KR102315172B1 - Aluminum alloy with high corrosion resistance - Google Patents

Abstract

The present invention is an aluminum alloy in weight%, Cu: 0.1% or less (excluding 0%), Si: 0.15% or less (excluding 0%), Fe: 0.2% or less (excluding 0%), Mn: 0.9 to 1.5% , Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: It relates to a high corrosion resistance aluminum alloy comprising at least one of 0.03 to 0.15%, and the remaining Al and unavoidable impurities.
The highly corrosion-resistant aluminum alloy according to the present invention is an aluminum alloy with improved corrosion resistance in a salt water environment at the level of excellent tensile strength and yield strength by additionally adding Ti, Cr, and Zr components to the aluminum alloy, or adding them in the same ratio. can provide

Description

High corrosion resistance aluminum alloy {ALUMINUM ALLOY WITH HIGH CORROSION RESISTANCE}

The technical idea of the present invention relates to a highly corrosion-resistant aluminum alloy, and more particularly, to an aluminum alloy having improved corrosion resistance in a salt water environment at the level of excellent tensile strength and yield strength.

In aluminum alloys commonly used in automobiles, pure aluminum has low strength, so various elements (Mn, Si, Mg, Cu, Zn, Cr, etc.) are added to improve strength by precipitation hardening. Aluminum has excellent corrosion resistance because the oxide film protects the base material in an environment of pH 4.5 to 8.5, but has a high ionization tendency.

The 3xxx series aluminum alloy is an alloy containing Mn as a main additive, and is a non-heat-treated alloy having various properties by cooling. Compared to pure aluminum, the strength is slightly higher, and the weldability, corrosion resistance, and molding processability are good. In particular, 3003 is a representative alloy of this type, and the strength is slightly increased without deteriorating the workability and corrosion resistance of pure aluminum by the addition of Mn. These alloys have a wide range of uses for aluminum objects, building materials, containers, and the like. The 3004 and 3014 aluminum alloys in which Mg is added to the alloy equivalent to 3003 by 1% by weight are alloys with further increased strength. However, it does not satisfy the formability and strength that meet the characteristics of parts that require higher quality, and also has a problem of corrosion in a salt water environment.

Therefore, an aluminum alloy composition with improved corrosion resistance in a salt water environment at the level of excellent tensile strength and yield strength that can be applied to a pipe structure used as a refrigerant line, a coolant line, and a variable speed oil cooler line of a receiver dryer for an automobile or an automobile refrigerant transport system. This is a necessary situation.

1. Japanese Patent No. 04411803 2. Korean Patent Publication No. 10-2005-0035447

The technical task to be achieved by the technical idea of the present invention is to further add Ti, Cr and Zr components to the aluminum alloy, or in particular, by adding them in the same ratio, the corrosion resistance is improved in a salt water environment at the level of excellent tensile strength and yield strength It is to provide an aluminum alloy.

The high corrosion-resistance aluminum alloy according to the technical idea of the present invention for achieving the above technical problem is as a weight%, Cu: 0.1% or less (excluding 0%), Si: 0.15% or less (excluding 0%), Fe: 0.2% or less (excluding 0%), Mn: 0.9~1.5%, Ti: 0.03~0.15%, Cr: 0.03~0.15%, and Zr: 0.03~0.15% can,

In some embodiments of the present disclosure, Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: 0.03 to 0.15% may all be included.

In some embodiments of the present invention, the Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: 0.03 to 0.15% including all, the Ti, Cr and Zr may be included in the same ratio .

In some embodiments of the present invention, Ti: 0.05 to 0.1%, Cr: 0.05 to 0.1%, and Zr: may include all of 0.05 to 0.1%.

In some embodiments of the present invention, the Ti: 0.05 to 0.1%, Cr: 0.05 to 0.1%, and Zr: including all of 0.05 to 0.1%, the Ti, Cr and Zr may be included in the same ratio .

The high corrosion resistance aluminum alloy according to the technical idea of the present invention provides an aluminum alloy with improved corrosion resistance at an excellent tensile strength and yield strength level by additionally adding Ti, Cr and Zr components to the aluminum alloy, or in particular adding them in the same amount ratio can do.

The above-described effects of the present invention have been described by way of example, and the scope of the present invention is not limited by these effects.

