CN108788032B - Crystallizer with adjustable cooling strength for continuous casting of magnesium alloy and method for controlling cooling - Google Patents
Crystallizer with adjustable cooling strength for continuous casting of magnesium alloy and method for controlling cooling Download PDFInfo
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- CN108788032B CN108788032B CN201710282495.5A CN201710282495A CN108788032B CN 108788032 B CN108788032 B CN 108788032B CN 201710282495 A CN201710282495 A CN 201710282495A CN 108788032 B CN108788032 B CN 108788032B
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- 238000001816 cooling Methods 0.000 title claims abstract description 151
- 229910000861 Mg alloy Inorganic materials 0.000 title claims abstract description 134
- 238000009749 continuous casting Methods 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 42
- 239000002826 coolant Substances 0.000 claims abstract description 71
- 239000007788 liquid Substances 0.000 claims abstract description 51
- 238000009826 distribution Methods 0.000 claims abstract description 31
- 238000005266 casting Methods 0.000 claims abstract description 29
- 238000007711 solidification Methods 0.000 claims abstract description 18
- 230000008023 solidification Effects 0.000 claims abstract description 18
- 238000010583 slow cooling Methods 0.000 claims description 21
- 238000002425 crystallisation Methods 0.000 claims description 18
- 230000008025 crystallization Effects 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000007790 solid phase Substances 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 3
- 238000012546 transfer Methods 0.000 claims description 3
- 239000013078 crystal Substances 0.000 abstract 1
- 239000000498 cooling water Substances 0.000 description 27
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000005336 cracking Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 101000608752 Phytolacca americana Lectin-C Proteins 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
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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
- B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
- B22D11/055—Cooling the moulds
-
- 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
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
The invention discloses a crystallizer for continuous casting of magnesium alloy with adjustable cooling strength, which comprises: a crystallizer body; a plurality of cooling cavities; a plurality of thermocouples; a control device which is respectively connected with each thermocouple, each flow control valve and the outlet control valve; in the casting process, the control device adjusts the type and/or flow of the cooling medium in each cooling cavity according to the position changes of the magnesium alloy liquid level, the magnesium alloy solidification starting point and the magnesium alloy liquid core end point; the control device also performs closed-loop control on the actual temperature distribution of the crystallizer body by controlling the flow of the cooling medium according to the preset temperature distribution of the crystallizer body and the real-time temperature measured by the reference thermocouple, so that the actual temperature distribution is infinitely close to the preset temperature distribution. In addition, the invention also discloses a method for controlling cooling by adopting the crystal for continuous casting of the magnesium alloy. The crystallizer for continuous casting of the magnesium alloy with adjustable cooling strength improves the product quality of the cooled magnesium alloy.
Description
Technical Field
The invention relates to a crystallizer and an application method thereof, in particular to a magnesium alloy crystallizer and a method for controlling cooling by adopting the magnesium alloy crystallizer.
Background
In the preparation process of the magnesium alloy ingot, in order to obtain an ideal ingot, besides strictly controlling alloy components and impurity content during smelting, the cooling process of the ingot is also an important link for ensuring the internal and external quality of the ingot. At present, magnesium alloy ingots are mainly prepared by direct water-cooling casting. However, because magnesium and magnesium alloy have the characteristics of low volume specific heat, low melting heat, low thermal conductivity and the like, the temperature of the part in contact with the wall of the crystallizer is fast to lower, and the heat of the part far away from the wall of the crystallizer is difficult to transfer to the wall of the crystallizer, so that high temperature gradient in the solidification direction of the magnesium alloy is caused, and larger solidification stress is brought to cause cracks to generate. Reducing the casting cooling rate before the magnesium alloy is fully solidified is effective in solving this problem.
the technology has succeeded in the casting production of aluminum alloy, but because of the high reactivity of magnesium alloy melt at high temperature, it is difficult to avoid reaction, forming corrosion pits and polluting the melt, and in addition, the hot top of the graphite layer is easy to wear, the processing technology is complex and the cost is high.
Chinese patent publication No. CN105108080A, published as 2015, 12, month 2, entitled "semi-continuous casting crystallizer for suppressing cracking of magnesium alloy ingot blank and method of using the same" discloses a semi-continuous casting crystallizer for suppressing cracking of magnesium alloy ingot blank and method of using the same. The technical scheme disclosed in the patent document is to manufacture the hot top by nesting a ceramic fiber paper heat-insulating layer on the inner wall of the crystallizer and covering an outer heat-insulating layer on the outer side of the crystallizer, but the inner heat-insulating layer and the crystallizer are bonded by an adhesive and are easy to fall off at high temperature.
