CN112170506A - Temperature compensation method and device for magnesium or magnesium alloy plate strip conveying roller way - Google Patents
Temperature compensation method and device for magnesium or magnesium alloy plate strip conveying roller way Download PDFInfo
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- CN112170506A CN112170506A CN202011095009.7A CN202011095009A CN112170506A CN 112170506 A CN112170506 A CN 112170506A CN 202011095009 A CN202011095009 A CN 202011095009A CN 112170506 A CN112170506 A CN 112170506A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
- B21B38/006—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring temperature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B39/00—Arrangements for moving, supporting, or positioning work, or controlling its movement, combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B39/02—Feeding or supporting work; Braking or tensioning arrangements, e.g. threading arrangements
Abstract
The invention provides a temperature compensation method and a temperature compensation device for a magnesium or magnesium alloy plate strip conveying roller way. The invention aims to solve the problem of temperature difference between the upper surface and the lower surface of a magnesium or magnesium alloy plate strip caused by different contact media in the conveying process, and finally improve the plastic processing capacity of the magnesium alloy plate strip. The method adopts an electric heating conveying roller, is provided with a temperature testing device and a temperature control and feedback system, ensures that the contact environment temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip is the same in the conveying process by adjusting the temperature of the conveying roller, and controls the temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip within 5 ℃ in the conveying process of a conveying roller way. The method of the invention ensures that the heat dissipation of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip is consistent in the conveying process, thereby achieving the purpose of uniform temperature along the thickness direction. Excellent microstructure and mechanical properties are obtained after rolling. The large-scale application of the magnesium or magnesium alloy plate strip in the market can be greatly expanded.
Description
Technical Field
The invention relates to the technical field of magnesium or magnesium alloy plate strip processing, in particular to a temperature supplementing method and device for a magnesium or magnesium alloy plate strip conveying roller way.
Background
The magnesium alloy is used as the lightest metal structure material, has higher specific strength and specific rigidity, is the most potential lightweight material in the lightweight field, and is widely applied to a plurality of fields such as automobiles, electronics, national defense, aerospace and the like. At present, most magnesium alloy products are mainly die castings. However, due to the characteristics of the casting process, the cast magnesium alloy often shows the problems of coarse grains, serious structural defects, unsatisfactory comprehensive mechanical properties and the like, which greatly limits the large-scale application of magnesium alloy products in the market. Different from cast magnesium alloy, the structure of the deformed magnesium alloy can be reasonably regulated and controlled through plastic processing and heat treatment, so that the deformed magnesium alloy has good mechanical properties. However, the close-packed hexagonal crystal structure of the magnesium alloy ensures that only basal plane slippage is easy to start at room temperature, and the plastic processing capability is poor, so that the application of the wrought magnesium alloy is not developed in a large scale.
The rising of the deformation temperature has a remarkable positive effect on the starting of the non-basal-plane slippage of the magnesium alloy, so that the magnesium alloy can coordinate the external deformation by depending on various slippage systems like the aluminum alloy, the plastic processing capability is greatly improved, and the method is one of the most effective means for improving the plastic processing capability of the magnesium alloy at present. However, the characteristics of low specific heat capacity and quick heat dissipation of the magnesium alloy lead the temperature to be greatly and quickly reduced in the plastic deformation process, the deformation temperature is difficult to control, and the shape stability of a plastic processing product is poor, so the temperature control in the plastic deformation process of the magnesium alloy is very important. More importantly, the temperature range suitable for magnesium alloy deformation is narrow, the microstructure and the mechanical property of the magnesium alloy can be influenced by small temperature change, and even the temperature difference in the same magnesium alloy deformation material can cause the instability of the shape and the mechanical property of the magnesium alloy deformation material. The instability of the shape and the mechanical property greatly limits the large-scale application of the deformed magnesium alloy plate strip in the market.
