JPS63161137A - High tensile aluminum alloy having excellent heat resistance - Google Patents

Abstract

PURPOSE:To obtain a high tensile aluminum alloy exhibiting high strength in a temp. area from the ordinary temp. to high temp. and having excellent heat resistance by specifying the compsn. consisting of Cu, Mg, Ni, Fe, Mn, Si, Zr and Al. CONSTITUTION:The high tensile Al alloy contains, by weight %, 2.5-4.0% Cu, 1.0-2.0% Mg 0.8-3.0% Ni, 0.8-1.5% Fe, 0.3-0.6% Mn and 0.1-0.3% Si, contains 0.006-0.3% Zr, further contains at need one or two kinds among 0.001-0.3% Cr and 0.001-0.3% V, and the balance consists of Al with inevitable impurities. Said alloy has the excellent heat resistance and has high strength in the temp. area from the ordinary temp. of about 200 deg.C. The Al alloy is thus optimum as the materials of the parts of engine, etc., and the constitutional parts of vacuum machinery, etc., to be used in a high temp. atmosphere.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a high-strength aluminum alloy with excellent heat resistance, and in particular to components of engines, compressors, etc. used in high-temperature atmospheres, and components of vacuum equipment. Regarding high-strength aluminum alloys used in

(Conventional technology and problems to be solved) Traditionally, iron-based materials have been used for parts such as engines and compressors, but recently, from the perspective of improving the output and fuel efficiency of these machines, iron-based materials have been used. There is an increasing demand for lighter parts, and the use of aluminum materials is progressing.

In addition, the use of aluminum members for vacuum equipment is increasing because of their low gas generation rate and low residual radioactivity.

Incidentally, these devices and members are often used in a temperature range from room temperature to 200° C., and therefore, the materials used need to be materials with high strength not only at room temperature but also at high temperatures.

In this respect, among Al materials, Al-Zn-M such as 7075
Although it is known that g-based alloys have the highest strength at room temperature, these alloys have the disadvantage that their strength rapidly decreases when kept at high temperatures for a long time.

On the other hand, heat-resistant A2 alloys include 2618 alloy and 2219 alloy, but these materials also have the drawback of insufficient high-temperature strength.

The present invention eliminates the drawbacks of the above-mentioned prior art and allows
In the temperature range up to high temperatures such as 0℃, conventional heat-resistant Al alloy 2
The purpose of this invention is to provide a high-strength aluminum alloy that has higher strength and superior heat resistance than 618.2219.

(Means for Solving the Problems) In order to achieve the above object, the inventors of the present invention found that conventional aluminum alloys do not have sufficient high-temperature strength.

In addition to analyzing the cause, we conducted extensive research to find chemical components that can exhibit high strength from room temperature to high temperatures.As a result, we found that the fiber structure is maintained even during the solution treatment performed after extrusion and forging during the manufacturing process. However, if the chemical components are adjusted in a well-balanced manner to suppress recrystallization, it is possible to maintain high strength not only at room temperature, but even when kept in a high-temperature atmosphere for a long time. This is where the present invention is made.

That is, in the present invention, Cu: 2.5 to 4.0%, Mg:
1.0-2.0%, Ni: 0.8-3. Q%, Fe: 0
．． 8-1.5%, Mn: 0.3-0.6% and Si: 0
．． Contains 1 to 0.3%, and Zr: 0.006 to 0
．． Contains 3%, and further contains Cr: 0.001-0.001 as necessary
0.3% and V: O, OOl ~ 0.3% (7) High strength with excellent heat resistance, characterized by containing one or two of them, with the remainder consisting of Al and inevitable impurities. The main focus is on aluminum alloys.

The present invention will be explained in detail below based on examples.

First, the reasons for limiting the chemical components of the high-strength aluminum alloy with excellent heat resistance according to the present invention will be explained.

Cu is an essential element for improving room temperature strength and high temperature strength. If the content is less than 2.5%, the effect of improving one strength is small, while if the content exceeds 4.0%, the melting point decreases.

On the contrary, the strength will decrease. Therefore, the Cu content is set to 2.5 to 4.0%.

Like Cu, Mg is an essential element for improving room temperature strength and high temperature strength. If the content is less than 1.0%, the effect of improving strength will be small, while if it is contained in excess of 2.0%, the strength will decrease. Therefore, the Mg content is set to 1.0 to 2.0%.

Ni is an element that improves room temperature strength and high temperature strength, but if its content is less than 0.8%, the effect of improving strength is small; on the other hand, if it exceeds 3.0%, it will combine with Cu in the alloy and cause crystallization. On the contrary, the strength decreases because it becomes a product. Therefore,
The N1 content is 0.8 to 3.0%.

