JP5455499B2 - Continuous casting start determination method and continuous casting start determination device - Google Patents

Description

  The present invention is a continuous method for determining the start of continuous casting when continuously casting a molten metal filled in a continuous casting mold together with a lower mold from an opening provided in a lower portion of the continuous casting mold as an ingot. The present invention relates to a casting start determination method and a continuous casting start determination device.

Techniques for performing various types of casting defects and performing stable continuous casting are known (see, for example, Patent Documents 1 to 4).
Patent Document 1 prevents overflow due to a delay in the start of continuous casting by accurately detecting the molten metal level. For this purpose, a plurality of temperature sensors are provided to calibrate the level meter and determine the continuous casting start timing.

  In Patent Document 2, a Si-rich structure is formed on the upper surface of the ingot in order to prevent seizure or breakout on the mold wall during horizontal continuous casting. The temperature difference between the temperature of the molten metal produced by melting in the melting furnace and the solidification temperature for the formation of the Si-rich structure is controlled.

  In Patent Document 3, the solid phase ratio of the semi-solid metal that passes through the gap between the cooling rolls is captured by a thermometer, and the rotation speed of the cooling roll is adjusted according to the solid phase ratio. This produces a stable continuous operation and a uniform and good quality sheet.

  In Patent Document 4, a molten aluminum alloy maintained at a temperature equal to or higher than the solidus temperature is continuously cast at a predetermined casting speed and a cooling speed. This makes it possible to produce an aluminum alloy material having excellent anodizing properties by suppressing excellent cutting properties and damage such as wear and chipping of the cutting tool.

JP-A-8-206805 (page 4-5, FIG. 2-3) JP 2004-663345 A (pages 12-14, FIG. 2) JP-A-5-220548 (page 3-5, FIG. 1-3) International Publication No. 2003/010349 (pages 10-11 and 27, FIG. 6)

  When continuous casting is performed by drawing the molten metal filled in the continuous casting mold together with the lower mold from the opening provided in the lower part of the continuous casting mold, the determination of the continuous casting start timing facilitates the subsequent continuous casting. Very important in execution.

  That is, at the start of continuous casting, the molten metal is injected into the continuous casting mold with the lower opening closed by the lower mold. The continuous casting is started by pulling out the ingot together with the lower mold from the continuous casting mold by pulling out the lower mold at the timing when the portion in contact with the lower mold is solidified after the injection.

  However, if the lower mold is pulled out too early, the ingot in contact with the lower mold is not sufficiently solidified and the opening opens, and the ingot is pulled, so the ingot is broken and the A breakout will occur where the molten metal on the top blows out. In particular, when the casting shape of the continuous casting mold is complicated or the core is present, the ingot may be thin or have a complicated cross-sectional shape, and breakout is easily promoted.

  On the other hand, if the timing of pulling out the lower mold is too late, thick solidification (overcoagulation) occurs from the opening to the inside of the continuous casting mold, making it difficult to pull out the ingot together with the lower mold. In particular, if the casting shape of the continuous casting mold is complex or the core is present, it becomes impossible to tighten part of the continuous casting mold or the core strongly and pull out the ingot together with the lower mold. There is a possibility that the continuous casting cannot be started by hanging from the opening of the mold.

  As described above, the determination of the start of continuous casting by the continuous casting mold must determine an extremely short time width. Actually, it is determined over time from the injection of the molten metal, but the appropriate continuous casting start timing also fluctuates due to changes in the working environment, so continuous casting more accurately besides this time determination. A technique capable of determining start is desired.

The patent document 1 is a technique regarding an overflow at the start of continuous casting, and cannot solve the above-described problem at the start of continuous casting.
Patent Document 2 is a countermeasure during continuous casting. When continuous casting is performed in this way, the solidified portion is already in a state of sliding with respect to the continuous casting mold or the core, and when continuous casting is started. That is, it cannot be applied in the transition period from the stopped state to the sliding state.

Patent Document 3 is in the field of rolling with rolls and is in continuous operation. Therefore, it is unrelated to the problem at the start of continuous casting and is not a solution.
The above-mentioned patent document 4 is a technique of ingot modification by continuous casting, and is therefore unrelated to the problem at the start of continuous casting and is not a solution.

  The present invention provides a continuous casting start timing when continuously casting a molten metal filled in a casting hole of a continuous casting mold together with a lower mold from a casting hole opening provided at a lower portion of the continuous casting mold. The purpose of this is to make an accurate determination.

In the following, means for achieving the above-mentioned purpose, and its operation and effect are described.
In the continuous casting start determination method according to claim 1, the molten metal filled in the casting hole of the continuous casting mold is pulled out together with the lower mold from the casting hole opening provided at the lower part of the continuous casting mold as an ingot. A continuous casting start determination method for determining the start of continuous casting when performing continuous casting according to the above, after filling the molten casting into the continuous casting mold in a state where the lower mold closes the casting hole opening, A condition for defining the solid phase ratio of the molten metal at a plurality of positions from the position in contact with the upper surface of the mold is provided, and the timing when all of these conditions are satisfied is determined as the continuous casting start timing. And

  Thus, the solidification state of a molten metal can be appropriately controlled by providing the conditions which prescribe | regulate the solid-phase rate of a molten metal in multiple positions, and determining the continuous casting start timing. For example, the solid phase ratio of the molten metal at the position of the casting hole opening is specified so that it is sufficiently solidified, and above this, the solid phase ratio is set so as not to oversolidify directly above the casting hole opening. Even if the shape of the continuous casting mold is complicated and the core exists, the force for tightening these can be reduced.

  By pulling out the lower mold from the casting hole opening at the timing satisfying the conditions for defining the solid phase rate of the molten metal at such multiple positions, a breakout that breaks the solidified part in the molten metal is caused. And without causing the suspension, it can be smoothly pulled out downward from the casting hole opening, and continuous casting can be started.

