CN110576164B - Device for measuring solidification shrinkage and thermal cracks of continuous casting billet - Google Patents
Device for measuring solidification shrinkage and thermal cracks of continuous casting billet Download PDFInfo
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- CN110576164B CN110576164B CN201911060180.1A CN201911060180A CN110576164B CN 110576164 B CN110576164 B CN 110576164B CN 201911060180 A CN201911060180 A CN 201911060180A CN 110576164 B CN110576164 B CN 110576164B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D2/00—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass
Abstract
The invention discloses a device for measuring solidification shrinkage and hot cracks of a continuous casting billet, which comprises a workbench, wherein a forming die is fixedly arranged on the workbench and is communicated with a pouring system through a pouring channel, the forming die is provided with a hollow inner cavity, two axial ends of the hollow inner cavity are provided with cooling systems for sealing the hollow inner cavity and forming a cavity and/or cooling the forming die, one of the two cooling systems is provided with a through hole for a stretching rod to movably penetrate/withdraw, the outer peripheral side of the forming die is coated with a heat preservation device, the forming die is provided with a temperature measurement device, a plurality of temperature measurement devices are electrically connected with a temperature recorder fixedly arranged on a base, the device also comprises a stress measurement unit consisting of a rotating arm, a driving device, a stress sensor and the stretching rod, the rotating arm is movably connected with the workbench through a rotating shaft and can rotate around the rotating shaft by 90 degrees, the driving device is fixedly arranged at one end of the rotating arm far away from the rotating shaft and is connected with the stress sensor and the stretching rod.
Description
Technical Field
The invention relates to the field of casting, in particular to a device for measuring solidification shrinkage and thermal cracks of a continuous casting billet.
Background
The main defects of the continuous casting billet are from cracks, and the cracks in the continuous casting billet are hot cracks (generated in the process of metal solidification) and cold cracks (generated in the process of continuous cooling after the metal is solidified). The former is formed and expanded along the grain boundary, the cracks are zigzag and irregular, and sometimes branched cracks exist, and the cracks are mostly distributed in the ingot mushy zone or the zones close to the mushy zone; the latter often occurs in an elastic state at relatively low temperatures, cracks often pass through the interior of the grains, the path is relatively regular, and some cold cracks are transformed on the basis of hot cracks. Among them, thermal cracking is one of the most serious defects in the production of either die casting or continuous casting, and is an important factor that limits the improvement of product quality.
Thermal cracks form in the mushy zone of the material during continuous casting, and the rheological behavior of the mushy zone, such as strength and stability, affects the formation of various defects during casting. The formation of defects such as thermal cracks, surface cracks, band defects, and the like, which are associated with stress, and also shrinkage cavities, is also associated with the paste zone strength, and therefore the rheological properties of fully molten and partially molten metals have been receiving attention from researchers. It is mainly the result of the interaction of two mechanisms, namely deformation of the solid phases which have been in contact with each other and insufficient feeding of the liquid phase between dendrites. The deformation process of the solidified portion is complicated because it depends on the interdendritic state, i.e., how the stress is transmitted and released on the microscopic level. The transition of the continuous liquid film to a fully solidified solid phase is gradual, with strain concentrated at the remaining mushy grain boundaries in the mushy critical regions where the solidified dendrites only partially contact. The scholars use several typical tests to characterize the sensitivity of the alloy to hot cracking, mainly including the tests of type I, dog-bone shaped samples, ring type, cone type and the like; also, a more complex system is developed, such as an experimental apparatus designed by Ackerman and composed of two water-cooled copper cylinders and a test system, the water-cooled copper cylinders can be directly put into molten metal, after a solidified shell with a certain thickness is formed around two half shafts of the cylinders, the cylinders are stretched in two directions, and mechanical data are recorded in real time. The advantage of this device is that it can accurately reproduce the conditions of hot cracking, but it has two disadvantages, safety and data and mechanism are difficult to interpret. Similar tensile testing equipment (adapted for use in the alloy mush zone) was also used to measure the solid linear shrinkage and the stress generated during shrinkage, the stress-strain curve during applied displacement, and the stress-strain data during hot crack formation. A short handle dumbbell-shaped device designed like rapaz and the like, wherein the dumbbell is vertically placed and cast and passes the upper end of the tensile dumbbell for hot cracking test; DAHLE and the like are designed into an I-shaped device, one end of an I-shaped casting is fixed, and the other end of the I-shaped casting is connected with a stretching mechanism and a sensor, so that the strength and the heat cracking behavior of an aluminum alloy mushy zone are researched; a similar apparatus designed by Wanglihua et al tests the hot cracking of aluminum-copper alloys. The design can describe the formation process of the thermal cracks in the metal solidification process at a certain angle, but the metal thermal cracking process of the device is basically limited by two ends of a rod-shaped test sample, the thermal cracks are automatically generated by the solidification shrinkage force of the metal, and the cooling process is different from the cooling process of continuous casting. The cooling and solidifying process of the continuous casting blank has the characteristics of strong cooling on the outer surface of the casting blank, and basically no influence of mechanical force on solidification shrinkage, and the traditional testing device and method are not suitable for the research on the hot cracks of the continuous casting.