1 is a configuration diagram illustrating an automobile air conditioner/engine cooling system.
2 is a configuration diagram of an automobile air conditioner (heat exchanger) and a receiver dryer.
Figures 3a and 3b is a photograph before and after the corrosion resistance evaluation of the receiver dryer manufactured with an aluminum alloy composition according to an embodiment of the present invention.
4a and 4b are photographs before and after corrosion resistance evaluation of a receiver dryer manufactured with an aluminum alloy composition according to a comparative example of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the technical idea of the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided so as to more fully and complete the present disclosure, and to fully convey the technical spirit of the present invention to those skilled in the art. As used herein, the term “and/or” includes any one and any combination of one or more of those listed items. The same symbols refer to the same elements from beginning to end. Furthermore, various elements and regions in the drawings are schematically drawn. Therefore, the technical spirit of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings.

This alloy may be used as a material for the receiver dryer 10 used in the automobile air conditioner/engine cooling system, the expansion valve 70 for expanding the refrigerant, and the pipes 30 and hoses 40 and 60 connecting them. The condenser 20 in the vehicle air conditioning system operates to remove heat from gas or steam, and when sufficient heat is removed, liquefaction is achieved. The condenser 20 is a kind of radiator for discharging the heat of the gaseous refrigerant supplied from the compressor 50 to the atmosphere to form a liquid refrigerant, and the more heat emitted, the better. The high-temperature, high-pressure refrigerant sent from the compressor 50 is cooled and liquefied by the temperature of the outside air, and then sent to the receiver dryer 10 made of aluminum in a long cylindrical shape. The receiver dryer 10 is a tank for storing the refrigerant and serves to remove moisture mixed in the refrigerant. When a car is operated for a long time, internal corrosion occurs due to the condensate generated inside. Moreover, due to the snow removal agent such as calcium chloride sprayed on the road surface in winter, external corrosion also occurs severely. Therefore, this alloy is required to have superior properties in high corrosion resistance.

The high corrosion-resistance aluminum alloy according to the present invention is a weight%, Cu: 0.1% or less (excluding 0%), Si: 0.15% or less (excluding 0%), Fe: 0.2% or less (excluding 0%), Mn: 0.9~ At 1.5%, Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: 0.03 to 0.15% may be included, and the remaining Al and unavoidable impurities may be included.

Cu serves to improve the strength and ductility of the alloy according to the hardening effect in the alloy. Cu is preferably controlled in the range of more than 0% by weight to 0.1% by weight (0wt.%<Cu≤0.1wt.%). More preferably, Cu is controlled in the range of more than 0 wt% to 0.05 wt% (0 wt.%<Cu≤0.05 wt.%). When Cu exceeds 0.1 wt%, it is preferably added in an amount of 0.1 wt% or less as corrosion resistance is lowered, and more preferably in an amount of 0.05 wt% or less.

Si serves to improve strength without deteriorating corrosion resistance in the alloy. Si is precipitated to improve mechanical properties. Si is preferably controlled in the range of more than 0% by weight to 0.15% by weight (0wt.%<Si≤0.15wt.%). More preferably, Si is controlled in the range of more than 0 wt% to 0.05 wt% (0 wt.%<Si≤0.05 wt.%). When Si exceeds 0.15 wt%, moldability may deteriorate as well as the surface quality of the molded product, so it is preferable to be added in an amount of 0.05 wt% or less.

Fe can contribute to the improvement of strength by increasing the density of the alloy in the alloy. Fe is preferably controlled in the range of more than 0% by weight to 0.2% by weight (0wt.%<Fe≤0.2wt.%). More preferably, Fe is adjusted in the range of 0.05 wt% or more to 0.15 wt% (0.05 wt.%≤Fe≤0.15 wt.%). If Fe is more than 0.2% by weight, it may decrease ductility as well as extrudability and productivity, and may cause corrosion of the material. Therefore, the upper limit of Fe is preferably 0.2 wt% or less, more preferably 0.15 wt% or less.

Mn plays a role in increasing the softening resistance at high temperature and improving the surface treatment properties without significantly weakening the corrosion resistance of the alloy. In addition, the strength is improved through the solid solution strengthening effect and the fine precipitate dispersion effect. Mn is preferably adjusted in the range of 0.9 wt% or more to 1.5 wt% (0.9wt.%≤Mn≤1.5wt.%). More preferably, Mn is adjusted in a range of 1.0 wt% or more to 1.5 wt% (1.0 wt.%≤Mn≤1.5 wt.%). When Mn is less than 0.9 wt%, it is difficult to expect an effect, and when Mn is more than 1.5 wt%, castability is deteriorated, which is not good.