Therefore, how to control the temperature of the magnesium or magnesium alloy sheet strip in the plastic working is a hot spot of research in the field. At present, related patents have been reported in the field for temperature control methods and devices in the process of preparing wrought magnesium alloys, but all focus on adjusting the system temperature and controlling the rolling temperature of magnesium alloy plates and strips. For example, chinese patent ZL201410407171.6, "a temperature control system for warm rolling of magnesium and magnesium alloy plates and strips", realizes temperature control and heat preservation by preheating and heating magnesium and magnesium alloy plates and strips before rolling, online temperature control of rollers, online temperature compensation of coils, environmental heat preservation and heat insulation, and preheating of a whole set of temperature control equipment, but this technology only increases the environmental temperature of the whole system, and the heat-insulation protective cover involved in this technology leads to increased maintenance cost and inconvenient maintenance, and the design of the auxiliary tool adopted is complicated, the cost is higher, the occupied space is large, and the problems such as interference with rolling mill equipment are easily caused. The method for online temperature compensation, constant temperature rolling and coiling of the deformed magnesium alloy plate strip in the Chinese patent ZL201510640182.3 is used for heat preservation in the rolling process of the magnesium or magnesium strip by arranging a plurality of stages in the rolling process, and comprises preheating by a chain type ingot casting heating furnace, preheating by a natural gas or electromagnetic induction heating preheating roller and preheating by a roller bottom heating furnace. Although the technology can heat and supplement heat on line, continuously, safely and effectively, and improve the production efficiency and the product quality, the heat preservation measures related to the technology are difficult to control the temperature accurately, the deformation temperature fluctuation is large, the equipped tools are various, the cost is high, the occupied space is large, the interference with host equipment is easy, and the like.
Compared with the prior art, the improvement measures are obviously different from the prior art by focusing on how to adjust the system temperature, control the rolling temperature of the magnesium alloy plate strip and the like, the inventor finds that the heat loss of the magnesium alloy on a conveying roller way is the most serious and the temperature of the magnesium alloy is the most difficult to control in the preparation process of the deformed magnesium alloy in the long-term experiment process, particularly the upper surface and the lower surface of the magnesium alloy plate strip have different heat dissipation capacities due to different contact media in the conveying process, and finally the temperature difference between the upper surface and the lower surface is larger. The temperature difference causes different plastic deformation behaviors to be generated when the upper surface and the lower surface of the plate enter a deformation zone, different plastic flows are shown, residual stress is easily formed inside the deformed plate, the deformed plate strip is seriously warped, and simultaneously the microscopic structures on the upper surface and the lower surface form a gradient microscopic structure due to the temperature difference, so that the mechanical property of the plate is unstable. Therefore, the key point for improving the plastic processing capacity of the magnesium alloy strip is to solve the problem of temperature difference between the upper surface and the lower surface of the magnesium alloy strip caused by different contact media.
However, no relevant research report aiming at solving the temperature equalization problem in the conveying process of the magnesium alloy plate strip, particularly the temperature difference between the upper surface and the lower surface of the plate strip caused by the contact of different media, exists in the field. The above patents and other published patents and papers do not relate to the solution of the temperature equalization problem during the transportation of magnesium alloy sheet and strip, especially the problem of large temperature difference between the upper and lower surfaces of the sheet and strip due to the contact with different media.
Disclosure of Invention
The object of the present invention is to find a simple and effective way to solve the above mentioned technical problems in the current technical background. Namely, the problem of temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip caused by different contact media in the conveying process is solved, and the plastic processing capacity of the magnesium or magnesium alloy plate strip is finally improved.
Therefore, the inventor obtains the temperature compensation method and device for the conveying roller way of the magnesium or magnesium alloy plate strip through research and experiments. The invention aims to control the temperature of the upper surface and the lower surface of a magnesium or magnesium alloy plate strip on a conveying roller way, and the temperature of the conveying roller is adjusted by adopting an electric heating conveying roller and being provided with a temperature control and feedback system such as a temperature testing device, a temperature analysis module, a temperature control module and the like, so that the temperature of the contact environment of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process is the same, and the problem of large temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying roller way due to different contact media of the upper surface and the lower surface.
Based on the above, in one aspect of the application, a method for supplementing temperature of a magnesium or magnesium alloy plate strip conveying roller way is provided. In the method, in the conveying process of the magnesium or magnesium alloy plate strip, an electric heating conveying roller is adopted, a temperature testing device and a temperature control and feedback system are arranged, the temperature of the conveying roller is adjusted, so that the contact environment temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process is the same, and the temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process of a conveying roller way is controlled within 5 ℃.
