diameter of 0.025 to 0.4 μm is 3.0 x 10 ⁶ particles / mm ² or more, preferably 3 , 8 x 10 ⁶ particles / mm ² or more, and more preferably 4.0 x 10 ⁶ particles / mm ² or more.

Although dispersion hardening and solid solution hardening are considered to increase the high temperature strength of a fin material made of an aluminum alloy during soldering heating, the inventors of the present invention have found that the high temperature strength can be improved by ensuring dense intermetallic compounds for dispersion hardening at a high temperature during soldering heat, can be improved. Although some of the intermetallic compounds (Al-Mn-Si (Fe) - and Al-Zr-based, Al-Cr-based and Al-V-based compounds) become solid solution during soldering heating, the distribution is based of intermetallic compounds remaining during soldering heating, on the distribution of intermetallic compounds before soldering. As a result, a material in which intermetallic compounds are densely distributed before soldering heating has the distribution of intermetallic compounds which remain densely distributed during soldering heating, and contributes to the improvement of the high-temperature strength. The inventors of the present invention have found that when the number density of intermetallic compounds having a circular equivalent diameter of 0.025 to 0.4 μm is below the above-mentioned range, precipitations at a high temperature during soldering heating are small, the effect of dispersion hardening is insufficient and a sufficient high-temperature strength can not be ensured during the soldering heating. The higher the number density of the intermetallic compounds described above, the higher the density of the remaining intermetallic compounds, and this leads to increased high-temperature strength. Accordingly, although the upper limit of the number density of intermetallic compounds having a circular equivalent diameter of 0.025 to 0.4 μm is not particularly limited, it is normally 2.0 x 10 ⁷ particles / mm ² or less.

In the aluminum alloy fin stock for heat exchangers of the present invention, the recrystallization completion temperature during a temperature rise at the time of soldering heating is 450 ° C or less, and preferably 400 ° C or less. When a processed structure of the fin material is recovered and recrystallized during soldering heating, deformation may take place due to diffusion of voids by dislocation and the like. When the recrystallization completion temperature exceeds the above-mentioned range, the deformation of the fin material accompanied with the above-described recrystallization becomes considerable, and the sag resistance during the soldering heating is lowered.

For setting the recrystallization completion temperature to 450 ° C or less during a temperature rise at the time of soldering heating, the amount of Mn in solid solution in the aluminum alloy according to the fin material made of an aluminum alloy for heat exchangers of the present invention is set to 0.3 mass%. % or less, and preferably set to 0.2 mass% or less. When the amount of Mn in solid solution exceeds 0.3 mass%, recrystallization due to precipitation of Al-Mn-Si (Fe) -based intermetallic compound during soldering heating may be retarded. The amount of Zr in solid solution is set to 0.1 mass% or less. When the amount of Zr in solid solution exceeds 0.1 mass%, recrystallization due to precipitation of Al-Zr-based intermetallic compounds during soldering heating may be retarded. The amount of Cr in solid solution is set to 0.1 mass% or less. When the amount of Cr in solid solution exceeds 0.1 mass%, the recrystallization due to precipitation of Al-Cr-based intermetallic compounds during soldering heating may be retarded. The amount of V in solid solution is set to 0.1 mass% or less. When the amount of V in solid solution exceeds 0.1 mass%, the recrystallization due to precipitation of Al-V-based intermetallic compound during soldering heating may be retarded.

In the fin alloy made of an aluminum alloy for heat exchangers of the present invention, the number density of intermetallic compounds having a equivalent circular diameter of 0.025 to 0.4 μm before soldering heat and the amount of Mn, Zr, Cr and V in solid solution become predominant in the operations from casting to hot rolling and in the subsequent process of tempering. Accordingly, in order to improve the material strength at a high temperature during soldering heating, it is necessary to set the conditions of these operations and the number density of intermetallic compounds having a equivalent circular diameter of 0.025 to 0.4 μm before the soldering heat and the amount of Mn, Zr, Cr and Adjust solid solution V to be within the scope of the present invention.

