JP2518618B2 - Mold for continuous casting of steel - Google Patents

Description

Description: <Industrial application> The present invention relates to a continuous casting mold for obtaining a steel slab with less surface defects during casting or hot working.

<Background Art> In recent years, in the production of steel, a continuous casting process using a vertical or curved continuous casting machine has been indispensable.However, such continuous casting method enables casting of blooms, slabs, etc. When a piece is manufactured, surface flaws (surface cracks) occur due to the thermal stress and bending stress applied to the slab in the middle of the casting, and this causes hot direct rolling (heating the slab obtained by continuous casting. However, the surface flaws were directly brought to the rolling step when attempting to perform hot rolling (i.e., rolling immediately performed without re-heating the slab obtained by continuous casting without cooling to room temperature). There was an inconvenience that the cracks were further promoted and the cracks were further promoted.
Further, even when subjecting the continuous cast slab to normal hot working (hot forging or hot rolling performed by reheating the slab once cooled to room temperature), a problem that surface defects are likely to occur is conspicuous, This has been a major obstacle to the production of hot-worked steel with good surface properties.

By the way, when it is observed that the occurrence of surface flaws as described above is accompanied by cracking of austenite (γ) grain boundaries, it is conventionally known that "casting" is one of the causes of the occurrence of surface flaws. Carbides and nitrides (NbC,) that precipitate or segregate at the austenite (γ) grain boundaries during solidification and cooling of the pieces
AlN, etc.), (Mn, Fe) S and other sulfides, as well as P and S and other impurity elements, lead to weakening of the grain boundaries, and the frequency of surface defects (cracks) It has become known that is greatly affected by the contents of the above-mentioned precipitates and elements that cause segregation.

Therefore, attempts have been made to prevent surface flaws on the slab by controlling the content of such elements, but in this case there is a limit in terms of ensuring product quality (characteristics) and cost, as well as the chemical composition. The adjustment standard of (1) is not yet clear, and therefore, the adjustment of the chemical components alone cannot provide a sufficiently satisfactory effect.

On the other hand, there is also the fact that the frequency of occurrence of such slab surface flaws largely depends on the C content of the slab, as shown in FIG. However, the cause is still unknown, and no measures can be found against it, and eventually the operation was carried out while avoiding such a C content range.

However, the "region where the frequency of surface flaws suddenly increases" as shown in Fig. 3 is not always constant and varies depending on the steel type. Especially, in the case of low alloy steel, it is estimated from the C content. In many cases, the frequency of occurrence of surface defects was extremely high in the unexpected composition range of components, which often resulted in extremely inconvenient results in operation.

Therefore, the conventional measures to prevent surface defects are insufficient, such as "to reduce the cooling rate of the steel slab" in order to make the oscillation mark shallower and reduce the thermal stress acting on the solidified shell. It was only a thing.

From this, it is possible to reliably prevent cracks from occurring on the surface of the steel slab during continuous casting of steel and hot working (hot rolling, etc.) that is subsequently performed, and to improve the hot workability with good surface properties. The advent of means capable of industrially stably mass-producing processed steel has been strongly desired.

<Matters clarified by research> From the above-mentioned viewpoints, the inventors have found that “a surface flaw is generated during the casting of a steel slab produced by continuous casting” or “a continuous cast slab is hot-cast. In order to find an easy-to-implement means that can surely prevent "generation of surface flaws that tend to occur during processing," for that purpose, the specific C as shown in FIG.
Based on the idea that it is indispensable to elucidate the cause of the rapid increase in the frequency of surface defects in the vicinity of the content range, the following findings were obtained.

(A) Grain boundary cracks in continuously cast slabs are carbides, nitrides, or the like which are precipitated or segregated at the grain boundaries, as has been conventionally said.
Not only is it affected by the content of elements related to sulfides and impurities, but it is also greatly affected by the grain size of the austenite (γ) grains that influence the precipitation and segregation density of these elements, and the austenite (γ) during solidification / cooling ) Grain coarsening significantly promotes grain boundary cracking of the slab.

(B) The degree of austenite (γ) grain coarsening of carbon steel slabs during solidification / cooling varies greatly with changes in C content, which also changes while maintaining a mere proportional relationship with C content. Rather, as shown in FIG. 4, it exhibits a behavior that becomes sharply remarkable in the above-mentioned “C content region where surface flaws are likely to occur” (because FIG. 4 shows solidification of Fe-C steel). C when the cooling rate is 5 ° C / sec during cooling
It is a curve showing the relationship between the content and the austenite grain size).

