Method for improving in-furnace temperature test accuracy of blank

Abstract

The invention relates to the field of temperature detection, and discloses a method for improving the in-furnace temperature test accuracy of a blank, which comprises the following steps: forming a plurality of test holes in the blank; mounting the mounting sections of the plurality of thermocouples into the plurality of measuring holes respectively, and filling the plurality of measuring holes with a filling medium; connecting the connecting ends of the plurality of thermocouples with a furnace temperature tracker, and then testing; wherein the multiple measuring holes comprise deep holes with the hole depth larger than or equal to a preset threshold value, and the step of installing the installation section into the deep holes comprises the steps that the installation section is bent, and the first end and the second end of the installation section abut against the bottom of the deep holes and the upper portions of the side walls of the deep holes respectively; wherein the first end of the mounting section is a temperature measuring end. According to the invention, the thermocouple can be simply and effectively fixed in the measuring hole, so that the temperature measurement accuracy and reliability can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of temperature detection, and in particular to a method for improving the accuracy of temperature testing of a blank in a furnace. Background Art

[0002] The online test of the slab heating in the heating furnace is generally carried out using a furnace temperature tracker, commonly known as the "black box" experiment, that is, holes are drilled in different positions of the slab, the thermocouple heads are buried and fixed, the thermocouple data transmission end is connected to the furnace temperature tracker, and the temperature measurement data is written into the furnace temperature tracker. The thermocouple and the furnace temperature tracker are put into the furnace with the experimental slab, and after the gradual heating until the uniform heating process, the experimental slab is taken out of the furnace. The whole thermocouple test data is recorded, so as to obtain the temperature rise curve of different measuring points of the slab.

[0003] In actual operation, there are many details that need to be paid attention to during the black box experiment, such as the production and installation of the insulation box, the opening of the measuring hole, the method of fixing the thermocouple, etc. If the preparation is sufficient, the method is correct, and the operation is proper, the experimental process can obtain real and effective test data. However, if there is a problem with the test method, the experimental process is prone to obtain wrong data information, or even no data information, such as the test data is higher or lower than the actual temperature. Since the black box experiment is a lossy experiment, thermocouples, thermal insulation cotton, etc. are scrapped after being used once. Experimental failure will cause economic losses. More importantly, wrong data will mislead production and require retesting, which is time-consuming and laborious. Therefore, it is necessary to consider all the details of the black box experiment, especially the key link of the installation and fixation of the thermocouple. If the thermocouple is not fixed firmly, or gas enters and contacts it, it will directly affect the test results. Based on this, it is necessary to study a simple and effective thermocouple fixing method to improve the accuracy of the test data. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for improving the accuracy of temperature testing of a blank in a furnace, so as to solve the technical problem of how to simply and effectively fix a thermocouple to improve the test accuracy.

[0005] According to one aspect of the present invention, a method for improving the accuracy of a blank temperature test in a furnace is provided, comprising: Opening a plurality of measuring holes on the blank; Installing the mounting sections of the plurality of thermocouples into the plurality of measuring holes respectively, and filling the filling medium into the plurality of measuring holes; Connect the connection ends of multiple thermocouples to the furnace temperature tracker and then conduct the test; Among them, multiple measuring holes include deep holes with a hole depth greater than or equal to a predetermined threshold, and installing the installation section into the deep hole includes: bending the installation section and the first end and the second end of the installation section respectively abut against the bottom and the upper part of the side wall of the deep hole; wherein the first end of the installation section is the temperature measuring end.

[0006] According to one embodiment of the present invention, the multiple measuring holes also include shallow holes with a hole depth less than a predetermined threshold, and the shallow holes are inclined relative to the surface of the blank; installing the installation section into the shallow hole includes: embedding the installation section into the shallow hole and the temperature measuring end contacts the bottom of the hole.

[0007] According to an embodiment of the present invention, the predetermined threshold is 10-20 mm.

[0008] According to one embodiment of the present invention, the blank is a titanium blank, and the filling medium is uncoated titanium dioxide powder.

[0009] According to one embodiment of the present invention, for the deep hole, the filling medium is filled and compacted in layers.

[0010] According to one embodiment of the present invention, for shallow holes, after the filling medium is filled, a pressing plate is used to cover the opening of the shallow hole.

[0011] According to one embodiment of the present invention, the blank is a titanium blank, the pressing plate is a titanium plate, and using the pressing plate to cover the opening of the shallow hole comprises: welding the titanium plate around the titanium blank.

[0012] According to one embodiment of the present invention, the method further comprises: covering the portion of the thermocouple located outside the measuring hole with a thermal insulation material.