Chinese patent publication No. CN201889396U, published as 7/6/2011, entitled "a hot top crystallizer for hot setting crystallization", discloses a hot top crystallizer made of Al 2O3、SiO2The refractory heat-insulating fiber material is made at high pressure and high temperature, and the hot top is pressed between the heat-insulating sleeve and the water jacket, so that the hot top is effectively prevented from falling off. However, the cooling rate of the upper part of the crystallizer is slowed to a certain extent by the device, but when the component type of the magnesium alloy is changed, the actual process requirement cannot be met The cooling rate is adjusted.
Chinese patent publication No. CN203992288U, published as 2014, 12 and 10, entitled "a structure of a magnesium alloy round billet continuous casting mold", discloses a structure of a magnesium alloy round billet continuous casting mold. In the technical scheme, the cooling part of the crystallizer is divided into an upper section, a middle section and a lower section, and each section supplies different cooling media and flows according to requirements, so that the purpose of controlling the cooling of the crystallizer in sections is achieved. However, in the actual casting process, due to the limitation of process equipment, the liquid level and the temperature of the magnesium alloy melt in the crystallizer fluctuate to a certain extent, and the cooling strength needs to be adjusted in time according to the actual conditions to meet the stability of the process; in addition, when the composition of the cast magnesium alloy melt is changed, the cooling condition of the mold is also changed to meet the change of the composition. It is evident that the above patents lack flexibility in the adjustment of the cooling conditions.
Disclosure of Invention
One of the objectives of the present invention is to provide a crystallizer with adjustable cooling strength for continuous casting of magnesium alloy, wherein during the casting process, the crystallizer is divided into a plurality of different regions, the cooling medium type and flow rate in each region are adjusted to adjust the cooling strength of each region in real time, so as to ensure that the liquid level of the molten magnesium alloy is maintained until the magnesium alloy ingot is completely solidified, and the temperature distribution of the corresponding position of the crystallizer for continuous casting of magnesium alloy is always maintained in a designed state, thereby ensuring the stability of the preparation process of the magnesium alloy ingot, and further stabilizing the quality of the cast ingot.
In order to achieve the above object, the present invention provides a mold for continuous casting of magnesium alloy with adjustable cooling strength, comprising:
A crystallizer body;
The cooling cavities are arranged on the periphery of the crystallizer body and are sequentially arranged in the height direction of the crystallizer body so as to cover a slow cooling zone, a crystallization zone and a chilling zone of the crystallizer body, wherein the area where the liquid level of the magnesium alloy is located and the area above the liquid level are the slow cooling zone, the area where the solidification starting point of the magnesium alloy is located is the crystallization zone, and the area where the liquid core end point of the magnesium alloy is located and the area below the solidification starting point of the magnesium alloy are the chilling zone; each cooling cavity is respectively connected with a plurality of cooling medium pipelines, cooling media with different cooling speeds are respectively arranged in the plurality of cooling medium pipelines, each cooling medium pipeline is provided with a flow control valve, and each cooling cavity is also provided with an outlet control valve;
The plurality of thermocouples are arranged on the wall of the crystallizer body, and a reference thermocouple corresponding to each cooling cavity is arranged on the wall of the crystallizer body corresponding to each cooling cavity;
A control device which is respectively connected with each thermocouple, each flow control valve and the outlet control valve;
In the casting process, the control device adjusts the type and/or flow of the cooling medium in each cooling cavity according to the position changes of the magnesium alloy liquid level, the magnesium alloy solidification starting point and the magnesium alloy liquid core end point; the control device also performs closed-loop control on the actual temperature distribution of the crystallizer body by controlling the flow of the cooling medium according to the preset temperature distribution of the crystallizer body and the real-time temperature measured by the reference thermocouple, so that the actual temperature distribution is infinitely close to the preset temperature distribution.
In the present invention, the magnesium alloy solidification start point refers to a position at which the magnesium alloy melt starts to appear as a solid phase, and the magnesium alloy liquid core end point refers to a position at which the magnesium alloy melt is completely solidified into a solid phase.