(C) These results and the confirmation items by the experiment that "coarsening of austenite (γ) grains during solidification / cooling occurs rapidly after becoming an austenite single phase, and the tendency is remarkable as the temperature rises" In view of this, the carbon steel slab during solidification / cooling is inevitably found to have the highest austenite single-phase temperature, which is apparent from the Fe-C system equilibrium diagram shown in Fig. 5 under the same cooling conditions. Of high composition ”,
That is, "peritectic point composition (0.18 wt% C in Fe-C system)" shows the most coarse austenite (γ) grains (the broken line in Fig. 5 shows the austenite grains shown in Fig. 4). It is concluded that the hot cracking susceptibility increases rapidly in the vicinity of this point.

(D) By the way, the austenite (γ) grain size coarsening behavior shown in FIG. 4 and the slab surface flaw occurrence frequency tendency shown in FIG. 3 do not necessarily match. However, this is due to the difference that FIG. 4 shows the experimental results in the pure Fe-C system, whereas FIG. 3 shows the data in the case of the practical steel. The peritectic point is shifted due to the effect of contained elements (alloying elements, etc.).

(E) Furthermore, depending on the type of elements other than C contained in the steel, the hot cracking susceptibility of the steel may become more sensitive, which may lead to an increase in the surface defects of the slab.

(F) Therefore, when evaluating the hot cracking susceptibility of a slab, it is necessary to use not only the C content but also the C equivalent (Cp) including the effect of alloying elements as an index.

(G) C, Mn, Ni, Cu, and N are listed as elements that are considered to affect the peritectic point of steel from the phase diagram examination.
Equivalent weight (Cp) should be arranged by the following formula (hereinafter,% representing the component ratio shall be% by weight).

(H) The above formula obtained by the phase diagram examination is in good agreement with the actual condition, and the hot cracking susceptibility of the slab can be evaluated extremely accurately based on this.

FIG. 6 shows the results of experiments conducted by the present inventors in order to confirm this. Small pieces taken from a total of 50 kinds of steels within the composition shown in Table 1 were regenerated in an alumina crucible. It is a graph arranged by the Cp value calculated by the above formula by measuring the austenite grain size after cooling after cooling after cooling with a cooling rate of 5 ° C / sec. As is clear from FIG. 6, the austenite (γ) grain size is well organized by the Cp value, and the maximum value is obtained when the Cp value is 0.18.

(I) As described above, the austenite (γ) grain size is Cp The reason for this depends on the austenite single-phase temperature (T
This is because γ) follows a change in Cp value and changes with a similar tendency, and is determined by that value.For example, the Cp value is a specific value (0.
18; That is, the maximum value of austenite (γ) grain size at the time of peritectic point is that the austenite single-phase temperature (Tγ) becomes highest at that Cp value and the austenite (γ) grain size in the cooling process This is because the growth period will be the longest, and there will be ample opportunity for coarsening.

This can be inferred from FIG. 5 shown above, but refer to FIG. 7 which summarizes the experimental results.

Fig. 7 shows small pieces taken from a total of 70 types of steel within the composition shown in Table 1 after remelting in an alumina crucible, and cooling rates: 0.1 ℃ / sec, 2.0 ℃ / sec and 10 ℃ / It is a graph in which cooling is performed for sec, the austenite single-phase temperature (Tγ) is measured, and the Cp values calculated by the above formula are arranged. As is clear from FIG. 7, the cooling rate is 0.1 ° C /
Below sec, the austenite single-phase temperature (Tγ) is well organized by the Cp value and expressed as the following equation, and the Cp value is 0.
It turns out that the maximum value is taken at 18.

(J) On the other hand, the austenite (γ) grain size of the slab when solidifying and cooling the same composition steel is affected by the Cp value (that is, “Tγ”), It is also greatly affected by the cooling rate, and in particular, it is almost determined by the cooling rate in the temperature range from the austenite single-phase temperature (Tγ) to about 1000 ° C.

FIG. 8 shows that carbon steels having various C contents were melted, then cooled at a cooling rate of 0.28 ° C./sec, and water-quenched in the middle to fix the structure, and the water-quenching temperature and austenite ( γ) A graph plotting the relationship with the particle size. Further, FIG. 9 is an example of the structure before and after Tγ, and shows a microscopic structure of 0.15% C-1.48% Mn steel when cooled at a cooling rate of 0.1 ° C./sec. a) is water-quenched from 1470 ° C (Tγ + 5 ° C),
And FIG. 9 (b) shows the ones water-quenched from 1460 ° C (Tγ-5 ° C). From these figures,
It can be seen that immediately after Tγ, the γ grains start to coarsen rapidly.