As for a method for producing a fin material made of an aluminum alloy for heat exchangers of the present invention, first, a billet is prepared by casting a molten aluminum alloy corresponding to the composition described above. Then, in order to provide excellent high temperature and kink resistance, it is preferable to suppress the precipitation of coarse intermetallic compounds and not to perform homogenizing treatment on the ingot obtained by casting in view of increasing the number density.

Next, the ingot obtained by casting is hot rolled. Incidentally, for finally obtaining an aluminum alloy having the number density of intermetallic compounds having a equivalent circular diameter of 0.025 to 0.4 μm, it is 3.0 × 10 ⁶ particles / mm ² or more, preferably 3.8 × 10 ⁶ particles / mm ² or more and more preferably 4.0 × 10 ⁶ particles / mm ² or more, and the amount of Mn in solid solution of 0.3 mass% or less and the respective amount of Zr, Cr and V in solid solution to 0.1 mass% or less, the range of the heating temperature before hot rolling to 380 to 480 ° C and more preferably 400 to 460 ° C set. When the heating temperature before hot rolling exceeds the above-mentioned range, the precipitated intermetallic compounds become coarse, sufficient dispersion hardening by the intermetallic compounds can not be obtained during soldering heating, and the high-temperature strength is deteriorated. If the heating temperature before the hot rolling is below the above-mentioned range, a high-performance hot rolling mill becomes necessary because the heat resistance of the material at the time of rolling is high, and further, rolling becomes difficult due to excessive ear cracking at the time of rolling , Although the hot rolling is started at the heating temperature before the above-described hot rolling, it is preferable to set the temperature of the hot rolled sheet to 360 to 480 ° C on the hot rolling stage until the total rolling ratio after the start of hot rolling reaches 50%. The processing, the recovery and the recrystallization in the rolled sheet take place successively during hot rolling and promote precipitation of intermetallic compounds on a partial grain boundary formed in the process of recovering. When the temperature of the hot rolled sheet on the hot rolling step exceeds the above range, intermetallic compounds grow and the number density becomes low, and a predetermined density of intermetallic compounds is not obtained, resulting in a reduction in material strength at a high temperature. When the temperature is lower than the above range, precipitation of intermetallic compounds becomes small, and also the amount of Zr, Cr and V in solid solution becomes excessive, and a predetermined number density of intermetallic compounds and a predetermined amount of solid solution can not be obtained become.

Next, the hot rolled sheet obtained by hot rolling is cold rolled. In cold rolling, a total of one or two intermittent anneals may be performed until the end sheet thickness is obtained, or final annealing may be performed after the last cold rolling. The tempering temperature during this time is preferably 100 to 280 ° C. When the tempering temperature exceeds the above range, the precipitated intermetallic compounds become coarse and the number density becomes small. Accordingly, in the temperature range of 400 to 580 ° C, before the filler alloy melts during brazing, sufficient dispersion strength by the intermetallic compounds can not be obtained, and the material strength is lowered. If the tempering temperature is lower than the above-mentioned range, the effect of tempering is not obtained and this is uneconomical.

The fin material made of an aluminum alloy for heat exchangers of the present invention is preferably used as a fin for heat exchangers. For example, the finned material made of an aluminum alloy for heat exchangers of the present invention, after being molded, is assembled into a fin shape by corrugating with heat exchange elements, e.g. a flow passage forming part, a head plate and the like, and subjected to a soldering heat, whereby a heat exchanger is obtained.

The above-mentioned heat exchanger is assembled by arranging the fin material on an outer surface of the flow passage forming member with both end portions attached to the top plate. Next, the superposed portions of both ends of the flow passage forming member, the fin material and the outer surface of the flow passage forming member and both ends of the flow passage forming member and the head plate are simultaneously connected by a single soldering heat. The method of soldering may be fluxless soldering, Nocolok soldering and vacuum brazing.

EXAMPLES

Next, the present invention will be described in more detail based on examples of the present invention and comparative examples, but the invention is not limited thereto.