In the process of casting the magnesium alloy, the problem that the liquid level and the temperature of the magnesium alloy melt entering a crystallizer fluctuate to a certain degree due to the limitation of process conditions. Therefore, in the technical scheme of the invention, reasonable magnesium alloy casting process conditions are formulated through tests and numerical simulation according to the components of the magnesium alloy, and in the casting process, because the temperature distribution below the liquid level of the molten magnesium alloy is a main factor influencing the continuous casting process of the magnesium alloy, the temperatures and the ranges of the slow cooling zone and the crystallization zone are sequentially determined from top to bottom from the liquid level, and for the alloy with the cold cracking tendency, the temperature and the range of the chilling zone can be determined in addition to the temperatures and the ranges of the slow cooling zone and the crystallization zone. Subsequently, the level of the magnesium alloy melt in the mold is measured in real time by a level meter, such as an ultrasonic level meter, to determine and transmit position information of the liquid level to the control device in real time. When the liquid level fluctuates greatly, the control program of the control device automatically takes the new liquid level as a reference, and then takes the determined casting process as a target parameter to redistribute the temperatures and the ranges of the slow cooling zone, the crystallization zone and the chilling zone from top to bottom. By this means, the relative position of the cooling zones is maintained stable. Finally, the crystallizer for magnesium alloy continuous casting is divided into a slow cooling zone, a crystallization zone and a chilling zone according to the position changes of the magnesium alloy liquid level, the magnesium alloy solidification starting point and the magnesium alloy liquid core end point, and the types and the flow rates of cooling media in the zones are adjusted in real time, so that the temperature distribution of the inner wall of the crystallizer for magnesium alloy continuous casting from top to bottom is consistent with the process requirement, and dynamic stability is kept; thereby stabilizing the cooling condition of the magnesium alloy in the solidification process and achieving the purpose of improving the process stability.
In addition, the crystallizer for magnesium alloy continuous casting is provided with a thermocouple in the crystallizer body for collecting the temperature of the crystallizer body at the corresponding specific position, and the crystallizer body can be composed of copper plates. In each zone, target values for the thermocouples in each zone are set according to process requirements. Transmitting the temperature signal acquired by the thermocouple to a control device, and controlling the type and flow of a cooling medium through the control device when the temperature of the thermocouple is higher than a set temperature, so as to increase the cooling strength and reduce the temperature of the area at the position; when the temperature of the thermocouple is lower than the set temperature, the type and the flow of the cooling medium are controlled by the control device, the cooling intensity is reduced, and the temperature of the area at the position is increased. By this method, the temperature of each zone is maintained and controlled to be dynamically stable.
further, in the mold for continuous casting of a magnesium alloy according to the present invention, the control device includes a plc.
Further, in the crystallizer for continuous casting of magnesium alloy according to the present invention, the plurality of cooling medium pipelines includes at least a first cooling medium pipeline and a second cooling medium pipeline. Different cooling media are arranged in the first cooling medium pipeline and the second cooling medium pipeline, so that the cooling intensity can be adjusted more conveniently.
Further, in the mold for continuous casting of magnesium alloy according to the present invention, at least two thermocouples are provided on the wall of the mold body corresponding to each cooling chamber, and one of the at least two thermocouples is provided as the reference thermocouple.
Further, in the crystallizer for continuous casting of magnesium alloy according to the present invention, the cooling medium is at least selected from the group consisting of air, water, heat transfer oil, and dissolved salts.
Accordingly, another object of the present invention is to provide a method for controlled cooling using the above-described mold for continuous casting of magnesium alloys, comprising the steps of:
Before casting, determining the preset temperature distribution of a crystallizer body according to the components of the magnesium alloy;
In the casting process, determining a slow cooling zone, a crystallization zone and a chilling zone according to the positions of the liquid level of the magnesium alloy, the solidification starting point of the magnesium alloy and the end point of the liquid core of the magnesium alloy;
The control device adjusts the type and/or flow of the cooling medium in the cooling cavity corresponding to the slow cooling zone, the crystallization zone and the chilling zone according to the distribution of the slow cooling zone, the crystallization zone and the chilling zone, and performs closed-loop control on the actual temperature distribution of the crystallizer body by controlling the flow of the cooling medium according to the preset temperature distribution of the crystallizer body and the real-time temperature measured by the reference thermocouple, so that the actual temperature distribution is infinitely close to the preset temperature distribution.
Furthermore, in the method, the first thermocouple below the liquid level of the magnesium alloy is used as a reference thermocouple in the corresponding cooling cavity, and other reference thermocouples are arranged at equal intervals with the reference thermocouple.
