JPS62112747A - Aluminum alloy having superior strength at high temperature - Google Patents

Abstract

PURPOSE:To obtain an Al alloy having superior strength and fatigue strength at high temp. by specifying the amounts of Si, Fe, Cu, etc., in an Al-Cu-Mg-Ni alloy. CONSTITUTION:This Al alloy consists of, by weight, 1.0-1.5% Si, 1.2-2.0% Fe, 3.0-5.5% Cu, 0.5-2.5% Mg and 0.5-2.5% Ni as essential elements, 0.01-0.30% Zr as an optional element and the balance Al. The Al alloy has superior tensile strength, yield strength and fatigue strength at high temp. and is suitable for use as a material for a heat engine member or the like in various vehicles, an industrial machine or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to aldanium bonding that has excellent high-temperature strength, and is intended to provide an aluminum alloy that has excellent strength and fatigue resistance under high-temperature conditions.

Industrial applications Aluminum alloys used under high temperature conditions such as heat engines in vehicles and industrial machinery.

Conventional technology Aluminum alloys are widely used in connecting rods and cylinders in the heat engines of bridge vehicles and industrial machinery, and the characteristics required of aluminum alloys used in such applications are high strength at high temperatures. It is.

In other words, what has been conventionally adopted for such purposes is #
-JIS AA 26 with N1 added to Cu-saki alloy
It is 18.

Problems that the invention aims to solveHowever, in recent years, aluminum-based products in the field of
There is a growing demand for base metal materials to have high strength and fatigue strength under high-temperature conditions, and the conventional aluminum base metals described above cannot adequately meet these demands.

"Structure of the invention" Means for solving the problem SL: 1.0 to 1.5 wt%, Fa: 1
．． 2-2. Owt%.

Cu: 3.0-5.5 wt%, A4: 0.5
~2.5wt%.

Ni: 0.5 to 2.5 wt% contained as a total essential element and Zr: 0.01 to 0.30 wt% as an optional element, with the remainder consisting of M and unavoidable impurities. nt aluminum association with excellent high temperature strength.

Action Si: 1. Owt% or more, pg: 1,2 w
t% or more, Cu: 3.3wt3 or more, Mg: 0.5
By containing 0.5 wt% or more of Ni and 0.5 wt% or more of Ni, the tensile strength, yield strength, and fatigue strength at high temperatures of the sial and -1 nium alloy are increased.

By setting Si: 1.5% or less, Fa: 2.0% or less, a decrease in ductility is avoided, CLli is 5.5% or less, and A
By setting Ni12.4 to 2.5% or less, casting cracks, deterioration of extrusion performance, and workability deterioration can be avoided. s%
By doing the following, deterioration in cold forgeability and machinability is prevented, and fatigue strength at high temperatures is maintained high.

By appropriately adding zr: o, o i to 0.3%, the recrystallized grains are made finer.

EXAMPLE To further explain the present invention as described above, the present inventors have developed the AA2, which has been widely used as described above.
After conducting research and development to obtain an aluminum association with high-temperature strength even better than that of AA2618 alloy, we increased the amount of Cu added to this AA2618 alloy, and moderately added SL and Fn. It was confirmed that excellent properties such as high-temperature strength can be obtained by increasing the temperature.

That is, the addition of each component in the unexploited 8A metal and the reason for limiting the composition wt% (hereinafter simply referred to as %) range are as follows.

, Sj: 1.0 to 1.5% In the presence of 1.0 to 1.5%, & promotes the age hardening ability of aluminum associations and contributes to increases in tensile strength, yield strength and fatigue strength at high temperatures. If the content is less than 1.5%, these effects will be insufficient, while if it exceeds 1.5%, the ductility will be significantly reduced, which is not preferable.

Fe: 1.2-2.0% h contributes to increasing the tensile strength, yield strength, and fatigue strength of the aluminum alloy at high temperatures.

That is, if it is less than 1.2%, these effects will be poor, and if it is less than 2.0%, these effects will be poor.
%, the tensile strength, yield strength, and ductility at room temperature decrease, so it was set at 1.2 to 2.0%.