Aluminum alloys having the chemical compositions shown in Table 1 were melted by a usual method, blocks were formed by semi-continuous casting, and both surfaces thereof were finished and finished. The thickness of each of the sized blocks was 400 mm. These ingots of aluminum alloys were not subjected to homogenization treatment and subjected to heating with a holding time of 6 hours at a temperature shown in Table 2 before hot rolling. Then, the hot rolling was started at this temperature and the hot rolling was carried out under the conditions shown in Table 2 until finally a thickness of 3.0 mm was obtained. Thereafter, cold rolling was performed, and in the course of which an intermediate annealing was performed with a holding time of 3 hours at the temperature shown in Table 2. Then, cold finish rolling was performed, and a fin material having a sheet thickness of 0.07 mm was obtained. The present invention is not limited to the sheet thickness of the finished sheet of the present example. The thickness of the finished sheet is generally about 0.03 to 0.10 mm. [Table 1] Alloy no. Chemical compositions (% by mass) Mn Si Fe Zr Cr V Zn Cu mg Ti example 1 1.5 1.0 0.15 0.2 - - 1.5 - - - 2 1.4 1.4 0.2 - 0.2 - 4.0 - 2.0 - 3 1.3 0.7 0.15 - - 0.1 1.0 - - - 4 2.0 1.0 0.15 0.1 0.1 - 0.5 0.20 - - 5 1.0 1.3 0.15 - - 0.2 2.0 - 0.10 - 6 1.6 1.2 0.1 0.3 0.05 - 1.0 - - - 7 1.2 1.0 0.2 0.05 - 0.3 2.0 - - - 8th 1.4 1.0 0.15 - 0.3 0.05 1.0 - - - 9 1.2 0.9 0.2 - 0.1 - - - 0.30 0.05 10 1.4 1.2 0.05 0.2 - - 0.5 - 0.10 - 11 1.6 1.3 0.12 - - 0.2 4.0 - - - 12 1.6 0.85 0.2 - 0.1 0.1 0.5 0.30 - - 13 1.8 1.2 0.2 - 0.2 - 1.0 0.10 - - 14 1.2 1.1 0.15 0.1 - - 3.0 - 0.10 0.30 15 1.4 1.2 0.3 - 0.2 - 0.5 0.01 - - 16 1.6 1.1 0.2 - - 0.1 2.0 0.40 0.05 - Comparative example 17 2.4 1.2 0.2 - 0.2 - - - - - 18 0.7 0.9 0.2 - 0.2 - 1.0 - - - 19 1.4 1.6 0.15 0.1 - - 1.0 - - - 20 1.2 0.6 0.2 - - 0.1 2.0 - - - 21 1.4 1.2 0.5 - - 0.2 1.0 - - - 22 1.6 1.3 0.02 0.2 - - 2.0 - - - 23 1.2 1.3 0.2 0.4 - - 1.0 - - - 24 1.4 1.6 0.15 - 0.4 - 1.0 - - - 25 1.2 1.0 0.2 - - 0.4 3.0 - - - 26 1.4 0.9 0.2 - 0.1 - 0.5 - - 0.4 27 1.6 1.1 0.12 0.1 - - 4.5 - - - 28 1.2 1.3 0.2 0.1 - - 2.0 0.6 - - 29 1.4 1.0 0.3 - - 0.1 2.0 - 0.4 - [Table 2] Example no. Alloy no. homogenization Hot rolling conditions Heating temperature at intermediate tempering (° C) Heating temperature before hot rolling (° C) Temperature of the hot-rolled sheet at the time of reaching a sheet thickness of 28 mm (° C) example 1 1 none 440 400 180 2 2 none 440 400 180 3 3 none 400 380 180 4 4 none 420 380 180 5 5 none 420 380 180 6 6 none 460 400 180 7 7 none 440 380 140 8th 8th none 380 360 180 9 9 none 480 420 160 10 10 none 480 440 200 11 11 none 460 420 180 12 12 none 460 420 180 13 13 none 400 360 180 14 14 none 440 400 180 15 15 none 480 440 160 16 16 none 440 400 180 17 1 none 480 440 180 18 1 none 420 400 180 19 1 none 380 360 180 20 9 none 440 400 180 21 10 none 380 360 180 22 11 none 440 400 160 23 12 none 420 380 180 24 13 none 440 400 180 25 14 none 460 420 160 26 16 none 460 420 160 Comparative example 27 1 500 ° C × 10 hours 440 400 200 28 11 none 500 440 220 29 6 none 400 320 140 30 2 none 380 320 180 31 5 none 400 320 180 32 9 none 460 400 320 33 1 none 360 Canceled during hot rolling 34 17 none 460 Canceled during hot rolling 35 18 none 400 360 160 36 19 none 440 400 180 37 20 none 420 400 140 38 21 none 400 380 220 39 22 none 440 390 140 40 23 none 460 420 Canceled during hot rolling 41 24 none 460 410 Canceled during hot rolling 42 25 none 460 420 Canceled during hot rolling 43 26 none 460 410 Canceled during hot rolling 44 27 none 400 370 180 45 28 none 440 400 220 46 29 none 440 400 180