In the method of the present invention, the equal span does not mean that the reference thermocouple is the same as another reference thermocouple at the same distance, but means that the number of thermocouples spaced apart from the reference thermocouple is the same, for example, if the span is set to five thermocouples apart, the first thermocouple below the magnesium alloy liquid level is set as the reference thermocouple, the sixth thermocouple below the magnesium alloy liquid level, which is five thermocouples spaced apart from the first thermocouple, is also set as the reference thermocouple, the eleventh thermocouple, which is five thermocouples spaced apart from the sixth thermocouple, is also set as the reference thermocouple, and the rest of the reference thermocouples are analogized in this order.
The method for cooling the crystallizer for continuous casting of magnesium alloy with adjustable cooling strength can be used for real-time adjustment according to the casting state, the type and the flow of the cooling medium are adjusted in real time through the control device according to the change of the liquid level parameter of the magnesium alloy melt, so that the temperature distribution of the inner wall of the crystallizer from top to bottom in the casting process of the magnesium alloy from the liquid level keeps dynamic consistency with the designed solidification condition, the casting process is stabilized, and the ingot casting quality is stabilized; when the alloy components change and the casting process changes, the temperature distribution of the metal inner wall of the crystallizer can be customized by adjusting the type and the flow of the cooling medium so as to adapt to the new casting process, so that the crystallizer for magnesium alloy continuous casting has wide application and wide application prospect.
Drawings
Fig. 1 is a schematic structural view of a mold for continuous casting of magnesium alloy according to the present invention.
FIG. 2 is a view showing the structure of a mold for continuous casting of magnesium alloy with the surface of the molten magnesium alloy in a certain cooling chamber.
FIG. 3 is a view showing the structure of a mold for continuous casting of magnesium alloy with the surface of the molten magnesium alloy in another cooling chamber.
FIG. 4 is a view showing the structure of a mold for continuous casting of magnesium alloy with the surface of the molten magnesium alloy in a further cooling chamber.
Detailed Description
The crystallizer for continuous casting of magnesium alloy with adjustable cooling intensity and the method for using the same according to the present invention will be further explained and illustrated with reference to the drawings and the specific embodiments of the present specification, however, the explanation and the illustration do not unduly limit the technical solution of the present invention.
Fig. 1 is a schematic structural view of a mold for continuous casting of magnesium alloy according to the present invention.
As shown in figure 1, the crystallizer for continuous casting of magnesium alloy with adjustable cooling strength comprises a crystallizer body 4 and cooling cavities 5 arranged on the periphery of the crystallizer body 4, wherein in order to schematically show the cooling control of the cooling cavities on magnesium alloy melt, and to better explain the working principle of the crystallizer for continuous casting of magnesium alloy, the cooling cavities 5 are divided into cooling cavities A, B, C, D according to the position of the crystallizer body, E, the cooling cavities A, B, C, D, E are sequentially arranged in the height direction of the crystallizer body 4 to cover a slow cooling zone, a crystallization zone and a chilling zone of the crystallizer body 4, wherein the area where the magnesium alloy melt is located and the area above the liquid level are slow cooling zones, the area where the magnesium alloy solidification starting point is located is a crystallization zone, the area where the magnesium alloy liquid core end point is located and the area below the magnesium alloy liquid core end point are chilling zones, the cooling cavities are respectively connected with cooling medium pipelines, the cooling medium pipelines are respectively communicated with different cooling media, the cooling medium is water and air, flow control valves 8 are arranged on the cooling pipelines, cooling cavities are also provided with cooling medium outlet valves 6, and thermocouple outlets of the cooling cavities are respectively connected with thermocouple bodies, and thermocouple outlets of the crystallizer, and thermocouple control valves are respectively arranged on the cooling cavities and the thermocouple bodies corresponding thermocouples, and the thermocouple outlets of the cooling cavities of the corresponding thermocouples respectively.
It should be noted that, in order to better explain the working principle of the crystallizer for continuous casting of magnesium alloy according to the present invention, the positions of the reference thermocouples a, b, c, d, e, f, g, h, i, j are schematically shown, but the number of thermocouples is not limited to the indicated number, for example, there may be unlabeled thermocouples between the reference thermocouples a and b, and the reference thermocouples may be arranged at equal intervals.
In the present embodiment, P1 denotes an inlet where the cooling medium is water, P2 denotes an inlet where the cooling medium is air, and P3 denotes an outlet where the cooling medium is discharged. In other embodiments, the cooling medium may also be selected from one of air, water, thermal oil, and dissolved salts.