[0013] According to one embodiment of the present invention, the method further comprises: bending the portion of the thermocouple located outside the measuring hole in a direction parallel to the surface of the blank.

[0014] According to one embodiment of the present invention, the diameter of the measuring hole is determined according to the diameter of the thermocouple wire, the condition of the drill bit and the type of the blank.

[0015] In the technical solution of the present invention, the mounting section is bent and the first end and the second end of the mounting section are respectively abutted against the bottom and the upper part of the side wall of the deep hole. Through such a bending and abutting method, the thermocouple can be simply and effectively fixed in the deep hole. Even when encountering external force, the thermocouple wire is not prone to shaking, which is beneficial to improving the accuracy and reliability of temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram showing a thermocouple installation section installed in a deep hole according to an embodiment of the present invention; Figure 2 A schematic diagram showing the influence of whether a thermocouple is covered with thermal insulation cotton on temperature measurement data according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0019] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0020] The present invention provides a method for improving the accuracy of temperature testing of a blank in a furnace, comprising: Opening a plurality of measuring holes on the blank; Installing the mounting sections of the plurality of thermocouples into the plurality of measuring holes respectively, and filling the filling medium into the plurality of measuring holes; Connect the connection ends of multiple thermocouples to the furnace temperature tracker and then conduct the test; Wherein, the plurality of measured holes include deep holes whose hole depth is greater than or equal to a predetermined threshold, and the reference Figure 1 Installing the installation section into the deep hole includes: bending the installation section and making the first end and the second end of the installation section abut against the bottom and the upper part of the side wall of the deep hole respectively; wherein the first end of the installation section is the temperature measuring end.

[0021] In an embodiment of the present invention, the mounting section is bent and the first end and the second end of the mounting section are respectively abutted against the bottom and the upper part of the side wall of the deep hole. The thermocouple can be simply and effectively fixed in the deep hole by such a bending and abutting method. Even when encountering external force, the thermocouple wire is not easy to shake. Compared with the method of vertically inserting the thermocouple into the measuring hole, the fixation is more secure, which is beneficial to improving the accuracy and reliability of temperature measurement.

[0022] The blank may be a steel billet, a titanium billet or other types of metal billets. The billet may be in the shape of a plate or other shapes. The measuring hole may be a structure with an opening at one end and a hole bottom at the other end (may also be called a slot). Multiple measuring holes may be opened on a specific surface (e.g., the upper surface) of the billet, and the multiple measuring holes have different depths. The temperature measuring ends of the thermocouples are placed at the bottoms of different measuring holes to detect the temperatures at different depths of the billet. The filling medium may be selected from a material corresponding to the material of the billet to reduce the impact on the temperature measurement process.

[0023] refer to Figure 1, the first end and the second end of the mounting section can be respectively located on two opposite sides of the deep hole in the radial direction, that is, the projection of the mounting section on the bottom wall of the deep hole is located on the diameter of the bottom wall, so that the mounting section can be more firmly fixed in the deep hole. The first end of the mounting section can abut against the junction of the bottom wall and the side wall of the deep hole, and the mounting section gradually extends from the first end to the other side opposite in the radial direction and bends upward. The mounting section can be tangent to the side wall at the second end, thereby providing a better stabilization effect. The deep hole can be a vertical hole that is roughly perpendicular to the opening surface of the blank.

[0024] In some embodiments, the plurality of measuring holes further include shallow holes with a hole depth less than a predetermined threshold, and the shallow holes are inclined relative to the surface of the blank; installing the mounting section into the shallow hole includes: embedding the mounting section into the shallow hole and making the temperature measuring end contact the bottom of the hole (i.e., the deepest part). By setting the shallow hole in the form of an inclined hole (or an inclined groove), it can be ensured that the measuring hole can extend a longer length at a limited depth, so that a thermocouple wire of sufficient length can be effectively embedded therein. The mounting section can extend along the extension direction of the shallow hole. The inclination angle between the shallow hole and the opening surface of the blank can be set according to actual conditions. In the case where the shallow hole is small in depth, the inclination angle can be appropriately reduced so that the shallow hole has a sufficient length to place the thermocouple wire.

[0025] In some embodiments, the predetermined threshold is 10 to 20 mm. The appropriate value of the threshold can be selected according to the actual situation. In some embodiments of the present invention, the depth of the deep hole varies in the range of 30 to 215 mm, and the depth of the shallow hole is 5 to 8 mm. Of course, the depth of the measuring hole can be set according to the test requirements and the thickness of the blank. The shallowest depth is surface mounting, and the deepest depth is ≤ the thickness of the blank.

