KR20030087109A - System for heating riser and gravity casting method using the same - Google Patents

Abstract

PURPOSE: An apparatus for heating a riser is provided to minimize product defects by properly heating the riser of the product, increase feeding effect and manufacture high quality molding by controlling heating amount and to reduce riser treatment cost after casting by reducing the amount of the riser, and a gravity casting method using the same is provided. CONSTITUTION: The apparatus(10) for heating a riser comprises a power supply unit(12) whose driving is selectively turned on or off according to control signals; a heat source(14) installed at the upper side of riser mold(3) to heat the upper surface of the riser(5) using a power supply supplied from the power supply unit(12) when driving of the power supply unit(12) is turned on; temperature measuring means(16) for outputting temperature signals according to detected current temperature values by detecting current temperature values of the upper surface of the riser(5); and a control means for outputting control signals for controlling on/off of the power supply unit(12) according to temperature signals inputted from the temperature measuring means(16), wherein the temperature measuring means(16) are infrared temperature measuring instruments.

Description

System for heating riser and gravity casting method using the same

The present invention relates to an apparatus for heating a pressure part and a gravity casting method using the same, and more particularly, when a molten metal is solidified after being injected into a mold and a pressure mold during gravity casting, an appropriate amount of heat is applied to the pressure part of the product. By preventing the sudden solidification of the product, defects in the product caused by the rapid solidification of the hot water part can be minimized, the effect of the hot water can be increased and the high quality casting can be manufactured by adjusting the heating amount, and the amount of the hot water part can be reduced. The present invention relates to a hot water heater heating apparatus and a gravity casting method using the same, which can reduce the cost of processing the hot water after casting.

In general, the gravity casting method refers to a casting method in which a molten metal is injected into a mold by gravity to make a casting. At present, pistons are made of non-ferrous alloys such as aluminum (Al), magnesium (Mg), and copper (Cu), cast iron, or steel. It is widely used to manufacture sleeves, crankcases, cylinders, bearings, and the like.

FIG. 3 is a cross-sectional view illustrating a mold, a press mold, a press part, and a cast product in a typical gravity casting method.

As shown in the figure, during gravity casting, a pressure mold 3 for the pressure portion 5 is provided on the upper side of the mold 1.

The pressure portion 5 is to prevent the defects of the cast product 7 by forming a space in the mold 1 when the molten metal injected into the mold 1 is cooled and solidified shrinkage, the top position of the mold (1) Refers to the extra melt contained in the pressure mold (3).

In the gravity casting method, an important role of the pressure part 5 is to serve as a heat source for replenishing material shortages due to solidification shrinkage inside the product 7 and preventing non-uniform solidification during the solidification of the molten metal.

In general, in the case of production of the product by the gravity casting method, in order to improve the quality inside the product, the pressure portion 5 equivalent to the weight of the product 7 is required.

However, in the gravity casting method as described above, there were the following problems due to the installation of the pressure portion.

In other words, it is difficult to quantify the weight of the hot water part and control the size and shape, and if solidification occurs first in the hot water part, defects such as pin holes, blow holes, or shrinkage cavities in the product may be caused. Can be generated.

In addition, after casting, the hot water part is cut from the product and recycled. The larger the amount of hot water parts, the higher the cost of pretreatment, post-treatment, and remelting.

Therefore, the present invention has been invented to solve the above problems, and when gravity casting is injected into the mold and the molten mold during solidification, by applying an appropriate amount of heat to the molten portion of the product to rapidly solidify the molten portion By preventing it, it is possible to minimize defects in the product caused by rapid solidification of the hot water part, to increase the effect of the hot water and to manufacture high-quality castings by adjusting the heating amount, and to reduce the amount of the hot water part after the casting. It is an object of the present invention to provide a pressure casting unit heating apparatus and a gravity casting method using the same, which can reduce the processing cost of the pouring unit.

1 is a block diagram showing a hot water heater heating device of the present invention

Figure 2 is a micrograph showing the microstructure of the pressurized portion of the gravity casting according to the present invention

3 is a cross-sectional view showing a mold, a press mold, a press part, and a cast product during a conventional gravity casting method

Figure 4 is a micrograph showing the microstructure directly under the pressure portion of the cast by a conventional gravity casting method

<Explanation of symbols for the main parts of the drawings>

1: mold 3: pressure mold

5: pressure part 7: product (or casting)

10: hot water heating device 12: power supply

14 heat source 16 temperature measuring means

18 control means

Hereinafter, the present invention will be described with reference to the accompanying drawings.

The hot water heater heating device according to the present invention is installed on the power supply device 12 that is selectively driven on (on) or off (off) in accordance with a control signal, the upper side of the hot water mold (3) of the power supply device 12 The heat source 14 which heats the upper surface of the hot water part 5 with the power supplied from the power supply 12 at the time of driving on, and the current temperature of the upper surface of the hot water part 5 are detected and A temperature measuring means 16 for outputting a temperature signal, and a control means 18 for outputting a control signal for on / off control of the power supply device 12 according to the temperature signal input from the temperature measuring means 16. It is characterized by consisting of.