Further, from FIG. 8 and FIG. 9 described above, it is extremely high temperature range where the rapid cooling has a great influence on the austenite (γ) grain growth, especially from the austenite single-phase temperature (Tγ) to 1000 ° C.
It is clear that the effect of quenching is not so remarkable in the lower temperature range.

And see FIG. This FIG. 10 shows that for a total of 30 steels within the composition shown in Table 1 above, the cooling rate after the austenite single-phase temperature (Tγ) was variously changed, and the structure was rapidly cooled after reaching 1000 ° C. 2 is a graph showing the austenite (γ) particle size of the powder with the fixed value of ∘, organized by the cooling rate. From FIG. 10, it can be seen that even if the “steel having a peritectic composition (Cp = 0.18)” has the highest austenite single-phase temperature (Tγ) and the austenite grains are likely to coarsen, the austenite single-phase temperature (Tγ) ) It is understood that if the cooling rate after that is increased, coarsening of austenite (γ) grains can be prevented.

(K) By the way, the surface cracking tendency of the slab in the middle of continuous casting and the surface cracking tendency of the slab in the hot direct rolling or hot charge rolling which is performed subsequent to the continuous casting are as follows. To about 3 mm, at most 10 mm).

(1) Therefore, even if the cast piece has a composition near the peritectic composition, if the cooling rate of the surface layer portion after the austenite single-phase temperature (Tγ) is increased, coarsening of austenite grains in the surface layer portion is suppressed and Since it becomes possible to obtain a fine grain structure having a large grain boundary area, the density of precipitates and segregation gathering at the grain boundaries becomes low, the crack susceptibility is alleviated and the toughness becomes high. Dispelling the fear of cracking.

(M) Because of this, there is a strong tendency for surface flaws (cracks) to occur during casting of slabs produced by continuous casting, and for surface flaws (cracks) to occur during hot rolling of continuously cast slabs. It is possible to easily and surely predict the steel grade by the above formula (formula for calculating the Cp value). Also, for these steel grades, the surface layer of the cast slab has a specific high temperature range (actually "Tγ"). It is possible to stably suppress the occurrence of surface defects by performing a rapid cooling process (cooling at which the cooling rate of the surface layer is 10 ° C / sec or more) during the above period.

Therefore, the present inventors intend to produce a slab with low surface cracking susceptibility by increasing the cooling rate in the high temperature region of the molten steel injected into the mold based on the findings of these (a) to (m). After trying, I found that the following problems were actually encountered.

That is, in the actual operation when continuously casting steel, solidification proceeds in the state where the solidification shell and the mold wall are in close contact with each other via the molten powder in the vicinity of the molten steel meniscus, but when the temperature is lower than that, "solidification shrinkage of molten steel "And" shrinkage due to the temperature drop of the slab "cause the slab to separate from the wall surface of the mold, resulting in an air gap that impairs the heat removal action of the mold. Therefore, in normal molds (length 700-900 mm or more) used in vertical or curved continuous casting machines,
After that, it is unavoidable that a significant cooling delay occurs, which causes the austenite grain boundary destruction to cause coarsening of the austenite grains to the extent that the surface defects are likely to occur.

Therefore, by shortening the length of the mold, solidification of molten steel in the mold is stopped only by forming a very thin slab surface solidification layer, and by spraying a cooling medium onto the slab that has been pulled out early from the lower end of the mold. We also tried to increase the cooling rate in the high temperature range,
In this case, the risk of causing breakout of the slab is extremely high, and this is not a preferable means in actual operation.

Therefore, we provide a means for producing a continuously cast slab that is less susceptible to surface cracking and less likely to cause "surface flaws that propagate along austenite grain boundaries" without being affected by the composition of the steel and with good productivity. After continuing to study as much as possible,
"As a double-sided open mold for continuous casting of steel, a means for detecting the surface temperature of the slab of the slab and a nozzle hole for blowing a cooling medium are provided on the inner wall surface of the lower part of the mold, and the" inner wall surface of the lower part of the mold " The surface temperature of the surface layer part was changed from the time when the cast molten steel solidified and began to form the surface layer part of the slab by using the one with the through hole for sucking and discharging the "blown cooling medium" at the upper position. While still at the austenite single-phase temperature, if a cooling medium is continuously blown into the site to circulate toward the discharge conduction hole to quench the surface layer of the cast slab, there is a risk of slab breakout. It is possible to easily secure a high cooling rate at a high temperature of molten steel cast while avoiding it reliably, and to cool the surface layer of the slab from a temperature of Tγ or higher to a cooling rate of 10 ° C / sec or higher. Can be achieved stably It was possible to obtain new knowledge and to become ". Moreover, in such a continuous casting mold, a relatively open gap is provided between the surface of the slab that has begun to solidify by retracting the "lower inner wall surface of the mold" to some extent. It was also clarified that the cooling effect is further improved by doing so.