Ti plays a role in improving formability and strength through grain refinement in the alloy. Ti is preferably adjusted in the range of 0.03 wt% or more to 0.15 wt% (0.03 wt.%≤Ti≤0.15 wt.%). More preferably, Ti is adjusted in the range of 0.05 wt% or more to 0.1 wt% (0.05 wt.%≤Ti≤0.1 wt.%). When Ti is less than 0.03% by weight, it is difficult to expect an effect, and when Ti is more than 0.15% by weight _{, large and coarse intermetallic compounds such as TiAl 3} are produced in large amounts, which is not good because the mechanical properties of the alloy are deteriorated. When Ti is less than 0.03 wt%, it is difficult to expect an effect, and when Ti is more than 0.15 wt%, mechanical properties are deteriorated, which is not good.

Cr forms a compound with Al in the alloy and distributes it at grain boundaries, thereby suppressing precipitation during aging treatment to improve elongation. Cr is preferably adjusted in the range of 0.03 wt% or more to 0.15 wt% (0.03 wt.%≤Cr≤0.15 wt.%). More preferably, Cr is adjusted in the range of 0.05 wt% or more to 0.1 wt% (0.05 wt.%≤Cr≤0.1 wt.%). When Cr is less than 0.03% by weight, it is difficult to expect an effect, and when Cr is more than 0.15% by weight, the strength is lowered, which is not good.

Zr plays a role in improving corrosion resistance as well as strength improvement at high temperatures in the alloy. Zr is preferably adjusted in the range of 0.03 wt% or more to 0.15 wt% (0.03 wt.%≤Zr≤0.15wt.%). More preferably, Zr is adjusted in the range of 0.05 wt% or more to 0.1 wt% (0.05 wt.%≤Zr≤0.1wt.%). When Zr is less than 0.03 wt%, it is difficult to expect an effect, and when Zr is more than 0.15 wt%, cracks or cracks occur, which is not good.

In particular, Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: 0.03 to 0.15% may all be included. In addition, the Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: 0.03 to 0.15%, including all, the Ti, Cr and Zr may be included in the same ratio. More preferably, Ti: 0.05 to 0.1%, Cr: 0.05 to 0.1% and Zr: 0.05 to 0.1% may be included.

As above, the high corrosion-resistance aluminum alloy according to the present invention is a weight%, Cu: 0.1% or less (excluding 0%), Si: 0.15% or less (excluding 0%), Fe: 0.2% or less (excluding 0%), Mn : 0.9 to 1.5%, Ti: 0.03 to 0.15%, Cr: 0.03 to 0.15%, and Zr: 0.03 to 0.15%, and may include the remaining Al and unavoidable impurities.

More preferably, the Ti: 0.05 to 0.1%, Cr: 0.05 to 0.1%, and Zr: including all of 0.05 to 0.1%, the Ti, Cr and Zr are included in the same ratio at the level of excellent tensile strength and yield strength Improves corrosion resistance in salt water environment.

Hereinafter, details of the process of the present invention will be described through Examples and Experimental Examples.

Aluminum alloy preparation

Table 1 is a table showing the composition of the high corrosion resistance aluminum alloy according to an embodiment of the present invention in weight %. An aluminum alloy composition (Examples 1 to 10) according to the present invention and an aluminum alloy composition to be compared thereto (Comparative Examples 1 to 5) were prepared in the following composition ratios. In Comparative Examples 4 and 5, compositions of the existing 3005 alloy and 3004 alloy were used. In Table 1, the aluminum alloy consists of Al and unavoidable impurities except for the alloy composition.

No Cu Mg Si Fe Mn Zn Ti Cr Zr Al Example 1 0.03 0 0.03 0.09 1.16 0 0.04 0.04 0.04 98.57 Example 2 0.03 0 0.03 0.09 1.16 0 0.05 0.05 0.05 98.54 Example 3 0.03 0 0.03 0.09 1.16 0 0.07 0.07 0.07 98.48 Example 4 0.03 0 0.03 0.09 1.15 0 0.09 0.09 0.09 98.43 Example 5 0.03 0 0.03 0.09 1.15 0 0.07 0.04 0.04 98.55 Example 6 0.03 0 0.03 0.09 1.15 0 0.04 0.07 0.04 98.55 Example 7 0.03 0 0.03 0.09 1.15 0 0.07 0.07 0.12 98.44 Example 8 0.03 0 0.03 0.09 1.15 0 0.07 0.12 0.07 98.44 Example 9 0.03 0 0.03 0.09 1.15 0 0.12 0.07 0.07 98.44 Example 10 0.03 0 0.03 0.09 1.15 0 0.12 0.12 0.12 98.34 Comparative Example 1 0.03 0 0.03 0.09 1.16 0 0.02 0.02 0.02 98.63 Comparative Example 2 0.03 0 0.03 0.09 1.16 0 0.18 0.18 0.18 98.15 Comparative Example 3 0.03 0 0.03 0.09 1.15 0 0.21 0.21 0.21 98.07 Comparative Example 4 0.3 0.2 0.6 0.7 0.8 0.25 0.1 0.2 0 96.85 Comparative Example 5 0.25 0.8 0.3 0.7 One 0.25 0 0 0 96.7