The initial phase of dendrite bridging is important in the study of hot cracking of alloy materials, whether experimental testing or in situ observation, because it corresponds to the transition period between a continuous liquid film network and a fully solidified dendrite framework, and the solidification process is completed by the formation of interdendritic bridges. One of the processes is intragranular bridging, i.e. the dendrite arms belonging to the same grain can be bridged at a relatively high temperature, and the process makes the inside of the grain solidified and become a basic unit of deformation and thermal shrinkage. And secondly, merging the small-angle crystal boundaries to form a cluster of small crystal grain groups so as to realize the growth of the crystal grains. This process occurs at the solidification stage where feeding begins to become difficult, i.e., in the early stages of the thermal cracking sensitive zone. For the research of thermal cracking, the determination of the temperature at which the above phenomenon occurs and the determination of the critical solid phase fraction during the formation of continuous solid phase is the basis for the further research of thermal cracking.
Therefore, the determination of the hot cracking of the continuous casting slab is carried out by developing a special device.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a device for measuring the solidification shrinkage and thermal cracks of a continuous casting billet aiming at the defects in the prior art, wherein the device simulates the forced cooling process of the continuous casting billet and measures the solidification shrinkage generated by the continuous casting billet, and quantitatively analyzes the thermal crack generation state under different cooling and tensile stress conditions.
According to a first aspect of the invention, a device for measuring the solidification shrinkage of a continuous casting blank comprises a workbench, a forming die is fixedly arranged on the workbench through a support frame and is communicated with a pouring system through a pouring channel, the forming die is provided with a hollow inner cavity, two axial ends of the hollow inner cavity are respectively provided with a cooling system which seals the hollow inner cavity and forms a cavity and/or cools the forming die, one of the two cooling systems is provided with a through hole for a stretching rod to movably penetrate/withdraw, the outer peripheral side of the forming die is coated with a heat preservation device, the forming die is provided with a plurality of temperature measuring devices which penetrate through the forming die and radially extend into the cavity, the temperature measuring devices are electrically connected with a temperature recorder fixedly arranged on a base, and the device further comprises a stress measuring unit consisting of a rotating arm, a driving device, a stress sensor and the stretching rod, the rotary arm is movably connected with the workbench through a rotating shaft and can rotate around the rotating shaft for 90 degrees, the driving device is fixedly arranged at one end of the rotary arm, which is far away from the rotating shaft, the driving device is connected with the stress sensor and the stretching rod, and when the rotary arm drives the driving device to rotate to be positioned at one end of the forming die in the axial direction, the driving device can drive the stretching rod to move along the axial direction of the forming die, so that the stretching rod penetrates into the die cavity to be connected with a casting blank in pouring and/or formed, and the stress sensor is pulled by the stretching rod in the process of casting blank shrinkage to complete shrinkage measurement.
As a further elaboration of the above technical solution:
in the technical scheme, the forming die is a hollow cylindrical corundum die or a hollow cylindrical graphite die, the length of the forming die is 100-200 mm, and the outer diameter of the forming die is 10-30 mm.
In the technical scheme, the cooling system comprises water-cooling copper plugs fixedly arranged at two axial ends of the forming die through a bolt matched support fixing frame, each water-cooling copper plug comprises a first water-cooling copper plug and a second water-cooling copper plug, each first water-cooling copper plug is provided with a screw rod extending towards the center of the forming die, the through hole is formed in the center of each second water-cooling copper plug, each first water-cooling copper plug and each second water-cooling copper plug are provided with containing cavities for containing refrigerants, and the containing cavities are connected with a circulating water cooling device or a water pump through water pipes.
