JP3489058B2 - Method for measuring copper content in aluminum alloys for casting - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for measuring the content of copper (Cu) in an aluminum alloy for casting, more specifically, a method for measuring the content of copper in an Al--Si based aluminum alloy. Regarding

[0002]

2. Description of the Related Art Casting aluminum alloys, especially Al-
Since Si-based aluminum alloys have good castability and have a beautiful finished surface by cutting, they can be used to manufacture parts with complex shapes such as automobiles, aviation engines, other general machinery, electric machinery and equipment, and building hardware. Widely used in.

In this Al-Si type aluminum alloy, the equivalent of silicon (Si) can be known from the primary crystal temperature of the molten metal by measuring the cooling curve of the molten metal.
This silicon equivalent is related to the content of silicon and the content of copper (Cu) in the aluminum alloy. Therefore,
Knowing the silicon equivalent (SiE) of the molten Al-Si based aluminum alloy can be analyzed before the furnace before casting the main component of the cast aluminum alloy.

[0004]

In the prior art, a molten metal of an aluminum alloy for casting is taken as a sample into a sampling container made of ceramic and equipped with a thermocouple, and its cooling curve is measured for thermal analysis. In this case, no additives have been added to the molten aluminum alloy in order to stabilize the primary crystal temperature, and the furnace was added before casting the main component in the alloy by measuring the silicon equivalent. There is no previous analysis.

That is, in the prior art, Al--Si
The degree of difference in the amount of nuclear substances that crystallize the primary crystals (α crystal) for crystallizing the main component of the aluminum alloy, even if the components of the supplied molten metal are the same for each thermal analysis of the aluminum alloy , Different primary crystal temperatures were shown. That is, there was a problem that the same primary crystal temperature could not be obtained despite the same donor sample.

Further, since it has not been considered at all to measure the equivalent weight of silicon contained in an aluminum alloy, for example, although the influence of individual elements forming the alloy on the fluidity is known, It was not possible to know the overall effect of the on the composition of the molten metal.

In view of the above-mentioned problems, the main object of the present invention is to cast aluminum alloys, especially Al-Si.
It is intended to provide a method for stabilizing the primary crystal temperature of a molten aluminum-based alloy.

Another object of the present invention is to determine the total influence of the individual elements contained in the molten Al-Si based aluminum alloy for casting in order to know the total effect of the individual elements in the molten state, especially the inclusion of copper in the molten state. It is to provide a method for measuring quantity.

A further object of the present invention is that A
It is an object of the present invention to provide a novel method for analyzing the main component of a molten metal before casting an 1-Si based aluminum alloy.

[0010]

DESCRIPTION OF THE INVENTION According to an equilibrium diagram of an aluminum alloy, particularly an Al--Si type aluminum alloy, as shown in FIG. 1, when the content of silicon (Si) is constant, the dendritic material containing aluminum as a main component is The crystallization temperature of the primary crystal of α crystal is supposed to be constant, but actually it crystallizes at a temperature lower than the temperature shown in the equilibrium diagram. The reason is that the amount of the substance that nucleates primary crystals is not sufficiently present in the molten metal.

Therefore, in the present invention, Al--Si
A primary crystal nuclear material, that is, a heterogeneous nuclear material that becomes crystal nuclei, is added to the molten aluminum-based alloy to make the primary crystal temperature of the molten metal constant.

As the foreign material to be added, Al--
5% Ti-1% B is selected and a small amount thereof is added in advance to a molten metal sampling container for thermal analysis. This addition amount is about 0.2% to about 0.4% based on the weight of the molten metal.

When Al-5% Ti-1% B is added as a heterogeneous nuclear material to a sample container for thermal analysis of molten metal, and the molten Al-Si based aluminum alloy is poured into this container. , Ti or TiB diffuses into the molten aluminum alloy in the container, but Ti or TiB as the nuclear material is not dissolved because it has a high melting point and exists in a state of being suspended in the molten aluminum alloy.

As a result, a thin film of Ti is formed around TiB, and this thin film transforms a binary alloy with a molten aluminum alloy, that is, a peritectic reaction that surrounds and solidifies a nuclear material to solidify nuclei of primary crystals. Therefore, the molten aluminum alloy exhibits a constant primary crystal temperature. Therefore, if this primary crystal temperature is measured, the silicon equivalent (SiE) can be obtained from the binary phase diagram of the Al-Si based aluminum alloy.