[0026] In the billet temperature test experiment, in addition to setting up multiple thermocouples installed in the measuring holes to measure the internal temperature of the billet, other thermocouples for measuring the external furnace temperature of the billet can also be set, for example, thermocouples for measuring the furnace temperature above or below the billet. For the thermocouple used to measure the furnace temperature above the billet, there is no need to open the corresponding measuring holes. The thermocouple can be fixed on the surface of the billet, and the temperature measuring end of the thermocouple is set above the upper surface of the billet and at a predetermined distance from the upper surface of the billet. For the thermocouple used to measure the furnace temperature below the billet, a through hole can be opened in the billet, so that the thermocouple passes through the through hole from top to bottom and the temperature measuring end of the thermocouple protrudes below the billet and at a predetermined distance from the lower surface of the billet.

[0027] The locations of the openings of multiple measuring holes can be selected according to actual needs. In some embodiments, measuring holes are opened at different depths on both sides and in the middle of the length direction of the blank for testing. For example, the upper surface, middle, and lower surface of the left side, middle, and right side of the blank are tested. Other locations that need to be tested can also be selected according to actual needs.

[0028] In some embodiments, the diameter of the measuring hole is determined according to the wire diameter of the thermocouple, the condition of the drill bit, and the type of blank. The aperture of the measuring hole needs to be larger than the diameter of the thermocouple wire, but the aperture cannot be too large, otherwise the thermocouple is easy to shake in the measuring hole and is not easy to fix. At the same time, it is necessary to evaluate the difficulty and feasibility of drilling in combination with the condition of the drill bit and the type of blank. If the aperture is too small, drilling is difficult and the drill bit is easy to break. In an embodiment of the present invention, the diameter of the armored thermocouple wire is 2 to 3 mm, and the corresponding measuring hole diameter is controlled at 8 to 12 mm.

[0029] In some embodiments, the blank is a titanium blank, and the filling medium is uncoated titanium dioxide powder. The inventors of the present application realize that the use of uncoated titanium dioxide powder as the filling medium is more reliable than using metal titanium powder, refractory wool, etc. as the filling medium. Metal titanium powder will burn under high temperature conditions and cannot play the role of fixing the thermocouple; if refractory wool is used for filling, the refractory wool is loose and porous, and will collapse after roasting, resulting in gaps in the measuring hole, and furnace gas enters the measuring hole to cause inaccurate temperature measurement. The surface of coated titanium dioxide is compounded with other substances, which may affect the temperature measurement. Therefore, the present invention uses uncoated titanium dioxide as the filling medium, which can further ensure the accuracy of the titanium blank in the furnace temperature test.

[0030] In recent years, with the rapid development of the titanium industry, the output of titanium products has increased day by day, and the quality requirements of titanium products have also increased day by day. However, compared with the heating of steel billets, the heating of titanium billets has insufficient experience due to the low output, especially when it comes to the development of new titanium products, it is more necessary to finely control the heating quality in order to provide high-quality and high-stability raw materials for rolling. Therefore, it is necessary to track and test the heating process of the titanium billet to obtain the heating curves of different parts of the titanium billet during the movement of the titanium billet in the heating furnace. This work can achieve multiple goals at one stroke. First, it can clarify the heating quality of the titanium billet under the current heating system, such as the cross-section temperature difference (temperature difference along the thickness direction of the titanium billet), the same plate temperature difference (temperature difference along the length direction of the titanium billet), etc.; second, it provides a basis for the subsequent increase in furnace temperature and shortening of heating time; third, it can be compared with the heating curve of the secondary model of the heating furnace, optimize the existing secondary model, and provide support for the improvement of automatic titanium burning accuracy. The method of the present invention can be effectively applied to the in-furnace temperature test of titanium billets.

[0031] In some embodiments, for deep holes, the filling medium is filled and compacted in layers. That is to say, after filling a layer of filling medium, compaction is performed, and then the next layer of filling medium is filled and compacted. An iron rod with a flat head can be used for compaction, and the iron rod can be hit with a hammer to ensure the compaction effect. After filling and compacting layer by layer, ensure that the filling medium is not lower than the surface position of the blank. After such treatment, the thermocouple can be firmly fixed in the measuring hole, further reducing the possibility of loosening of the thermocouple, and effectively preventing gas from entering the measuring hole to interfere with the test results. When the filling medium is uncoated titanium dioxide powder, since the uncoated titanium dioxide powder has a smaller density and a finer particle size, it is particularly necessary to ensure that it is firmly filled in the measuring hole through the operation of filling and compacting layer by layer and will not easily loosen and escape.

