JP2006326646A - Ladle for casting and casting method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of a cast product by removing slag from molten metal. <P>SOLUTION: In the inner part of a hollow cylindrical shaped ladle 20 for casting, a slag-trapping plate 30 and a plate 32 for pocket part, are arranged so as to bridge to both side wall parts 20a, 20b. In additive 6, such as spheroidizing agent, inoculant, held in the upper part (pocket part 52) of the plate 32 for pocket part, the one which is not melted in the molten metal L is remained as the slag S and floated up on the surface of the molten metal L. When the ladle 20 for casting, is tilted, the molten metal L is introduced from the lower position than the molten metal surface floating the slag S through a molten metal tapping hole 34. In this case, even the descended molten metal surface is reached to the upper end surface of the slag-trapping plate 30, the slag S existing on the molten metal surface is stuck to the slag-trapping plate 30 and caught. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a casting ladle that stores molten metal to be filled in a casting mold and is tiltably supported by a tilting means, and a casting method using the same.

  A schematic longitudinal sectional view of a general casting ladle 1 is shown in FIG. The ladle for casting 1 has a rear wall portion 2 and a front wall portion 3 that are inclined and rise from the bottom surface, and an upper portion is open. Further, side wall portions 4 extend to the rear wall portion 2 and the front wall portion 3, and a slag trap plate 5 is bridged between the side wall portions 4. The casting ladle 1 is tiltably supported by tilting means (not shown).

  Hereinafter, a case where casting is performed using a cast iron melt and Mg as a spheroidizing agent is used as the additive 6 will be described as an example. Additive 6 (Mg) is accommodated close to the rear side wall. It is difficult to say that Mg is dissolved in the molten metal well, and therefore, an excessive amount is used.

  When casting using this type of ladle 1 for casting, first, the molten metal L is introduced so as to avoid the additive 6 from above the opening. At this time, although most of Mg is dissolved in the molten metal L, a part of it remains and becomes slag S shown in FIG. 9 and floats on the liquid surface of the molten metal L.

  Next, as shown in FIG. 9, the ladle for casting 1 is tilted at a constant speed under the action of the tilting means, whereby the molten metal L is transferred to the pouring pan 7 from the opened upper part.

  At the lower end of the pouring pan 7, a flange 8 is provided, and this flange 8 is inserted into the runner 10 of the casting mold 9. The molten metal L transferred to the pouring pan 7 passes through the runner 10 and reaches the cavity. There is no particular need to insert the flange portion 8 into the runner 10. That is, the flange portion 8 may be disposed above the runner 10 at a predetermined interval.

  At this time, in the ladle 1 for casting, the slag S floating on the liquid surface of the molten metal L is blocked by the slag trap plate 5. However, a part of the slag S may reach the hot water outlet avoiding the lower end of the slag trap plate 5. When such a situation occurs, it becomes difficult to maintain the discharge rate of the molten metal L from the casting ladle 1 within a predetermined range, and the slag S is introduced into the cavity of the casting mold 9 together with the molten metal L. Therefore, so-called gas defects and so-called foreign matter biting in which the slag S is aggregated are caused in the cast product.

  In order to avoid such a problem, Patent Document 1 proposes a ladle for receiving molten metal from a melting furnace and transferring the molten metal directly to a pouring pan.

  Patent Document 2 proposes that an additive is enclosed in a capsule and the additive is dissolved together with the capsule in a molten metal.

JP 2001-105130 A JP-A-8-176636

  The present invention has been made in connection with the above-described technology, and is excellent in the ability to collect slag. For this reason, a casting ladle capable of avoiding the occurrence of gas defects and foreign matter biting in a cast product, and It aims at providing the used casting method.

In order to achieve the above object, the present invention stores a molten metal to be filled in a casting mold, and in a ladle for casting supported by a tilting means in a tiltable manner,
A hot water inlet for introducing the molten metal and a hot water outlet for extracting the molten metal are formed,
It has a slag trap plate that collects slag present in the molten metal inside,
When the slag trap plate extends in the horizontal direction while tilting to lead out the molten metal, the outlet port is located below the upper end surface of the slag trap plate.

