Quenching coolant monitoring device and quenching device using the same

Abstract

To monitor changes in cooling performance of quenching coolant.SOLUTION: A quenching coolant monitoring device includes: a circulation pipe for taking quenching coolant from a water reservoir and circulating the same into the water reservoir; a thermal flow meter for measuring a flow rate of the quenching coolant in the circulation pipe; and a monitoring unit for monitoring the change in cooling performance of the quenching coolant based on the amount of change in the flow rate of the quenching coolant measured by the thermal flow meter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a quenching coolant monitoring device and a quenching device using the same. [Background technology]

[0002] Quenching is a process in which steel material heated to a predetermined high temperature is rapidly cooled using a quenching coolant such as a polymer solution, and polymer quenching coolants that can adjust the cooling curve are known (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-62612 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when quenching coolant is recycled, additives from previous processes or equipment cooling water may be mixed into the quenching coolant, and even if the polymer concentration is adjusted, the desired cooling curve may not be met (cooling performance may change).

[0005] Therefore, one embodiment of the present invention provides a quenching coolant monitoring device that monitors (estimates) changes in the cooling performance of a quenching coolant, and a quenching device using the same. [Means for solving the problem]

[0006] In order to solve the above problems, according to one embodiment of the present invention, a quenching coolant is taken in from a water tank and circulated to the water tank; a thermal flow meter that measures the flow rate of the quenching coolant in the circulation pipe; and a monitoring unit that monitors changes in the cooling performance of the quenching coolant based on changes in the flow rate of the quenching coolant measured by the thermal flow meter.

[0007] According to one embodiment of the present invention, a heating unit that heats a workpiece made of steel material; a water tank containing a quenching coolant that cools and quenches the workpiece heated by the heating unit; a quenching coolant monitoring device that extracts the quenching coolant from the water tank and circulates it, The quenching coolant monitoring device includes: a circulation pipe for taking in the quenching coolant from the water tank and circulating it to the water tank; a thermal flow meter that measures the flow rate of the quenching coolant in the circulation pipe; and a monitoring unit that monitors changes in the cooling performance of the quenching coolant based on changes in the flow rate of the quenching coolant measured by the thermal flow meter. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating the overall configuration of a quenching coolant monitoring device and a quenching device using the same; [Figure 2] FIG. 1 is a schematic external view of a thermal flow meter. [Figure 3] 10 is a diagram showing the measurement results of a thermal flow meter and an electromagnetic flow meter. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of a quenching coolant monitoring device and a quenching device using the same will be described with reference to the drawings. The following description will focus on the main components of the quenching coolant monitoring device and the quenching device using the same, but the quenching coolant monitoring device and the quenching device using the same may include components and functions that are not shown or described. The following description does not exclude components and functions that are not shown or described.

[0010] Fig. 1 is a diagram showing the overall configuration of a quenching coolant monitoring device 1 according to this embodiment and a quenching device 2 using the same. The quenching device 2 in Fig. 1 is a device that quenches a workpiece made of steel. Once the workpiece has been sufficiently heated, it is rapidly cooled (quench cooling) with a quenching coolant, thereby quenching the workpiece.

[0011] As shown in Figure 1, the quenching coolant monitoring device 1 is attached to the water tank 3 of the quenching device 2. When workpieces are repeatedly quenched using the quenching device 2, additives from the previous process or equipment cooling water adhering to the workpiece may become mixed into the quenching coolant in the water tank 3 when the workpiece is cooled with the quenching coolant, increasing the polymer concentration in the quenching coolant in the water tank 3. While polymer quenching allows for slow cooling over a wider temperature range than water quenching, if the cooling curve changes, the workpiece may not be cooled at the desired cooling rate, which could result in changes in the quenching quality. Therefore, the quenching coolant in the quenching coolant monitoring device 1 is monitored, for example, at predetermined time intervals, to determine whether the cooling performance is appropriate.

[0012] The quenching coolant monitoring device 1 of FIG. 1 includes a circulation pipe 4, a thermal flow meter 6, and a monitoring unit .