The method comprises the following specific steps:
(1) a conveying roller way temperature compensating device consisting of an electric heating system of a conveying roller, a temperature testing device, a temperature analysis module and an intelligent control system of a temperature control module is built; the intelligent control system can realize closed-loop feedback of temperature test, temperature analysis and temperature control;
(2) placing a magnesium or magnesium alloy plate strip to be processed on a conveying roller way; starting the conveying roller way and starting the temperature compensating device;
(3) the intelligent control system starts a temperature testing device to test the initial temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip to be processed, and continuously tests the temperature of the upper surface and the lower surface of the plate strip in real time in the conveying process;
(4) calculating the temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip by a temperature analysis module in an intelligent control system, comparing the temperature difference with a preset tolerance temperature, and outputting a control instruction; the temperature control module controls the working state of the electric heating system of the conveying roller;
if the temperature difference value of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip exceeds the set tolerance temperature, starting an electric heating system of the conveying roller; if the temperature is less than or equal to the set tolerance temperature, the power supply is cut off, and the electric heating system of the conveying roller stops working.
The technological process of the temperature supplementing method for the magnesium or magnesium alloy plate and strip conveying roller way is shown in figure 1. The method can control the temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip within 5 ℃ in the conveying process of the conveying roller way.
In another aspect of the present invention, a temperature compensation device for a magnesium or magnesium alloy plate strip material conveying roller bed is provided, which comprises an electric heating system for conveying rollers and an intelligent control system (fig. 2); the conveying roller electric heating system comprises a conveying roller 2 arranged on the conveying roller way frame 1 and an electric heating element 5 positioned in the conveying roller; the conveying roller 2 is a hollow roller, and a rotating shaft 4 with a hole is arranged in the roller; the electric heating element 5 is nested in the rotating shaft 4 with the hole, and the electric heating element and the rotating shaft are connected with the conveying roller 2 through the bearing 3 to form an electric heating conveying roller (figure 3); the electric heating conveying rollers are arranged on the conveying roller way frame 1 side by side.
The intelligent control system comprises a temperature testing device and a control terminal; the temperature testing device comprises a plurality of infrared sensors 6 which are respectively arranged above and below the conveying roller way frame 1; the infrared sensors 6 are positioned 200-400 mm above and below the conveying rollers, and the infrared sensors 6 are connected with the control terminal 10; the control terminal 10 comprises an LED display screen 7, a built-in temperature analysis module 8 and a temperature control module 9. The control terminal 10 controls the switching of the conveyor roller heating system. Forming a closed loop feedback system of temperature test, temperature analysis and temperature control.
When the temperature compensating device for the magnesium or magnesium alloy plate strip conveying roller way works, when a magnesium or magnesium alloy plate strip 11 to be processed is conveyed by the conveying rollers, the plurality of infrared sensors 6 above and below the conveying rollers 2 respectively continuously test the temperatures of the upper surface and the lower surface of the plate strip to be processed in real time, data are input into the control terminal 10, the temperature analysis module 8 of the control terminal 10 calculates the temperature difference value of the upper surface and the lower surface, compares the temperature difference value with the preset tolerance temperature, and outputs a control instruction to the temperature control module 9; the temperature control module 9 receives a control instruction, turns on/off a power supply, and controls the working state of the electric heating system of the conveying roller, namely, the temperature of the conveying roller is adjusted, and finally the temperature of the upper surface and the lower surface of the magnesium alloy plate strip in the conveying process is controlled. The operator can observe and judge in real time through the LED display screen 7 to make correction and proofreading.
The temperature compensation method and the temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller bed can be used for magnesium or magnesium alloy plate strip rolling, extrusion, forging and other plastic deformation processes. The invention is not only suitable for magnesium or magnesium alloy plates and strips, but also suitable for rolling, extruding, forging and other plastic deformation processes of aluminum or aluminum alloy, titanium alloy and other metal materials.