In the technical scheme, the heat preservation device is a high-temperature carbon felt heat preservation layer, the temperature measuring devices are K-type thermocouples or S-type thermocouples, the forming die is provided with four temperature measuring devices, and the pouring system is communicated with the cavity through a single pouring channel located at the position where the first water-cooling copper plug is arranged.
In the technical scheme, the driving device comprises a driving motor, the driving motor is connected with the stress sensor and the stretching rod through a transmission screw rod, the driving motor can drive the stress sensor and the stretching rod to move along the axial direction of the forming die through the transmission screw rod, the stretching rod penetrates into the cavity to be connected with a casting blank during pouring and/or forming, and the stretching rod pulls the stress sensor to complete shrinkage measurement in the process of shrinkage of the casting blank.
According to a second aspect of the invention, another technical scheme is that the device for measuring the hot cracks of the continuous casting slab comprises a base, a casting mold is fixedly arranged on the base through a support frame and is communicated with a casting system through a runner, the casting mold is provided with a cross-shaped inner cavity formed by a transverse inner cavity and a longitudinal inner cavity, two ends of the transverse inner cavity are respectively provided with a cooling component for sealing the inner cavity and/or cooling the casting mold, one end of the longitudinal inner cavity is sealed, the other end of the longitudinal inner cavity is sealed through a first plug, the first plug is provided with a through hole through which a stretching rod movably penetrates or withdraws, a heat preservation device is coated on the outer peripheral side of the casting mold, a plurality of temperature measurement devices penetrating through the casting mold and extending into the inner cavity are arranged on the casting mold, the temperature measurement devices are electrically connected with a temperature recorder fixedly arranged on the base, and a rotating arm, a temperature measurement instrument is arranged on the base in a position of the temperature measurement instrument, The device comprises a driving device, a stress sensor and a stretching rod, wherein the rotating arm is movably connected with the base through a rotating shaft and can rotate around the rotating shaft by 90 degrees, the driving device is fixedly arranged at one end of the rotating arm far away from the rotating shaft, the driving device is connected with the stress sensor and the stretching rod, and when the rotating arm drives the driving device to rotate to the front end of the casting die in the longitudinal direction, the driving device can drive the stretching rod to penetrate into the inner cavity along the through hole to be in threaded connection with a casting blank, and then actively stretches the casting blank and completes thermal crack measurement in cooperation with the detection of the stress sensor.
As a further elaboration of the above technical solution:
in the technical scheme, the casting mold is provided with a middle longitudinal mold part and two transverse mold parts, the two transverse mold parts are symmetrically arranged on the two transverse sides of the middle longitudinal mold part, hollow cylindrical inner cavities of the two transverse mold parts form the transverse inner cavity, the longitudinal inner cavity is formed in the middle longitudinal mold part, the middle longitudinal mold part and the two transverse mold parts are integrally formed to form the cross-shaped inner cavity, the transverse length of the casting mold is 100-200 mm, the transverse outer diameters of the two transverse mold parts of the casting mold are 10-30 mm, and the first plug is a graphite plug.
In the above technical scheme, the cooling assembly includes water-cooled copper plugs fixedly arranged at two axial ends of the casting mold through a bolt-matched supporting fixing frame, the two water-cooled copper plugs are respectively provided with a containing cavity for containing a refrigerant, and the containing cavities are connected with a circulating water cooling device or a water pump through a water pipe.
In the technical scheme, the heat preservation device is a high-temperature carbon felt heat preservation layer, the temperature measuring devices are K-type thermocouples or S-type thermocouples, the casting mold is provided with two longitudinally and symmetrically arranged temperature measuring devices, and the casting system is communicated with the inner cavity through the transversely and symmetrically arranged double runners.
In the technical scheme, the driving device comprises a driving motor, the driving motor is connected with the stress sensor and the stretching rod through a transmission screw rod, the driving motor drives the stretching rod to penetrate into the inner cavity along the through hole to be in threaded connection with the casting blank, and then the casting blank is actively stretched and the hot crack measurement is completed by matching with the detection of the stress sensor.