The number density of intermetallic compounds before the soldering heating and the amount of Mn in solid solution were measured with respect to the fin material obtained in the manner described above. As properties during the soldering heating, it was confirmed by a tensile test of the material heated up to 400 ° C whether recrystallization of the fin material at the time of reaching 400 ° C during the soldering heating was completed or not, and the amount of hanging of the fin material up to 550 ° C was measured by a sag test. In addition, a solderability test and a corrosion resistance test were carried out. Their results are shown in Table 3 and Table 4.

Density of intermetallic compounds before soldering

A field emission scanning electron microscope (FE-SEM) was used for the measurement. Compounds on a surface of a sample of a rib sample were examined and the number density of intermetallic compounds having a given equivalent circular diameter was measured by image analysis. In particular, 20 fields of view were magnified at 20,000 magnification, and the number density of intermetallic compounds having a circle equivalent diameter of 0.025 μm to 0.4 μm was calculated by a binarization method.

Tensile strength of the rib at 500 ° C

A specimen of a rib material before brazing heating was formed into a JIS No. 13 B tensile specimen, and tensile strength was measured at 500 ° C by a tensile testing machine. The temperature raising rate of the fin material to 500 ° C was 100 ° C / min. Then, after the fin material reached 500 ° C, a tensile test was performed at a pulling speed of 2 mm / min while maintaining the temperature. The tensile strength was read from the obtained stress-strain curve. When the tensile strength was 17 MPa or more, the result was expressed as "⊙", when the tensile strength was 15 MPa or more below 17 MPa, the result was expressed as "○" and when the tensile strength became below 15 MPa the result is given as "×".

Amount of Mn, Zr, Cr and V in solid solution before soldering

A rib material before soldering heating was dissolved in a phenol solution, the undissolved intermetallic compounds were removed by filtration, subjected to emission analysis, and the amount of Mn, Zr, Cr and V in solid solution was measured.

Tensile test at room temperature after heating up to 400 ° C

The fin material was heated at a temperature elevation rate of 100 ° C / min to 400 ° C and subjected to a tensile test according to JIS Z2241 under conditions of a tensile speed of 10 mm / min and a gauge length of 50 mm at room temperature. The 0.2% proof stress was read from the obtained stress-strain curve. Recrystallization was determined to be complete when the value was 80 MPa or less, and was reported as successful (○). Recrystallization was determined to be incomplete when the value exceeded 80 MPa and was reported as failure (×).