In this way, the continuous casting start timing can be accurately determined.
Further, in the continuous casting start determination method according to claim 1, before Symbol continuous casting mold, and wherein the one having a core.

  In the continuous casting mold in which the core exists in this way, the continuous casting start timing that prevents the suspension by the present invention can be easily caused by the molten metal tightening the core during over-solidification. Can be accurately determined.

Further, in the continuous casting start determining method according to claim 1, the condition for defining the solid phase rate of the molten metal at a plurality of positions is a condition for defining the solid phase rate of the molten metal at four locations. To do.

In this way , the continuous casting start timing can be determined sufficiently accurately under the conditions that define the solid phase ratio of the molten metal at four locations.
In the continuous casting start determination method according to claim 1, the conditions are as follows: a condition A in which the solid phase ratio of the molten metal contacting the upper surface of the lower mold is 100%, and a position 10 mm upward from the upper surface of the lower mold. Condition B where the solid phase ratio of the molten metal is in the range of 10.6 to 12.8%, the solid phase ratio of the molten metal is further lowered above the position of 10 mm, and the position of 20 mm upward from the upper surface of the lower mold Then, the solid phase rate of the molten metal is in the range of 1.1 to 4.9%, and the solid phase rate of the molten metal is further lowered above the position of 20 mm, so that the solid phase rate of the molten metal is 0 in the continuous casting mold. The three conditions A, B, and C of the condition C that is% are characterized in that it is determined that the timing when all of these conditions A, B, and C are satisfied is the continuous casting start timing.

  Condition A represents a completely solidified state because the solid phase ratio of the molten metal at the upper surface position of the lower mold, that is, the position of the casting hole opening is 100%. Further, by adding Condition B, the solid phase ratio is also in the range of 10.6 to 12.8% in the portion 10 mm above the casting hole opening, and the position 10 mm from the casting hole opening. Until then, solidification has not increased, but solidification has progressed to some extent, and breakout can be prevented even if the casting hole opening is opened. In addition, the solid phase ratio is not increased in a wide upper range due to the condition C, and the conditions B and C do not cause overcoagulation immediately above the casting hole opening. Even if the shape of the continuous casting mold is complicated or there is a core, the force to tighten them is very small.

  For this reason, by pulling out the lower mold from the casting hole opening at the timing when all of the above conditions A, B, and C are satisfied, the molten metal can be suspended without causing a breakout in which the solidified portion is broken. Since it can be smoothly pulled out downward from the casting hole opening without causing it, continuous casting can be started.

Thus, by determining the timing that satisfies all of the conditions A, B, and C, the continuous casting start timing can be accurately determined.
In the continuous casting start determining method according to claim 2 , in the continuous casting start determining method according to claim 1 , the condition C is such that the solid phase ratio of the molten metal further decreases at a position above the 10 mm position, The condition is that the solid phase ratio of the molten metal is 0% at a position of 30 mm or more from the upper surface of the lower mold upward in the continuous casting mold.

More specifically, as described above, the condition C can be a condition in which the solid phase ratio of the molten metal gradually decreases and the solid phase ratio of the molten metal becomes 0% at a position of 30 mm or more.
This makes it possible to accurately determine the continuous casting start timing without causing breakout or suspension.

In the continuous casting start determination method according to claim 3 , in the continuous casting start determination method according to claim 1 or 2 , in the condition C, the solid phase ratio of the molten metal is further lowered at a position above the position of 10 mm. The solid phase rate is greater than 0% below this region and the solid phase rate is 0% above this region, with a boundary of 30 mm from the upper surface of the lower die upward in the continuous casting die. It is characterized by being.

  In this way, the solid phase rate is 0% at the position of 30 mm from the upper surface of the lower mold to the upper part in the continuous casting mold, and the condition C may be a state where no solid phase exists above this (solid phase rate of 0%). Thus, it is possible to accurately determine the continuous casting start timing without causing breakout or suspension.

In the continuous casting start determination method according to claim 4 , in the continuous casting start determination method according to any one of claims 1 to 3 , the condition A is a solid phase ratio of the molten metal immediately above the upper surface of the lower mold. Is less than 100%, and the solid phase ratio of the molten metal reaches 100% at a position in contact with the upper surface of the lower mold.

  By setting the condition A in this manner, the solid phase ratio is not unnecessarily increased immediately above the upper surface of the lower mold, and therefore, a more appropriate continuous casting start timing can be accurately determined.

In the continuous casting start determination method according to claim 5 , in the continuous casting start determination method according to any one of claims 1 to 4 , the solid fraction of the molten metal is determined by measuring a molten metal temperature. It is characterized by that.

  In the molten alloy, the temperature and the solid phase rate correspond to each other. Therefore, the solid phase rate at the position can be estimated by measuring the temperature at each position. This makes it possible to easily measure the solid phase ratio at each position of the molten metal filled in the casting hole of the continuous casting mold, and to accurately detect the start timing of continuous casting without causing breakout or suspension. Can be determined.

  In addition, since the solid phase ratio is obtained from the temperature, it can be easily determined whether or not the desired solid phase ratio, particularly 100% or 0%, is in a boundary with another solid phase ratio. That is, even if the solid phase rate is 100%, the temperature is not lower than necessary, and even if the solid phase rate is 0%, the temperature is not higher than necessary. The casting start timing can be determined.

In the continuous casting start determination method according to claim 6 , in the continuous casting start determination method according to any one of claims 1 to 4 , the solid phase ratio of the molten metal is determined by measuring with ultrasonic waves. It is characterized by being.

Thus, the solid phase ratio can be measured even by ultrasonic waves, and the continuous casting start timing without causing breakout or hanging can be easily and accurately determined.
In continuous casting start determination method according to claim 7, in the continuous casting start determination method according to any one of claims 1 to 6, wherein the molten metal is characterized in that an aluminum alloy.

