JPH0224184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The following describes improvements in pouring furnaces that hold molten metal for timely injection, particularly improvements in pressurized pouring furnaces. (Prior art) Molten metal pouring furnaces, which have begun to be used to replace the old manual pouring method using a ladle, are used in the casting of castings, especially in casting lines that perform sequential continuous casting. There are pressurized types, tilting types, electromagnetic pump types, etc. Among them, the pressurized type is advantageous in terms of pouring accuracy and power consumption.
52 ('79), 619; Mitsubishi Electric Technical Report 53 ('79), 652;
As disclosed in Mitsubishi Electric Technical Report 52 ('78), 450, etc. These pressurized pouring furnaces have a hot water storage chamber whose upper part is sealed, a hot water receiving path and a hot water outlet path rising from the bottom of the hot water storage chamber, and a groove-shaped induction heating section for heating molten metal that communicates with the bottom of the hot water storage chamber. , When pouring, just before pouring, the level of the hot water in the pouring path is set at a fixed position (pre-level).
A base pressure P is pressurized in the hot water storage chamber so as to maintain the same, and when pouring hot water, a shot pressure ΔP corresponding to a predetermined pouring speed is added to the base pressure and the hot water is pressurized. reference). With this method, molten metal can be replenished from the receiving channel as needed and the molten metal can be continuously poured.Since the molten metal pouring operation is easy to control, it can be used continuously or sequentially for single alloy types such as castings. It is extremely effective for pouring hot water. (Problem to be solved by the invention) However, in a pressurized pouring furnace, when the amount of molten metal decreases and becomes below the lower limit, the pressurized gas flows into the pouring furnace, causing a bumping phenomenon, and therefore, the amount of molten metal always decreases. A limited amount of residual molten metal is required, and the amount is 30 to 50% of the total weight. (Refer to the cited document above) This residual molten metal is discharged when changing the alloy type or replacing the furnace, leading to a decrease in yield, and especially when pouring with a wide variety of alloy types, the remaining molten metal remains after changing the composition. Since it is necessary to drain the molten metal, a decrease in yield results in a large loss. Therefore, it is desirable to provide a pressurized pouring furnace that can reduce the amount of remaining metal required for the pressurized pouring furnace as much as possible and significantly reduce the decrease in yield due to drainage of residual metal during multi-product production. This is the object of the invention. (Means for solving the problem) The minimum amount of remaining metal in a pressurized pouring furnace is determined by the lower limit molten metal level, which corresponds to the upper surface of the rising part of the tapping furnace. That is, if the molten metal level is lowered by this level, the pressurized gas will only flow out through the outlet path during pressurization, and the molten metal will no longer be pushed out by gas pressure. The larger the cross-sectional area of the hot water storage chamber at the above-mentioned lower limit molten metal level, the larger the amount of remaining hot metal. Therefore, by making the cross-sectional area of the hot water storage chamber as small as possible at the lower limit molten metal level, it is possible to reduce the amount of remaining hot metal. Therefore, the present invention provides a pouring furnace having a pressurizable hot water storage chamber 1 which stores molten metal 2 and which is sealed at the upper part, and a hot water outlet path 3 rising from the bottom of this hot water storage chamber 1. This pressurized pouring furnace is characterized in that the rising portion 8 is located below the bottom surface 9 of the hot water storage chamber 1. Here, the hot water storage chamber 1 is provided with a groove-type induction heating section 10 that communicates with the lower part thereof, and that the groove-type induction heating section 10 is connected to the rising portion of the tapping furnace 3 and is directed downward toward the groove-type induction heating section 10. It is practical to have a communication path with a bottom surface inclined at an angle of 3 degrees or more, and furthermore, it is preferable that the hot water storage chamber 1 has a hot water receiving furnace that communicates with the hot water storage chamber 1 and can be pressurized simultaneously with the hot water storage chamber. The structure of this invention is specifically shown in FIGS. 1 and 2. In the figure, 1 is the hot water storage chamber, 2 is the molten metal, 3 is the outlet path,
4 is a tap for pouring into a mold, etc.; 5 is a receiving channel for receiving molten metal from another molten metal holding container; 6 and 7 are lids for sealing; 8 is a rising portion of the tapping channel; 9 1 is the bottom surface of the hot water storage chamber 1 located particularly above the rising portion 8 of the tapping path, and 10 is a groove-type induction heating device for heating the molten metal. (Function) As illustrated in FIG. 3, which shows a comparison before and after the above-mentioned improvement made to the rising portion 8 of the tapping channel 3, the pressurized pouring limit amount of the molten metal 2 is higher than that of the conventional structure b. It can be reduced by that amount with the bottom raised structure a. By pressurizing the molten metal receiving path 5 as well, the amount of molten metal in the molten metal receiving path can also be reduced. What should be considered is that by raising the bottom of the furnace, the heat generated by the groove-type induction heating device 10 is not transmitted to the tapping path 3, and the molten metal is prevented from solidifying in the tapping path. That is, since the groove-type induction heating device 10 does not have a very large stirring ability for the molten metal, heat transfer in the molten metal 2 is mainly dependent on natural convection. Under natural convection, the low-temperature molten metal 2 stays in a lower part due to the density difference, but if the tapping furnace riser part 8 is simply installed lower than the bottom surface 9 of the hot water storage chamber, this part will be exposed to the low-temperature molten metal 2. There is a possibility that the metal 2 is stuck and the heat from the heating part is not sufficiently transmitted. In the case of the example in FIG. 1, this means that the bottom surface 9 of the hot water storage chamber 1 and the rising portion 8 of the hot water outlet path 3 are all directed toward the groove-type induction heating device 10, as indicated by arrows α and β, and have a downwardly sloping bottom surface. This can be solved by communicating through the path 11. That is, the low-temperature molten metal flows from the bottom of the furnace of the hot water storage chamber 1 along the slope (arrows α, β) toward the groove-type induction heating device 10 and is heated, and the molten metal that has been heated flows in the direction of the slope. The molten metal flows in the opposite direction, and the convection of the molten metal in the outlet path 3 and the hot water storage chamber 1 is extremely smooth, and there is no risk of solidification. The angle of the bottom surface of the communication path that slopes from the rising portion 8 of the hot water outlet path 3 toward the groove-type guiding device 10 is shown in FIG.