Extent of drooping of the rib at 550 ° C

Each fin stock was cut to a size of 10 mm width and 55 mm length. A section at a length of 40 mm was projected in an unsupported state, and the remaining 15 mm section was heated to 580 ° C in a state of being horizontally held by a device. The temperature raising rate of the fin material up to 550 ° C was 100 ° C / min. After the heating, the amount of drooping of the edge of the protruding portion of the fin material was measured. When the amount was 15 mm or less, the result was indicated as "⊙", when the amount exceeded 15 mm and was 18 mm or less, the result was indicated as "○", and when the amount exceeded 18 mm, became Result indicated as "×".

solderability

Anzahl aller verbundenen Abschnitte: Die Anzahl aller Lötabschnitte
Anzahl von nicht verbundenen Abschnitten: Die Anzahl von Abschnitten, bei denen kein Rückstand von Verbindungsteilen nach dem Löten zurückgeblieben istEach fin material was corrugated, and a miniature core was manufactured by assembling with a pipe material having a thickness of 0.25 mm using JIS A3003 alloys as core material and JIS A4045 alloys as cladding material (filler alloy, cladding rate of 10%). A fluoride-based flux at a concentration of 3% was applied, heated for 3 minutes at 600 ° C in a nitrogen gas atmosphere, and brazing was performed. Next, each solder-bonded fin material was physically removed from the pipe material by a cutting blade, and a residue of a fin joint portion remaining on the surface of the pipe material was examined. Then, the number of unconnected portions (portions where no residue of connecting parts remained after soldering) was counted, and a connection ratio based on the following formula was obtained. A compound ratio of 90% or more was indicated as "○" and a compounding ratio of less than 90% was indicated as "○". $$\begin{array}{l}\text{connection ratio}\left(\text{\%}\right)=(1-\text{Number of unconnected sections}/\text{number}\\ \text{all connected sections})\times 100\end{array}$$

Number of all connected sections: The number of all soldered sections
Number of Unconnected Sections: The number of sections where there is no residue of connectors after soldering

Further, every fifty portions of the cross section of the joint portions of the fin material of the miniature solder-bonded core and the pipe were examined, and the number of portions in which half or more of the thickness of the fin material was melted was counted, and a rib melt ratio was based on the following formula receive. $$\begin{array}{l}\text{Ribs melt ratio}\left(\text{\%}\right)=(\text{Number of connecting sections}\text{, at them}\\ \text{half or more of the thickness of the fin material had melted / number of festge}-\\ \text{set connection sections})\times 100\end{array}$$

A rib melt ratio of 10% or less was given as,, a fin melt ratio of more than 10% and 20% or less was indicated as "○", and a rib melt ratio of more than 20% was given as "×".