FIG. 2 is a view showing the structure of a mold for continuous casting of magnesium alloy with the surface of a molten magnesium alloy melt in a certain cooling chamber; FIG. 3 is a view showing the structure of a mold for continuous casting of magnesium alloy with the surface of the molten magnesium alloy in another cooling chamber; FIG. 4 is a view showing the structure of a mold for continuous casting of magnesium alloy with the surface of the molten magnesium alloy in a further cooling chamber.
The working principle of the crystallizer for continuous casting of magnesium alloy according to the present invention is further explained with reference to fig. 1 to 4:
when the crystallizer for continuous casting of the magnesium alloy is in work, the liquid level meter 1 is used for measuring the liquid level of a magnesium alloy melt 3 in a crystallizer body 4 in real time, the magnesium alloy melt is monitored through the liquid level meter, the position of the liquid level is determined and transmitted to P L C in real time, when the liquid level fluctuates greatly, a PL C control program serving as a control device automatically takes the new liquid level as a reference, and takes the determined casting process as a target, and the ranges of a slow cooling zone, a crystallization zone and a chilling zone are redistributed from top to bottom.
The crystallizer for magnesium alloy continuous casting is provided with a thermocouple in a crystallizer body for acquiring the temperature of the crystallizer body at the corresponding specific position, and the crystallizer body can be composed of copper plates. In each zone, target values for the thermocouples in each zone are set according to process requirements. Transmitting the temperature signal acquired by the thermocouple to a control device, and controlling the type and flow of a cooling medium through the control device when the temperature of the thermocouple is higher than a set temperature, so as to increase the cooling strength and reduce the temperature of the area at the position; when the temperature of the thermocouple is lower than the set temperature, the type and the flow of the cooling medium are controlled by the control device, the cooling intensity is reduced, and the temperature of the area at the position is increased. By this method, the temperature of each control area is maintained to be dynamically stable.
specifically, when the liquid level of the magnesium alloy melt is at the position shown in FIG. 1, namely the liquid level is between reference thermocouples C and d, a flow control valve 8 and a cooling medium outlet control valve 6 (wherein the flow control valve and the cooling medium outlet control valve control pipelines of two media, including a water cooling medium pipeline and an air cooling medium pipeline) corresponding to each cooling cavity are opened, air with smaller flow is introduced into the cooling cavities A and B, thermal resistance is increased, and a slow cooling area is formed in the area of the cooling cavities A and B;
according to the process requirement set by P L C, the cooling cavity C takes a reference thermocouple f as a reference point, when the temperature of the f point received by P L C is lower than a set value, a flow control valve and a cooling medium outlet control valve of the cooling cavity C are automatically adjusted, the flow of the cooling water in the cooling cavity C is reduced until the temperature of the f point is raised to the set temperature, when the temperature of the f point received by P L C is higher than the set value, the flow control valve and the cooling medium outlet control valve of the cooling cavity C are automatically adjusted, and the flow of the cooling water in the cooling cavity C is increased until the temperature of the f point is lowered to the set temperature;
the method comprises the steps of filling cooling water into cooling cavities D and E to enable the cooling cavities D and E to be chilling zones, filling the cooling water into the cooling cavities D and E to enable the cooling cavities D and E to be cooling zones, enabling the flow of the filling cooling water to form closed-loop control with thermocouples g or h and i or j, enabling the cooling cavities D to use a reference thermocouple h as a reference point according to the process requirement set by the P L C, automatically adjusting a flow control valve and a cooling medium outlet control valve of the cooling cavities D when the P L C receives that the temperature of the point h is lower than a set value, reducing the flow of the cooling water in the cooling cavities D until the temperature of the point h is reduced to the set temperature, enabling the cooling cavities E to use a reference thermocouple j as the reference point, automatically adjusting a flow control valve and a cooling medium outlet control valve of the cooling cavities E when the P L C receives that the temperature of the point j is lower than the set value, reducing the flow of the cooling water in the cooling cavities E until the temperature of the point j is increased to the set temperature, automatically adjusting the flow control valve and the cooling medium outlet control valve of the cooling cavities E to reduce the flow of the cooling water after the casting process of the magnesium alloy ingot is completely, and the magnesium alloy is formed, and the magnesium alloy ingot casting process nozzle is completely.
