JPH0435805Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a thermal analysis device that determines the content of constituent elements of molten cast iron from the cooling curve of the molten metal.

[Prior art] Conventional thermal analysis equipment for molten cast iron inputs temperature data obtained from the cooling process of the molten metal moment by moment, and calculates the point at which this temperature stagnates within a predetermined temperature range as the primary crystal temperature and eutectic temperature. A device is known that detects temperature and visually displays carbon, silicon content, and carbon equivalent as numerical values from the obtained primary crystal temperature and eutectic temperature. However, conventional devices only display component content and carbon equivalent, and there is a problem with the accuracy of detecting the primary and eutectic temperatures of the cooling curve, so the displayed values are not necessarily reliable. It was nothing. Therefore, in determining whether the displayed value is correct or not, the operator's intuition is often relied upon, and accurate detection accuracy has not been achieved.

[Problems to be solved by the invention] The present invention has been made in order to improve the above-mentioned drawbacks of the conventional method. The purpose is to easily determine whether a value is valid.

[Means and effects for solving the problems] FIG. 1 is a block diagram showing the concept of the present invention.

The present invention includes a temperature measuring device that measures the temperature of molten metal in time series during the cooling process, and a data analysis device that inputs a signal from the temperature measuring device, analyzes the data, and outputs the signal to an output device. , and an output device that inputs a signal from the data analysis device and performs display based on the signal, wherein the data analysis device converts the time-series temperature data input from the temperature measurement device in real time. a cooling curve display unit that outputs a graph of the cooling curve of the molten metal to the output device; and a stagnation point determination unit that determines that the temperature has reached a stagnation point when the amount of temperature drop on the cooling curve within a certain instantaneous time is within a reference temperature. , The temperature stagnation point determined by the stagnation point determination unit is counted, and when the count number is equal to or higher than a reference number of times corresponding to the primary crystal temperature, it is detected as the primary crystal temperature, and when the count number corresponds to the eutectic temperature. a first primary eutectic temperature detection unit that detects the eutectic temperature when the number of times the count is greater than the reference number and the temperature drop during counting is within a predetermined temperature; and the first primary eutectic temperature detection unit detects the primary temperature. and when at least one of the eutectic temperature cannot be detected, traces back to the highest temperature of the cooling curve, finds a stagnation zone under a judgment condition that is gentler than the judgment condition of the first primary eutectic temperature detection section, and detects the one. a second primary crystal eutectic temperature detection unit, and a carbon content based on the primary crystal temperature and eutectic temperature determined by the first and second primary crystal eutectic temperature detection units,
a calculation unit that calculates silicon content and carbon equivalent; and outputs display data of the primary crystal temperature, eutectic temperature, carbon content, silicon content, and carbon equivalent to the output device after the measurement of the cooling curve is completed. the output device is a device for displaying the cooling curve, the primary crystal temperature, the eutectic temperature, the carbon content, the silicon content, and the carbon equivalent on the same display screen; In the cooling curve graph displayed by the output device, the data display section includes primary crystal temperatures detected by the first and second primary crystal eutectic temperature detection sections;
A microcomputer-type thermal analysis device for molten cast iron characterized by outputting a signal that marks a region corresponding to the eutectic temperature.

The thermal analysis device of the present invention displays the temperature data measured moment by moment by the temperature measuring device on the output device in real time, and also detects the primary and eutectic temperatures by detecting the predetermined stagnation point from the temperature data obtained moment by moment. Detects the carbon content, silicon content, and carbon equivalent based on that, outputs those values to the output device together with the cooling curve upon completion of the measurement, and displays the primary crystal of the cooling curve graph displayed on the output device. It is characterized by marking the area corresponding to temperature and eutectic temperature. The output device consists of a CRT, XY plotter, dot printer, etc., and the display screen displays the cooling curve, the detected primary crystal, the eutectic temperature, the calculated carbon content, and the silicon content on a single screen. It displays the content rate and carbon equivalent.