Corrosion resistance test

A miniature core of a heat exchanger made similarly as in the case of the soldering test was subjected to CASS test according to JIS H8681 for 1 month, the corrosion state of the fin material and the pipe material was examined, and the corrosion resistance was evaluated. The quality of corrosion resistance was evaluated as follows. If the tubing had no through holes, it was rated as ○: good. When the pipe material had through-holes and the self-corrosion of the fin material was large, it was evaluated as ×: poor. [Table 3] Example no. Alloy no. Density of intermetallic compounds with a circle equivalent diameter of 0.025 to 0.4 μm before soldering: D (particles / mm ² ) Amount of Mn in solid solution before soldering heating mass% Amount of Zr in solid solution before soldering heating mass% Amount of Cr in solid solution before soldering heating mass% Amount of V in solid solution before soldering heating mass% example 1 1 6.1 × 10 ⁶ 0.09 0.03 - - 2 2 5.2 × 10 ⁶ 0.15 - 0.04 - 3 3 4.0 × 10 ⁶ 0.22 - - 0.04 4 4 6.6 × 10 ⁶ 0.19 0.03 0.02 - 5 5 4.1 × 10 ⁶ 0.21 - - 0.07 6 6 6.3 × 10 ⁶ 0.10 0.06 0.02 - 7 7 5.3 × 16 ⁶ 0.13 0.01 - 0.07 8th 8th 3.8 × 10 ⁶ 0.21 - 0.09 0.03 9 9 4.7 × 10 ⁶ 0.18 - 0.04 - 10 10 6.0 × 10 ⁶ 0.12 0.04 - - 11 11 3.9 × 10 ⁶ 0.26 - - 0.06 12 12 3.5 × 10 ⁶ 0.28 - 0.06 0.06 13 13 3.9 × 10 ⁶ 0.28 - 0.08 - 14 14 4.7 × 10 ⁶ 0.14 0.03 - - 15 15 6.1 × 10 ⁶ 0.11 - 0.04 - 16 16 5.6 × 10 ⁶ 0.18 - - 0.03 17 1 3.3 × 10 ⁶ 0.28 0.08 - - 18 1 5.8 × 10 ⁶ 0.11 0.04 - - 19 1 3.8 × 10 ⁶ 0.26 0.06 - - 20 9 5.0 × 10 ⁶ 0.17 - 0.04 - 21 10 3.7 × 10 ⁶ 0.23 0.07 - - 22 11 6.3 × 10 ⁶ 0.09 - - 0.04 23 12 6.0 × 10 ⁶ 0.13 - 0.03 0.02 24 13 7.1 × 10 ⁶ 0.08 - 0.02 - 25 14 4.5 × 10 ⁶ 0.19 0.03 - - 26 16 6.2 × 10 ⁶ 0.10 - - 0.03 Comparative example 27 1 1.5 × 10 ⁶ 0.28 0.08 - - 28 11 1.8 × 10 ⁶ 0.24 - 0.06 - 29 6 3.3 × 10 ⁶ 0.26 0.14 0.03 - 30 2 3.0 × 10 ⁶ 0.21 - 0.11 - 31 5 3.1 × 10 ⁶ 0.19 - - 0.12 32 9 2.6 × 10 ⁶ 0.25 - 0.05 - 33 1 No measurement because hot rolling was not possible 34 17 No measurement, as hot rolling was not possible 35 18 2.4 × 10 ⁶ 0.09 - 0.08 - 36 19 4.3 × 10 ⁶ 0.14 0.04 - - 37 20 3.0 × 10 ⁶ 0.34 - - 0.04 38 21 2.8 × 10 ⁶ 0.26 - - 0.06 39 22 3.8 × 10 ⁶ 0.36 0.08 - - 40 23 No measurement due to the occurrence of cracking during cold rolling 41 24 No measurement due to the occurrence of cracking during cold rolling 42 25 No measurement due to the occurrence of cracking during cold rolling 43 26 No measurement due to the occurrence of cracking during cold rolling 44 27 5.0 × 10 ⁶ 0.14 0.04 - - 45 28 4.1 × 10 ⁶ 0.14 0.04 - - 46 29 4.6 × 10 ⁶ 0.12 - - 0.04 [Table 4] Example no. Alloy no. Rekristallisationsvollständigkeitstemperatur Sag test extent of droop up to 550 ° C Miniaturkernlötbewertung Solderability (%) Rib melt ratio (%) corrosion resistance example 1 1 ○ 8th ⊙ 100 ○ 4 ⊙ ○ 2 2 ○ 10 ⊙ 98 ○ 10 ⊙ ○ 3 3 ○ 15 ○ 100 ○ 6 ⊙ ○ 4 4 ○ 8th ⊙ 100 ○ 2 ⊙ ○ 5 5 ○ 15 ⊙ 98 ○ 8th ⊙ ○ 6 6 ○ 8th ○ 100 ○ 4 ⊙ ○ 7 7 ○ 10 ⊙ 100 ○ 4 ⊙ ○ 8th 8th ○ 16 ○ 100 ○ 4 ⊙ ○ 9 9 ○ 14 ⊙ 95 ○ 2 ⊙ ○ 10 10 ○ 9 ⊙ 97 ○ 14 ○ ○ 11 11 ○ 16 ○ 100 ○ 6 ⊙ ○ 12 12 ○ 17 ○ 100 ○ 2 ⊙ ○ 13 13 ○ 16 ○ 100 ○ 4 ⊙ ○ 14 14 ○ 13 ⊙ 100 ○ 4 ⊙ ○ 15 15 ○ 10 ⊙ 100 ○ 4 ⊙ ○ 16 16 ○ 11 ⊙ 100 ○ 4 ⊙ ○ 17 1 ○ 18 ○ 100 ○ 4 ⊙ ○ 18 1 ○ 14 ⊙ 100 ○ 4 ⊙ ○ 19 1 ○ 17 ○ 100 ○ 4 ⊙ ○ 20 9 ○ 11 ⊙ 96 ○ 2 ⊙ ○ 21 10 ○ 17 ○ 98 ○ 14 ○ ○ 22 11 ○ 8th ⊙ 100 ○ 6 ⊙ ○ 23 12 ○ 9 ⊙ 100 ○ 2 ⊙ ○ 24 13 ○ 13 ⊙ 100 ○ 4 ⊙ ○ 25 14 ○ 15 ⊙ 100 ○ 4 ⊙ ○ 26 16 ○ 9 ⊙ 99 ○ 2 ⊙ ○ Comparative example 27 1 ○ 24 × 100 ○ 4 ⊙ ○ 28 11 ○ 23 × 100 ○ 4 ⊙ ○ 29 6 × 32 × 97 ○ 2 ⊙ ○ 30 2 × 29 × 95 ○ 4 ⊙ ○ 31 5 × 28 × 96 ○ 4 ⊙ ○ 32 9 ○ 22 × 95 ○ 2 ⊙ ○ 33 1 No measurement, as hot rolling was not possible 34 17 No measurement, as hot rolling was not possible 35 18 ○ 23 × 100 ○ 4 ⊙ ○ 36 19 ○ 16 ○ 94 ○ 32 × ○ 37 20 × 33 × 100 ○ 22 × ○ 38 21 ○ 23 × 100 ○ 4 ⊙ × 39 22 × 29 × 96 ○ 26 × ○ 40 23 No measurement due to the occurrence of cracking during cold rolling 41 24 No measurement due to the occurrence of cracking during cold rolling 42 25 No measurement due to the occurrence of cracking during cold rolling 43 26 No measurement due to the occurrence of cracking during cold rolling 44 27 ○ 13 ⊙ 100 ○ 12 ○ × 45 28 ○ 15 ⊙ 100 ○ 24 × × 46 29 ○ 14 ⊙ 82 × 16 ○ ○