  By setting it as such a structure, a molten metal is derived | led-out from the downward direction of the liquid surface where the slag floated. Therefore, it can be avoided that slag is accompanied by a pouring pan or the like that receives the molten metal. For this reason, it is possible to fill the cavity of the casting mold with the molten metal in which slag does not exist as much as possible, and eventually it is possible to avoid the occurrence of gas defects and foreign matter biting in the cast product.

  You may make it provide this pocket part for accommodating an additive in this ladle for casting. Thereby, after a molten metal is introduce | transduced, this molten metal and an additive can be made to contact.

The casting method according to the present invention includes a step of storing the molten metal to be filled in the casting mold in a casting ladle provided with a slag trap plate inside,
When the ladle for casting is tilted and the slag trap plate extends in a horizontal direction, the molten metal is led out from the outlet port located below the upper end surface of the slag trap plate. And a process of
It is characterized by having.

  By going through such a process and deriving the molten metal from below the liquid surface where the slag has floated, it is possible to avoid the slag accompanying the molten metal. Therefore, a cast product with good quality can be obtained.

  Note that when the slag trap plate extends in the horizontal direction while the molten metal is led out from the outlet, the liquid level of the molten metal that comes down contacts the upper end surface of the slag trap plate. At this time, the slag present in the molten metal adheres to the slag trap plate and is collected, thereby improving the slag collection efficiency.

  In this case, if the casting ladle is provided with a pocket portion, and the additive contained in the pocket portion is brought into contact with the molten metal and then the molten metal is led out from the outlet, the molten metal is spheroidized or inoculated. Processing can be easily performed.

  Note that either the molten metal or the additive may be introduced into the ladle for casting first or at the same time.

  According to the present invention, the molten metal is led out from below the liquid surface where the slag has floated and transferred to a pouring pan or a casting mold. For this reason, it is possible to avoid the slag from being entrained by the molten metal up to the cavity of the casting mold, so that it is possible to avoid the occurrence of gas defects and foreign matter biting in the cast product. In other words, a cast product with good quality can be obtained.

  Hereinafter, preferred embodiments of the casting method according to the present invention will be described in relation to a casting ladle for carrying out the casting method, and will be described in detail with reference to the accompanying drawings.

  The schematic longitudinal cross-sectional view of the ladle for casting which concerns on this Embodiment is shown in FIG. The ladle for casting 20 constituting the pouring device 18 is a hollow cylindrical body having a substantially circular cross section. As shown in FIG. 2, the height direction from one bottom surface 20a to the other bottom surface 20b is horizontal. It is arranged along. For this reason, the ladle for casting 20 has both bottom surfaces 20a and 20b as side wall portions, and the side peripheral wall 20c is bridged from one side wall portion 20a to the other side wall portion 20b. . And the ladle 20 for casting is provided with the hot water inlet 22 by notching a part of both side wall part 20a, 20b and the side surrounding wall 20c in circular arc shape.

  A rotating shaft 24 is passed through substantially the center of both side walls 20a, 20b of the casting ladle 20, and this rotating shaft 24 is rotatably supported by tilting means (not shown). Furthermore, the rotating shaft 24 is supported by a support member 26 that extends along the diametrical direction of the side walls 20a, 20b. The support member 26 is placed on the first load cell 28. Accordingly, the total weight of the support member 26, the ladle 20 for casting, and the molten metal L is applied to the first load cell 28 as a load.

  Inside the ladle 20 for casting, the slag trap plate 30 and the pocket portion plate 32 are bridged from one side wall portion 20a to the other side wall portion 20b, and the pocket portion plate 32 therein is bridged. Are also joined to the side peripheral wall 20c. Moreover, the edge part which faces the side peripheral wall 20c in these slag trap board 30 and the board 32 for pocket parts is extended in parallel with respect to the diametrical direction of the side wall parts 20a and 20b.

  And the hot water outlet 34 is provided by notching a part of the side surrounding wall 20c, and the elongate guide rod member 36 for guiding the molten metal L is being fixed to the hot water outlet 34 vicinity. The hot water outlet 34 is formed at a position closer to the guide rod member 36 side than the extension line when a virtual extension line is drawn from the end face of the slag trap plate 30 facing the rotating shaft 24. The guide rod member 36 may be provided at least below the opening of the tap 34, but may be provided so as to surround the entire opening of the tap 34.

