JPH041561A - Blister testing method for die casting product - Google Patents

Abstract

PURPOSE:To realize casting management with smalle amount of entrainment of gas by dipping a die casting product in medium molten metal with low wettability and reactivity with die casting alloy and heat-controlled at a constant temperature, and taking it out after the lapse of a prescribed time. CONSTITUTION:In a blister device A, heat insulting materials 2 are provided at the side circumferential plane and outside the bottom plane of a crucible 1 made of iron in closely contact shape, and also, a sheath heater 3 is wound and embedded in the side circumferential plane and the bottom plane wall part of the crucible 1. The medium molten wetal with low wetability and reactivity with the die casting alloy is heat-controlled at the constant temperature (holding temperature) in the crucible 1, and the die casting product C is dipped in the fusion hot water B, and the product is heated, then, it is taken out after the lapse of the prescribed time. Therefore, it is possible to realize the casting management by which the die casting product with small amount of entrainment of gas and high quality can be casted by the blister testing method.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a blister testing method for die-cast products. Specifically, the present invention relates to a blister testing method for die-cast products. This invention relates to a blister test method for checking the occurrence of blisters.

<Prior art and its problems> In general, blister testing of die-cast products is carried out at a constant temperature (maintenance temperature) at which the product does not undergo shape deformation due to heat, for example, in the case of aluminum die-cast products cast from an aluminum alloy. 5. When the temperature is controlled (maintained) at a constant temperature of around 500°C, the product surface bulges due to gas pressure trapped in internal pinholes and blowholes.
Heat the product to a heating temperature range of about 00°C and check the location, amount, and size of gas involved. In other words, in the case of an aluminum die-cast product that is cast at a predetermined casting pressure, entrained gas is trapped inside the product at a pressure close to the casting pressure and remains inside the product as pinholes or cavities. The product material at the location where it is rolled up is deformed by the gas pressure involved, and blisters appear on the surface. The gas entrainment situation is confirmed by looking at the heating temperature range.The above heating temperature range is said to be preferably around 500℃,
It is said that by heating the product to about ℃, it is possible to confirm the location, amount, and size of all gases involved.

However, in the conventional blister test method, an aluminum die-cast product is placed in a heating furnace (usually a hot air oven) that is heated at a constant temperature of about 500°C, and the inside of the product is determined by the occurrence of blisters on the surface of the product. Because we checked the location, amount, and size of the gas involved, we were able to confirm the heating temperature range 5 where the surface would be blistered.
It takes too much time to heat the product to around 00℃, and as a result, the product quality can only be checked numerically, such as checking only a selected product from a large number of cast products. Couldn't use it.

<Problem to be solved by the invention> The present invention has been made in view of the above-mentioned conventional circumstances, and the technical problem to be solved is to quickly increase the heating temperature to a heating temperature range where blistering occurs on the surface. To provide a blister testing method that can heat the product, change and set casting conditions while checking the state of gas entrainment inside the product, and realize casting management with less gas entrainment.

<Means for Achieving the Technical Problem> The technical means taken by the present invention to achieve the above-mentioned problem is to use die casting in a molten medium that has low wettability and reactivity with the die casting alloy and is heated to a constant temperature. The feature is that the product is immersed and the die-cast product is taken out after a predetermined period of time has passed.

<Function> According to the above-mentioned technical means of the present invention, a die-cast product is immersed in a molten medium whose temperature is controlled (maintained) at a constant temperature. At this time, since the molten metal with low wettability and reactivity with the die-casting alloy is used, the die-cast product is less susceptible to corrosion due to reaction with the molten metal, and the molten metal does not adhere to the surface of the molten metal. Heated effectively and quickly by heat. After a predetermined period of time has elapsed, the die-cast product is removed from the molten metal, and blisters are confirmed on the surface of the product.