Examples 1 to 26 satisfied the conditions given in the present invention, and the extent of hanging the rib at 550 ° C was successful. Soldering properties and corrosion resistance were equally successful.

In Comparative Examples 27 and 28, the homogenizing treatment condition and the hot rolling condition were not appropriate, and the precipitated intermetallic compounds were coarse and the number density of intermetallic compounds having a equivalent circular diameter of 0.025 to 0.4 μm was less than 3.0 particles / μm ² . Accordingly, the extent of the rib hanging down at 550 ° C resulted in failure.

In Comparative Example 29, the hot rolling condition was not appropriate, the amount of Zr in solid solution before soldering heat exceeded 0.1 mass%, and recrystallization during soldering heating was not complete at 450 ° C. Accordingly, the amount of drooping of the fin material at 550 ° C resulted in failure.

In Comparative Example 30, the hot rolling condition was not appropriate, the amount of Cr in solid solution before soldering heat exceeded 0.1 mass%, and the recrystallization during soldering heating was not complete at 450 ° C. Accordingly, the amount of drooping of the fin material at 550 ° C resulted in failure.

In Comparative Example 31, the hot rolling condition was not adequate, the amount of solid solution V before soldering heat exceeded 0.1 mass%, and recrystallization during soldering heating was not complete at 450 ° C. Accordingly, the amount of drooping of the fin material at 550 ° C resulted in failure.

In Comparative Example 32, the tempering condition was not appropriate, the precipitated intermetallic compounds were coarse and the number density of the intermetallic compounds having a equivalent circular diameter of 0.025 to 0.4 μm was less than 3.0 particles / μm ² . Accordingly, the amount of drooping of the fin material at 550 ° C resulted in failure.