In particular, the temperature measuring means 16 is characterized in that the infrared temperature measuring instrument.

On the other hand, the gravity casting method according to the present invention in the gravity casting method for molding the molten product (7) having a predetermined shape by injecting the molten metal into the mold (1) and the pressure mold (3) and solidified

When the molten metal is solidified, the temperature measuring means (16) of claim 1 detecting the current temperature of the upper surface of the hot water unit (5) and outputting a temperature signal according to the detected value;

The control means 18 of claim 1 receives a temperature signal output from the temperature measuring means 16 and outputs a control signal when the temperature of the upper surface of the hot water part 5 reaches a preset temperature. Driving the power supply unit 12 for a predetermined time;

Heating the upper surface of the hot water unit (5) during the time by receiving power from the heat source (14) of claim 1 by driving the power supply (12);

Characterized in that it comprises a.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block diagram showing an apparatus for heating a hot water unit of the present invention.

In Fig. 1, reference numerals 1, 3, 5, and 7 denote molds, pressure molds, pressure parts, and products (or castings), respectively.

The present invention prevents rapid solidification of the hot water part by applying an appropriate amount of heat to the hot water part of the product when the molten metal is injected into the mold and the molten mold during solidification, thereby preventing the rapid solidification of the hot water part. It is possible to minimize defects, increase the effect of the hot water and manufacture high-quality castings, reduce the amount of hot water and reduce the processing cost of the hot water after casting, and a gravity casting method using the same. will be.

The hot water heating device 10 of the present invention is a power supply device 12 that can be turned on (on) / off (off), by receiving power from the power supply device 12 to heat the upper surface of the hot water heater (5) The main power supply is supplied according to the heat source 14, the temperature measuring means 16 for detecting the present temperature of the upper surface of the hot water unit 5, and the temperature of the upper surface of the hot water unit 5 detected from the temperature measuring unit 16. Control means 18 for controlling the device 12 on / off.

Here, the power supply device 12 is for supplying power to the heat source 14, is selectively driven on or off in accordance with the control signal output from the control means 18, only when necessary It is intended to supply power.

The heat source 14 is installed to heat the upper surface of the hot water part 5 exposed from the hot water mold 3, and is connected to the power supply 12 to drive the power on of the power supply 12. It is designed to receive power.

The heat source 14 may be implemented using a high frequency wave, a laser, an electron beam, or a halogen lamp. The heat source 14 may be any one as long as the calorific value can be known per hour and the hot water unit 5 can be heated.

The heating amount of the hot water unit 5 by the heat source 14 may be adjusted according to the time that power is supplied from the power supply device 12.

The temperature measuring means 16 detects the current temperature of the upper surface of the hot water unit 5 and outputs a temperature signal according to the detected value. The temperature signal output from the temperature measuring means 16 is transferred to the control means 18. It is supposed to be input.

The temperature measuring means 16 is preferably carried out with an infrared temperature measuring device capable of accurately measuring the temperature of the upper surface of the hot water unit 5 at a predetermined distance.

On the other hand, the control means 18 is to output a control signal for the on / off control of the power supply device 12 in accordance with the temperature signal input from the temperature measuring means 16, it may be implemented by a PID controller or the like. have.

In this way, the apparatus for heating the hot water part may apply an appropriate amount of heat to the hot water part when the melt is solidified after being injected into the mold and the hot water mold during gravity casting, thereby preventing rapid solidification of the hot water part. do.

Hereinafter, the gravity casting method of the present invention using the hot water heater is as follows.

First, a product material such as nonferrous alloy, cast iron or steel is melted at a predetermined temperature, and the molten metal, that is, molten metal is injected into the mold 1 and the molten mold 3 through a mold inlet and then solidified.

In the solidification process of the molten metal, the temperature measuring means 16 of the hot water heating unit 10 detects the temperature of the exposed upper surface of the hot water heating unit 5 and outputs a temperature signal according to the detected value.

The control means 18 receives the temperature signal output from the temperature measuring means 16 and compares the temperature of the upper surface of the hot water unit 5 with a preset temperature, and the temperature of the upper surface of the hot water unit 5 is set. When the temperature drops, a control signal is output to drive the power supply 12 for a predetermined time.

When the power supply device 12 is driven, the heat source 14 receives power from the power supply device 12 to heat the upper surface of the hot water unit 5 during the time, and after this time, the control means 18 The control signal is output to turn off the driving of the power supply 12.

Here, the heating amount of the hot water unit 5 by the heat source 14 may be adjusted according to the time that the power is supplied from the power supply device 12 as described above, the power supply time is the power supply device 12 ) Is the driving time.

Therefore, in order to adjust the heating amount of the hot water supply unit 5 by the heat source 14, the driving time of the power supply device 12 in consideration of the amount of heat generated per hour of the heat source 14 is input to the control means 18 in advance. It should be natural.