  The pouring device 18 further includes a pouring pan 38. The pouring pan 38 has a molten metal receiving portion 40 that is inclined and opened, and a flange 42 that is formed to protrude from the lower end surface of the molten metal receiving portion 40.

  The pouring pan 38 is supported by the second load cell 50 via a support member 48 at a position where the flange 42 is not inserted into the runner 46 of the casting mold 44. That is, the total weight of the support member 48, the pouring pan 38, and the molten metal L is added to the second load cell 50 as a load (see FIG. 5).

  In the above configuration, the tilting means, the first load cell 28 and the second load cell 50 are electrically connected to a control circuit (not shown).

  Next, the casting method according to the present embodiment will be described by exemplifying a case where a casting operation is performed using a molten iron L of cast iron.

  In the present embodiment, first, an additive 6 containing a spheroidizing agent such as Mg or an inoculating agent is accommodated in the upper end surface of the pocket portion plate 32. That is, the pocket part plate 32 functions as a separator for isolating the part where the molten metal L is introduced from the part where the additive 6 is accommodated (the pocket part 52).

  Next, cast iron melt L from the melting furnace is introduced from the hot water inlet 22 so as to avoid the pocket portion 52. At this time, since the hot water outlet 34 faces obliquely upward, the molten metal L does not leak from the hot water outlet 34. Moreover, since the part plate for pockets exists, the additive 6 does not contact the molten metal L at this time.

  Next, as shown in FIG. 3, the casting ladle 20 tilts about the rotation shaft 24 under the action of the tilting means. When tilted by about 35 ° to 45 °, the slag trap plate 30 and the pocket portion plate 32 extend along the vertical direction. Then, the additive 6 comes into contact with the molten metal L, whereby the inoculation process and the spheroidizing process are performed on the molten metal L in the deep part of the molten metal L.

  When the additive 6 contacts the molten metal L, slag S may be generated. When the slag S is generated, it waits for a while until the majority of the slag S floats on the liquid surface of the molten metal L as shown in FIG. At this time, the slag S that has moved to the slag trap plate 30 adheres to the surface of the slag trap plate 30 and is collected.

  Thereafter, as shown in FIG. 4, the casting ladle 20 is tilted at a high speed in a direction opposite to the above so that the pouring gate 34 approaches the pouring pan 38. At this time, the surface of the molten metal L is stirred in the direction opposite to the tilting direction by the slag trap plate 30, whereby the molten metal L is directed inwardly (from the slag trap plate 30 side) from the side peripheral wall 20 c of the casting ladle 20. A flow occurs. Accordingly, the slag S flows from the side peripheral wall 20c side to the slag trap plate 30 side.

  When the ladle for casting 20 is tilted by 50 ° to 60 °, the upper end surface of the slag trap plate 30 extends in a substantially horizontal direction as shown in FIG. At this time, the hot water outlet 34 is positioned immediately below the upper end surface of the slag trap plate 30, and the molten metal L is transferred to the molten metal receiving portion 40 of the pouring pan 38 while being guided by the guide rod member 36.

  At the time of this liquid transfer, as shown in FIG. 5, the outlet 34 is below the liquid level of the molten metal L, and the slag S floats on the liquid level, so that the slag S is not mixed. The molten metal L is led out from the outlet 34. Moreover, when the liquid level of the molten metal L descends, the slag S adheres to the upper end surface of the slag trap plate 30, and thereby the slag S is collected.

  That is, in the present embodiment, the molten metal L is led out from below the liquid surface where the slag S floats. For this reason, it is possible to avoid the slag S from being transferred to the pouring pot 38 and thus to the cavity of the casting mold 44, and eventually it is possible to avoid the occurrence of gas defects and foreign matter biting in the cast product. That is, the quality of the cast product can be improved.