[0013] The circulation pipe 4 is a pipe that takes in the quenching coolant from the water tank 3 of the quenching device 2 and circulates it to the water tank 3. A pump (not shown) is attached to the circulation pipe 4, and depending on the driving force of the pump, the quenching coolant in the water tank 3 is taken into the circulation pipe 4 and circulated to the water tank 3. Although FIG. 1 shows an example of a U-shaped circulation pipe 4, the shape of the circulation pipe 4 is not particularly limited.

[0014] The thermal flow meter 6 measures the flow rate of the quenching coolant based on the cooling rate after the temperature of the quenching coolant in the circulation line 4 is raised. The thermal flow meter 6 has a table showing the correspondence relationship between the cooling rate of the pure water and the flow rate. This table is data recording the flow rate corresponding to the cooling rate of the pure water, and is stored in advance, for example, in a storage unit (not shown) provided in the thermal flow meter 6. By using this table, the flow rate of the quenching coolant can be calculated from the cooling rate measured by the thermal flow meter 6.

[0015] Note that the table in the thermal flowmeter 6 is based on data for pure water, so if the quenching coolant contains polymers, there will be a discrepancy with the table. This is because, in general, the higher the polymer concentration in the quenching coolant, the slower the flow rate of the quenching coolant.

[0016] FIG. 2 is a schematic external view of the thermal flow meter 6. The thermal flow meter 6 in FIG. 2 has a display unit 6a and an operation unit 6b. The thermal flow meter 6 is attached to a branching portion 4a in the circulation line 4, and the tip 6c of the thermal flow meter 6 contacts the quenching coolant 4b in the circulation line 4. By passing a pulse current through a resistance element attached to the tip 6c of the thermal flow meter 6, the temperature of the quenching coolant 4b rises by several degrees Celsius. The tip 6c is constantly in contact with the quenching coolant 4b, and the rate at which the temperature of the tip 6c decreases (hereinafter referred to as the cooling rate) varies depending on the flow rate of the quenching coolant 4b. The thermal flow meter 6 has a function to measure the temperature of the tip 6c. The thermal flow meter 6 collects and stores data in advance in a table showing the correspondence between the cooling rate, which is the change in temperature of the tip 6c over time, and the flow rate of the quenching coolant 4b. Therefore, the thermal flow meter 6 detects the cooling rate of the tip 6c after raising the temperature of the quenching coolant 4b by several degrees Celsius, and then references the table to find the flow rate corresponding to the detected cooling rate. This makes it possible to detect the flow rate of the quenching coolant 4b in the circulation line 4. However, as described above, because the thermal flow meter 6 has a table showing the correspondence between the cooling rate of pure water and the flow rate, if the quenching coolant 4b contains polymers, an error will occur in the detected flow rate. Furthermore, if the cooling curve of the quenching coolant changes, the detected flow rate will also change.

[0017] 1 monitors the cooling curve of the quenching coolant 4b based on changes in the flow rate of the quenching coolant 4b measured by the thermal flow meter 6. More specifically, the monitoring unit 7 estimates the cooling curve of the quenching coolant 4b in the water tank 3 of the quenching device 2 based on an error in the flow rate of the quenching coolant 4b measured by the thermal flow meter 6.

[0018] That is, as described above, the thermal flow meter 6 has a table showing the correspondence between the cooling rate of pure water and the flow rate, so if the quenching coolant 4b contains polymers, an error occurs in the detected flow rate. Therefore, if the cooling curve of the quenching coolant 4b changes, the error also changes. Therefore, this error, i.e., the amount of change in the flow rate of the quenching coolant 4b measured by the thermal flow meter 6, can be used to confirm the change in the cooling curve of the quenching coolant 4b, and this characteristic can be used to monitor changes in the cooling performance of the quenching coolant.