  By applying to continuous casting of aluminum alloy in this way, when aluminum alloy is continuously cast by a continuous casting mold, breakout occurs when the ingot of aluminum alloy comes out from the opening of the casting hole at the start. It is possible to accurately determine the start timing of continuous casting without causing or suspension.

The continuous casting start judging method according to claim 8 is the continuous casting start judging method according to claim 7 , wherein the molten metal is an aluminum alloy containing 15 to 25% of Si.

  In particular, when continuous casting is started using an aluminum alloy containing 15 to 25% of Si as a molten metal, it is possible to accurately determine the continuous casting start timing without causing breakout or hanging.

In the continuous casting start determination method according to claim 9 , in the continuous casting start determination method according to any one of claims 1 to 8 , the continuous casting mold is for cylinder liner casting of an internal combustion engine. Features.

As described above, the casting start timing for continuously casting the cylinder liner of the internal combustion engine can be used for accurate start determination, and continuous casting with high productivity can be performed.
Continuous casting start determination device according to claim 1 0, was filled in the casting hole of the continuous casting mold molten, pulled with the lower mold from the casting hole opening provided in the lower portion of the continuous casting mold as an ingot This is a continuous casting start determination device for determining the start of continuous casting when continuously casting, and detects the solid phase ratio of the molten metal at a plurality of positions from the position in contact with the upper surface of the lower mold to the upper side. The solid ratio of the molten metal detected by the solid phase ratio detecting means at a plurality of positions with respect to the molten metal filled in the continuous casting mold in which the lower mold closes the casting hole opening. There is provided a continuous casting start timing determining means for determining that a timing at which a prescribed condition is satisfied is a continuous casting start timing.

  In this way, the solid fraction detection means is arranged, and the continuous casting start timing determination means uses the solid fraction at a plurality of positions, and the timing at which the conditions for defining this are satisfied is the continuous casting start timing. judge.

  Accordingly, as described in the first aspect, the continuous casting start timing can be accurately extracted so that the solidified molten metal can be smoothly drawn down from the casting hole opening without causing breakout and hanging. Can be determined.

Further, in continuous casting start determination device according to claim 1 0, wherein the continuous casting mold is characterized in that it is one having a core.
In the continuous casting mold in which the core exists in this way, the continuous casting start timing that prevents the suspension by the present invention can be easily caused by the molten metal tightening the core during over-solidification. Can be accurately determined.

Further, in continuous casting start determination device according to claim 1 0, wherein the solid phase rate detecting means is a solid phase rate detection means in which a plurality disposed in four places, the continuous casting start timing determining means, a plurality of It is characterized in that the timing at which all the conditions defining the solid phase ratio of the melt detected at each position by the solid phase ratio detecting means are satisfied is determined as the continuous casting start timing.

A plurality of solid phase ratio detection means may be arranged at four locations, and the continuous casting start timing can be determined sufficiently accurately under the conditions that define the solid phase ratio of the molten metal detected at these positions. it can.

Further, in continuous casting start determination device according to claim 1 0, wherein the plurality of solid phase rate detecting means includes a first solid phase rate detecting means for detecting a solid fraction of the molten metal at the upper surface position of the lower mold, The second solid phase ratio detecting means for detecting the solid phase ratio of the molten metal at a position 10 mm upward from the upper surface of the lower mold, and the solid phase ratio of the molten metal at a position of 20 mm upward from the upper surface of the lower mold to the inside of the continuous casting mold A fourth solid phase ratio detection means for detecting the solid phase ratio detection means for detecting the solid phase ratio of the molten metal at a position above the 20 mm position, the continuous casting start timing determination means, Condition 1 where the solid phase ratio of the molten metal detected by the first solid phase ratio detecting means is 100%, and the solid phase ratio of the molten metal detected by the second solid phase ratio detecting means is 10.6-12.8% a condition 2, condition 3 the solid fraction of the molten metal wherein the third solid phase rate detecting means for detecting is 0%, the fourth solid Four conditions conditions 4 solid fraction of the molten metal rate detecting means for detecting is from 1.1 to 4.9% 1,2,3, determined 4 is a continuous casting start timing all filled timing It is characterized by doing.

Thus by placing the solid phase rate detection unit, a continuous casting start timing determining means, using the respective solid fraction, four conditions 1, 2, 3, 4 starts continuous casting timing filled all It is determined that it is timing.

  Accordingly, as described in the first aspect, the continuous casting start timing can be accurately extracted so that the solidified molten metal can be smoothly drawn down from the casting hole opening without causing breakout and hanging. Can be determined.

In continuous casting start determination device according to claim 1 1, in the continuous casting start determination device according to claim 1 0, wherein the continuous casting start timing determining means, the condition 1, the first solid phase ratio detecting means The solid phase ratio of the molten metal is less than 100% immediately above the position, and the solid phase ratio of the molten metal reaches 100% at the position of the first solid phase ratio detecting means.

  By setting the condition 1 in this way, the solid phase ratio is not unnecessarily increased immediately above the upper surface of the lower mold. Therefore, it is possible to more accurately determine the continuous casting start timing that can prevent breakout and hanging.

In continuous casting start determination device according to claim 1 2, in the continuous casting start determination device according to claim 1 0 or 1 1, wherein the continuous casting start timing determining means, the condition 3, the third solid phase The solid phase ratio of the molten metal is 0% up to the position of the rate detecting means, and the solid phase ratio of the molten metal exceeds 0% immediately below the position of the third solid phase ratio detecting means. To do.

By setting condition 3 in this way, a more appropriate continuous casting start timing can be accurately determined.
In continuous casting start determination device according to claim 1 3, in the continuous casting start determination device according to any one of claims 1 0 to 1 2, wherein the third solid phase rate detecting means, the upper surface of the lower die The solid phase ratio of the molten metal at a position of 30 mm or more is detected upward in the continuous casting mold.