when the liquid level in the crystallizer body 4 changes and rises, and is positioned between the reference thermocouples a or B, namely in the state shown in figure 2, the cooling cavity A is filled with air with smaller flow, the thermal resistance is increased, and the area of the cooling cavity A forms a slow cooling area;
according to the process requirement set by the point P L C, the cooling cavity B takes the reference thermocouple d as a reference point, when the temperature of the point d received by the point P L C is lower than a set value, a flow control valve and a cooling medium outlet control valve of the cooling cavity B are automatically adjusted, the flow of the cooling water in the cooling cavity B is reduced until the temperature of the point d is raised to the set temperature, when the temperature of the point D received by the point P L C is higher than the set value, the flow control valve and the cooling medium outlet control valve of the cooling cavity B are automatically adjusted, and the flow of the cooling water in the cooling cavity B is increased until the temperature of the point d is lowered to the set temperature;
the method comprises the steps of introducing cooling water into cooling cavities C, D and E to enable the regions of the cooling cavities C, D and E to be chilling zones, introducing the flow of the cooling water and reference thermocouples E and f, or g and h, or i and j to form closed-loop control, taking the reference thermocouples f, h and j as reference points for the cooling cavities C, D and E according to the set process requirements of the PLC, automatically adjusting flow control valves and cooling medium outlet control valves of the cooling cavities C, D and E when the temperature of the f, h and j points received by the PLC is lower than a set value, reducing the flow of the cooling water in the cooling cavities C, D and E until the temperature of the f, h and j points rises to the set temperature, automatically adjusting flow control valves and cooling medium outlet control valves of the cooling cavities C, D and E when the temperature of the f, h and j points received by the PLC is higher than the set value, increasing the flow of the cooling water in the cooling cavities C, D and E until the temperature of the f, h and j points is reduced to the set temperature, completely solidifying the magnesium alloy melt in the regions to form ingots after 7 ingots are formed, and further reducing the flow of the water nozzles of the magnesium alloys.
When the liquid level in the crystallizer is changed again and is reduced and is positioned between the reference thermocouples d and e, namely in the state shown in fig. 3, air with a small flow rate is introduced into the cooling cavities A, B and C, the thermal resistance is increased, and a slow cooling zone is formed in the areas of the cooling cavities A, B and C;
the cooling medium pipeline of the cooling cavity C needs to be switched to an air cooling medium pipeline from a water cooling medium pipeline, for the cooling medium inlet, the PLC controls a corresponding inlet to control a flow control valve, closes a cooling water valve and opens a cooling air valve, for the cooling medium outlet, the PLC controls a cooling medium outlet control valve and simultaneously opens two outlets of a cooling medium outlet valve, after cooling water is drained, one outlet is closed, and the other outlet is kept open.
according to the process requirement set by the PLC, the cooling cavities A, B and C respectively use the reference thermocouples a, C and e as reference points, when the external PLC receives that the temperatures of the points a, C and e are lower than the set values, the flow control valves of the cooling cavities A, B and C and the cooling medium outlet control valves are automatically adjusted, the flow of the air in the cooling cavities A, B and C is reduced until the temperatures of the points a, C and e are increased to the set temperatures, when the external PLC receives that the temperatures of the points a, C and e are higher than the set values, the flow control valves of the cooling cavities A, B and C and the cooling medium outlet control valves are automatically adjusted, the flow of the air in the cooling cavity A is increased until the temperatures of the points a, C and e are reduced to the set temperatures;
according to the process requirement set by the point P L C, the cooling cavity D takes the reference thermocouple g as a reference point, when the temperature of the point D received by the point P C is lower than a set value, a flow control valve and a cooling medium outlet control valve of the cooling cavity D are automatically adjusted, the flow of the cooling water in the cooling cavity D is reduced until the temperature of the point g is raised to the set temperature, when the temperature of the point P L C received by the point P C is higher than the set value, the flow control valve and the cooling medium outlet control valve of the cooling cavity D are automatically adjusted, and the flow of the cooling water in the cooling cavity D is increased until the temperature of the point g is lowered to the set temperature;
the method comprises the steps of filling cooling water into a cooling cavity E to enable the area of the cooling cavity E to be a chilling area, enabling the flow of the filled cooling water and a reference thermocouple i or j to form closed-loop control, enabling the cooling cavity E to take the reference thermocouple i as a reference point according to the process requirement set by the P L C, automatically adjusting a flow control valve and a cooling medium outlet control valve of the cooling cavity E when the P L C receives that the temperature of the point i is lower than a set value, reducing the flow of the cooling water in the cooling cavity E until the temperature of the point i is raised to a set temperature, automatically adjusting the flow control valve and the cooling medium outlet control valve of the cooling cavity E when the P L C receives that the temperature of the point i is higher than the set value, increasing the flow of the cooling water in the cooling cavity E until the temperature of the point i is lowered to the set temperature, enabling a magnesium alloy melt to be completely solidified in the area to form a magnesium alloy cast ingot 7, then cooling and moving out, adjusting the flow of a.