<Example> An example of the implementation of the present invention will be described below. Fig. 1 shows a blister device A using this construction method, and such a blister device A has a heat insulating material 2 on the outside of the side circumferential surface and bottom surface of an iron crucible 1. are arranged in close contact with each other, and a sheath heater 3 is wound and buried in the side peripheral surface and bottom wall of the iron crucible 1 as a heating means, and the wettability with the die-cast alloy in the iron crucible 1 is improved.
The medium molten metal B with low reactivity is controlled to be heated to a constant temperature (holding temperature), the die-cast product C is immersed in the molten metal B, the product C is heated, and the product C is taken out after a predetermined period of time has elapsed.

In the figure, reference numeral 4 denotes an opening/closing lid made of a desired material such as iron or refractory, which closes the opening of the iron crucible 1.

Next, a comparative example will be described in which the time taken to heat the die-cast products C of the present method and the conventional method to the temperature range where blistering occurs under the following experimental conditions.

a. Product material: ADCI2 (12 types of aluminum alloy die casting) b. Product shape: Shown in Figure 2 (Product weight: 127.3 g) C0 temperature measurement position (temperature sensor insertion position): A in Figure 2
-A cross section center d, holding temperature (molten metal temperature for this method, furnace temperature for conventional method)
: Approximately 500℃ e, Product heating temperature (blistering temperature range): Approximately 500℃ In this method, lead (PB) is used as the molten metal B, and this lead is placed in the iron crucible 1 of the blister device A. Controls (maintains) the temperature of molten lead at a constant temperature.

As shown in Fig. 3 (this method) and Fig. 4 (conventional method), which show the temperature rise state of aluminum (ADC12) die-cast products by heating curves, respectively, in the case of the conventional method, the aluminum die-cast product It takes 20 m1n to reach the heating temperature of about °C, whereas in the case of this method, it takes 1.0 m1n.

Therefore, in this method, by immersing an aluminum die-cast product in molten lead and taking it out after 1.0 m1, the position, amount, and size of gas entrained inside the product can be confirmed by checking the bulges formed on the surface. Therefore, it is possible to quickly check the gas entrainment situation inside the product every 1.0 m1 and change the casting conditions of the die-casting machine, such as changing the plunger speed of the injection mechanism from low to high speed, or from low to high speed. By changing and setting injection conditions, such as changing the switching timing to reduce the entrainment of air into the molten aluminum inside the injection sleeve, we can optimize the casting conditions to cast products with fewer pinholes and cavities. Since accurate judgment can be made, casting management that produces high quality products can be realized.

The blister device A used in this method heats the molten metal B while storing heat in the iron crucible 1, so that the temperature of the molten metal B can be controlled with high precision.

<Effects of the Invention> Since the blister testing method of the present invention is configured in a push-up manner, the die-casting product can be heated to a constant temperature in a heating temperature range in which blisters can be effectively and quickly formed on the surface by the heat of the molten metal in a medium that is controlled to a certain temperature. The temperature can be raised to about 500°C.

Therefore, it is possible to change and set the casting conditions of the die-casting machine while checking the gas entrainment situation inside the product, so the blister test method can be used to control casting to cast high-quality die-cast products with less gas entrainment. It can be realized by

Therefore, the intended purpose was achieved.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an example of a blister device used in the blister testing method of the present invention, Fig. 2 shows a die-cast product sample used in the heating temperature increase experiment of the present method and the conventional method, and Fig. 3 FIG. 4 is an experimental graph showing the temperature rising curve obtained by this method, and FIG. 4 is an experimental graph showing the temperature rising curve obtained by the conventional method. In addition, B in the figure: Medium molten metal (lead molten metal) C: Die-cast product

Claims (1)

[Claims] A pristar test method for die-cast products, which is characterized by immersing the die-cast product in a molten medium whose wettability and reactivity with the die-cast alloy is controlled at a constant temperature, and taking out the die-cast product after a predetermined period of time has elapsed. .