JP5747726B2 - Temperature estimation method and temperature estimation device - Google Patents

Description

  The present invention relates to a temperature estimation method and a temperature estimation device for a steel slab in a continuous casting machine.

  In the current iron making process, a technique called a continuous casting method is generally used as a method of producing a steel piece by casting refined molten steel. This is because the continuous casting method is excellent in productivity because it can process molten steel continuously, and has higher thermal efficiency and energy saving than the method of pouring molten steel into a batch mold. Furthermore, the continuous casting method also has an advantage that the internal quality can be stabilized by the floating removal of inclusions.

  By the way, in the continuous casting method, the molten steel in a liquid state is poured into the apparatus and cooled to finally form a solid steel piece. If this cooling is too strong, the steel slab temperature in the apparatus becomes too low and the strength becomes excessive, making it difficult to pass through the apparatus. On the other hand, if the cooling is too weak, the strength of the solidified portion becomes too small, the portion where the strength is too small when passing through the apparatus breaks, and the unsolidified molten steel inside flows out of the machine, so-called It can cause an accident called a breakout. Therefore, in the continuous casting method, appropriate temperature control by controlling appropriate cooling conditions is required. Thus, a temperature estimation method based on empirical knowledge has been proposed (see, for example, Patent Documents 1 and 2).

  When predicting the change in temperature for a given cooling condition, it is important to accurately predict the heat transfer coefficient, a value that represents the ease of heat exchange (heat transfer) with the outside of the billet. It is. The heat transfer coefficient varies greatly depending on the cooling method and environment. Many studies have been conducted to determine an appropriate heat transfer coefficient for each cooling method, and many formulas have been proposed to estimate the heat transfer coefficient required for predicting the temperature transition of the cooling method. (For example, refer nonpatent literature 1).

  In a continuous casting machine, in consideration of average casting conditions and the like, it is common to arrange different cooling devices depending on the location of the apparatus. Therefore, in order to accurately predict the temperature of the steel slab in the continuous casting machine, predict the appropriate heat transfer mode according to the location based on the cooling device such as spray and the estimated temperature. It is necessary to predict the transition of temperature using an equation for calculating the heat transfer coefficient. Therefore, conventionally, a method of predicting a temperature transition by changing a formula for obtaining a heat transfer coefficient according to a location in a casting direction has been widely used (see, for example, Patent Documents 3, 4, and 5).

Japanese Patent Laid-Open No. 63-235055 Japanese Patent Laid-Open No. 08-276258 JP 60-54257 A JP 60-54258 A JP 2003-136208 A

"Cooling Technology in Steel Manufacturing Process" (Japan Iron and Steel Institute), 1988, p.70-71

  In recent years, further improvement in productivity and quality of continuous casting has been demanded. As a technique for improving productivity, for example, a technique of increasing the casting speed is taken. However, when the casting speed is increased, manufacturing troubles due to poor solidification are likely to occur. In addition, the generation of thermal stress that is assumed to be caused by non-uniform cooling, surface defects such as cracks caused by it, and non-uniform composition of the steel slab center due to non-uniform solidification within the slab Part, so-called center segregation, etc. are also likely to occur. In order to avoid such a situation, development of a technology for uniformly cooling has been demanded. For this purpose, a technique for accurately predicting the local temperature distribution of the steel slab is important.

  However, the conventional local temperature distribution prediction method has a problem that it is necessary to predict the degree of change in the heat transfer coefficient at the temperature prediction position in advance. For this reason, an appropriate correction coefficient is often given in order to match the predicted value to the actual measurement value, and there are often cases where the rationality and versatility are lacking. Furthermore, the formula for obtaining the heat transfer coefficient usually has a range of application with respect to the amount of water in the spray, but in some cases, calculation with an inappropriate amount of water may be performed. These problems are due to the fact that the heat transfer mode changes locally, while the heat transfer mode is predicted and analyzed in advance.

  The present invention has been made in view of the above problems, and its purpose is to predict the local temperature distribution of a steel slab in a continuous casting machine without analyzing the form of heat transfer in advance. It is to provide a possible temperature estimation method and apparatus therefor.