when the liquid level in the crystallizer is changed again, and the liquid level is reduced to be between reference thermocouples e and f, namely in the state shown in fig. 4, air with smaller flow is introduced into cooling cavities A, B and C, so that the thermal resistance is increased, and the areas of the cooling cavities A, B and C form slow cooling areas;
according to the process requirement set by the point P L C, the cooling cavity D takes the reference thermocouple h as a reference point, when the temperature of the point D received by the point P C is lower than a set value, a flow control valve and a cooling medium outlet control valve of the cooling cavity D are automatically adjusted, the flow of the cooling water in the cooling cavity D is reduced until the temperature of the point h is raised to the set temperature, when the temperature of the point P L C received by the point P C is higher than the set value, the flow control valve and the cooling medium outlet control valve of the cooling cavity D are automatically adjusted, and the flow of the cooling water in the cooling cavity D is increased until the temperature of the point h is lowered to the set temperature;
according to the set process requirement of the PL, the cooling cavity E takes the reference thermocouple j as a reference point, when the temperature of the point j received by the PL is lower than a set value, a control valve of the cooling cavity E is automatically adjusted to reduce the flow of the cooling water in the cooling cavity E until the temperature of the point j is raised to a set temperature, when the temperature of the point j received by the PL is higher than the set value, the control valve of the cooling cavity E is automatically adjusted to increase the flow of the cooling water in the cooling cavity E until the temperature of the point j is lowered to the set temperature, magnesium alloy melt is completely solidified in the region to form a magnesium alloy ingot 7, the magnesium alloy ingot is cooled and moved out, and according to the process requirement, the flow of a cooling water nozzle 9 is adjusted to further reduce the temperature of the formed ingot, so that the casting is completed.
therefore, the method for cooling the crystallizer for magnesium alloy continuous casting with adjustable cooling intensity can be used for real-time adjustment according to the casting state, the top-down temperature distribution of the inner wall of the crystallizer for magnesium alloy continuous casting from the liquid level is kept in dynamic consistency with the designed solidification condition by using the PL C as the control device to adjust the type and the flow rate of the cooling medium in real time when the crystallizer body changes according to the liquid level parameters, the casting process is stabilized, the ingot quality is stabilized, and the temperature distribution of the metal inner wall of the crystallizer can be customized by adjusting the type and the flow rate of the cooling medium when the alloy components change and the casting process changes, so that the crystallizer for magnesium alloy continuous casting is widely applied and has wide application prospect.
It should be noted that the above-mentioned embodiments are only specific examples of the present invention, and obviously, the present invention is not limited to the above-mentioned embodiments, and many similar variations exist. All modifications which would occur to one skilled in the art and which are, therefore, directly derived or suggested from the disclosure herein are deemed to be within the scope of the present invention.
Claims (7)
1. A mold for continuous casting of magnesium alloy with adjustable cooling strength, comprising:
A crystallizer body;
The cooling cavities are arranged on the periphery of the crystallizer body and are sequentially arranged in the height direction of the crystallizer body so as to cover a slow cooling zone, a crystallization zone and a chilling zone of the crystallizer body, wherein the area where the liquid level of the magnesium alloy is located and the area above the liquid level are the slow cooling zone, the area where the solidification starting point of the magnesium alloy is located is the crystallization zone, and the area where the liquid core end point of the magnesium alloy is located and the area below the solidification starting point of the magnesium alloy are the chilling zone; each cooling cavity is respectively connected with a plurality of cooling medium pipelines, cooling media with different cooling speeds are respectively arranged in the plurality of cooling medium pipelines, each cooling medium pipeline is provided with a flow control valve, and each cooling cavity is also provided with an outlet control valve; wherein the magnesium alloy solidification starting point refers to the position where the magnesium alloy melt begins to appear as a solid phase, and the magnesium alloy liquid core end point refers to the position where the magnesium alloy melt is completely solidified into the solid phase;
The plurality of thermocouples are arranged on the wall of the crystallizer body, and a reference thermocouple corresponding to each cooling cavity is arranged on the wall of the crystallizer body corresponding to each cooling cavity;
A control device which is respectively connected with each thermocouple, each flow control valve and the outlet control valve;
In the casting process, the control device adjusts the type and/or flow of the cooling medium in each cooling cavity according to the position changes of the magnesium alloy liquid level, the magnesium alloy solidification starting point and the magnesium alloy liquid core end point; the control device also performs closed-loop control on the actual temperature distribution of the crystallizer body by controlling the flow of the cooling medium according to the preset temperature distribution of the crystallizer body and the real-time temperature measured by the reference thermocouple, so that the actual temperature distribution is infinitely close to the preset temperature distribution.