[Examples] Hereinafter, the present invention will be described in detail based on specific examples. FIG. 2 is a block diagram showing the configuration of a measuring device according to a specific embodiment of the device of the present invention. 2 is a cup for taking out a part of the molten metal and measuring its cooling curve; a thermocouple 4 made of alumel-chromel is installed at the bottom of the cup 2; Electric power is input to the thermometer 6 via a conductor. thermometer 6
samples the analog electromotive force every 0.4 seconds, converts it into a digital signal, and outputs it to the parallel/serial converter 8 as an encoded code expressed in binary coded decimal (BCD). The parallel/serial converter 8 converts the BCD data into serial data and outputs it to the serial data input port of the microcomputer 10. The microcomputer 10 is connected to a printer 12 and a CRT 16 that output predetermined measurement results, and to a floppy disk device 14 that stores predetermined programs, calculation formulas, and their coefficients.

FIG. 3 is a flowchart showing the processing steps of the microcomputer 10 used in the device of the present invention. Step 100 is a step for setting initial values of various parameters. In step 102, the axis of a graph for displaying the measured temperature data on the CRT 16 is displayed. step
At 104, temperature data is read from the thermometer 6. When the measured temperature data reaches a predetermined temperature or higher in step 106, it is assumed that molten metal has been poured into the cup 2, and measurement is started. If the temperature is below the predetermined temperature, the process returns to step 104 since molten metal has not yet been poured into the cup 2.

At step 108, the parameter storing the sampling number of the measurement data is updated by 1. step
Read temperature data at 100. Next, in step 112, it is determined whether the measurement of the cooling curve has been completed. The conditions for determining the end of the measurement of the cooling curve are that the number of measurements is greater than or equal to a predetermined number of times, or that the measured temperature is less than or equal to a predetermined temperature. The temperature data measured in step 114 is displayed on the CRT 16. That is, temperature data is measured and displayed on the CRT 16 in real time. Next, in step 116, the maximum temperature of the cooling curve is detected. The cooling curve shows that after pouring into cup 2, the temperature rises rapidly to the maximum temperature, and then the cooling process continues. Therefore, by detecting the temperature change,
Maximum temperature can be detected. step 118
If the maximum temperature is not detected in step 108
Go back and repeat the cycle. If the maximum temperature is detected, the process moves to step 120.

In step 102, the temperature difference ΔT between the two points is determined.
Next, the process moves to step 122, and it is determined whether the detection of the primary crystal temperature has been completed. If not, the process moves to step 124. In step 124, the range in which the primary crystal temperature exists is determined. The judgment condition is the following equation.

2070〓<T<2300〓 If the measured temperature T is within the primary crystal temperature range, the process moves to step 140.

Steps 140, 142, and 145 correspond to a stagnation section detection section that detects stagnation sections. △T at step 140
is smaller than 1, that is, the temperature gradient is ±2.5〓/
When it exists within the range of sec, it is considered a stagnation area.
That is, in step 142, the number of sampling points in the stagnation section is counted to detect the stagnation section. If the above conditions are not met, a register for counting sampling points is reset in step 145 in preparation for detecting the next stall period.

Steps 144 and 146 correspond to a primary crystal temperature detection section which determines the primary crystal temperature when the number of stagnation points in the stagnation section detected by the stagnation section detection section is seven or more.
If the number of stagnation points at step 146 is 7 or more,
The average temperature in that section is detected as the primary crystal temperature TL.

In step 148, the primary crystal temperature TL is displayed on the CRT. The primary crystal temperature was detected through the above processing steps.

Next, the process of detecting the eutectic temperature will be described. Next, cooling progresses further and in step 128, if the measured temperature data exists within the eutectic temperature range,
Move to step 170. The determination conditions of this eutectic temperature range determination section are as follows.

2028〓<T<2070〓 Steps 170, 172, and 174 are stagnation section detection sections having the same functions as those described above.

Steps 176, 178, and 180 proceed to step 178 when the number of stagnation points existing in the stagnation section is 20 or more in step 176, which is the eutectic temperature detection section, that is, when the stagnation time is 8 seconds or more. In step 178,
18 Determine whether the temperature difference between two points separated by the number of samples is less than 1〓, and when the condition is met,
In step 180, the temperature at the later sampling point is detected as the eutectic temperature. And in step 182
Display the eutectic temperature TE on the CRT.