[0015]

[Experiment] An Al-7.0% Si alloy was melted and the temperature of the molten metal was maintained at 720 ° C. In order to measure the cooling curve of this melt, the melt was subjected to thermal analysis without adding any additives to a conventionally known sampling container, and the primary crystal temperature was 610.8 ° C.

Next, 0.1 to 0.4% of Al-5% TiB, which is the weight of the sample to be injected into the sampling container, has been added in advance, and Al-7.0% kept at 720 ° C. has been added. Si
The cooling curve was measured by pouring the molten alloy.

As a result, as shown in FIG. 2, 0.1% of Al-5% Ti-1% B previously added to the sample container was obtained.
In the case of, the temperature rises to 614.0 ° C and the addition amount is 0.3
%, 0.4%, and 0.5%, all the primary crystal temperatures did not change at 614.0 ° C. From this experiment, the primary crystal temperature of the molten metal was 614.0 ° C., and when this was examined using a binary equilibrium diagram, the silicon equivalent (S
iE) was found to be 7.0% and the amount of Al-5% Ti-1% B added was 0.
It can be seen that the optimum value is 2%.

If the silicon equivalent of the molten aluminum alloy for casting can be measured in this manner, the silicon equivalent is 1/2 of the silicon content and the copper content,
That is, the amount of silicon and the amount of copper in the molten metal can be easily calculated from the relationship of SiE = Si + Cu / 2.

[0019]

As described in detail above, the present invention has a significant effect on the components contained in the aluminum alloy for casting and the properties of the aluminum alloy casting by thermal analysis of the molten aluminum alloy. It is a method of calculating the content of copper, and since it can be known in front of the furnace before casting the molten metal, it is a very significant technique in the production of aluminum alloy castings.

[Brief description of drawings]

FIG. 1 is a binary equilibrium state diagram of an Al—Si based aluminum alloy.

FIG. 2 is a diagram showing the effect of the addition amount of Al-5% Ti-1% B on the primary crystal temperature of the molten metal of Al-7.0% Si alloy.

Continuation of the front page (56) Reference JP 2001-50920 (JP, A) JP 2000-146879 (JP, A) JP 2001-99797 (JP, A) JP 2000-241374 (JP, A) International Publication 91/18285 (WO, A1) Patent 3390813 (JP, B2) Morinaka Masayuki, "Estimation of Eutectic Structure of Al-Si Alloy by Sodium Equivalent", Casting Engineering, Japan, Japan Foundry Engineering Society, 2001 May 25, Vol. 73, No. 5, p. 331-334 Hironori Ogura, Hirokazu Naga, Takanobu Suzuki, Masayuki Morinaka, "Hinkability of Al-Si-Cu ternary alloys", Casting Engineering, Japan, Japan Foundry Engineering Society, August 25, 2000 72, No. 8, p. 530-534 Morinaka Masayuki, “Structural Control by Triple Cup System”, Abstracts of the Japan Foundry Technology Association Conference, Japan, Japan Foundry Technology Association, November 7, 1996, Autumn 1996, p. 17-21 (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 25/00-25/72 C22C 21/00-21/18 G01N 33/00-33/46 JISST file (JOIS)

Claims (4)

(57) [Claims] 1. Preparing a sampling container equipped with a thermocouple used for thermal analysis of a molten aluminum alloy for casting, and a foreign substance which becomes a crystal nucleus of a primary crystal of a molten metal injected into the sampling container. The addition of the nuclear material, measuring the primary crystal temperature of the molten metal from the cooling curve obtained by injecting the molten metal into the sampling container, and the primary crystal temperature according to the binary phase diagram of the aluminum alloy. The method for measuring the content of copper in the aluminum alloy for casting, which comprises: determining the silicon equivalent of the alloy in 1 .; and calculating the content of copper in the molten metal from the silicon equivalent. 2. The method of claim 1, wherein the amount of said foreign nuclear material added to said sampling container is about 0.2 to 0.4% by weight of said aluminum alloy injected into said container. 3. The heterogeneous nuclear material is Al-5% Ti-1%
The method of claim 1, wherein B. 4. The casting aluminum alloy is Al--S.
The method according to claim 1, wherein the aluminum alloy is an i-based aluminum alloy.