  In order to solve the above-described problems and achieve the object, the temperature estimation method according to the present invention includes an input step for inputting a position for estimating the temperature of a steel slab in a continuous casting machine, and an operation for calculating a heat transfer coefficient. An acquisition step of acquiring a condition; a calculation step of calculating a plurality of heat transfer coefficients at the position based on the operating condition; a selection step of selecting one of the plurality of heat transfer coefficients; and the selected heat And a heat transfer calculation step for performing heat transfer calculation using the transfer coefficient.

  In order to solve the above problems and achieve the object, the temperature estimation apparatus according to the present invention includes an input means for inputting a position for estimating the temperature of a steel piece in a continuous casting machine, and an operation for calculating a heat transfer coefficient. Acquisition means for acquiring conditions, calculation means for calculating a plurality of heat transfer coefficients at the position based on the operating conditions, selection means for selecting one of the plurality of heat transfer coefficients, and the selected heat And heat transfer calculation means for performing heat transfer calculation using the transfer coefficient.

  According to the temperature estimation method and the temperature estimation apparatus according to the present invention, it is possible to predict the local temperature distribution of the steel slab in the continuous casting machine without analyzing the shape of the heat transfer in advance. .

FIG. 1 is a schematic diagram showing a schematic configuration of a continuous casting machine according to an embodiment of the present invention. FIG. 2 is a flowchart showing a temperature estimation method according to the embodiment of the present invention. FIG. 3 is a flowchart showing a conventional temperature estimation method. FIG. 4 is a graph showing the estimated position of the solidification position inside the steel slab by the temperature estimation method according to the embodiment of the present invention and the comparative example. FIG. 5 is a block diagram illustrating an example of a functional configuration of the temperature estimation apparatus according to the embodiment of the present invention.

  Hereinafter, a steel slab temperature estimation method and a temperature estimation device in a continuous casting machine according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing a schematic configuration of a continuous casting machine according to an embodiment of the present invention. As shown in FIG. 1, a continuous casting machine 1 according to an embodiment of the present invention has a tundish 3 into which molten steel 2 is injected and a molten steel 2 poured from the tundish 3 through an immersion nozzle 4 on the surface. A copper mold 6 which is shaped and semi-solidified until the solidified shell 5 grows into dendrites, a steel piece support roll 8a which cools while pulling a steel piece 7 in a semi-solid state from the mold 6 vertically downward, and a steel piece A steel piece support roll 8b for cooling and conveying the steel piece 7 drawn out by the support roll 8a, a steel piece support roll 8c for cooling and conveying the steel piece 7 conveyed by the steel piece support roll 8b in the horizontal direction, and a steel piece support And a gas cutter 9 for cutting the steel piece 7 conveyed by the roll 8c into a predetermined length. The steel pieces 7 cut by the gas cutter 9 are sequentially sent to a subsequent process such as a rolling process.

  The steel slab in the continuous casting machine 1 in the embodiment of the present invention is cooled by the mold 6 by heat removal from the mold surface. Thereafter, in the conveyance section (that is, the secondary cooling zone) by the billet support rolls 8a to 8c, the billet is extracted by water or air sprayed from the spray, and is extracted by contact between the roll and the billet. It is cooled by a combination of heat removal by radiation and heat removal by convection. Here, spray spraying includes water spray cooling, mist spray cooling, and the like.

  Hereinafter, the temperature estimation method according to the embodiment of the present invention will be described using the example of the continuous casting machine 1 described above. First, boundary conditions and heat transfer coefficients used as a premise in the description of the embodiment of the present invention will be described.

  The boundary condition referred to here is a boundary condition on the surface of the billet when calculating the heat transfer of the billet. In the temperature estimation method according to the embodiment of the present invention, this boundary condition is changed according to time and position in order to accurately predict a local temperature according to time and position. What is necessary is just to set the pitch to change arbitrarily according to how short time or the temperature of a detailed area | region is estimated. When the time interval for which a change in temperature is to be predicted is Δt (s), the temperature reflecting the time change of the boundary condition can be predicted by setting a value smaller than Δt. As for the change due to the position, when the casting speed is Vc (m / s), if the change due to the position is larger than Vc (m / s) × δt (s), the change due to the position of the boundary condition is changed. It is possible to predict the reflected temperature.

  Note that the change in boundary conditions is to reproduce the fact that the actual heat transfer mode has changed, and it is not necessary to change it when the actual heat transfer mode has not changed. Is natural. Practically, considering the complexity and calculation amount of calculation, the certainty of measurement of boundary conditions, and the thermal conductivity of the steel material that is the object, about 1 (s) is the lower limit for time, and the position Is about 5 (mm).