Through the above steps, if the cooling curve is typical, the primary crystal temperature TL and the eutectic temperature TE are detected, and it is determined in step 112 that the measurement is complete.

On the other hand, if the cooling curve is not typical, for example if no primary crystal temperature is detected in step 126, then parameter A is set to 1 in step 127. Also, if the primary crystal temperature is detected but the eutectic temperature is not detected, the step
At 130, parameter A is set to 2.

When the cooling curve measurement is completed, proceed to the step
Move to 190. If the parameter A is 0, this means that the primary crystal temperature and the eutectic temperature have been detected, and the process moves to step 206 to calculate the silicon content, carbon content, and carbon equivalent, and calculate these values. Display in 208. Further, in step 210, the cooling curve, primary crystal temperature, eutectic temperature, carbon content, silicon content, carbon equivalent, etc. are output to the plotter. The output diagram is shown in FIG.

The CRT screen at the end of step 208 is similar to that shown in FIG. 5a. In this way, CRT
Or, the output screen of the XY plotter shows the cooling curve, primary crystal temperature TL, eutectic temperature TE,
Carbon content C%, silicon content Si%, carbon equivalent
CE is displayed. Therefore, the validity of the primary crystal temperature and eutectic temperature determined by the above method can be easily determined.

Furthermore, as shown in Figure 5 a, b, and c, on the cooling curve on the output screen, marks such as ○ marks are placed at measurement points corresponding to the determined primary crystal temperature and eutectic temperature. The validity of the detected temperature can be determined more easily.

On the other hand, if it is determined in step 192 that parameter A is 1, the process moves to step 194.
That is, this is a case where the primary crystal temperature is not detected. In this case, in step 194, trace back from the final measurement point to the highest temperature, find the longest stagnation section within that range, and find the number of stagnation points in that stagnation section.
The conditions for determining this stagnation section are the same as the conditions for the stagnation section detection section described above. If the number of stagnation points is 27 or more at step 196, move to step 198,
Let the representative point of the stagnation zone be the eutectic temperature. Next, proceed to step 200 to further find the longest stagnation interval between the maximum temperature and the eutectic temperature just found.
Find the longest stagnation section and the number of stagnation points that exist in that stagnation section. If the number of stagnation points is 5 or more in step 202, the process moves to step 204 to obtain the primary crystal temperature TL. In this way, when the primary crystal temperature and the eutectic temperature are not detected under the above-mentioned primary crystal determination conditions and eutectic determination conditions, the eutectic temperature and the primary crystal temperature are determined using another, somewhat relaxed, determination condition. Detected.

Also, if the value of A is 2 in step 220,
This is a case where the primary crystal temperature is detected but the eutectic temperature is not detected. In that case, proceed to step 222,
The same processing as step 194 is performed. step
224 and the number of stagnation points is 27 or more, step 226
The average temperature in the stagnation zone is detected as the eutectic temperature. In this way, since the primary crystal and eutectic temperatures are detected under two-stage conditions, detection is performed reliably and with high accuracy. In this example, the primary eutectic temperature is determined in step 144, and the eutectic temperature is determined in steps 172, 176, and 178, thereby achieving the first primary eutectic temperature detection section. Also, step 196 or step 224
When the stagnation point exceeds 27, the eutectic temperature is determined, and in step 202, the primary crystal temperature is determined when the stagnation point is 5 or more, so that the second primary eutectic temperature detection section is achieved. Ru. In this way, in the second primary eutectic temperature detection section, the judgment in step 178 used in the first primary eutectic temperature detection section is removed, and the stagnation score when determining the primary crystal temperature is lower than 7. less than 5
Therefore, it can be said that the judgment conditions are relaxed.
In addition, in this example, the stagnation point determination section is at steps 140 and 170.
is achieved.