Compared with the prior art, the invention has the beneficial effects that: firstly, the invention is matched with the heat-insulating layer through the preheating of the mould and the water inlet and outlet speed of the water-cooling copper cap, can effectively control the cooling speed of the sample, simulate the cooling process of a casting blank and the growth of a structure, simultaneously the sample can freely shrink in a smooth die, thereby conveniently and accurately measuring the solidification shrinkage in the thickness direction of the casting blank; secondly, on the basis of controlling cooling and heat preservation of the sample along the length direction, variable loads including stress magnitude, strain rate, loading time and loading temperature can be applied to the radial direction of the sample, so that stress loading along the direction perpendicular to the dendrite is realized, and the relation between the stress state of the mushy zone and the thermal stress generation of the mushy zone is tested; moreover, the device can simulate the cooling process of the casting blank, and effectively control the tissue growth of the sample, thereby realizing the measurement of the solidification shrinkage of the casting blank; meanwhile, the device can also be used for realizing the stress applied in the direction vertical to the dendritic growth direction of the casting blank by rotating the tension test system, researching the relation between the mechanical property and the stress state of a mushy zone between branches and crystals of the casting blank, thereby carrying out the research work of influencing the hot crack generation parameters in the continuous casting process, has simple structure, reasonable design and convenient operation, can accurately measure the solidification shrinkage of the continuous casting blank, can also carry out the research on the stress state of the mushy zone between branches and crystals of the casting blank, overcomes the defect that a thermal stress test device is lack of special continuous casting thermal stress and hot crack test equipment, promotes the research on the hot cracks of the continuous casting, can control the cooling strength at two ends of the sample, simulate the forced cooling process of the outer surface of the continuous casting blank, simultaneously carry out temperature monitoring in the mushy zone of the casting blank, and after the center of the sample enters the temperature range of the mushy zone, the relationship between the formation process of the thermal crack and the structure state can be determined by loading tensile stress with different magnitudes in the radial direction of the sample.
Drawings
FIG. 1 is a front sectional view of a continuous casting billet solidification shrinkage measurement;
FIG. 2 is a top cross-sectional view of a solidification shrinkage measurement of a continuous casting slab;
FIG. 3 is a top sectional view of the active generation and determination of the thermal cracks of the continuous casting slab;
FIG. 4 is a top sectional view of the active generation and measurement of the thermal cracks of the continuous casting slab.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Example 1
Referring to the attached drawings 1-2, the invention provides a device for measuring solidification shrinkage of a continuous casting billet, which comprises a workbench 1, wherein a forming mold 3 is fixedly arranged on the workbench 1 through a support frame 2, the forming mold 3 is communicated with a pouring system 5 through a pouring channel 4, the forming mold 3 is provided with a hollow inner cavity 301, two axial ends of the hollow inner cavity 301 are respectively provided with a cooling system 6 for sealing the hollow inner cavity 301 and forming a cavity and/or cooling the forming mold 3, one of the two cooling systems 6 is provided with a through hole 601 for a stretching rod 14 to movably penetrate/withdraw, the outer peripheral side of the forming mold 3 is coated with a heat preservation device 7, the forming mold 3 is provided with a plurality of temperature measurement devices 8 penetrating through the forming mold 3 and radially extending into the cavity, the temperature measurement devices 8 are electrically connected with a temperature recorder 9 fixedly arranged on the workbench 1, and the device further comprises a rotating arm 10, a temperature detector 9, A stress measuring unit consisting of a driving device 11, a stress sensor 12 and a stretching rod 14, wherein in this embodiment, the stretching rod 14 is a water-cooling high-temperature alloy, the stress sensor 12 is electrically connected with a computer for data processing, the rotating arm 10 is movably connected with the workbench 1 through a rotating shaft 13 and can rotate for 90 degrees around the rotating shaft 13, that is, the rotating arm 10 can rotate between a horizontal position relative to the forming mold 3 and a vertical position relative to the forming mold 3, the driving device 11 is fixedly arranged at one end of the rotating arm 10 far away from the rotating shaft 13, the driving device 11 is connected with the stress sensor 12 and the stretching rod 14, the rotating arm 10 drives the driving device 11 to rotate to be positioned at one axial end of the forming mold 3 (when the driving device 11 is that an output shaft is positioned on the same straight line with the stretching rod 14 and the central axis of the forming mold 3), the driving device 11 can drive the stretching rod 14 to move along the axial direction of the forming mold 3, the stretching rod 14 penetrates into the cavity to be connected with the casting blank in the process of casting and/or forming, and the stretching rod 14 pulls the stress sensor 12 in the process of casting blank shrinkage so as to complete shrinkage measurement.