  More specifically, the third solid phase ratio detecting means may detect the solid phase ratio of the molten metal at a position of 30 mm or more. Therefore, Condition 3 is a condition in which the solid phase ratio of the molten metal is 0% at a position of 30 mm or more.

This makes it possible to accurately determine the continuous casting start timing without causing breakout or suspension.
In continuous casting start determination device according to claim 1 4, in continuous casting start determination device according to any one of claims 1 0 to 1 2, wherein the third solid phase rate detecting means, the upper surface of the lower die The solid phase ratio of the molten metal at a position of 30 mm is detected in the upper part of the continuous casting mold.

  Thus, a 3rd solid-phase-rate detection means is good also as detecting the solid-phase rate of the molten metal in the position of 30 mm. Therefore, Condition 3 is a condition in which the solid phase rate is 0% at a position of 30 mm. This makes it possible to accurately determine the continuous casting start timing without causing breakout or suspension.

With a continuous casting start determination device according to claim 1 5, in continuous casting start determination device according to any one of claims 1 0-1 4, wherein the solid phase rate detecting means measures the melt temperature The solid phase ratio is obtained from the molten metal temperature measured based on the relationship between the molten metal temperature and the solid phase ratio.

  In molten alloy, the temperature and the solid phase rate correspond to each other, so the solid phase rate detecting means uses the solid phase rate from the melt temperature measured based on the relationship between the molten metal temperature and the solid phase rate at that position. Can be requested. This makes it possible for the solid fraction detection means to easily measure the solid fraction at each position filled in the continuous casting mold with a simple configuration, and to accurately detect the start timing of continuous casting without causing breakout or suspension. Can be determined.

  In addition, since the solid phase ratio is obtained from the temperature, it can be easily determined whether or not the desired solid phase ratio, particularly 100% or 0%, is in a boundary with another solid phase ratio. That is, even if the solid phase rate is 100%, the temperature is not lower than necessary, and even if the solid phase rate is 0%, the temperature is not higher than necessary. For this reason, the continuous casting start timing determination means can determine a more appropriate continuous casting start timing.

In continuous casting start determination device according to claim 1 6, in continuous casting start determination device according to any one of claims 1 0-1 4, wherein the solid phase rate detecting means, the solid fraction by ultrasonic It is characterized by measuring.

  The solid phase ratio detecting means may measure the solid phase ratio with ultrasonic waves, and can easily and accurately determine the continuous casting start timing without causing breakout or hanging.

In continuous casting start determination device according to claim 1 7, in the continuous casting start determination device according to any one of claims 1 0-1 6, wherein the molten metal is characterized in that an aluminum alloy.

  By applying this continuous casting start determination device at the start of continuous casting of an aluminum alloy, there is no breakout or hanging when the aluminum alloy ingot comes out from the casting hole opening of the continuous casting mold. The casting start timing can be accurately determined.

The continuous casting start determining device according to claim 18 is characterized in that, in the continuous casting start determining device according to claim 17 , the molten metal is an aluminum alloy containing 15 to 25% of Si.

  In particular, when continuous casting of a molten aluminum alloy containing 15 to 25% of Si is started, it is possible to accurately determine the continuous casting start timing without causing breakout or suspension.

It a continuous casting start determination device according to claim 19, in the continuous casting start determination device according to any one of claims 1 0-18, wherein the continuous casting mold is a cylinder liner casting of an internal combustion engine It is characterized by.

  This continuous casting start determination device can be used for accurate start determination with respect to the casting start timing for continuously casting the cylinder liner of the internal combustion engine, and can perform continuous casting with high productivity.

FIG. 3 is a longitudinal sectional view showing a main part configuration of the vertical continuous casting apparatus according to the first embodiment. The flowchart of the continuous casting start determination process which the controller of Embodiment 1 performs. (A), (b) Structure explanatory drawing of map MAPsf which shows the relationship between the molten metal temperature used in Embodiment 1, and the solid-phase rate Sf, and its expansion explanatory drawing. (A)-(c) The graph which shows the relationship between a molten metal position, a solid-phase rate, and molten metal temperature. The flowchart of the continuous casting start determination process which the controller of Embodiment 2 performs.

[Embodiment 1]
FIG. 1 is a longitudinal sectional view showing a main part configuration of a vertical continuous casting apparatus 2 to which the invention of the continuous casting start determining method and the continuous casting start determining apparatus described above is applied. This vertical continuous casting apparatus 2 is for continuously casting a cylinder liner of an internal combustion engine, and includes a continuous casting mold 4, a core 6, a lower mold 8, and a hot top 10. The continuous casting mold 4 has a torus shape, and cooling water is supplied to the internal space 4a. A slit hole 4b is provided around the center hole on the lower surface of the continuous casting mold 4 so that the cooling water in the internal space 4a is jetted obliquely downward toward the center side.

  A central hole is continuously provided over the continuous casting mold 4 and the hot top 10 made of a heat insulating material, and a cylindrical core 6 is indicated at the axial position of the central hole. Therefore, a cylindrical casting hole 12 through which the molten metal 11 passes is formed between the continuous casting mold 4 and the core 6. In addition, with respect to the molten metal poured into the casting hole 12, an electromagnetic stirring device is provided on the outer peripheral portions of both the continuous casting mold 4 and the hot top 10, thereby energizing the electromagnetic acting force (the coil of the electromagnetic stirring device). The agitation may be performed by a force induced by a magnetic field generated at the time.

  The lower mold 8 closes a casting hole opening 12a at the lower part of the casting hole 12 formed between the continuous casting mold 4 and the core 6 from the lower side. The lower mold 8 can be moved up and down in the axial direction, that is, in the vertical direction by the lower mold moving device 14.