  The heat transfer coefficient referred to here is a value representing the ease with which heat energy is transferred between the steel slab and the outside. Examples of the boundary conditions for temperature prediction include temperature and heat transfer coefficient. In the temperature estimation method according to the embodiment of the present invention, a heat transfer coefficient is used. When the surface temperature is defined as a boundary condition, the internal temperature can be easily predicted. However, in a high-temperature medium such as a billet in the continuous casting method, the temperature measured by the thermometer may not necessarily correspond to the actual temperature of the billet, and it is difficult to know the exact temperature. There are many. In particular, it is more difficult to know such an accurate temperature if one wishes to predict a temperature that varies locally with time and position. Therefore, it is not desirable to give temperature as a boundary condition. On the other hand, the heat transfer coefficient is suitable for use in predicting the temperature when the form of heat transfer locally changes with time and position, as in the temperature prediction method according to the embodiment of the present invention.

  The boundary condition is usually set on the surface of the steel slab in the case of an apparatus that cools the steel slab by spraying or bringing it into contact with the surface as in continuous casting. However, if there is a mechanism for cooling from the inside by some method, for example, heating by electromagnetic induction or some method, the boundary condition may be set inside the steel slab.

  Hereinafter, an example of the temperature estimation method according to the above-described embodiment of the present invention will be described with reference to FIG. In the temperature estimation method according to the embodiment of the present invention, when estimating the form of heat transfer that varies locally depending on time and position, a plurality of heat transfer coefficients expected in the scene are calculated, and the heat transfer coefficients are calculated. The optimum heat transfer coefficient is selected from the above.

  FIG. 2 is a flowchart showing a temperature estimation method according to the embodiment of the present invention. First, a position to which the temperature estimation method according to the embodiment of the present invention is applied is input (step S1). And the value of the operation conditions required for calculation of a heat transfer coefficient, such as the amount of water supply in the position and time, and the amount of air supply, is acquired (step S2). The values of these operation conditions may be obtained by calculating operation data using information obtained off-line such as the arrangement and performance of spray nozzles or the like, or values measured by some method may be used.

Next, based on the value acquired at step S2, a plurality of heat transfer coefficients at the position and time input at step S1 are calculated (steps S3 to S8). In the temperature estimation method according to the embodiment of the present invention described below, a water spray heat transfer coefficient _HA , a mist spray heat transfer coefficient H _B, and a forced convection heat transfer coefficient H are used as a plurality of heat transfer coefficients. Six types of heat transfer coefficients are calculated: _C , heat transfer coefficient H _D due to radiation, heat transfer coefficient H _E due to roll contact, and heat transfer coefficient H _F due to natural convection.

Step S3 calculates the heat transfer coefficient _HA of the water spray. For example, as a formula for calculating the heat transfer coefficient, the following formula based on “Nippon Iron and Steel Institute:“ Cooling Technology in Steel Manufacturing Process ”(1988), p. 70” of the aforementioned Non-Patent Document 1 can be used.

Step S4 is for calculating a heat transfer coefficient H _B of the mist spray. For example, as a formula for calculating the heat transfer coefficient, the following formula based on “Nippon Iron and Steel Institute:“ Cooling Technology in Steel Manufacturing Process ”(1988), p. 71” of the aforementioned Non-Patent Document 1 can be used.

Step S5 is to calculate the heat transfer coefficient H _C forced convection. For example, the following formula can be used as a formula for calculating the heat transfer coefficient.

なお、放射率は定形境界条件ファイルなど、雰囲気温度は計算設定ファイルなどに別途保存したデータを参照して用いる。 Step S6 is for calculating a heat transfer coefficient H _D by radiation. For example, the following Stefan-Boltzmann equation can be used as an equation for calculating the heat transfer coefficient.

The emissivity is used by referring to data stored separately in a fixed boundary condition file and the ambient temperature is stored separately in a calculation setting file.

Step S7 is to calculate the heat transfer coefficient H _E by the roll contact. There are a method of calculating based on contact pressure, roll diameter, etc., and a method of calculating based on pre-collected data, but in this example, refer to the data separately stored in the fixed boundary condition file and Get the heat transfer coefficient of the roll to be placed.