Specimen fabrication and mechanical evaluation

Among the alloys according to the present invention, three types of alloys of Examples 2 to 4 were prepared as ASTM standard test pieces, and then, yield strength and tensile strength were measured at room temperature with a tensile tester. As a result, as shown in Table 2, all of Examples 2 to 4 of the present invention exhibited a tensile strength of 180N/mm 2 or more. In addition to Examples 2, 3, and 4, the tensile strength of the alloys according to other Examples also exhibited characteristics of 180N/mm 2 or more. The tensile strength of the comparative example measured under relatively the same conditions was found to be inferior to less than 180N/mm 2 .

No Tensile strength (N/㎟) Yield strength (N/㎟) Example 2 191 79 Example 3 185 70 Example 4 187 77

Receiver dryer manufacturing and corrosion resistance evaluation

An aluminum billet was prepared with the aluminum alloy composition according to Examples 1 to 10 of the present invention and the aluminum alloy composition compared (Comparative Examples 1 and 5), and an aluminum pipe was manufactured by extruding and drawing the billet, and then the aluminum pipe A receiver dryer is manufactured by forming and bending the left and right ends of the to form a receiver dryer shape.

After manufacturing the thickness 1.6T and 1.8T receiver dryer, corrosion resistance was evaluated. Figure 2 is a photograph before and after the corrosion resistance evaluation of the receiver dryer manufactured with the aluminum alloy composition according to the embodiment of the present invention, Figures 4a and 4b are before and after the corrosion resistance evaluation of the receiver dryer manufactured with the aluminum alloy composition according to the comparative example of the present invention is a picture of As shown in FIG. 4(b), LEAK can be confirmed after corrosion resistance evaluation.

Table 3 shows the results of completing the corrosion resistance test of the receiver dryer manufactured with the aluminum alloy composition of Table 1. Corrosion resistance test (SWAAT-Seawater Acidified Test) investigates corrosion resistance by accelerating corrosion by spraying saline solution to the sample according to the regulations. Nitrogen pressure of 1.6±0.04 MPa (16.7kgf/cm ² ) is applied inside the condenser, Concentration: Synthetic sea salt 42g/1L, Spray amount: 1~2 ml/h, Specific gravity: 1.0255 ~ 1.0400, PH: 2.8~3.0 ( 500 to 2000 hours in accordance with ASTM G85 94-A3).

Distilled water was put into the tank, and the synthetic sea salt was added according to the amount of distilled water and stirred until completely dissolved. After adding acetic acid to the amount of distilled water and stirring, it was checked whether the test solution satisfies the condition with a hydrometer and a PH meter. Test run for 1 hour to check if the amount of spray meets the conditions, and put the sample in the chamber. Set the atmosphere in the chamber to 49 ℃, spray for 30 minutes, leave it for 90 minutes, 250 Cycles (500 hr), 500 cycles (1,000 hr) and 1000 cycles (2,000 hr) were tested.