In Comparative Example 33, the heating temperature before hot rolling was as low as 360 ° C, the hot strength of the material at the time of rolling was high, cracking occurred during rolling, and this made production impossible.

In Comparative Example 34, cracking occurred during rolling because the components of Mn in the fin material were excessive, and this made production impossible.

In Comparative Example 35, the number density of intermetallic compounds having a circular equivalent diameter of 0.025 to 0.4 μm was below 3.0 particles / μm ² because the components of Mn in the fin material were insufficient. Accordingly, the tensile strength at 500 ° C resulted in failure.

In Comparative Example 36, the melting of the rib in the soldering test was considerable and resulted in failure because the components of Si in the fin material were excessive.

In Comparative Example 37, the amount of Mn in solid solution before soldering heating exceeded 0.3 mass%, and recrystallization during soldering heating was not completed at 450 ° C since the components of Si in the fin material were insufficient. Accordingly, the amount of drooping of the fin material at 550 ° C resulted in failure. Further, as a result of the increase of the amount of Mn in solid solution and the like and the lowering of the solidus temperature of the fin material, the melting of the rib in the solderability test was considerable and resulted in failure.

In Comparative Example 38, the number density of intermetallic compounds having a circle equivalent diameter of 0.025 to 0.4 μm was below 3.0 particles / μm ² and the tensile strength at 500 ° C resulted in failure because the components of Fe in the fin material were excessive. When evaluating corrosion resistance, corrosion of the fin material was significant and resulted in failure.

In Comparative Example 39, the amount of Mn in solid solution before soldering heat exceeded 0.3 mass%, and the recrystallization during soldering heating was not completed at 450 ° C because the components of Fe in the fin material were insufficient. Accordingly, the amount of drooping of the fin material at 550 ° C resulted in failure. Further, as a result of increasing the amount of Mn and the like in solid solution and lowering the solidus temperature of the fin material, the melting of the rib in the solderability test was considerable and resulted in failure.

In Comparative Examples 40 to 43, cracks occurred at the time of rolling because the components of Zr, Cr, V or Ti in the fin material were excessive, and the fin material could not be produced.

In Comparative Example 44, the corrosion of the fin material in the corrosion resistance test was considerable and resulted in failure because the components of Zn in the fin material were excessive.

In Comparative Example 45, the sacrificial anode effect of the fin material in the corrosion resistance test was insufficient and resulted in failure because the components of Cu in the fin material were excessive.

In Comparative Example 46, the compounding ratio in the solderability test was poor and resulted in failure because the components of Mg in the fin material were excessive.

The fin material made of aluminum alloy for heat exchangers of the present invention has excellent material strength at a high temperature during soldering heating and excellent kink resistance during soldering heating.

Claims (2)

Finned material made of an aluminum alloy for heat exchangers, the finned material comprising: 1.0 to 2.0 mass% Mn, 0.7 to 1.4 mass% Si and 0.05 to 0.3 mass% % Fe and one or more species of 0.05 to 0.3 mass% Zr, 0.05 to 0.3 mass% Cr and 0.05 to 0.3 mass% V, wherein it is the remainder being Al and unavoidable impurities, wherein the number density of intermetallic compounds having a circle equivalent diameter of 0.025 to 0.4 μm before soldering heat is 3.0 x 10 ⁶ particles / mm ² or more, the amount of Mn in solid solution Is 0.3 mass% or less and the respective amount of Zr, Cr and V in solid solution is 0.1 mass% or less, and the recrystallization completion temperature during a temperature rise at the time of soldering heating is 450 ° C or less. Ridge material, which is made of an aluminum alloy, for heat exchanger after Claim 1 further comprising one or more species of 0.5 to 4.0 mass% Zn, 0.01 to 0.4 mass% Cu, 0.01 to 0.3 mass% Mg, and 0.05 to 0.3 mass% Ti.