Step S8 is for calculating a heat transfer coefficient H _F by natural convection. For example, the following formula can be used as a formula for calculating the heat transfer coefficient. However, the ambient temperature T _ambient is used by referring to data separately stored in the calculation setting file.

As described above, the heat transfer coefficient H _A water spray, the heat transfer coefficient H _B of the mist spray, the heat transfer coefficient H _C forced convection heat transfer coefficient H _D by radiation, heat transfer coefficient due to roll contact and H _E, after calculating the heat transfer coefficient H _F by natural convection, selects the largest value as the heat transfer coefficient H _X among these (step S9). Thereafter, heat transfer calculation is performed using the heat transfer coefficient selected in step S9 (step S10).

  In the embodiment described above, the method of selecting the maximum value is used as the method of selecting the heat conduction coefficient. However, the present invention is not limited to this example, and for example, the median value is calculated. And a method of selecting a value in an arbitrary order, such as a method of calculating a minimum value, a method of selecting a value that comes second from the top when arranged in descending order, and the like. In addition, the simple average value of the calculated heat transfer coefficients, and the three-way value that uses the value obtained by arithmetically averaging the values in three arbitrary orders (for example, maximum value; median value; minimum value) when arranged in descending order. You can use the law.

  If the method using the maximum value as in the embodiment described above, for example, in a mist spray using water and air in combination, a location where a large amount of water and air hits the center of the spray nozzle, and water away from the center. It has been experimentally confirmed that the heat transfer mode in the place where the air almost disappears can be selected appropriately. Therefore, in the practice of the present invention, it is more preferable to select the maximum value and a value according to it as the heat transfer coefficient.

  Hereinafter, the effect of the temperature estimation method according to the embodiment of the present invention will be examined by comparison with the temperature estimation method of the prior art. Here, as the effect of the temperature estimation method according to the embodiment of the present invention, the position of the solidification position inside the steel slab is estimated. In other words, the position reaching the solidification temperature inside the steel slab was used as an index for temperature estimation.

  FIG. 3 is a flowchart showing a conventional temperature estimation method (comparative example) used for comparison with the embodiment of the present invention. Since the flowchart of the comparative example demonstrated below has many parts which are common in the temperature estimation method concerning embodiment of this invention mentioned above, it abbreviate | omits suitably and demonstrates.

  First, also in the comparative example, the position where the temperature estimation method is applied is input, and the operating conditions necessary for calculating the heat transfer coefficient are acquired (steps S1 'and S2'). Then, based on the spray arrangement information, it is determined whether the input analysis position is a water spray installation location (step S3 ′), and if it is a water spray installation location, a heat transfer coefficient of the water spray is calculated. (Step S4 ′). On the other hand, it is determined whether the input analysis position is a mist spray installation location (step S5 '), and if it is a mist spray installation location, a heat transfer coefficient of the mist spray is calculated (step S6'). Further, it is determined whether the input analysis position is a roll installation location (step S7 '), and if it is a roll installation location, a heat transfer coefficient due to roll contact is calculated (step S8').

  Furthermore, the heat transfer mode is estimated based on the distance from the spray at the analysis position at the end of the steel piece and the estimated temperature, and the heat transfer coefficient is calculated based on this. Specifically, when the distance from the spray is far (outside the spray range of the spray at the extreme end) and the estimated temperature is 300 ° C. or more (step S9 ′), the heat transfer coefficient by radiation is Calculate (step S10 '). If the distance from the spray is not far (step S11 ′), the heat transfer coefficient due to forced convection is calculated (step S12 ′). Otherwise (step S11 ′), the heat transfer coefficient due to natural convection is calculated. (Step S13 ′). Heat transfer calculation is performed using the heat transfer coefficient calculated in this way (step S14 ').

  The temperature distribution inside the steel slab was calculated by the comparative example in which the heat transfer coefficient was obtained as described above and the temperature estimation method according to the embodiment of the present invention, and the solidification position inside the steel slab was estimated from the result.

  FIG. 4 is a graph showing the estimated position of the solidification position inside the steel slab by the temperature estimation method according to the embodiment of the present invention and the comparative example. In the graph shown in FIG. 4, the measurement result by the ultrasonic of the solidification position of a steel piece is described collectively. In the graph shown in FIG. 4, the horizontal axis represents the distance from the center of the steel piece to the solidification position, and the vertical axis represents the distance from the meniscus (that is, the surface position of the molten steel in the mold) to the solidification position.