Fe is an element that improves high temperature strength, but when the content is 0
．． If the content is less than 8%, the effect will be small, while if the content exceeds 1.5%, giant pieces will occur and the strength will decrease. Therefore, the Fe content is set to 0.8 to 1.5%.

Mn is an element that makes the material structure fibrous, suppresses recrystallization, and improves high-temperature strength. Although recrystallization tends to occur during heat treatment (solution treatment) after forging, Mn is a particularly effective element in suppressing such recrystallization. However, if the content is less than 0.3%, the effect of improving high-temperature strength will be small, while if it is contained in a large amount exceeding 0.6%, extrusion workability and forging workability will be deteriorated. Therefore, the Mn content is set to 0.3 to 0.6%.

Si is an element that mainly improves strength at room temperature, but if the content is less than 0.1%, the effect is small;
If the content exceeds 0.3%, the solid solution amount of Mg decreases, resulting in a decrease in high temperature strength. Therefore, the Si content is 0.1
~0.3%.

Zr is an element that forms a fiber structure in the material and suppresses recrystallization, and is an element that improves strength from room temperature to high temperature. If the content is less than 0.06%, the effect will be small, while if the content exceeds 0.3%, giant crystallized substances will be generated and the strength will be reduced.

Therefore, the Zr content is set to 0.06 to 0.3%.

Note that Cr and V are elements that form a fiber structure in the material and suppress recrystallization, and are elements that improve strength from room temperature to high temperature, so one or both of them may be used as necessary.
Seeds can be contained in an appropriate amount. When the content of each element is less than 0.01%, the above effect is small;
If the content exceeds 0.01 to 0.3%, the strength will decrease due to the generation of giant crystallized substances.
shall be.

In addition to these above-mentioned components, we also refine the ingot structure,
Ti is added in the range of 0°01 to 0.1 to stabilize mechanical properties.
It may be contained at 0%.

A high-strength aluminum alloy having the above-mentioned chemical components is produced in a conventional manner through processes including casting, extrusion, forging, solution treatment, etc., and is subjected to product processing.

Next, examples of the present invention will be shown.

(Example) An aluminum alloy having the chemical components (wt%) shown in Table 1 was melted by a normal method, cast into a 155φ billet, then subjected to a predetermined homogenization treatment, and extruded at a temperature of 450.
A 40φ round bar was extruded at ℃.

Next, this round bar was hot forged into a cross-sectional shape with a thickness of 17 m+w and a width of 74 mm. Forging temperature is 370°C.

After that, a round bar tensile test piece was prepared and subjected to T6 treatment, and the strength at room temperature and after being kept at high temperature for a long time (150"CX 100
hr) was measured. The results are shown in Table 1. For comparison, 2618 alloy, 2219 alloy, and 7075 alloy are also listed.

From the same table, it can be seen that the alloys Nα1 to Nα4 of the present invention have higher strength than the conventional heat-resistant alloys 2618 alloy and 2219 alloy both at room temperature and high temperature, and are high-strength aluminum alloys with particularly excellent heat resistance.

Also, in comparison with 7075 alloy, although its room temperature strength is slightly inferior, it has far superior heat resistance in terms of high temperature strength.

Furthermore, comparative alloy No. 5, which has a low Mn content, has lower high temperature strength than the invention alloy.

(Effects of the Invention) As detailed above, the high-strength aluminum alloy of the present invention is particularly superior in high-temperature strength compared to conventional high-strength aluminum alloys, and is comparable in room-temperature strength. Therefore, it is optimal as a material for parts such as engines and compressors used in high-temperature atmospheres, as well as components of vacuum equipment, and will greatly contribute to the expansion of the material's applications.

Claims (2)

[Claims] (1) In weight% (the same applies hereinafter), Cu: 2.5 to 4.0
%, Mg: 1.0-2.0%, Ni: 0.8-3.0%
, Fe: 0.8-1.5%, Mn: 0.3-0.6%,
and Si: 0.1 to 0.3%, and Zr: 0
．． A high-strength aluminum alloy with excellent heat resistance, characterized by containing 0.006 to 0.3%, with the remainder consisting of Al and inevitable impurities. (2) Cu: 2.5-4.0%, Mg: 1.0-2.0
%, Ni: 0.8-3.0%, Fe: 0.8-1.5%
, Mn: 0.3-0.6% and Si: 0.1-0.3%
and further contains Zr: 0.006 to 0.3%, further Cr: 0.001 to 0.3% and V: 0.001
A high-strength aluminum alloy with excellent heat resistance, characterized in that it contains ~0.3% of one or two types, with the remainder consisting of Al and inevitable impurities.