Cu: 3.0 to 5.5% An element that promotes the age hardening ability of aluminum alloys and contributes to increases in tensile strength, yield strength, and fatigue strength at high temperatures; if it is less than 3.0%, these effects are not properly Moreover, if it exceeds 5.5%, cracks are likely to occur during DC casting, reducing the workability of the drawn or cast material, so the upper limit is set at 5.5%.

kiI: o, s ~ 2.5% Ml promotes the age hardenability of the alloy due to the presence of &,
Contributes to increased tensile strength, yield strength and fatigue strength at high temperatures. If it is less than 0.5%, these effects will be small, while if it exceeds 2.5%, casting cracks may occur during DC casting or gold casting, and extrusion performance may deteriorate, so this should be the upper limit.

Ni: o, s ~ 2.5% Increases the tensile strength, yield strength and fatigue strength of aluminum alloys at high temperatures and improves M-1? , -1
It is an element that forms 1Ji-based intermetallic compounds and improves the wear resistance of the alloy, and if it is less than 0.5%, these effects are insufficient. Moreover, if it exceeds 2.5%, it is undesirable because it reduces cold forgeability and machinability, and it also tends to cause coarsening of the lue Fa-Ni system, which becomes the origin of fatigue cracks or fatigue cracks. Since it becomes a propagation path and reduces fatigue strength under high temperatures, it should be kept at 2.5% or less.

In addition, in the present invention, zr is suitably set to 0.01 to 0.30.
Add in a range of %. That is, it refines the zrVi casting structure and has the effect of preventing casting cracks.

Recrystallized grains are also made finer during stretching.

If it is less than 0.01%, these effects can hardly be expected;
On the other hand, if t-4 is increased by 0.30%, these effects will be saturated and further effects cannot be expected.

In addition, there are cases where blood, ZN, CR, V, etc. are contained as impurities, but Ms and Zn are below 0.3%, and C.
There is no problem in containing r and V at 0.2% or less.

Furthermore, as an agent for refining the ingot structure, Ti: 0.003 to 0
．． 05% or at the same time B: 0.0005-0.
There is no problem even if 0.01% is contained, and the characteristics of the present invention are not impaired.

The alloy according to the present invention as described above is melted by a conventional method and made into an ingot for extrusion or rolling by a semi-continuous casting method using a water-cooled caster. This ingot is heated at 450-550℃ for 2~
After undergoing homogenization heat treatment for 48 hours, it is subjected to processing such as extrusion, forging, or drawing, and then further heat treated to become a product.

A specific manufacturing example of the product according to the present invention will be described below.

Part 1.2 of the present invention having a composition as shown in Table 1 below
and a conventional AA2618 alloy as a comparison alloy.

The above-mentioned valley alloy was cast into 2031111 billets (8 inch billets) by a hand continuous casting method using a water-cooled mold, and these billets were subjected to a homogenization heat treatment at 480°C for 6 hours, followed by a gold layer of 430~450°C. It was preheated to ℃ and extruded into a 42 mm round bar.

The solid material obtained as described above was subjected to solution treatment at 520°C for 2 hours, water quenching, and then artificial aging treatment at 180°C for 10 hours.

The sample materials obtained through the above treatments are as follows:
Tensile strength If, 0.2% yield strength, elongation at room temperature and 200°C, and fatigue strength f at 150°C were tested and measured. The fatigue test was performed using a Krause type rotary bending fatigue tester (30
The test results were as shown in Table 2 below.

According to Table 2, that is, Section 2, the present invention group is the comparative alloy (AA2
618), it is clear that the tensile strength and yield strength at 200°C are considerably superior, and it was also confirmed that the fatigue strength at 150°C is also high.

"Effects of the Invention" The invention according to the present invention as explained above has excellent tensile strength at high mK, proof stress and fatigue strength, and is suitable for use as heat engine parts in various vehicles, industrial machines, etc. 9 in a wide range,
This invention has great industrial effects.

Patent applicant: Nippon Light Metal Co., Ltd. Inventor: Kamio
Harutoshi Kitaokayama
Akira Iwamoto Mito
Mountain 1) Attainment - Shigoyu

Claims (1)

[Claims] Si: 1.0 to 1.5 wt%, Fe: 1.2 to 2.0 w
t%, Cu: 3.0-5.5wt%, Mg: 0.5-2
．． 5 wt%, Ni: 0.5 to 2.5 wt% as an essential element, Zr: 0.01 to 0.30 wt% as an optional element, and the balance consists of Al and inevitable impurities. An aluminum alloy with excellent high-temperature strength.