  The continuous casting mold 4 is provided with four temperature sensors 16, 18, 20, and 22 made of thermocouples on the inner peripheral surface of the center hole. These temperature sensors 16 to 22 are arranged at intervals of 10 mm in the axial direction (vertical direction) of the center hole. The first temperature sensor 16 present at the lowermost position is disposed at the position of the upper surface 8a of the lower mold 8 in a state of closing the casting hole opening 12a. The second temperature sensor 18 is disposed 10 mm above the position of the first temperature sensor 16, the third temperature sensor 22 is disposed 30 mm above the first temperature sensor 16, and the fourth temperature sensor 20 is the first temperature sensor 16. It is arrange | positioned 20 mm above.

  Since the molten metal 11 flows into the casting hole 12 between the continuous casting mold 4 and the core 6 from the rod 24 through the hot top 10 during continuous casting, the four temperature sensors 16 to 22 are cast at respective positions. The temperature of the molten metal 11 in the insertion hole 12 is detected.

  The detected values THm1, THm2, THm3, and THm4 output by the four temperature sensors 16, 18, 22, and 20 are input to the continuous casting controller 26 and are used as data for continuous casting control including the start of continuous casting. Used. The continuous casting controller 26 is configured by an electronic control circuit centered on a computer, and is a device that executes continuous casting control by a program.

  Next, among the control processes executed by the continuous casting controller 26, a flowchart of the continuous casting start determination process is shown in FIG. This process is repeatedly executed at a predetermined time period. The steps in the flowchart corresponding to the individual processing contents are represented by “S˜”.

  When this process is started, it is first determined whether or not a determination start condition is satisfied (S102). For example, the determination start condition is established by starting the operation of injecting the molten metal 11 existing in a melting furnace, a holding furnace, a ladle, or the like, in this case, the molten metal 11 of aluminum alloy (Si is 15 to 25%) from the tub 24. The determination start condition may be satisfied by turning on a start instruction switch provided in the continuous casting controller 26. Or you may make it start from the following step S104 at the time of power-on of the controller 26 for continuous casting, without providing step S102.

In the present embodiment, before starting the pouring of molten metal, it is determined as NO in step S102, and the process is left as it is. Therefore, substantially no determination is made.
When the above-described determination start condition is satisfied by the start of molten metal injection (YES in S102), the detected values THm1, THm2, THm3, THm4 of the molten metal temperatures measured at the respective positions by the four temperature sensors 16, 18, 22, 20 are next. Is read into the working memory (S104).

  Next, based on the detection values THm1, THm2, THm3, THm4, from a map MAPsf showing the relationship between the metal temperature constituting the molten metal 11, here the molten metal temperature set in advance for the aluminum alloy and the solid phase ratio, The solid phase ratios Sf1, Sf2, Sf3, Sf4 of the molten metal 11 at each position are calculated (S106). The map MAPsf is as shown by a solid line in FIG. FIG. 3B is a partially enlarged view of the map MAPsf on the low solid phase ratio side.

  As the aluminum alloy, an aluminum alloy having a Si component in the range of 15% to 25% is used. As other components contained in the aluminum alloy, in addition to Si, components usually contained as an aluminum alloy such as Cu, Mg, and Fe are included. For example, Si: 23%, Cu: 2.5%, Mg: 0.2%, Fe: 0.2% or less.

  Then, when the solid phase ratios Sf1, Sf2, Sf3, Sf4 are calculated at the respective positions as described above, all the following four conditions for the solid phase ratios Sf1, Sf2, Sf3, Sf4 are determined as the continuous casting start determination. It is determined whether or not it is satisfied (S108).

First condition: The solid phase ratio Sf1 based on the detection value THm1 of the molten metal temperature detected by the first temperature sensor 16 is 100%. (Corresponding to condition A and condition 1 of the claims)
Second condition: The solid phase ratio Sf2 based on the detection value THm2 of the molten metal temperature detected by the second temperature sensor 18 is between 10.6 and 12.8%. (Equivalent to Condition B and Condition 2 in the claims)
Third condition: The solid phase ratio Sf3 based on the detection value THm3 of the molten metal temperature detected by the third temperature sensor 22 is 0%. (Corresponding to part 3 of the condition C of the claims, condition 3)
Fourth condition: The solid phase ratio Sf4 based on the detection value THm4 of the molten metal temperature detected by the fourth temperature sensor 20 is between 1.1 and 4.9%. (Corresponding to part 4 of the condition C in the claims, condition 4)
That is, it is determined whether or not the solid phase distribution is as indicated by the solid line in FIG. FIG. 4 shows the distribution of the solid fraction at each position in the case where the molten metal 11 of 15% and 25% of the Si component satisfies the above four conditions in the vertical continuous casting apparatus 2. And a molten metal temperature distribution. 4A is an arrangement view of the temperature sensors 16 to 22 in the vertical continuous casting apparatus 2, FIG. 4B is a solid fraction distribution with respect to an upper position from the upper surface 8a of the lower mold 8, and FIG. (C) is a graph which shows the molten metal temperature distribution of each aluminum alloy with respect to the upper position from the upper surface 8a of the lower mold | type 8. FIG. In FIG. 4C, the molten metal temperature values of the aluminum alloy of 25% Si and the aluminum alloy of 15% Si are overlapped at the 0 mm position and the 10 mm position.

  The molten aluminum alloy 11 has just reached the upper surface 8a of the lower mold 8 by the injection, and at the positions of the first temperature sensor 16, the second temperature sensor 18, and the fourth temperature sensor 20, the solid phase ratios Sf1, Sf2, Sf4. Is low, and if at least one of the first condition, the second condition, and the fourth condition is not satisfied, NO is determined in step S108. Therefore, this processing is temporarily exited as it is. Therefore, since the continuous casting start determination is not made, the process in which the lower mold 8 is pulled downward by the lower mold moving device 14 is not executed.

Thereafter, during a period in which any of the four conditions is not satisfied in step S108 for each control cycle, NO is determined in step S108, and continuous casting is not started.
Then, with the passage of time (for example, several seconds after the molten metal injection), the solid phase rate state as shown in FIG. 4B is reached, and when the above four conditions are satisfied (YES in S108), continuous casting is started. Determination is made, continuous casting start determination processing end setting is performed, and continuous casting start setting is performed (S110).