[Effects of the invention] The present invention outputs temperature measurement data in real time and displays the determined primary crystal temperature, eutectic temperature, and the carbon content, silicon content, and carbon equivalent calculated from these temperatures on the same display screen. This is a thermal analysis device that outputs output from above. Therefore, it is easy to compare the displayed values such as the primary crystal temperature and the eutectic temperature with the cooling curve, and the reliability of the obtained values can be easily determined from the cooling curve. In particular, in the present invention, when temperature stagnation during the primary crystal reaction or temperature stagnation during the eutectic reaction clearly appears, even the first primary eutectic temperature detection means with strict judgment conditions can detect the primary crystal temperature and the eutectic temperature. Crystal temperature is easily determined.
Further, depending on the composition of the molten cast iron, temperature stagnation during the primary crystal reaction and temperature stagnation during the eutectic reaction may not be clearly expressed. In this case, there is a possibility that the first primary crystal eutectic temperature detection means cannot detect the primary crystal temperature and the eutectic temperature. In this case, the second
The primary crystal eutectic temperature detection means can detect the primary crystal temperature or the eutectic temperature under a slightly looser judgment condition than the judgment condition of the first primary crystal eutectic temperature detection means. Therefore, in the present invention, the primary crystal temperature and eutectic temperature of molten cast iron having various compositions can be detected, and it is possible to cope with molten cast iron having various compositions.

By the way, when temperature stagnation at the primary crystal temperature and temperature stagnation during eutectic reaction are not clearly expressed, the accuracy of determining carbon content, silicon content, and carbon equivalent is slightly lower than when they clearly occur. descend. However, unless the carbon content, silicon content, and carbon equivalent are displayed on the screen of the output device, the operator will have no idea of the composition of the molten metal, which is not desirable in practice. In this regard, in the present invention,
Primary crystal temperature, eutectic temperature,
Displays carbon content, silicon content, carbon equivalent,
Furthermore, the cooling curve itself is also displayed on the same surface. In addition, markings can be immediately seen in the primary temperature range and eutectic temperature range of the cooling curve graph displayed on the display screen of the output device, so the carbon content, silicon content, The accuracy of carbon equivalent determination can be assumed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the concept of the device of the present invention. Figure 2 shows a concrete example of this invention.
1 is a block diagram showing the configuration of a thermal analysis device according to an example. FIGS. 3 and 4 are flowcharts showing the processing of the computer used in the apparatus of this embodiment. FIG. 5 is an output diagram showing an output screen.

Claims (1)

[Claims for Utility Model Registration] A temperature measuring device that measures the temperature of molten metal in time series during the cooling process; and a device that inputs a signal from the temperature measuring device, analyzes the data, and outputs a signal to an output device. A device comprising a data analysis device, and an output device that inputs a signal from the data analysis device and performs display based on the signal, the data analysis device comprising: a time series input from the temperature measurement device; a cooling curve display unit that outputs temperature data in real time as a graph of a cooling curve of the molten metal to the output device; and a stagnation point that determines a temperature stagnation point when the amount of temperature drop on the cooling curve within a certain instantaneous time is within a reference temperature. A temperature stagnation point determined by the point determination unit and the stagnation point determination unit is counted, and when the count number is equal to or greater than a reference number of times corresponding to the primary crystal temperature, it is detected as the primary crystal temperature, and when the count number is the same a first primary eutectic temperature detection unit that detects the eutectic temperature when the number of times is equal to or higher than a reference number corresponding to the crystal temperature and the temperature drop during counting is within a predetermined temperature; and the first primary eutectic temperature detection unit. When at least one of the primary crystal temperature and the eutectic temperature cannot be detected, trace back to the maximum temperature of the cooling curve and find a stagnation zone under a judgment condition that is gentler than the judgment condition of the first primary crystal eutectic temperature detection section, a second primary eutectic temperature detection unit that detects the one; and a carbon content based on the primary temperature and eutectic temperature determined by the first and second primary eutectic temperature detection units;
a calculation unit that calculates silicon content and carbon equivalent; and outputs display data of the primary crystal temperature, eutectic temperature, carbon content, silicon content, and carbon equivalent to the output device after the measurement of the cooling curve is completed. the output device is a device for displaying the cooling curve, the primary crystal temperature, the eutectic temperature, the carbon content, the silicon content, and the carbon equivalent on the same display screen; The data display section includes, in the cooling curve graph displayed by the output device, the primary crystal temperature detected by the first and second primary crystal eutectic temperature detection sections;
A microcomputer-type thermal analysis device for molten cast iron characterized by outputting a signal that marks a region corresponding to the eutectic temperature.