The present invention is of great significance since, until now, the person skilled in the art has hardly paid attention to the influence of the temperature changes of the upper and lower surfaces of the magnesium or magnesium alloy sheet strip during the transport on the flow behaviour of the sheet strip during rolling. However, the inventor of the invention finds that if the temperature of the magnesium or magnesium alloy plate strip is regulated and controlled only in the rolling process, the improvement of the microstructure and the mechanical property of the end product cannot achieve satisfactory results. However, if the temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip is controlled from the conveying process, especially from a long distance, better microstructure and better mechanical property can be obtained after the magnesium or magnesium alloy plate strip enters the roller for rolling. The principle is that in the process of conveying magnesium or magnesium alloy plates and strips, the upper surfaces and the lower surfaces of the plates and strips are always contacted with different media in a conveying roller way, for example, the upper surfaces are air, and the lower surfaces are steel conveying rollers. This easily causes different temperature drop ranges of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip, so that the plate strip has different plastic deformation behaviors on the upper surface and the lower surface due to different temperatures of the upper surface and the lower surface when entering the deformation zone, and the residual stress is easily formed in the plate, which is not favorable for obtaining the magnesium or magnesium alloy plate strip with excellent formability.
The temperature of media contacted with the upper surface and the lower surface of the plate strip can be adjusted by simply modifying the existing common conveying roller in the field and adding an electric heating device and a temperature control system, so that the heat dissipation of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip is consistent in the conveying process, and the aim of uniform temperature in the thickness direction is fulfilled. Excellent microstructure and mechanical properties are obtained after rolling. Thereby greatly expanding the large-scale application of the magnesium or magnesium alloy plate strip in the market and having great application and popularization prospects.
In summary, the invention has the following beneficial effects:
(1) novel originality, design benefit. The invention starts from a magnesium or magnesium alloy plate strip conveying roller way originally, and controls the temperature of the upper surface and the temperature of the lower surface of a magnesium or magnesium alloy plate strip in the conveying process by arranging a temperature compensating device on the conveying roller way, so that the heat dissipation of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process is consistent, and the aim of uniform temperature in the thickness direction is fulfilled. Finally, the performance of the rolled plate is improved. The unexpected good effect is achieved.
(2) The device is simple, easy to operate and control. Through add simple control by temperature change frock on current conventional rollgang, need not carry out extensive transformation to current equipment, and the device occupation space is little, does not have the interference with host computer equipment, and the operation is maintained easily, and the cost is extremely low.
(3) The operation is automatic and intelligent. The temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller is provided with a temperature control and feedback system, has the characteristic of closed-loop feedback, and can perform self-adaptive judgment according to the external environment so as to ensure that the temperature difference of the upper surface and the lower surface of a plate strip in different external environments is controlled within a small range.
(4) High practicability and wide application. The invention is suitable for temperature compensation of all conveying roller ways in the field, and is particularly suitable for solving the problem of overlarge temperature difference between the upper surface and the lower surface of a plate strip caused by different heat dissipation in the long-distance conveying process. The invention is not only used for magnesium or magnesium alloy plate and strip materials, but also can be used for other various metal materials such as aluminum, titanium and the like, and various plastic deformation processes such as rolling, extruding, forging and the like, and has strong transportability.
Drawings
FIG. 1 is a flow chart of the temperature compensation method for the magnesium or magnesium alloy plate and strip rollgang of the invention.
FIG. 2 is a schematic view of the temperature compensating device for the magnesium or magnesium alloy plate and strip conveying roller way.
FIG. 3 is a schematic view of the conveying roller structure of the temperature compensating device for the magnesium or magnesium alloy plate and strip conveying roller bed.
In the figure: the device comprises a conveying roller way frame, 2 conveying rollers, 3 bearings, 4 rotating shafts with holes, 5 heating elements, 6 infrared sensors, 7 LED display screens, 8 temperature analysis modules, 9 temperature control modules, 10 control terminals and 11 magnesium plate strips.
Fig. 4 to 6 are a temperature change contrast diagram, a microstructure change contrast diagram after deformation, and a mechanical property change contrast diagram of the upper and lower surfaces of the AZ31 magnesium alloy plate when the rollgang temperature compensation device of the present invention is opened and closed in comparative experimental example.
Fig. 7 to 10 are a temperature change contrast diagram, a microstructure change contrast diagram after deformation, a mechanical property change contrast diagram, and a shape change contrast diagram of the upper surface and the lower surface of a ZK60 magnesium alloy plate respectively when the rollgang temperature compensation device of the present invention is opened and closed in a comparative experimental example two.
Fig. 11 to 14 are a temperature change contrast diagram, a microstructure change contrast diagram after deformation, a mechanical property change contrast diagram, and a shape change contrast diagram of the upper and lower surfaces of an Mg-Nd-Zn-Zr magnesium alloy plate respectively when the conveying roller way temperature compensation device of the third comparative experimental example is opened and closed.