<Means for Solving the Problems> The present invention has been completed based on the above-mentioned various findings and the like, and a double-ended open mold for continuous casting of steel can be obtained as shown in FIG. A temperature sensor 3 for measuring the surface temperature of the cast slab and a nozzle hole 4 for blowing a cooling medium, and a communication hole 6 for sucking a cooling medium above the lower inner wall surface 2 of the slab. As a result, the temperature sensor 3 detects whether or not the temperature of the surface layer of the slab that has reached the lower inner wall surface is within the appropriate range described above (a range in which a quenching effect of “Tγ” or more can be expected). 10 ℃ for the surface layer of the slab in the proper temperature range
Temperature sensor 3 so that it can be cooled at a cooling rate of over / sec
The amount of the cooling medium blown from the cooling medium blowing nozzle hole 4 can be adjusted through the cooling medium blown through, and the blown cooling medium is the upper inner wall surface 5 of the mold 1 and the meniscus 8 of the molten steel 7.
It is possible to surely prevent the unstable cooling of the vicinity of the meniscus 8 by making a gap between the cooling medium suction hole 6 and the gap and to prevent it from flowing smoothly through the cooling medium suction through hole 6, or As shown in FIG. 2, in addition to these, the lower inner wall surface 2 of the mold 1 in which the temperature detecting sensor 3 for measuring the surface temperature of the slab and the nozzle hole 4 for blowing the cooling medium are arranged from the upper inner wall surface 5 This is because the cooling effect by the cooling medium and its uniformity are further increased by retreating also (because it is possible to reliably prevent partial retention of air and the cooling medium between the slab surface and the lower inner wall surface). ), The cooling medium suction through-hole 6 can be easily sucked to enhance the suction ability, so that the high cooling rate of the cast molten steel at high temperature can be facilitated. Secured and slab It is possible to reliably avoid the risk of rake-out, and it is possible to stably mass-produce continuous cast slabs that are not affected by the steel type, have no surface flaws, and have low surface cracking susceptibility. are doing.

Incidentally, the steel to be cast in the present invention does not matter the type, but in terms of the effect obtained, C: 0.
7% or less, Mn: 3% or less, Ni: 3% or less, Cu: 2% or less and N: 0.5
% Or less, and if necessary, Cr: 3% or less, Nb: 0.5% or less, V:
Contains at least one of 0.5% or less, Ti: 0.5% or less, Al: 0.1% or less, and Si: 3% or less, and has the formula Cp = C (%) + Mn (%) / 33 + Ni (%) / 25 + Cu. (%)/Four
This is especially noticeable when targeting low alloy steels with a Cp value of less than 0.6 calculated by 4 + N (%) / 1.7 (which is not affected even if ordinary unavoidable impurities are contained).

By the way, in the casting using the mold according to the present invention, the cooling condition of the slab surface layer portion immediately after being formed from molten steel (about 3 mm from the surface of the slab, up to about 10 mm at most) is set to the "austenite single-phase temperature". Therefore, it is better to set "cool at a cooling rate of 10 ° C / sec or more."

This is because, as is clear from FIGS. 8 to 9 pointed out above, when the temperature of the surface layer of the cast slab formed by solidification in the mold becomes Tγ or lower, the tendency of γ grains to become coarse becomes remarkable. However, if the surface layer of the slab is cooled at a specific high cooling rate at this time, coarsening of the austenite (γ) grains is suppressed, and the occurrence of surface defects on the slab can be sufficiently suppressed. However, if the cooling rate at this time is less than 10 ° C / sec, the effect of suppressing coarsening of austenite (γ) grains becomes insufficient,
It becomes impossible to stably obtain a slab with low susceptibility to cracking. Therefore, the cooling conditions for the surface layer of the cast slab immediately after solidification / formation from molten steel are as follows:
It is recommended to set "Cool at a cooling rate of 10 ° C / sec or more" as a guide.