In this way, in the gravity casting method of the present invention using the apparatus for heating the hot water part, by applying an appropriate amount of heat during the solidification of the hot water part, it is possible to prevent sudden solidification of the hot water part, which can be seen through the following experimental example. As described above, it is possible to increase the effect of the hot water and manufacture a high quality cast product.

In addition, it is possible to reduce the amount of the hot water part, thereby reducing the processing cost of the hot water part after casting, and defects in the structure of the casting which are caused by rapid solidification of the hot water part, that is, pin holes, blow holes, or shrinkage cavities. It is possible to cast high quality products with little or no shrinkage cavities.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example

10 kg of the specimen was manufactured by applying the apparatus for heating the pressure part of the present invention and the gravity casting method using the same (see FIG. 1).

To this end, 18 kg of an aluminum alloy was melted at 750 ° C. and slowly injected into a mold 1 and a pressure mold 3 preheated to 180 ° C., and then solidified.

In addition, when the temperature of the hot water unit 5 detected from the infrared temperature measuring device during the coagulation process drops to a set temperature of 550 ° C., the power supply device 12 is driven on by the control signal of the control means 18. The heating time of the hot water part by the heat source 14 was set to 90 seconds.

The heat source 14 used at this time was a high frequency heating device, and this high frequency heating device 14 had a capacity of 100 Hz.

Comparative example

A 10 kg specimen was prepared using a conventional gravity casting method (see FIG. 3).

To this end, 20 kg of an aluminum alloy of the same material as in Example was melted at 750 ° C., and slowly injected into a mold 1 and a pressure mold 3 preheated to 180 ° C., and then solidified.

Experimental Example 1

The metal tissue of the specimen obtained by directing the molten portion of the specimen obtained through the above Examples and Comparative Examples was shown in FIGS. 2 and 4, respectively.

As a result, it was confirmed that no internal defects such as pin holes, holes, or shrinkage cavities existed in the specimens of the embodiment (in FIG. 2). A large number of internal defects such as micropores, pores or shrinkage cavities were found (in FIG. 4).

Experimental Example 2

The porosity in the tissue and the weight of the pressure part were measured using the respective specimens obtained through the examples and the comparative examples.

(1) porosity percentage (%)

The porosity indicates the defect content in the product, measured by a test method of an image analyzer, and the results are shown in Table 1 below.

(2) Weight of the pressure part (kg)

The pressure was measured by cutting the pressure portion of each specimen, and the results are shown in Table 1 below.

Looking at the results, as shown in Table 1, the porosity was significantly reduced compared to the specimen obtained through the comparative example in the specimen obtained through the example even though the weight of the hot water in the embodiment compared to the comparative example by 20% And it was found.

As a result, in the hot water heating device and the gravity casting method using the same according to the present invention, by applying an appropriate amount of heat to the hot water during solidification, it prevents rapid solidification of the hot water, thereby effectively preventing defects in the product structure. It is possible to manufacture high quality castings while reducing the amount of hot water.

As described above, according to the present invention, when the molten metal is injected into the mold and the molten mold during gravity casting, the molten metal is prevented from sudden solidification by applying an appropriate amount of heat to the molten portion of the product. It works.

1) It is possible to minimize defects in products such as micropores, pores or shrinkage cavities generated during rapid solidification of the hot water part.

2) By controlling the heating amount, it is possible to increase the effect of the hot water and manufacture high quality castings, and to reduce the amount of hot water, thereby reducing the processing cost of the hot water after casting.

Claims (3)

The power supply 12 which is selectively turned on or off in accordance with the control signal and the pressure supply mold 3 is installed above the power supply 12 when the power supply 12 is driven on. A heat source 14 for heating the upper surface of the hot water unit 5 with the power supplied from the apparatus 12, and temperature measuring means for detecting a current temperature of the upper surface of the hot water unit 5 and outputting a temperature signal according to the detected value ( 16) and control means 18 for outputting a control signal for on / off control of the power supply device 12 according to the temperature signal input from the temperature measuring means 16. Hot water heater. The hot water heater according to claim 1, wherein the temperature measuring means (16) is an infrared temperature measuring device. In the gravity casting method of injecting the molten metal into the mold (1) and the pressure mold (3) and then solidified by molding the product (7) of a predetermined shape, When the molten metal is solidified, the temperature measuring means (16) of claim 1 detecting the current temperature of the upper surface of the hot water unit (5) and outputting a temperature signal according to the detected value; The control means 18 of claim 1 receives a temperature signal output from the temperature measuring means 16 and outputs a control signal when the temperature of the upper surface of the hot water part 5 reaches a preset temperature. Driving the power supply unit 12 for a predetermined time; Heating the upper surface of the hot water unit (5) during the time by receiving power from the heat source (14) of claim 1 by driving the power supply (12); Gravity casting method comprising a.