Preferably, in this embodiment, the forming mold 3 is a hollow cylindrical corundum mold or a hollow cylindrical graphite mold, the length of the forming mold 3 is 100 to 200mm, the outer diameter of the forming mold 3 is 10 to 30mm, in this embodiment, the cooling system 6 includes water-cooled copper plugs 63 fixedly disposed at two axial ends of the forming mold 3 by bolts 61 in cooperation with supporting holders 62, the water-cooled copper plugs 63 include a first water-cooled copper plug 631 and a second water-cooled copper plug 632, the first water-cooled copper plug 631 is provided with a screw rod extending toward the center of the forming mold 3, the screw rod is provided with a coarse thread, the through hole 601 is formed at the center of the second water-cooled copper plug 632, the first water-cooled copper plug 631 and the second water-cooled copper plug 632 are both provided with receiving cavities 602 for receiving a coolant, the receiving cavities 602 are connected to a circulating water cooling device or a water pump through a water pipe, in this embodiment, the coolant is cooling water; in the embodiment, the heat preservation device 7 is a high-temperature carbon felt heat preservation layer, the temperature measuring devices 8 are K-type thermocouples or S-type thermocouples, and the forming die 3 is provided with four temperature measuring devices 8, the pouring system 5 of the embodiment is provided with one pouring gate 4, and the pouring system 5 is communicated with the cavity through the single pouring gate 4 positioned at the position where the first water-cooling copper plug 631 is arranged (the fixed end of the forming die 3); in the present embodiment, the driving device 11 includes a driving motor 111, the driving motor 111 is connected to the stress sensor 12 and the stretching rod 14 through a transmission screw (not shown in the drawings), the driving motor 111 can transmit the stress sensor 12 and the stretching rod 14 through the transmission screw to move along the axial direction of the forming die 3, so that the stretching rod 14 penetrates into the cavity to be connected to the casting blank being poured and/or formed, and the stretching rod 14 pulls the stress sensor 12 during the casting blank shrinkage process to complete shrinkage measurement.
The structure of the apparatus for measuring solidification shrinkage of a continuous casting slab according to the present invention and the shrinkage measuring process will be further described as follows: referring to fig. 1-2, in this embodiment, the gating system 5 is fixed to the worktable 1 by the supporting frame 2, the runner 4 is a single channel, and the runner 4 is communicated with the fixed end of the forming mold 3 and is poured into the hollow cavity 301 and the cavity of the forming mold 3; the forming die 3 is made of corundum and is a cylindrical through pipe, a through hole is formed in the radial center of the fixed end (left end) of the forming die 3, the through hole is communicated with the pouring channel 4 and is connected with the pouring system 5, and therefore the forming die 3 can finish pouring of a casting blank; during the experiment, the forming die 3 is preheated to 800 ℃ in a heating furnace, taken out and then penetrated into a heat preservation device 7 and fixed on the workbench 1 through a support frame 2, the heat preservation device 7 consists of a high-temperature carbon felt or a high-temperature refractory material, the cylinder is hollow, the inner diameter is the same as the outer diameter of the forming die 3, the length and the outer diameter change along with the size of the experimental casting blank, and the preheated forming die 3 is fixed on the workbench 1 through the support frame 2 after penetrating into the heat preservation device 7; the temperature monitoring and recording mechanism comprises a thermocouple (temperature measuring device) and a temperature recorder 9, wherein, the thermocouple has different temperatures according to the pasty zone of the measured material, k-type and S-type thermocouples can be selected, the thermocouple 5 is connected with a temperature recorder 9 in advance and is tested, after the forming die 3 is fixed on the workbench 1, a thermocouple is quickly inserted into the closed hole, the temperature change is recorded, and the thermocouple is connected with a temperature recorder 9 to monitor and record the temperature data of the casting blank in real time; while the molding die 3 is fixed to the table 1, the cooling system 6 is additionally arranged at two ends of the forming die 3, a screw rod with coarse threads is arranged at the center of the first water-cooling copper plug 631, the second water-cooling copper plug 632 with the length of 7 mm is fixed at the right side of the forming die 3 through the supporting and fixing frame 62, and a hole is formed in the center of the second water-cooling copper plug, so that the stress sensor 12 and the stretching rod 14 can conveniently penetrate through the hole; the stress applying and sensing recording part comprises a stretching rod 14, a stress sensor 12, a driving device 11 and a rotating arm 10, wherein a coarse thread is processed at the end part of the stretching rod 14, a good connection is established with a casting blank after the casting blank is solidified, and the casting blank can be smoothly unscrewed and separated from the casting blank after an experiment is finished; the stretching rod 14 is connected with the driving device 11 through the stress sensor 12 and is connected with a computer, and the computer controls and records mechanical data and the start and stop of the driving motor 11 of the driving device 11, so that the tension data is controlled and recorded in real time; the driving motor 11 is disposed in the rotating arm 10, and the rotating arm 10 can drive the driving device 11 to rotate around the forming mold by 90 degrees.