As described above, FIG. 10 is a graph showing the relationship between the cooling rate after the temperature of the surface layer of the cast slab is below Tγ and the austenite (γ) grains. Also, if the cooling rate is 10 ℃ / sec or more, while sufficient austenite grain coarsening suppression effect can be obtained, while the cooling rate is less than 10 ℃ / sec austenite of the slab surface layer part It is clear that the grains show a tendency to coarsen, leading to frequent occurrence of slab surface defects accompanied by austenite grain boundary fracture.

Further, as described above, in the mold of the conventional vertical type or curved type continuous casting machine, it is impossible to set the cooling rate of the slab surface layer portion in the high temperature region to 10 ° C / sec or more, This cooling rate level can be sufficiently ensured by using the mold according to the present invention. Although the instability of the casting work cannot be denied, after shortening the length of the mold with both ends open and adjusting the withdrawal speed of the slab so that the surface temperature of the slab at the outlet becomes Tγ or higher, The cooling rate can be secured by means such as employing a method of spraying a cooling medium on the slab just below the mold.

The continuous casting operation of steel by the "mold according to the present invention" illustrated in FIG. 1 or 2 will be described below.

When molten steel 7 is cast into the mold 1, an extremely thin solidified shell 9 is formed by the heat removal effect of the upper inner wall surface 5 of the mold (reference numeral 10 indicates a cooling water passage). If the length of the wall surface 5 is made extremely short, for example, about 500 mm (the length under the meniscus is about 300 mm), the portion of the slab where the solidified shell has just been formed is immediately lowered to the position of the lower inner wall surface 2. Therefore, the cooling medium (for example, He gas) that is blown from the cooling medium blowing nozzle hole 4 and flows back to the cooling medium suction conducting hole 6 is efficiently cooled. In this case, by retracting the lower inner wall surface 2 as in the mold shown in FIG. 2, it is possible to reliably prevent the air and the cooling medium from partially remaining between the slab surface and the lower inner wall surface. Therefore, the cooling efficiency is further improved.

As the cooling medium blown from the cooling medium blowing nozzle hole 4, a cooling gas such as He gas or a mixed gas of these and water may be adopted.

Therefore, there is a problem that "the solidified shell surface separates from the inner wall surface of the mold due to shrinkage due to solidification or cooling to form an air layer between both surfaces, which causes a cooling delay", as in the conventional open-ended mold for continuous casting. I will never come.

Moreover, in the mold according to the present invention, since the temperature detecting sensor 3 is attached to the lower inner wall surface 2, the temperature detecting sensor 3 can accurately confirm the surface layer temperature of the quenching start slab, and also the cooling rate. Adjustment is also easy. Therefore, a high cooling rate in the high temperature region of the surface layer of the cast slab is stably ensured. Therefore, coarsening of the austenite grains in the surface layer portion can be surely prevented, and it is possible to efficiently produce a slab with no surface flaw and low surface cracking susceptibility.

Further, in such a mold, the cast piece until the solidified shell having a desired thickness is formed can be stopped in the mold, so that there is no risk of breakout.

Then, the slab on which such a sound solidified shell is formed is continuously drawn out from the lower part of the mold and is conveyed while being sufficiently cooled by the cooling water spray nozzle 11.

Next, the present invention will be described by way of Examples in comparison with Comparative Examples.

<Example> Example 1 As shown in Table 2, according to the present invention as shown in Fig. 1, by melting A steel, which is liable to have many surface defects, in a continuously cast slab. Practical curved continuous casting machine equipped with water-cooled copper mold or conventional water-cooled copper mold (curvature radius: 1
2.5m), a slab having a cross-sectional dimension of 250mm × 1200mm was produced at a casting speed of 1.2m / min for about 150m.

The water-cooled copper mold according to the present invention has the shape and dimensions shown in Table 3, and the conventional water-cooled copper mold has a full length.
It was 800 mm.

Further, in the mold according to the present invention used at this time, the temperature of the surface layer of the slab reached "Tγ" calculated from the Cp value obtained from the addition amount of C and the component element using the Cp equation. When the temperature sensor detects, the amount of cooling medium ejected from the cooling medium injection nozzle hole controlled by the computer increases from 0.2l / min to 0.4l / min only for "the nozzle hole immediately above the temperature sensor that senses Tγ". It was set to do. Therefore, the cooling rate of the surface layer of the cast slab having a temperature of Tγ was stably maintained at 10 ° C / sec or more.