NO. product thickness Test result After 250Cycle_500hr test After 500Cycle_1,000hr test After 1000Cycle_2,000hr test LEAK presence LEAK presence LEAK presence Example 1
1.6T No LEAKs No LEAKs LEAK Occurrence Example 2 No LEAKs No LEAKs No LEAKs Example 3 No LEAKs No LEAKs No LEAKs Example 4 No LEAKs No LEAKs No LEAKs Example 5 No LEAKs No LEAKs LEAK Occurrence Example 6 No LEAKs No LEAKs LEAK Occurrence Example 7 No LEAKs No LEAKs LEAK Occurrence Example 8 No LEAKs No LEAKs LEAK Occurrence Example 9 No LEAKs No LEAKs LEAK Occurrence Example 10 No LEAKs No LEAKs LEAK Occurrence Comparative Example 1 No LEAKs LEAK Occurrence LEAK Occurrence Comparative Example 2 No LEAKs LEAK Occurrence LEAK Occurrence Comparative Example 3 No LEAKs LEAK Occurrence LEAK Occurrence Comparative Example 4 No LEAKs LEAK Occurrence LEAK Occurrence Comparative Example 5 No LEAKs LEAK Occurrence LEAK Occurrence Example 1
1.8T No LEAKs No LEAKs No LEAKs Example 2 No LEAKs No LEAKs No LEAKs Example 3 No LEAKs No LEAKs No LEAKs Example 4 No LEAKs No LEAKs No LEAKs Example 5 No LEAKs No LEAKs No LEAKs Example 6 No LEAKs No LEAKs No LEAKs Example 7 No LEAKs No LEAKs No LEAKs Example 8 No LEAKs No LEAKs No LEAKs Example 9 No LEAKs No LEAKs No LEAKs Example 10 No LEAKs No LEAKs No LEAKs Comparative Example 1 No LEAKs No LEAKs LEAK Occurrence Comparative Example 2 No LEAKs No LEAKs LEAK Occurrence Comparative Example 3 No LEAKs No LEAKs LEAK Occurrence Comparative Example 4 No LEAKs LEAK Occurrence LEAK Occurrence Comparative Example 5 No LEAKs LEAK Occurrence LEAK Occurrence

As shown in Table 3, in the evaluation of corrosion resistance, LEAK showed good results without LEAK in both Examples and Comparative Examples in the evaluation after the 250Cycle_5000hr test. After the 500Cycle_1,000hr test, LEAK, which does not appear in Examples 1 to 10, was observed in Comparative Examples 1 to 5, respectively. In particular, in the case of the receiver dryer manufactured with a thickness of 1.6T, LEAK occurred in Comparative Examples 1 to 5. Therefore, the receiver dryer made of the aluminum alloy of Examples 1 to 10 according to the composition of the present invention does not cause LEAK in both 1.6T and 1.8T thickness in a 500Cycle_1,000hr salt water environment, so it has sufficient corrosion resistance to be used in the receiver dryer. Confirmed.

In addition, corrosion resistance was evaluated in a harsh environment of 1000Cycle_2,000hr. As a result of the experiment, in the case of Examples 2 to 4, it was confirmed that LEAK did not occur even in a harsh environment of 1000Cycle_2,000hr at both 1.6T and 1.8T thicknesses, and thus had excellent corrosion resistance properties. In Examples 2 to 4, it was confirmed that Ti Cr and Zr had excellent corrosion resistance properties with a composition including the same amount in the range of 0.05 to 0.1%.

As described above, the high corrosion resistance aluminum alloy according to the present invention can provide an aluminum alloy with improved corrosion resistance in a salt water environment at the level of excellent tensile strength and yield strength. The high corrosion resistance aluminum alloy according to the present invention can be applied to all aluminum parts in addition to the receiver dryer, and the same effect can be obtained. Therefore, the high corrosion resistance aluminum alloy can manufacture not only a receiver dryer for automobiles, but also a pipe structure used as a refrigerant line, a coolant line, and a variable speed oil cooler line of an automobile refrigerant transport system by extrusion and drawing methods.

In addition, the high corrosion-resistance aluminum alloy according to the present invention can be used in a variety of ways to prevent corrosion, such as refrigerators, washing machines, home air conditioners, heat sinks such as LEDs, electrical appliances, roofing materials, chemical devices, kitchen appliances, and ship exterior materials.

The technical spirit of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is the technical spirit of the present invention that various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which this belongs.

10: receiver dryer 20: condenser
30: pipe 40: hose
50: compressor 60: hose
70: expansion valve 80: evaporator

Claims (5)

As wt%, Cu: 0.1% or less (excluding 0%), Si: 0.15% or less (excluding 0%), Fe: 0.2% or less (excluding 0%), Mn: 0.9 to 1.5%, Ti: 0.05 to 0.1%, Cr: 0.05 to 0.1% and Zr: In the high corrosion resistance aluminum alloy containing all of 0.05 to 0.1%, and the remaining Al and unavoidable impurities,
When the thickness of the alloy is 1.6T or less, the high corrosion resistance aluminum alloy, characterized in that the Ti, Cr and Zr are included in the same ratio.



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