[0019] The main body of the quenching device 2 in Fig. 1 includes, for example, a workpiece support unit 11, a rotation drive unit 12, a heating unit 13, and a water tank 3. The workpiece support unit 11 supports the workpiece to be quenched. The rotation drive unit 12 drives the workpiece support unit 11 to rotate. The water tank 3 brings quenching coolant into contact with the heated workpiece to rapidly cool it. The quenching coolant 4b in the water tank 3 is monitored by a quenching coolant monitoring device 1 for changes in cooling performance.

[0020] As shown in FIG. 1, the quenching coolant monitoring device 1 preferably further includes an electromagnetic flow meter 9 that measures the flow rate of the quenching coolant in the circulation pipeline 4, and the monitoring unit 7 preferably monitors changes in the cooling performance of the quenching coolant based on the difference between the flow rate of the quenching coolant measured by the thermal flow meter 6 and the flow rate of the quenching coolant measured by the electromagnetic flow meter 9.

[0021] The electromagnetic flowmeter 9 is a flowmeter that detects flow rate using Faraday's electromagnetic induction and is composed of, for example, an electromagnetic coil that generates a magnetic field and electrodes that detect electromotive force, and is not affected by the temperature, pressure, density, or viscosity of the liquid, and can detect liquids containing impurities. Therefore, the electromagnetic flowmeter 9 can measure the flow rate of quenching coolant without being affected by the polymer, even if the quenching coolant contains polymer.

[0022] For the above reasons, it is preferable to further provide an electromagnetic flow meter 9 as described above, because it is possible to verify (monitor) in real time that the change in flow rate detected by the thermal flow meter 6 is not a change in the flow rate through the circulation pipeline 4.

[0023] As shown in FIG. 1, the quenching coolant monitoring device 1 preferably further includes a concentration sensor 5 and a temperature sensor 8.

[0024] The concentration sensor 5 measures the Brix value (sugar content) to monitor the polymer concentration of the quenching coolant (polymer concentration is proportional to the Brix value). The temperature sensor 8 measures the temperature of the quenching coolant.

[0025] In this way, by further equipping the quenching coolant monitoring device 1 with the concentration sensor 5 and temperature sensor 8, it is possible to not only estimate changes in the cooling curve of the quenching coolant, but also simultaneously measure other characteristics of the quenching coolant (concentration and temperature), making it possible to estimate the cause of changes in the cooling performance of the quenching coolant.

[0026] FIG. 3 shows the measurement results of the thermal flow meter 6 and the electromagnetic flow meter 9. The horizontal axis of FIG. 3 represents the polymer concentration [%] of the quenching coolant 4b, and the vertical axis represents the flow rate [liters L 3 3 shows the measurement results of the thermal flow meter 6, and waveform w2 shows the measurement results of the electromagnetic flow meter 9. When performing the measurements in FIG. 3, the flow rate of the quenching coolant 4b in the circulation pipe 4 is assumed to be constant.

[0027] As shown by waveform w1 in Figure 3, the thermal flow meter 6 measures a smaller flow rate of the quenching coolant 4b in the circulation line 4 as the polymer concentration of the quenching coolant 4b increases. On the other hand, as shown by waveform w2, the electromagnetic flow meter 9 measures a flow rate of the quenching coolant 4b in the circulation line 4 that barely changes even if the polymer concentration of the quenching coolant 4b changes.

[0028] In this way, even if the flow rate of the quenching coolant 4b in the circulation line 4 is constant, the higher the polymer concentration of the quenching coolant 4b, the larger the error in the flow rate measured by the thermal flow meter 6. Therefore, the difference between the flow rate measured by the thermal flow meter 6 and the flow rate measured by the electromagnetic flow meter 9 can be used to estimate changes in the cooling performance of the quenching coolant 4b in the circulation line 4.

[0029] The monitoring unit 7 determines whether the absolute value of the difference between the flow rate measured by the thermal flow meter 6 and the flow rate measured by the electromagnetic flow meter 9 is within a range of a first threshold value or more and a second threshold value or less. If the difference deviates from the threshold value even when the polymer concentration is at an appropriate value, the unit 7 prompts the user to replace the quenching coolant.