Detailed Description
The present invention is further illustrated by the following examples, which are set forth to illustrate several specific forms of the invention, but are not to be construed as limiting the scope of the invention. It should be noted that the following examples and experimental examples include temperature compensation devices or temperature compensation tools related to the drawings, which are all temperature compensation devices for magnesium or magnesium alloy plate and strip conveying roller ways.
As shown in fig. 2 and 3, the device comprises a conveying roller electric heating system and an intelligent control system; the conveying roller electric heating system comprises a conveying roller 2 arranged on the conveying roller way frame 1 and an electric heating element 5 positioned in the conveying roller; the conveying roller 2 is a hollow roller, and a rotating shaft 4 with a hole is arranged in the roller; the electric heating element 5 is nested in the rotating shaft 4 with the hole, and the electric heating element and the rotating shaft are connected with the conveying roller 2 through the bearing 3 to form an electric heating conveying roller (figure 3); the electric heating conveying rollers are arranged on the conveying roller way frame 1 side by side.
The intelligent control system comprises a temperature testing device, a temperature analysis module and a temperature control module; the temperature testing device comprises a plurality of infrared sensors 6 which are respectively arranged at 200-400 mm positions above and below the conveying roller way frame 1; the infrared sensor 6 is connected with the control terminal 10; the control terminal 10 comprises an LED display screen 7, a built-in temperature analysis module 8 and a temperature control module 9. The control terminal 10 controls the switching of the conveyor roller heating system. Forming a closed loop feedback system of temperature test, temperature analysis and temperature control.
The temperature compensation working flow of the temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller way is shown in fig. 1, when a magnesium or magnesium alloy plate strip 11 to be processed is conveyed by the conveying roller, a plurality of infrared sensors 6 above and below the conveying roller 2 respectively continuously test the temperature of the upper surface and the temperature of the lower surface of the plate strip to be processed, and data are input into a control terminal 10; a temperature analysis module 8 in the control terminal 10 calculates the temperature difference of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip, compares the temperature difference with a preset tolerance temperature and outputs a control instruction to a temperature control module 9; the temperature control module 9 receives a control instruction, turns on/off a power supply, and controls the working state of the electric heating system of the conveying roller, namely, the temperature of the conveying roller is adjusted, and finally the temperature of the upper surface and the lower surface of the magnesium alloy plate strip in the conveying process is controlled. The operator can observe and judge in real time through the LED display screen 7 to make correction and proofreading.
Example 2 temperature compensation method for magnesium or magnesium alloy plate strip conveying roller way
The work flow is shown in fig. 1, and the specific method comprises the following steps:
(1) adopting a temperature compensating device of a magnesium or magnesium alloy plate strip conveying roller way in the embodiment 1;
(2) placing a magnesium or magnesium alloy plate strip to be processed on a conveying roller way; starting the conveying roller way and starting the temperature compensating device;
(3) the temperature control system tests the initial temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip to be processed in real time, and continuously tests the temperature of the upper surface and the lower surface of the plate in the conveying process;
(4) calculating the temperature difference between the upper surface and the lower surface of the plate and strip material by a temperature analysis module in the temperature control system, comparing the temperature difference with a preset tolerance temperature, and outputting a control instruction; the temperature control module controls the working state of the electric heating system of the conveying roller; if the temperature exceeds the set tolerance temperature, starting the heating element to work; if the temperature is less than or equal to the set tolerance temperature, the power supply is cut off, and the heating element stops working.
Comparative experiment example I,
Taking an AZ31 plate as an example, the method and the device are used for carrying out online temperature compensation on a plate to be processed by using the method and the device and carrying out online temperature compensation without using the device, and the influence of temperature change of the upper surface and the lower surface in the plate conveying process and the microscopic structure observation and mechanical property test on the deformed AZ31 plate are respectively carried out.
1) starting the conveying roller way and opening the temperature compensating device;
2) placing a 30mm thick AZ31 plate in a roller conveyor for conveying, and measuring the temperature of an initial AZ31 plate to be 300 ℃;
3) respectively testing the temperatures of the upper surface and the lower surface of the AZ31 plate when the plate just enters the conveying roller way by using the infrared sensors;
4) continuously testing the temperature of the upper surface and the lower surface of the AZ31 board by using an infrared sensor during the conveying process;
5) the AZ31 sheet was fed into the mill to produce a thickness reduction deformation.