  That is, the continuous casting start determination process (FIG. 2), which is the main process, is ended by the continuous casting start determination process end setting, and the continuous casting process is separately performed by the program provided in the continuous casting controller 26 by the continuous casting start setting. Is started.

  By starting the continuous casting process, the lower die 8 is started to be drawn downward, and the solid phase corresponding to the continuous casting conditions is used by using any or all of the detected values THm1 to THm4 of the temperature sensors during continuous casting. The ingot having a desired quality is manufactured by adjusting the drawing speed of the lower mold 8, the molten metal pouring speed, the cooling state, etc. Here, a cylindrical ingot that becomes a cylinder liner of the internal combustion engine is manufactured.

  In the above-described configuration, the relationship with the claims corresponds to the continuous casting start determination device in which the continuous casting controller 26 performs the continuous casting start determination method, and the first temperature sensor 16 corresponds to the first solid phase ratio detection means. The second temperature sensor 18 corresponds to the second solid phase ratio detection means, the third temperature sensor 22 corresponds to the third solid phase ratio detection means, and the fourth temperature sensor 20 corresponds to the fourth solid phase ratio detection means.

Steps S104 to S110 of the continuous casting start determination process (FIG. 2) correspond to the process as the continuous casting start timing determination means.
According to the first embodiment described above, the following effects can be obtained.

  (1) Four temperature sensors 16 to 22 are arranged at an interval of 10 mm from the upper surface 8a of the lower mold 8, and based on detected values THm1 to THm4 that are molten metal temperatures at the respective positions, the solid phase of the molten metal 11 at the respective positions. The rates Sf1 to Sf4 are obtained.

  Then, it is determined that the timing at which these solid phase ratios Sf1 to Sf4 become a specific solid ratio distribution satisfying the first to fourth conditions is the continuous casting start timing. The specific distribution of the solid phase ratio is that the solid state ratio Sf1 of the molten metal 11 is 100% on the upper surface 8a (position of the casting hole opening 12a) of the lower mold 8 according to the first condition. Represents.

  And at the position of 10 mm upward from the upper surface 8a of the lower mold 8 due to the second condition, the solid phase ratio Sf2 of the molten metal 11 is in the range of 10.6 to 12.8%, and the position of 10 mm from the casting hole opening 12a. Up to this point, it is shown that solidification has progressed to some extent although it is not large, and breakout can be prevented even if the casting hole opening 12a is opened.

  In addition, since the solid phase ratio Sf3 is 0% at a position above 10 mm, here at a position of 30 mm, according to the third condition, the solid phase ratio is not increased over a wide range. Therefore, it turns out that the force which clamps the core 6 just above the casting hole opening part 12a by these 2nd conditions and 3rd conditions is a very small state.

  Moreover, according to the fourth condition, the solid phase ratio Sf4 of the molten metal 11 is in the range of 1.1 to 4.9% at a position of 20 mm. Therefore, when determining the start of continuous casting in the vertical continuous casting apparatus 2 having the core 6, it is possible to set an appropriate solid fraction distribution so that the solid fraction is neither too high nor too low. It is possible to more accurately determine the continuous casting start timing at which no occurrence occurs.

  By pulling out the lower mold 8 from the casting hole opening 12a at a timing satisfying all of these four conditions, the molten metal 11 does not cause a breakout that destroys the solidified portion and is caused by overcoagulation. The core 6 is smoothly pulled down from the casting hole opening 12a without being suspended.

  (2) The solid phase ratio is determined at each position based on the molten metal temperature (detected values THm1 to THm4). For this reason, as shown in FIG. 3, it is possible to capture the moment when the solid phase ratio Sf1 on the upper surface 8a of the lower mold 8 becomes 100%. Therefore, even when the same 100%, the molten metal temperature (detection value THm1) is not caught in a state where the temperature is unnecessarily lowered, and the solid phase ratio directly above the upper surface 8a of the lower mold 8 is not increased more than necessary.

  This is the same even when the solid phase ratio Sf3 at the position of 30 mm is 0%, and since it can be easily determined that the solid phase ratio is higher than 0% immediately below 30 mm, the molten metal temperature at the position of 30 mm. The (detection value THm3) is not increased more than necessary, and the solid phase ratio can be prevented from reaching 0% below the detection value THm3.

  (3) As described above, when the continuous casting controller 26 continuously casts the cylinder liner of the internal combustion engine, an accurate determination is made with respect to the casting start timing. Continuous casting can be performed.

[Embodiment 2]
In the present embodiment, instead of the temperature sensors 16 to 22 shown in FIG. 1, an ultrasonic sensor composed of a combination of an ultrasonic transmission element and an ultrasonic reception element is used as the upper surface 8a position, 10 mm position, and 20 mm of the lower mold 8. Position, provided at 30 mm position. However, the ultrasonic sensor is disposed on the wall surface on the inner space 4a side of the continuous casting mold 4 through which the cooling water W flows, and is superposed through the wall portion of the continuous casting mold 4 toward the molten metal 11 in the casting hole 12. It arrange | positions so that a sound wave may be transmitted and the reflected wave from the molten metal 11 may be received.

And the continuous casting start determination process shown in FIG. 5 is performed instead of FIG. The other configuration is the same as that of the first embodiment, and will be described with reference to FIGS.
The continuous casting start determination process (FIG. 5) will be described. This process is repeatedly executed at a predetermined time period as in FIG. Steps S202, S208, and S210 are the same processes as steps S102, S108, and S110 in FIG. 2, and steps S204 and S206 performed after the determination start condition is satisfied (YES in S202) are the same as steps S104 and S104 in FIG. The process is different from the continuous casting start determination process of FIG.