2. the mold for continuous casting of magnesium alloy according to claim 1, wherein said control means comprises P L C.
3. The crystallizer defined in claim 1, wherein said plurality of coolant lines includes at least a first coolant line and a second coolant line.
4. The mold for continuous casting of magnesium alloy according to claim 1, wherein each cooling chamber has at least two thermocouples formed on a wall of the mold body, and one of the at least two thermocouples is provided as the reference thermocouple.
5. The crystallizer for magnesium alloy continuous casting according to claim 1, wherein the cooling medium is air, water, heat transfer oil or dissolved salt.
6. A method for performing controlled cooling using the mold for continuous casting of magnesium alloy according to any one of claims 1 to 5, comprising the steps of:
Before casting, determining the preset temperature distribution of a crystallizer body according to the components of the magnesium alloy;
In the casting process, determining a slow cooling zone, a crystallization zone and a chilling zone according to the positions of the liquid level of the magnesium alloy, the solidification starting point of the magnesium alloy and the end point of the liquid core of the magnesium alloy;
The control device adjusts the type and/or flow of the cooling medium in the cooling cavity corresponding to the slow cooling zone, the crystallization zone and the chilling zone according to the distribution of the slow cooling zone, the crystallization zone and the chilling zone, and performs closed-loop control on the actual temperature distribution of the crystallizer body by controlling the flow of the cooling medium according to the preset temperature distribution of the crystallizer body and the real-time temperature measured by the reference thermocouple, so that the actual temperature distribution is infinitely close to the preset temperature distribution.
7. The method as claimed in claim 6, wherein the first thermocouple below the liquid level of the magnesium alloy is used as a reference thermocouple in the corresponding cooling chamber, and other reference thermocouples are arranged at equal intervals with the reference thermocouple; wherein the equal span arrangement means that the number of thermocouples spaced between the reference thermocouple and the other reference thermocouple is the same.
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| CN109807311A (en) * | 2019-03-05 | 2019-05-28 | 溧阳市新力机械铸造有限公司 | A kind of cooling heat radiator and casting solidification method improving casting solidification efficiency |
| CN110202102A (en) * | 2019-06-10 | 2019-09-06 | 常州市武进长虹结晶器有限公司 | The method and its crystallizer of slab crystal growth in a kind of promotion crystallizer |
| CN110802208B (en) * | 2019-11-13 | 2021-06-08 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Method for adjusting water yield of continuous casting production in high-latitude area |
| CN111304468A (en) * | 2020-03-16 | 2020-06-19 | 广西大学 | Preparation device and production method of high-purity gallium |
| CN112536425B (en) * | 2020-12-03 | 2022-04-22 | 中南大学 | Molten steel solidification and casting blank simulation device for continuous casting funnel-shaped crystallizer and use method of molten steel solidification and casting blank simulation device |
| CN113145818B (en) * | 2021-01-26 | 2023-01-17 | 燕山大学 | Smelting manufacturing production process and device for prolonging service life of crystallizer |
| CN113426969B (en) * | 2021-06-16 | 2022-05-24 | 武汉科技大学 | Oil cooling method and oil cooling device for continuous casting mould |
| CN114262805B (en) * | 2021-12-27 | 2023-02-28 | 西安交通大学 | Smelting-free compact metal magnesium ingot preparation device and method |
| CN114406214A (en) * | 2022-01-18 | 2022-04-29 | 江西理工大学 | Sectional type horizontal continuous casting crystallizer |
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| DE69518359T2 (en) * | 1994-06-06 | 2000-12-21 | Danieli Off Mecc | Method for controlling the deformation of the side walls of a mold and continuous casting mold |
| JP2013076129A (en) * | 2011-09-30 | 2013-04-25 | Hitachi Cable Ltd | Sputtering target and method for production thereof |
| CN105642852A (en) * | 2016-01-26 | 2016-06-08 | 东北大学 | Air-cooled semi-continuous casting system and method of high-activity alloy |
| CN106180603A (en) * | 2016-08-30 | 2016-12-07 | 中国重型机械研究院股份公司 | Magnesium alloy slab casting crystallizer |
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