When measuring the solidification shrinkage of the continuous casting blank, the driving motor 111 rotates to be in the horizontal position with the forming die 3, the stretching rod 14 in transmission connection with the driving motor 111 penetrates through the second water-cooling copper plug 632 II to enter the inner cavity and is connected with the casting blank in a solidification mode after casting, when the casting blank is solidified, cooled, solidified and shrunk, the stretching rod 14 is pulled to move, and the stress sensor 12 can detect displacement and tension data and record the data through a computer.
Example 2
Referring to the attached drawings 3-4, the invention provides a device for measuring the hot cracks of a continuous casting blank, which comprises a base 15, wherein a casting mold 17 is fixedly arranged on the base 15 through a support frame 16, the casting mold 17 is communicated with a casting system 19 through a runner 18, the casting mold 17 is provided with a cross-shaped inner cavity formed by a transverse inner cavity 172 and a longitudinal inner cavity 171, both ends of the transverse inner cavity 172 are respectively provided with a cooling component 20 for sealing the inner cavity and/or cooling the casting mold 17, one end of the longitudinal inner cavity 171 is sealed, the other end of the longitudinal inner cavity is sealed through a first plug 21, a through hole 211 for movably penetrating/withdrawing a stretching rod 22 is formed in the first plug 21, a heat preservation device 23 is coated on the outer peripheral side of the casting mold 17, a plurality of temperature measuring devices 24 penetrating through the casting mold 17 and extending into the inner cavity are arranged on the casting mold 17, the temperature measuring devices 24 are electrically connected with a temperature recorder 25 fixedly arranged on the base 15; and also a thermal crack measuring unit consisting of a rotating arm 26, a drive device 27, a stress sensor 28 and a stretch rod 22, which, in practice, the stretching rod 22 is made of water-cooling high-temperature alloy, the stress sensor 28 is electrically connected with a computer for data processing, the rotating arm 26 is movably connected with the base 15 through a rotating shaft 29, and is capable of rotating 90 ° around a rotating shaft 29, the driving device 27 is fixed on one end of the rotating arm 26 far away from the rotating shaft 29, the drive device 27 is connected with the stress sensor 28 and the stretching rod 22; when the rotating arm 26 drives the driving device 27 to rotate to be located at the front end of the casting mold 17 in the longitudinal direction, the driving device 27 can drive the stretching rod 22 to penetrate into the inner cavity along the through hole 211 to be in threaded connection with the casting blank, and then the casting blank is actively stretched and the hot crack measurement is completed in cooperation with the detection of the stress sensor 28.
Preferably, in this embodiment, the casting mold 17 is provided with a middle longitudinal mold portion 173 and two transverse mold portions 174, the two transverse mold portions 174 are symmetrically arranged on two lateral sides of the middle longitudinal mold portion 173, the hollow cylindrical inner cavities of the two transverse mold portions 174 form the transverse inner cavity 172, the longitudinal inner cavity 171 is formed on the middle longitudinal mold portion 173, the middle longitudinal mold portion 173 and the two transverse mold portions 174 are integrally formed to form the cross-shaped inner cavity, the transverse length of the casting mold 17 is 100-200 mm, the transverse outer diameters of the two transverse mold portions 174 of the casting mold 17 are 10-30 mm, the first plug 21 is a graphite plug, in this embodiment, the cooling assembly 20 includes water-cooled copper plugs 203 fixedly arranged at two axial ends of the casting mold 17 by supporting and fixing frames 202 through bolts 201, each of the two water-cooled copper plugs 203 is provided with a containing cavity 204 for containing a coolant, the containing cavity 204 is connected to a circulating water cooling device or a water pump through a water pipe, the pouring system 19 is communicated with the inner cavity through the horizontally symmetrically arranged double runners 18; in this embodiment, the driving device 27 includes a driving motor 271, the driving motor 271 is connected with the stress sensor 28 and the stretching rod 22 through a transmission lead screw (not shown in the drawings), and after the driving motor 271 transmits the stretching rod 22 to penetrate into the inner cavity along the through hole 211 to be screwed with the casting blank, the casting blank is actively stretched and the detection of the stress sensor 28 is matched to complete the measurement of the hot cracks.