As shown in the effect on the temperature of the molten metal in the tap path 3 when holding the molten metal 2 at 1600℃, the above slope of 3 degrees is sufficient, and if it is less than that, the molten metal solidifies in the tap furnace 3. I found out that there is something I am happy about. Of course, if the communication path 11 is opened in the shape of a clevis at the bottom surface 9 of the hot water storage chamber 1 as in the specific example shown in FIG. 2, and heating is performed by the groove-type induction heating device 10,
Since there is no low-temperature molten metal in the tapping path 3, the induction-heated molten metal flows directly into the tapping path 3. A further advantage of the present invention is that the ratio of the total molten metal to the effective molten metal amount is small, so the groove type induction heating device 1
Since the molten metal holding power consumed at zero is small, it is also effective from the viewpoint of energy saving. (Example) When the effective capacity is 5.0t, the total capacity of the conventional pouring furnace shown in Figure 3b is 7.7t, whereas in the example shown in Figure 3a, the total capacity of the pouring furnace is The total weight was almost 6.4t. Therefore, the amount of molten metal remaining in the furnace at the level where the melt cannot be tapped is 2.7 tons in the conventional example, but
It is 1.4t. Now, using both the pouring furnaces shown in Figure 3 a and b,
SUS430, SUS308 and Incoloy 800 were sequentially poured. First, 5 tons of SUS430 molten metal, then
SUS308 molten metal and Incoloy 800 molten metal respectively
How to add hot water when casting 2 tons and Ni in that case,
Table 1 shows a comparison of the yields of Cr and Fe. [Table] In the example, the amount of remaining hot water is small, so from SUS430
When transitioning from SUS308 to Incoloy 800, the amount of Cr and Ni in the additional molten metal was lower than in the comparative example, and when transitioning from SUS308 to Incoloy 800, the furnace was tilted to drain the molten metal before adding molten metal with a high concentration of Cr and Ni. However, in the example, the amount of hot water discharged was only 0.2 t, which was significantly lower than in the comparative example, which exceeded 1.0 t. In other words, when changing the type of alloy to be poured, the method of the present invention allows the type of alloy to be easily changed without draining the hot metal or with a very small amount of hot metal draining, even if the composition of the alloy before and after the change is significantly different. Since it can be changed, the flexibility of changing the alloy type is greatly expanded compared to conventional methods. In addition, the final amount of remaining hot water is also shown in the example.
1.4t, whereas the comparative example was 2.7t, which was about half that. Therefore, the yields of Ni, Cr, and Fe can be maintained much higher in the example than in the comparative example. Next, Table 2 shows a comparison of the amount of power held by the pouring furnaces, and the average value is the average value after holding molten metal for about three months in both the example and the comparative example. 10kw less power is sufficient. [Table] (Effects of the invention) According to the present invention, the amount of remaining metal required for the pressurized pouring furnace can be reduced, which not only improves the yield of molten metal, but also requires no intermediate discharge or only a small amount of intermediate discharge. It is revolutionary in that it allows the composition of the molten metal to be easily changed and is advantageous for continuous pouring of a wide variety of molten metals, as well as the ability to maintain the minimum necessary amount of molten metal at all times, which in turn requires less power consumption.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are cross-sectional views of the respective embodiments, FIG. 3 is a comparison diagram of the required amount of remaining molten metal, and FIG. 4 is a comparison graph of molten metal temperature in the outlet channel. 1... hot water storage chamber, 2... molten metal, 3... tapping furnace, 8... rising portion, 9... bottom surface of hot water storage chamber.

Claims (1)

[Scope of Claims] 1. A pouring furnace having a pressurizable hot water storage chamber 1 that stores molten metal 2 and is sealed at the top, and a hot water tap path 3 rising from the bottom of the hot water storage chamber 1, including: A pressurized pouring furnace characterized in that a rising portion 8 of the molten metal is located below the bottom surface 9 of the hot water storage chamber 1. 2. The pouring furnace according to claim 1, wherein the hot water storage chamber 1 is provided with a groove-shaped induction heating section 10 communicating with a lower part thereof. 3. The groove-type induction heating section 10 is connected to the rising part of the tapping furnace 3 and extends downward toward the groove-type induction heating section 10.
3. The pouring furnace according to claim 2, wherein the pouring furnace has a communication path having a bottom surface with an inclination of more than 100 degrees. 4 Claims 1 and 2, in which the hot water storage chamber 1 has a hot water receiving path that communicates with the hot water storage chamber and can be pressurized at the same time as the hot water storage chamber.
Or the pouring furnace described in 3.