  When the determination start condition is satisfied (YES in S202), the ultrasonic wave is transmitted and the reflected wave is received in each of the four ultrasonic sensors, and the ultrasonic sensor detection time differences dTm1, dTm2, dTm3, and dTm4 are set. The data is read into the memory work area (S204). The ultrasonic sensor detection time differences dTm1, dTm2, dTm3, and dTm4 are reflected by the ultrasonic wave reflected from the surface of the continuous casting mold 4 in contact with the molten metal 11, and reflected from the surface of the core 6 through the molten metal 11. It is the arrival time difference from the coming ultrasound.

  The propagation speed of the ultrasonic wave changes according to the solid phase ratio of the molten metal 11. That is, the higher the solid phase ratio, the faster and the lower the ratio. Therefore, if the detection time difference is small, the solid phase ratio is high, and if the detection time difference is large, the solid phase ratio is low. For this reason, a map MAPsft showing the relationship between the detection time difference and the solid phase ratio can be created beforehand by measurement with respect to the type of molten metal 11 and the radial thickness of the molten metal 11 shown in FIG. .

Next, solid phase ratios Sf1 to Sf4 at each position are calculated based on the ultrasonic sensor detection time differences dTm1 to dTm4 using this map MAPsft (S206).
Then, it is determined whether or not the solid phase ratios Sf1 to Sf4 satisfy all four conditions (first condition to fourth condition) described in step S108 of FIG. 2 (S208). If any one is not satisfied (NO in S208), the process is temporarily exited.

  If satisfied, the continuous casting start determination is made (YES in S208), and as described in step S110 of FIG. 2, the continuous casting start determination process end setting is performed and the continuous casting start setting is made (S210).

  In the above-described configuration, the relationship with the claims corresponds to the continuous casting start determination device in which the continuous casting controller 26 performs the continuous casting start determination method, and the four ultrasonic sensors used instead of the temperature sensor are These correspond to the first solid phase ratio detection means, the second solid phase ratio detection means, the third solid phase ratio detection means, and the fourth solid phase ratio detection means, respectively.

Steps S204 to S210 of the continuous casting start determination process (FIG. 5) correspond to the process as the continuous casting start timing determination means.
According to the second embodiment described above, ultrasonic waves are used in place of temperature, but the same effects as (1) and (3) of the first embodiment can be obtained.

[Embodiment 3]
In the first embodiment, the temperature is measured using the fourth temperature sensor 20 at a position 20 mm from the upper surface 8a of the lower mold 8, and the fourth condition is determined in step S108 based on the measurement result. Similarly, in the second embodiment, a detection time difference is measured using a fourth ultrasonic sensor at a position 20 mm from the upper surface 8a of the lower mold 8, and the fourth condition is determined in step S208 based on the measurement result.

As described above, in the first and second embodiments, the temperature or the detection time difference is measured at four points. However, the position 20 mm upward from the upper surface 8a of the lower mold 8 may be omitted.
Although the accuracy is slightly lowered, the effects of the first or second embodiment can be produced.

[Other embodiments]
In each of the above embodiments, the conditions for defining the solid phase ratio of the molten metal at a plurality of positions are the conditions for defining the solid phase ratio of the molten metal at three or four positions. If it is more than one place, the continuous casting start timing can be determined with a certain degree of accuracy. However, it is particularly important that the number of locations is 3 or 4 as in each of the embodiments described above, in order to determine a sufficiently accurate continuous casting start timing with as little solid phase ratio measurement as possible.

  In each of the above embodiments, the temperature sensor 22 or the ultrasonic sensor provided at a position 30 mm upward from the upper surface 8a of the lower mold 8 may be disposed at a position exceeding 30 mm. Even with such a configuration, it is possible to accurately determine the continuous casting start timing without causing breakout or suspension.

-The detection of the solid phase ratio is not limited to temperature and ultrasound. Other sensors may be used as long as the solid phase ratio can be detected.
In each of the above embodiments, the present invention relates to the start of continuous casting of the cylinder liner of the internal combustion engine, but the present invention can also be applied to the start of continuous casting of other various members using a core.

  In each of the above-described embodiments, the example is a continuous casting mold having a core, but the present invention can also be applied to a continuous casting start determination using a continuous casting mold that does not use a core. By applying the present invention even in continuous casting where the casting shape of the continuous casting mold is particularly complicated, it is difficult to pull out the ingot together with the lower mold by strongly tightening a part of the continuous casting mold by over-solidification. It is possible to accurately determine the continuous casting start timing without causing breakout or suspension.

  DESCRIPTION OF SYMBOLS 2 ... Vertical type continuous casting apparatus, 4 ... Continuous casting type | mold, 4a ... Internal space, 4b ... Slit hole, 6 ... Core, 8 ... Lower mold | type, 8a ... Upper surface, 10 ... Hot top, 11 ... Molten metal, 12 ... Casting Insertion hole, 12a ... casting hole opening, 14 ... lower mold moving device, 16 ... first temperature sensor, 18 ... second temperature sensor, 20 ... fourth temperature sensor, 22 ... third temperature sensor, 24 ... soot, 26: Controller for continuous casting, W: Cooling water.