The apparatus of this embodiment is substantially the same as that of embodiment 1, with the difference that: the cooling assemblies 20 of the present embodiment are fixed at the two transverse ends of the casting mold 17, so as to completely seal the two axial ends of the casting mold 17; and the device for carrying out the hot crack test, during the experiment, the rotating arm 26 rotates the driving device 27, the stress sensor 28 and the stretching rod 22 to be vertical to the casting die 17, and the casting blank is actively stretched along the longitudinal direction, so that the experiment is completed. Meanwhile, the thermocouple is connected with a computer through a data acquisition card, temperature data are recorded in real time, when the temperature is reduced to the preset temperature of the experiment, a driving motor is started to stretch, and the sample generates hot cracks under different tensile forces and temperatures.
The technical scope of the present invention is not limited to the above embodiments, and any modifications, equivalent variations and modifications made to the above embodiments according to the technical spirit of the present invention still fall within the technical scope of the present invention.
Claims (8)
1. A device for measuring the solidification shrinkage of a continuous casting billet is characterized by comprising a workbench, wherein a forming die is fixedly arranged on the workbench through a support frame and is communicated with a pouring system through a pouring channel, the forming die is provided with a hollow inner cavity, two axial ends of the hollow inner cavity are respectively provided with a cooling system for sealing the hollow inner cavity and forming a cavity and/or cooling the forming die, one of the two cooling systems is provided with a through hole for a stretching rod to movably penetrate/withdraw, the outer peripheral side of the forming die is coated with a heat preservation device, the forming die is provided with a plurality of temperature measurement devices which penetrate through the forming die and radially extend into the cavity, and the temperature measurement devices are electrically connected with a temperature recorder fixedly arranged on a base; the stress measuring device comprises a workbench, a stress sensor, a rotary arm, a driving device, a stress sensor and a stretching rod, wherein the rotary arm is movably connected with the workbench through a rotary shaft and can rotate around the rotary shaft for 90 degrees; the cooling system comprises water-cooling copper plugs fixedly arranged at two axial ends of the forming die through a bolt matched supporting and fixing frame, the water-cooling copper plugs comprise a first water-cooling copper plug and a second water-cooling copper plug, the first water-cooling copper plug is provided with a screw rod extending towards the center of the forming die, the through hole is formed in the center of the second water-cooling copper plug, and the first water-cooling copper plug and the second water-cooling copper plug are provided with accommodating cavities for accommodating refrigerants, the accommodating cavity is connected with a circulating water cooling device through a water pipe, and the screw rod is provided with a coarse thread.
2. The device for measuring the solidification shrinkage of the continuous casting billet according to claim 1, wherein the forming die is a hollow cylindrical corundum die or a hollow cylindrical graphite die, the length of the forming die is 100-200 mm, and the outer diameter of the forming die is 10-30 mm.
3. The device for measuring the solidification shrinkage of the continuous casting billet according to claim 1, wherein the heat preservation device is a high-temperature carbon felt heat preservation layer; the temperature measuring devices are K-type thermocouples or S-type thermocouples, and the forming die is provided with four temperature measuring devices; and the pouring system is communicated with the cavity through a single pouring gate positioned at the arrangement position of the first water-cooling copper plug.
4. The device for measuring the solidification shrinkage of the continuous casting billet according to claim 3, wherein the driving device comprises a driving motor, the driving motor is connected with the stress sensor and the stretching rod through a transmission screw rod, the driving motor can drive the stress sensor and the stretching rod to move along the axial direction of the forming die through the transmission screw rod, the stretching rod penetrates into the cavity to be connected with the casting billet which is being poured and/or formed, and the stress sensor is pulled by the stretching rod during the shrinkage of the casting billet to complete the shrinkage measurement.