[0032] In some embodiments, for shallow holes, after filling the above-mentioned filling medium, a pressure plate is used to cover the opening of the shallow hole, so that the temperature measuring end of the thermocouple can be effectively fixed at the measuring point position, solving the problem of inaccurate temperature measurement caused by loose thermocouples, and effectively preventing gas from entering the measuring hole to interfere with the test results. In some embodiments, the blank is a titanium blank, the pressure plate is a titanium plate, and the use of the pressure plate to cover the opening of the shallow hole includes: welding the titanium plate to the titanium blank on all sides. The use of titanium plates of the same material ensures the feasibility and effectiveness of welding. Welding is used to ensure that the titanium plate is firmly fixed and the opening is effectively sealed. The size of the titanium plate can be larger than the opening of the shallow hole by a certain margin to facilitate welding.

[0033] In some embodiments, the method of the present invention further includes: wrapping the portion of the thermocouple outside the measuring hole with a heat-insulating material (e.g., refractory cotton). The inventors studied the effect of whether the thermocouple wire is wrapped with cotton on the temperature measurement data. When conducting a black box experiment on a steel billet, two thermocouples were placed in the same measuring hole. The measuring hole was filled and compacted with iron oxide powder. For the treatment of the thermocouple wire outside the measuring hole, one of the thermocouple wires was wrapped with refractory cotton, and the other thermocouple wire was exposed without cotton. Figure 2 The temperature measurement data of the two thermocouples are shown in Figure 2. Figure 2 It can be seen that after the temperature rises to above 600℃, the thermocouple data without refractory cotton wrapping jumps significantly and fluctuates greatly, while the test data curve of the thermocouple wrapped with refractory cotton is relatively smooth, without obvious jumps. Considering that the two thermocouples are buried in the same measuring hole and the measuring hole filling method is also the same, the main difference is whether the thermocouple wire is wrapped with cotton. Therefore, it can be judged that the thermocouple wire wrapped with cotton can effectively eliminate the fluctuation of the thermocouple. Therefore, during the black box test, the thermocouple wire is wrapped with cotton to avoid direct contact with the high-temperature billet and to avoid being eroded by high-temperature furnace gas in order to obtain stable and reliable test data. The insulation cotton can be bundled with thin iron wire to ensure that the insulation cotton will not fall off.

[0034] In some embodiments, the method of the present invention also includes: bending the portion of the thermocouple located outside the measuring hole in a direction parallel to the surface of the billet, so that the couple wires are arranged compactly along the surface of the titanium billet, making it easier to guide the connecting end of the thermocouple to the furnace temperature tracker.

[0035] The following is a description based on specific embodiments.

[0036] Example 1 The experimental titanium billet is made of TA1 titanium alloy, with a length, width and thickness of 8100mm, 1500mm and 220mm respectively. The billet temperature is tracked online on the upper surface, sub-upper surface, middle, sub-lower surface and lower surface of the left side, middle and right side of the titanium billet. In addition, the upper and lower furnace gas temperatures in the middle of the titanium billet are also tested for comparison with the billet temperature.

[0037] (1) Titanium billet hole measurement and opening The diameter of the armored thermocouple wire is 3mm, and the measuring hole diameter is selected to be 11mm.

[0038] The depth requirements of the measuring hole are as follows: Upper surface measuring hole: as close to the surface of titanium billet as possible, using slotting method, the depth of the position where the thermocouple head is placed at the end of the slot is 6mm; Second upper surface measuring hole: depth 30mm, filled with uncoated titanium dioxide powder; Center measuring hole: depth 115mm, filled with uncoated titanium dioxide powder; Second lower surface measuring hole: depth 190mm, filled with uncoated titanium dioxide powder; The bottom surface measuring hole: depth 214mm, filled with uncoated titanium dioxide powder; The middle part of the titanium billet is heated by furnace gas: no hole is drilled, the thermocouple is fixed on the surface of the titanium billet, and the temperature measuring head is 20mm away from the upper surface of the titanium billet; The middle part of the titanium billet has a through hole, and the temperature measuring head protrudes out of the lower surface of the titanium billet, and the temperature measuring head is 20mm away from the lower surface of the titanium billet.

[0039] (2) Thermocouple buried a. For the measuring holes on the secondary upper surface, center, secondary lower surface, and lower surface, when burying the thermocouple, bend the temperature measuring end of the thermocouple so that the thermocouple head rests on the bottom of the measuring hole and the thermocouple wire makes point contact with the inner wall of the measuring hole.