Claims (19)

To determine the start of continuous casting when continuous casting is performed by drawing the molten metal filled in the casting hole of the continuous casting mold together with the lower mold from the casting hole opening provided at the bottom of the continuous casting mold as an ingot. The continuous casting start determination method of
After filling the molten metal into the continuous casting mold having the core while the lower mold is closed in the casting hole opening, the molten metal is solidified at four locations from the position in contact with the upper surface of the lower mold to the upper side. Establishing conditions to define the phase rate,
The condition is
Condition A where the solid phase ratio of the molten metal contacting the upper surface of the lower mold is 100%,
Condition B in which the solid phase ratio of the molten metal at a position 10 mm upward from the upper surface of the lower mold is in the range of 10.6 to 12.8%,
Above the position of 10 mm, the solid phase ratio of the molten metal further decreases, and at a position of 20 mm upward from the upper surface of the lower mold, the solid phase ratio of the molten metal is in the range of 1.1 to 4.9%. Condition C in which the solid phase ratio of the molten metal is further lowered above the position and the solid phase ratio of the molten metal is 0% in the continuous casting mold,
The continuous casting start determination method is characterized in that it is determined that the timing when all of these conditions A, B, and C are satisfied is the continuous casting start timing. 2. The continuous casting start determination method according to claim 1, wherein the condition C is such that the solid phase ratio of the molten metal further decreases at a position above the position of 10 mm, and is 30 mm or more from the upper surface of the lower mold to the upper side in the continuous casting mold. A method for determining the start of continuous casting, characterized in that the solid phase ratio of the molten metal at the position is 0%. 3. The continuous casting start determination method according to claim 1, wherein the condition C is such that the solid phase ratio of the molten metal further decreases at a position above the position of 10 mm, and from the upper surface of the lower mold toward the upper side in the continuous casting mold. A method for determining the start of continuous casting, characterized in that the solid phase rate is greater than 0% below this region and the solid rate is 0% above this region with a position of 30 mm as a boundary. The continuous casting start determination method according to any one of claims 1 to 3, wherein the condition A is that the solid phase ratio of the molten metal is less than 100% immediately above the upper surface of the lower mold and is in contact with the upper surface of the lower mold. A continuous casting start determining method, characterized in that the solid phase ratio of the molten metal reaches 100% at a position where The continuous casting start determination method according to any one of claims 1 to 4 , wherein the solid phase ratio of the molten metal is determined by measuring a molten metal temperature. The continuous casting start determination method according to any one of claims 1 to 4 , wherein the solid phase ratio of the molten metal is determined by measuring with ultrasonic waves. The continuous casting start determining method according to any one of claims 1 to 6 , wherein the molten metal is an aluminum alloy. The continuous casting start determination method according to claim 7 , wherein the molten metal is an aluminum alloy containing 15 to 25% of Si. The continuous casting start determination method according to any one of claims 1 to 8 , wherein the continuous casting mold is for cylinder liner casting of an internal combustion engine. To determine the start of continuous casting when continuous casting is performed by drawing the molten metal filled in the casting hole of the continuous casting mold together with the lower mold from the casting hole opening provided at the bottom of the continuous casting mold as an ingot. A continuous casting start determination device of
First solid phase ratio detection means for detecting the solid phase ratio of the molten metal at the upper surface position of the lower mold, and second solid phase ratio detection for detecting the solid phase ratio of the molten metal at a position 10 mm upward from the upper surface of the lower mold Means, a fourth solid phase ratio detecting means for detecting the solid phase ratio of the molten metal at a position of 20 mm from the upper surface of the lower mold upward in the continuous casting mold, and the solid phase of the molten metal at a position above the position of 20 mm. A third solid phase ratio detecting means for detecting the rate, a plurality of solid phase ratio detecting means arranged in four locations from the position contacting the upper surface of the lower mold to the upper side,
With respect to the molten metal filled in the continuous casting mold having the core while closing the casting hole opening, the solid phase ratio of the molten metal detected by the first solid phase ratio detecting means is 100%. Condition 1, Condition 2 where the solid phase ratio of the molten metal detected by the second solid phase ratio detecting means is 10.6 to 12.8%, Solid phase ratio of the molten metal detected by the third solid phase ratio detecting means condition 3, the fourth fraction solid four conditions of the solid fraction of the molten metal detection means for detecting the condition 4 is 1.1 to 4.9% 1,2,3, 4 are all but 0% Continuous casting start timing determining means for determining the satisfied timing as the continuous casting start timing;
A continuous casting start determining device comprising: In continuous casting start determination device according to claim 1 0, wherein the continuous casting start timing determining means, the condition 1, the solid fraction of the molten metal just above the position of the first solid phase ratio detecting means is less than 100% The continuous casting start determining device is characterized in that the solid phase ratio of the molten metal reaches 100% at the position of the first solid phase ratio detecting means. In continuous casting start determination device according to claim 1 0 or 1 1, wherein the continuous casting start timing determining means, the condition 3, the solid fraction of the molten metal to the position of the third solid phase rate detecting means 0% The continuous casting start determining device is characterized in that the solid phase ratio of the molten metal exceeds 0% immediately below the position of the third solid phase ratio detecting means. In continuous casting start determination device according to claim 1 0-1 any one of 2, the third solid phase rate detecting means, the molten metal at the position of more than 30mm from the upper surface of the lower mold into the continuous casting mold in the upper A continuous casting start determining device, characterized by detecting a solid phase ratio of the solid casting. In continuous casting start determination device according to any one of claims 1 0 to 1 2, wherein the third solid phase rate detecting means, the molten metal at the position of 30mm from the upper surface of the lower mold into the continuous casting mold in the upper A continuous casting start determination device characterized by detecting a solid phase ratio. In continuous casting start determination device according to any one of claims 1 0-1 4, wherein the solid phase rate detecting means is adapted to measure the temperature of molten metal, based on the relationship between the melt temperature and the solid fraction measurement A continuous casting start determination device characterized in that the solid phase ratio is obtained from the molten metal temperature. In continuous casting start determination device according to any one of claims 1 0-1 4, wherein the solid phase rate detecting means, starts continuous casting, characterized in that to measure the solid fraction by ultrasonic Judgment device. In continuous casting start determination device according to any one of claims 1 0-1 6, wherein the molten metal is continuously cast start determination device, characterized in that an aluminum alloy. The continuous casting start determining apparatus according to claim 17 , wherein the molten metal is an aluminum alloy containing 15 to 25% of Si. In continuous casting start determination device according to any one of claims 1 0-18, wherein the continuous casting mold, the continuous casting start determination device which is a cylinder liner casting of an internal combustion engine.

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