5. The device for measuring the hot cracks of the continuous casting billet is characterized by comprising a base, wherein a casting mold is fixedly arranged on the base through a support frame and is communicated with a casting system through a runner, the casting mold is provided with a cross-shaped inner cavity formed by a transverse inner cavity and a longitudinal inner cavity, two ends of the transverse inner cavity are respectively provided with a cooling assembly for sealing the inner cavity and/or cooling the casting mold, one end of the longitudinal inner cavity is sealed, the other end of the longitudinal inner cavity is sealed through a first plug, and the first plug is provided with a through hole through which a stretching rod movably penetrates into/withdraws from the longitudinal inner cavity; the periphery of the pouring mould is coated with a heat preservation device, the pouring mould is provided with a plurality of temperature measuring devices which penetrate through the pouring mould and extend into the inner cavity, and the temperature measuring devices are electrically connected with a temperature recorder fixedly arranged on the base; the thermal crack measuring device comprises a base, a rotary arm, a driving device, a stress sensor and a stretching rod, wherein the rotary arm is movably connected with the base through a rotary shaft and can rotate around the rotary shaft for 90 degrees; the cooling assembly comprises water-cooling copper plugs fixedly arranged at two axial ends of the casting mold through a bolt matched support fixing frame, the two water-cooling copper plugs are provided with accommodating cavities for accommodating refrigerants, and the accommodating cavities are connected with a circulating water cooling device through water pipes.
6. The device for measuring the hot cracks of the continuous casting billet as claimed in claim 5, wherein the casting die is provided with a middle longitudinal die part and two transverse die parts, the two transverse die parts are symmetrically arranged at two transverse sides of the middle longitudinal die part, hollow cylindrical inner cavities of the two transverse die parts are formed into the transverse inner cavity, and the longitudinal inner cavity is formed on the middle longitudinal die part; the middle longitudinal mould part and the two transverse mould parts are integrally formed to form the cross-shaped inner cavity; the transverse length of the casting mold is 100-200 mm, and the transverse outer diameters of two transverse mold parts of the casting mold are 10-30 mm; the first plug is a graphite plug.
7. The device for measuring the thermal cracks of the continuous casting billet as claimed in claim 5, wherein the heat preservation device is a high-temperature carbon felt heat preservation layer; the temperature measuring devices are K-type thermocouples or S-type thermocouples, and the casting mold is provided with two temperature measuring devices which are longitudinally and symmetrically arranged; the pouring system is communicated with the inner cavity through two laterally symmetrically arranged pouring channels.
8. The device for measuring the hot cracks of the continuous casting billet as claimed in claim 7, wherein the driving device comprises a driving motor, the driving motor is connected with the stress sensor and the stretching rod through a transmission screw rod, and the driving motor drives the stretching rod to penetrate into the inner cavity along the through hole to be in threaded connection with the casting billet, and then the casting billet is actively stretched and the hot crack measurement is completed in cooperation with the detection of the stress sensor.
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| CN101075287A (en) * | 2007-06-26 | 2007-11-21 | 上海大学 | Physical simulating method and device during continuous-casting billet coagulation tissue growth process |
| CN101722291A (en) * | 2009-11-26 | 2010-06-09 | 上海大学 | Method and device for simulating horizontal growth process of solidification structure |
| CN102680326A (en) * | 2012-05-09 | 2012-09-19 | 山东大学 | Device and method for testing hot crack of aluminum alloy under condition of active applied load |
| CN207730582U (en) * | 2018-02-02 | 2018-08-14 | 红河学院 | A kind of active loaded type hot cracking tendency system safety testing device |
| CN108931421A (en) * | 2018-08-23 | 2018-12-04 | 上海大学 | A kind of fire check test device of In Situ Heating |
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| DE102008031777A1 (en) * | 2008-07-04 | 2010-01-14 | Gkss-Forschungszentrum Geesthacht Gmbh | Device for determining the hot crack sensitivity of metallic melts |
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| CN2068677U (en) * | 1990-02-23 | 1991-01-02 | 大连理工大学 | Cast alloy cold crack stress analyzer |
| CN101075287A (en) * | 2007-06-26 | 2007-11-21 | 上海大学 | Physical simulating method and device during continuous-casting billet coagulation tissue growth process |
| CN101722291A (en) * | 2009-11-26 | 2010-06-09 | 上海大学 | Method and device for simulating horizontal growth process of solidification structure |
| CN102680326A (en) * | 2012-05-09 | 2012-09-19 | 山东大学 | Device and method for testing hot crack of aluminum alloy under condition of active applied load |
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