[0030] The monitoring unit 7 can be configured using a computer device such as a personal computer (hereinafter referred to as a PC), a workstation, a PLC (programmable logic controller), a tablet, or a smartphone.

[0031] As described above, in this embodiment, if the cooling performance of the quenching coolant 4b in the reservoir 3 in the quenching device 2 is inappropriate, the quality of the quenching of the workpiece will deteriorate. Therefore, a coolant monitoring device 1 is attached to the quenching reservoir 3 as necessary. The coolant monitoring device 1 has a circulation line 4 that takes in quenching coolant 4b from the reservoir 3, measures changes in the cooling performance of the quenching coolant 4b, and then returns the quenching coolant to the reservoir 3. A thermal flow meter 6 is attached to the circulation line 4. A monitoring unit 7 in the coolant monitoring device 1 estimates changes in the cooling curve of the quenching coolant 4b based on the amount of change in the flow rate of the quenching coolant 4b measured by the thermal flow meter 6. More specifically, the thermal flow meter 6 and an electromagnetic flow meter 9 are provided in the circulation line 4. Since the flow rate measured by the thermal flow meter 6 varies greatly depending on the cooling curve of the quenching coolant 4b, the cooling performance of the quenching coolant 4b is estimated from the difference between the flow rate measured by the thermal flow meter 6 and the flow rate measured by the electromagnetic flow meter 9, which is not affected by the cooling curve. This makes it possible to estimate changes in the cooling performance of the quenching coolant 4b in the water tank 3.

[0032] In the above-described embodiment, an example of monitoring changes in the cooling performance of a quenching coolant for quenching a workpiece made of metal components (especially steel) has been described, but the embodiment of the present invention can be applied to the purpose of monitoring changes in the cooling performance of coolants used in various applications.

[0033] The aspects of the present disclosure are not limited to the individual embodiments described above, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and spirit of the present disclosure, which is derived from the contents defined in the claims and their equivalents. [Explanation of symbols]

[0034] 1 Coolant monitoring device, 2 Quenching device, 3 Water tank, 4 Circulation pipe, 4a Branching section, 4b Quenching coolant, 5 Concentration sensor, 6 Thermal flow meter, 6a Display section, 6b Operation section, 6c Tip section, 7 Monitoring section, 8 Temperature sensor, 9 Electromagnetic flow meter, 11 Workpiece support section, 12 Rotation drive section, 13 Heating section

Claims

1. a circulation pipe for taking in quenching coolant from a water tank and circulating it to the water tank; a thermal flow meter that measures the flow rate of the quenching coolant in the circulation pipe; a monitoring unit that monitors changes in the cooling performance of the quenching coolant based on changes in the flow rate of the quenching coolant measured by the thermal flow meter.

2. an electromagnetic flow meter for measuring a flow rate of the quenching coolant in the circulation pipe; 2. The quenching coolant monitoring device according to claim 1, wherein the monitoring unit monitors a change in the cooling performance of the quenching coolant based on a difference between the flow rate of the quenching coolant measured by the thermal flow meter and the flow rate of the quenching coolant measured by the electromagnetic flow meter.

3. The quench-coolant monitoring device according to claim 2 , wherein the monitoring unit estimates that the greater the change in the difference, the greater the change in the cooling curve of the quench-coolant.

4. 4. The quenching coolant monitoring device according to claim 1, further comprising a concentration sensor that measures the sugar content of the quenching coolant in the circulation pipe.

5. a heating unit that heats a workpiece made of steel; a water tank containing a quenching coolant that cools and quenches the workpiece heated by the heating unit; a quenching coolant monitoring device that extracts the quenching coolant from the water tank and circulates it, The quenching coolant monitoring device includes: a circulation pipe for taking in the quenching coolant from the water tank and circulating it to the water tank; a thermal flow meter that measures the flow rate of the quenching coolant in the circulation pipe; a monitoring unit that monitors changes in the cooling performance of the quenching coolant based on changes in the flow rate of the quenching coolant measured by the thermal flow meter.

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