[0040] After the thermocouple is inserted into the measuring hole, the measuring hole is filled with uncoated titanium dioxide powder and compacted. The operation mode of layered filling and layered compaction is adopted. Since the density of uncoated titanium dioxide powder is small and the particle size is fine, it is necessary to use a flat iron rod for compaction, and use a hammer to hit the iron rod to ensure the compaction effect. After filling and compacting layer by layer, ensure that the uncoated titanium dioxide powder is not lower than the upper surface of the titanium billet. After such treatment, the thermocouple has been firmly fixed in the measuring hole.

[0041] b. For the surface measurement hole, a slotting method is adopted. An inclined slot is opened near the test position on the surface of the titanium billet. The length of the inclined slot is 100mm. The deepest part of the slot is at the measuring point, with a depth of 6mm. The slot body is a cylindrical body with a part cut off, and the depth gradually decreases. The diameter of the cylinder is 8mm. The temperature measuring end of the thermocouple is embedded in the titanium billet along the inclined slot. The head of the temperature measuring end of the thermocouple touches the body of the titanium billet and is filled with uncoated titanium dioxide powder. Subsequently, it is covered with a 150mm×25mm×2mm titanium plate, and the thin titanium plate is welded to the titanium billet on all sides by argon arc welding.

[0042] (3) Thermocouple cotton packing After the thermocouple is buried, bend the external thermocouple wire of the measuring hole so that it is arranged along the upper surface of the titanium billet. Wrap the thermocouple wire with 20mm thick insulation cotton and tie it with thin iron wire to ensure that the insulation cotton will not fall off.

[0043] According to the above steps, holes were opened, thermocouples were fixed, and wire was wrapped with cotton. Then, the titanium billet black box experiment was carried out to obtain the temperature rise curves of various parts. The data trend was correct. Except for the upper and lower furnace gas temperature curves, the other test data curves all rose smoothly without significant fluctuations. The data was in good condition.

[0044] In summary, the present invention proposes a method for improving the accuracy of furnace temperature testing of billets (especially suitable for titanium billets). By means of measures such as embedding the thermocouple in the measuring hole for fixation (including different fixing methods for deep holes and shallow holes, and selection of filling media), wrapping the thermocouple wire with thermal insulation cotton, etc., the temperature measurement accuracy of the thermocouple is effectively improved, and abnormal fluctuations in the test value are avoided, thereby providing a strong guarantee for the smooth implementation of the titanium billet black box experiment.

[0045] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for improving the accuracy of blank temperature testing in a furnace, characterized in that: include: Opening a plurality of measuring holes on the blank; Installing the mounting sections of the plurality of thermocouples into the plurality of measuring holes respectively, and filling the filling medium into the plurality of measuring holes; Connecting the connecting ends of the plurality of thermocouples to a furnace temperature tracker and then conducting a test; Among them, the multiple measuring holes include deep holes with a hole depth greater than or equal to a predetermined threshold, and installing the mounting section into the deep hole includes: bending the mounting section and the first end and the second end of the mounting section respectively abut against the bottom and the upper part of the side wall of the deep hole; wherein the first end of the mounting section is the temperature measuring end.

2. The method according to claim 1, characterized in that The plurality of measuring holes further include shallow holes having a hole depth less than the predetermined threshold, and the shallow holes are inclined relative to the surface of the blank; Installing the installation section into the shallow hole includes: embedding the installation section into the shallow hole and making the temperature measuring end contact the bottom of the hole.

3. The method according to claim 1, characterized in that The predetermined threshold is 10 to 20 mm.

4. The method according to claim 1, characterized in that: The blank is a titanium blank, and the filling medium is uncoated titanium dioxide powder.

5. The method according to claim 1, characterized in that The deep holes are filled with the filling medium in layers and compacted in layers.

6. The method according to claim 2, characterized in that For the shallow hole, after the filling medium is filled, the opening of the shallow hole is covered with a pressing plate.

7. The method according to claim 6, characterized in that The blank is a titanium blank, the pressing plate is a titanium plate, and the method of covering the opening of the shallow hole with the pressing plate includes: welding the four sides of the titanium plate to the titanium blank.

8. The method according to claim 6, characterized in that Also includes: The portion of the thermocouple located outside the measuring hole is covered with a heat-insulating material.

9. The method according to claim 6, characterized in that Also includes: The portion of the thermocouple located outside the measuring hole is bent in a direction parallel to the surface of the blank.

10. The method according to claim 1, characterized in that The diameter of the measuring hole is determined according to the wire diameter of the thermocouple, the condition of the drill bit and the type of the blank.

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