The surface flaws of the slab thus obtained were visually evaluated, and the results are shown in FIG. The "crack index" in FIG. 11 is the total number of surface cracks generated per 1 m ^{2 of} slab.

As is clear from FIG. 11, continuous casting is performed using the mold of the present invention while cooling the surface layer of the cast slab from Tγ or higher at a cooling rate of 10 ° C./sec or higher, and it is a steel with a strong surface cracking orientation. However, it can be seen that almost no surface flaws are generated and that no maintenance is required.

Example 2 As shown in Table 2, B steel, which is a component composition in which surface flaws are unlikely to occur in a continuously cast slab but is likely to cause cracks during subsequent hot rolling, is melted and shown in FIG. Water-cooled copper mold (lower inner wall 2 is 20 mm thicker than upper inner wall)
(Similar to FIG. 1 except that it is retracted) and the cross-sectional dimensions are 250 mm × 1200 mm under the same conditions as in Example 1.
Manufactured slabs of.

Then, the surface temperature was observed for the slab that passed through the slab straightening point at a surface temperature of 950 ° C., and any slab in the case of using the mold according to the present invention and the case of using the conventional mold had a surface flaw. Although it was not recognized, the slab that passed the slab straightening point was cut and rolled at a temperature of about 900 ° C. to a thickness of 125 mm for 5 passes, and the mold according to the present invention was used. No surface defects were observed in the sample, whereas it was observed that the conventional mold had many cracks.

<Summary of Effects> As described above, according to the present invention, by using a steel type that is prone to cracks during continuous casting or during hot working (for example, hot direct rolling or hot charge rolling). However, it is possible to carry out the production of a desired product without causing such troubles, resulting in an extremely useful effect in industry.

[Brief description of drawings]

1 and 2 are schematic views showing the situation of continuous casting using the mold of the present invention, and FIGS. 1 and 2 show examples of using different types of molds, respectively. There is. FIG. 3 is a graph showing the relationship between the C content and the slab surface flaw occurrence frequency. Fig. 4 is a graph showing the relationship between the C content of Fe-C steel and the austenite grain size. FIG. 5 is an equilibrium diagram of the Fe-C system. FIG. 6 is a graph showing the relationship between the Cp value of steel and the austenite grain size. Fig. 7 shows Cp value of steel and austenite single-phase temperature (Tγ)
It is a graph which shows the relationship with. FIG. 8 is a graph showing the relationship between the water-quenching temperature and the austenite grain size when carbon steel with various C contents during cooling is water-quenched at various temperatures to fix the structure. FIG. 9 is a microstructure photograph comparing the changes in the metal structure before and after the austenite single-phase conversion temperature (Tγ), and FIG. 9 (a) shows the state of water quenching from 1470 ° C. (Tγ + 5 ° C.), and Figure 9 (b) shows 1460 ° C (Tγ-5
It shows the state of water quenching from (.degree. C.). FIG. 10 is a graph showing the relationship between the cooling rate of the steel after the austenite single phase temperature and the austenite grain system. FIG. 11 is a graph comparing the crack index of a slab when the normal mold and the mold according to the present invention are used. In the drawings, 1 ... Mold, 2 ... Lower inner wall surface, 3 ... Temperature sensor, 4 ... Cooling medium blowing nozzle hole, 5 ... Upper inner wall surface, 6 ... Cooling medium suction through hole, 7 ... Molten steel, 8 ... Meniscus, 9… Solidification shell, 10… Cooling water passage, 11… Cooling water spray nozzle.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kei Kanazawa 1-3, Nishi-Nagasumotodori, Amagasaki, Hyogo Sumitomo Metal Industry Co., Ltd. (72) Inventor Hiroshi Tomono 1850 Minato, Wakayama, Wakayama Sumitomo Metal Co., Ltd. Wakayama Works (56) References JP 54-4224 (JP, A) JP 61-195761 (JP, A)

Claims (2)

(57) [Claims] 1. A continuous casting open-ended mold, wherein a temperature sensor and a cooling medium blowing nozzle hole are provided on the inner wall surface of the lower part of the mold, and a conduction hole for sucking the cooling medium is provided above the inner wall surface of the lower part of the mold. A mold for continuous casting of steel, comprising: 2. A continuous casting open-ended mold, wherein the inner wall surface of the lower part of the mold is retracted, and a temperature sensor and a cooling medium blowing nozzle hole are provided on the retracted inner wall surface, and the lower part of the mold is provided. A casting mold for continuous casting of steel, characterized in that a cooling medium suction through hole is provided above the inner wall surface.