  When the transfer of the molten metal L to the pouring pan 38 is continued, a part of the molten metal L may solidify in the flange 42. In this case, since the inner diameter of the flange portion 42 is reduced, the passage speed of the molten metal L in the flange portion 42 is reduced, which may reduce the efficiency of the casting operation and may deteriorate the quality of the cast product. .

  Therefore, during the casting operation, it is desirable that the passing speed of the molten metal L, and hence the filling speed into the cavity of the casting mold 44, be within a predetermined range. Therefore, in the present embodiment, the tilt angle and the tilt angular velocity of the casting ladle 20 are controlled by the control circuit.

  Specifically, the control circuit calculates a weight change amount per unit time of the molten metal L derived from the outlet 34 based on the weight of the molten metal L measured by the first load cell 28, and the weight change amount. Is monitored as the discharge flow rate of the molten metal L from the outlet 34. On the other hand, the control circuit calculates a weight change amount per unit time of the molten metal L derived from the flange 42 based on the weight measured by the second load cell 50 that supports the pouring pan 38. This weight change amount is monitored as the flow rate of the molten metal L derived from the flange 42.

Here, the present inventor is in the initial stage of monitoring, that is, when the molten metal L is first derived from the flange 42 through the outlet 34 and the molten metal receiving portion 40, when the following expression (1) holds: It has been found that the quality of the cast product finally obtained does not deteriorate.
Derived flow rate of the molten metal L at the outlet 34> Derived flow rate of the molten metal L in the flange 42 (1)

  Therefore, in the present embodiment, the flow rate of the molten metal L from the eaves portion 42 is satisfied so as to satisfy the above formula (1) until a predetermined time elapses from the time when the molten metal L is derived from the outlet 34. To control. In other words, the control circuit tilts the ladle 20 for casting when it violates the equation (1), that is, when the flow rate of the molten metal L at the eaves portion 42 is equal to or higher than the flow rate of the molten metal L at the outlet 34. Increase the angle.

  The amount of change in weight per unit time of the molten metal L staying in the pouring pan 38 is obtained as the difference between the flow rate derived from the outlet 34 and the flow rate derived from the gutter 42. That is, if these two derived flow rates are the same, the amount of change in weight per unit time of the molten metal L in the pouring pan 38 is zero. Judgment is not possible.

  On the other hand, when the molten metal L is solidified in the flange 42 as described above, the flow rate derived from the flange 42 decreases. Along with this, the amount of change in weight per unit time of the molten metal L in the pouring pan 38 increases. At this time, the control circuit determines that “the molten metal L stays in the pouring pan 38”.

  In this case, the control circuit issues a control signal to the tilting means, and further tilts the casting ladle 20 as shown in FIG. 6 by this control signal. As a result, the amount of the molten metal L transferred to the molten metal receiver 40 of the pouring pan 38 increases, and the liquid level of the molten metal L in the molten metal receiver 40 increases. That is, the liquid level H is directed in the α direction. Along with this, the dead weight of the molten metal L increases, thereby increasing the flow rate at the eaves portion 42.

  When the derived flow rate of the molten metal L from the eaves portion 42 increases, the derived flow rate approaches the derived flow rate of the molten metal L at the hot water outlet 34. If this is left as it is, the relationship of the above formula (1) will not be satisfied.

  Therefore, the control circuit monitors the flow rate derived from the flange 42, and if the derived flow rate exceeds a preset flow rate, in other words, the staying amount of the molten metal L in the pouring pan 38 is equal to or less than a predetermined amount. In this case, a control signal is issued to the tilting means to reduce the tilting angle of the ladle 20 for casting, and the flow rate to the molten metal receiving part 40 is limited.

  On the other hand, when the flow rate derived from the hot water outlet 34 is smaller than the flow rate derived from the eaves part 42, the control circuit determines that “an excessive amount of molten metal L is derived”. In this case, the control circuit issues a control signal to the tilting means to reduce the tilting angle of the casting ladle 20 and to reduce the flow rate to the molten metal receiving part 40. As a result, the amount of the molten metal L transferred to the molten metal receiving portion 40 of the pouring pan 38 is decreased, and the liquid level of the molten metal L in the molten metal receiving portion 40 is lowered. That is, the liquid level H is directed in the β direction. As a result, since the dead weight of the molten metal L is reduced, the flow rate derived from the flange 42 is reduced.