  As apparent from the graph shown in FIG. 4, the temperature estimation method according to the embodiment of the present invention is more accurate than the comparative example according to the prior art, in addition to the accuracy in the absolute position of the actual solidification position, and its distribution in the width direction. The shape can also be accurately reproduced. This result shows that the temperature estimation method according to the embodiment of the present invention can estimate temperature more accurately than the comparative example according to the prior art.

  Finally, an example of a functional configuration of the temperature estimation apparatus that performs the temperature estimation method according to the embodiment of the present invention described above will be described. However, in order to implement the temperature estimation method according to the embodiment of the present invention, it is preferable to change the configuration appropriately according to the implementation environment of the present invention, not limited to the example of the temperature estimation device described below.

  FIG. 5 is a block diagram illustrating an example of a functional configuration of the temperature estimation apparatus according to the embodiment of the present invention. As shown in FIG. 5, the temperature estimation device 10 is realized by using a general-purpose computer such as a workstation or a personal computer, and includes an arithmetic processing unit 11 and a storage unit 12. Moreover, the temperature estimation apparatus 10 is provided with the input means 13 and the display means 14 incidentally.

  The input unit 13 is realized by various input devices such as a keyboard, a mouse, a touch panel, and various switches, and outputs an input signal corresponding to an operation input to the arithmetic processing unit 11. The display unit 14 is realized by a display device such as an LCD, an EL display, or a CRT display, and displays various screens based on a display signal input from the arithmetic processing unit 11.

  The storage unit 12 is realized by various IC memories such as ROM and RAM such as flash memory that can be updated and stored, information storage media such as a built-in or data communication terminal connected to a hard disk, a CD-ROM, and a reading device thereof. It is. In the storage unit 12, a program for operating the temperature estimation device 10 and realizing various functions provided in the temperature estimation device 10, data used during the execution of the program, and the like are stored in advance, or It is temporarily saved for each processing. For example, the storage unit 12 stores an operation condition 12a and a heat transfer coefficient 12b.

The operation condition 12a is data necessary for calculating the heat transfer coefficient such as the water supply amount and the air supply amount in the temperature estimation method described above. That is, the operation condition 12a stores the above-described fixed boundary condition file and calculation setting file. The heat transfer coefficient 12b includes a water spray heat transfer coefficient H _A , a mist spray heat transfer coefficient H _B , a forced convection heat transfer coefficient H _C , a heat transfer coefficient H _D by radiation, a heat transfer coefficient H _E by roll contact, and a data and program the formula for calculating the heat transfer coefficient H _F by natural convection.

  The arithmetic processing unit 11 includes a heat transfer coefficient calculation unit 11a, a maximum heat transfer coefficient selection unit 11b, and a heat transfer calculation unit 11c. The heat transfer coefficient calculation means 11a, the maximum heat transfer coefficient selection means 11b, and the heat transfer calculation means 11c can be realized by a program stored in the storage unit 12 or as hardware. The heat transfer coefficient calculation means 11a calculates the heat transfer coefficient with reference to the operation condition 12a and the heat transfer coefficient 12b of the storage unit 12, and the maximum heat transfer coefficient selection means 11b is calculated by the heat transfer coefficient calculation means 11a. The heat transfer coefficient having the maximum value is selected from the heat transfer coefficients, and the heat transfer calculation means 11c performs the heat transfer calculation using the heat transfer coefficient selected by the maximum heat transfer coefficient selection means 11b.

  From the above, in the temperature estimation method according to the embodiment of the present invention, the input step (step S1) for inputting the position for estimating the temperature of the steel slab 7 in the continuous casting machine 1 and the operation condition for calculating the heat transfer coefficient. Obtaining step (step S2), calculating step (steps S3 to S8) for calculating a plurality of heat transfer coefficients at the position based on operating conditions, and selection for selecting one of the plurality of heat transfer coefficients Since it includes a step (step S9) and a heat transfer calculation step (step S10) for performing heat transfer calculation using the selected heat transfer coefficient, it is possible to continuously analyze without predicting the form of heat transfer in advance. An accurate prediction of the local temperature distribution of the billet in the casting machine can be made.