  When the flow rate of the molten metal L from the flange 42 decreases, the amount of the molten metal L in the pouring pan 38 becomes excessively large. Therefore, the control circuit monitors the derivation flow rate at this time, and when the derivation flow rate falls below a preset flow rate, in other words, when the residence amount of the molten metal L in the pouring pan 38 exceeds a predetermined amount, A control signal is issued to the tilting means to increase the tilting angle of the ladle for casting 20 and increase the flow rate leading to the molten metal receiving part 40. In addition, when it is judged that it is near until the molten metal L leaks from the pouring ladle 38 based on the measured weight in the 2nd load cell 50, it cannot be overemphasized that tilting of the ladle 20 for casting is reduced.

  As can be understood from the above, the flow rate at the heel portion 42 can be controlled by raising and lowering the liquid level of the molten metal L from the heel portion 42 to the molten metal receiving portion 40.

  Thus, according to the present embodiment, the weight is measured by the first load cell 28 and the second load cell 50, and the flow rate of the molten metal L is controlled by the control circuit. For this reason, since the filling speed of the molten metal L to the casting mold 44 can be controlled within a predetermined range, the quality of the cast product is improved.

  As shown in FIG. 7, the ladle for casting 20 is tilted to a position where the entire amount of the molten metal L is derived. The molten metal L is filled in the cavity of the casting mold 44, and then the molten metal L is cooled and solidified to obtain a cast product.

  In the embodiment described above, the shape of the casting ladle 20 is a hollow cylindrical body, but is not particularly limited thereto, and may be other shapes such as a substantially spherical body.

  Further, although cast iron and Mg are used as the molten metal L and the additive 6, respectively, it goes without saying that the present invention may be in an environment where slag S is generated in the ladle 20 for casting. .

It is a schematic longitudinal cross-sectional view of the ladle for casting which concerns on this Embodiment. It is a whole schematic perspective view of the ladle for casting of FIG. It is a schematic longitudinal cross-sectional view which shows the state which tilted the ladle for casting of FIG. 1 in the direction which a molten metal contacts an additive. It is a schematic longitudinal cross-sectional view which shows the state which returned the ladle for casting to the position of FIG. 1 after the said tilting. It is a schematic longitudinal cross-sectional view which shows the state which inclined the ladle for casting of FIG. It is a schematic longitudinal cross-sectional view which shows the state which further tilted the ladle for casting of FIG. 1 from FIG. It is a schematic longitudinal cross-sectional view which shows the state which further tilted the ladle for casting of FIG. 1 from FIG. It is a schematic longitudinal cross-sectional view of the ladle for casting which concerns on a prior art. It is a schematic longitudinal cross-sectional view which shows the state which tilted the ladle for casting of FIG. 8 so that a molten metal might be guide | induced from the opening upper surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20 ... Ladle for casting 5,30 ... Slag trap board 6 ... Additive 7,38 ... Pouring hot pot 8,42 ... Saddle 9,44 ... Casting die 18 ... Pouring device 22 ... Hot water inlet 24 ... Rotating shaft 28, 50 ... Load cell 32 ... Pocket plate 34 ... Outlet port 36 ... Guide rod member 40 ... Melt receiving portion 52 ... Pocket portion S ... Slag L ... Molten metal

Claims (3)

In the ladle for casting that is stored in the casting mold and is tiltably supported by the tilting means,
A hot water inlet for introducing the molten metal and a hot water outlet for extracting the molten metal are formed,
It has a slag trap plate that collects slag present in the molten metal inside,
Casting characterized in that when the slag trap plate extends in the horizontal direction while tilting to lead out the molten metal, the outlet is located below the upper end surface of the slag trap plate. Ladle.   The ladle according to claim 1, further comprising a pocket portion for accommodating the additive. Storing molten metal to be filled in a casting mold in a casting ladle provided with a slag trap plate inside;
When the ladle for casting is tilted and the slag trap plate extends in a horizontal direction, the molten metal is led out from the outlet port located below the upper end surface of the slag trap plate. And a process of
A casting method characterized by comprising:

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