  Since the selection step (step S9) in the temperature estimation method according to the embodiment of the present invention selects the one having the maximum value among the plurality of heat transfer coefficients, the most appropriate selection can be made experimentally.

The calculation steps (steps S3 to S8) in the temperature estimation method according to the embodiment of the present invention include water spray heat transfer coefficient H _A , mist spray heat transfer coefficient H _B , and forced convection heat as a plurality of heat transfer coefficients. It is conceivable to calculate a heat transfer coefficient H _C , a heat transfer coefficient H _D due to radiation, a heat transfer coefficient H _E due to roll contact, and a heat transfer coefficient H _F due to natural convection.

  Moreover, the temperature estimation apparatus which concerns on embodiment of this invention acquires the input condition 13 which inputs the position which estimates the temperature of the steel slab 7 in the continuous casting machine 1, and the operation condition 12a for calculating a heat transfer coefficient. An acquisition means, a heat transfer coefficient calculation means 11a for calculating a plurality of heat transfer coefficients at the position based on operating conditions, a maximum heat transfer coefficient selection means 11b for selecting one of the plurality of heat transfer coefficients, and a selection The heat transfer calculation means 11c that performs heat transfer calculation using the heat transfer coefficient thus obtained is used, so that the local temperature distribution of the steel slab in the continuous casting machine can be analyzed without predicting and analyzing the heat transfer mode in advance. Can be accurately predicted.

  As described above, the present invention has been described based on the embodiment. However, in the practice of the present invention, any method may be used as a method for calculating the temperature as long as it is physically reasonable. Absent. For example, the equation of heat conduction is solved and solved analytically or numerically, and the change due to time and position is calculated, or a certain steady-state condition is assumed, and the change due to position is mainly calculated using it. The method or the method of calculating using the relational expression measured by experiment etc. is mentioned. In applying the present invention, any of these methods may be used. Moreover, even if it is other than the method given here, it may be used if it is reasonable. Note that a method of numerically solving a heat conduction equation using numerical calculation using an electronic computer is preferable because a solution can be obtained even in a system in which boundary conditions change with time and position. Also, since the shape of the object whose temperature is to be predicted is discretized, the heat conduction equation is treated as a difference equation between the discretized points, and the method of numerically solving it can predict the temperature even in various shapes, Further preferred.

DESCRIPTION OF SYMBOLS 1 Continuous casting machine 2 Molten steel 3 Tundish 4 Immersion nozzle 5 Solidification shell 6 Mold 7 Steel piece 8a-c Steel piece support roll 9 Gas cutting machine 10 Temperature estimation apparatus 11 Arithmetic processing part 12 Storage part 13 Input means 14 Display means

Claims (3)

A temperature estimation method for estimating the temperature of a steel slab in a continuous casting machine ,
An input step for inputting the distance from the meniscus of the position of the billet for estimating the internal temperature distribution ;
An acquisition step of acquiring operating conditions for calculating a heat transfer coefficient;
A calculation step of calculating a heat transfer coefficient of each of the plurality of cooling means applied to the billet up to the position where the temperature is estimated based on the operation condition;
A selection step of selecting a maximum value among the respective heat transfer coefficients;
A heat transfer calculation step for performing heat transfer calculation using the selected heat transfer coefficient;
The temperature estimation method characterized by including. The calculation step includes, as the respective heat transfer coefficients, water spray heat transfer coefficient, mist spray heat transfer coefficient, forced convection heat transfer coefficient, radiation heat transfer coefficient, roll contact heat transfer coefficient, and natural convection. The temperature estimation method according to claim 1 , wherein a heat transfer coefficient is calculated according to claim 1 . A temperature estimation device for estimating the temperature of a steel slab in a continuous casting machine ,
An input means for inputting the distance from the meniscus of the position of the billet for estimating the internal temperature distribution ;
Obtaining means for obtaining operating conditions for calculating a heat transfer coefficient;
Calculating means for calculating a heat transfer coefficient of each of a plurality of cooling means applied to the billet up to the position where the temperature is estimated based on the operating conditions;
Selecting means for selecting a maximum value of the respective heat transfer coefficients;
Heat transfer calculation means for performing heat transfer calculation using the selected heat transfer coefficient;
A temperature estimation device comprising:

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