The temperature profile of the upper and lower surfaces of AZ31 panels during test 1 is shown in fig. 4 a.
In a comparative test 1, the temperature compensating device for the magnesium or magnesium alloy plate strip conveying roller bed is not used, namely, a conventional method is adopted:
1) starting the conveying roller way without starting the temperature compensating device;
2) placing and conveying a 30mm thick AZ31 plate in a roller conveyor, wherein the temperature of an initial AZ31 plate is 300 ℃;
3) respectively testing the temperatures of the upper surface and the lower surface of the AZ31 plate when the plate just enters the conveying roller way by using the infrared sensors;
4) continuously testing the temperature of the upper surface and the lower surface of the AZ31 board by using an infrared sensor during the conveying process;
5) the AZ31 sheet was fed into the mill to produce a thickness reduction deformation.
The temperature profiles of the upper and lower surfaces of the AZ31 boards during the above comparative test 1 are shown in fig. 4 b.
As can be seen from the comparative analysis of fig. 4a and 4b, when the temperature compensation tool on the roller conveyor is opened, the temperature difference between the upper surface and the lower surface of the AZ31 plate is small and within 3 ℃, and when the temperature compensation tool on the roller conveyor is closed, the temperature difference between the upper surface and the lower surface of the AZ31 plate is large and can reach 13 ℃ at most. The deformed AZ31 plate was then subjected to microstructure observation and mechanical property test as shown in fig. 5 and 6, respectively. As can be seen from FIG. 5, when the temperature compensation tool is opened, the microscopic structures of the upper surface and the lower surface after plastic deformation are mainly fine isometric recrystallized structures, and the structural difference is small; when the temperature compensation tool is closed, the difference of microstructures of the upper surface and the lower surface after plastic deformation is large, wherein the upper surface is dynamically recrystallized to show a dynamic recrystallization structure of equiaxed grains, and the lower surface is not obviously dynamically recrystallized due to low temperature but generates a large amount of twin structures due to deformation coordination. Due to the difference of microstructures of the upper surface and the lower surface after plastic deformation, the mechanical properties of the upper surface and the lower surface also show larger difference: when the temperature compensation tool in the test 1 is opened, the mechanical properties of the upper surface and the lower surface are not greatly different, the yield strength is only different by 3.7MPa, and the elongation is only different by 1.6%; when the temperature compensation tool in the comparative test 1 is closed, the difference of the mechanical properties of the upper surface and the lower surface is large, the yield strength difference is 39.4MPa, and the elongation difference is 6.3 percent (figure 6). The analysis shows that when the temperature compensation tool is closed, the large temperature difference generated by the AZ31 plate in the conveying process can generate large difference of microstructures and mechanical properties on the upper surface and the lower surface of the AZ31 plate after plastic deformation, and the temperature difference between the upper surface and the lower surface of the plate strip in the conveying process is effectively reduced by the temperature compensation tool, so that the difference between the microstructures and the mechanical properties of the plate strip after deformation is small.
Comparative experiment example two,
Taking ZK60 plate as an example, the method and the device of the invention are used for carrying out online temperature compensation on the plate to be processed and the method and the device of the invention are not used for carrying out online temperature compensation, and the influence of temperature change of the upper surface and the lower surface in the plate conveying process and the microstructure observation and the mechanical property test of the deformed ZK60 plate are respectively carried out.
1) starting the conveying roller way and opening the temperature compensating device;
2) placing a ZK60 plate with the thickness of 10mm in a roller conveyor for conveying, wherein the temperature of the initial ZK60 plate is 350 ℃;
3) the infrared sensors respectively test the temperatures of the upper surface and the lower surface of the ZK60 plate when the plate just enters the conveying roller way;
4) continuously testing the temperatures of the upper surface and the lower surface of the ZK60 plate by using an infrared sensor in the conveying process;
5) entering a rolling mill to generate thickness reduction deformation. The temperature profile of the upper and lower surfaces of the ZK60 sheet during the above process is shown in fig. 7 a.
In contrast test 2, the temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller bed is not used, namely, the conventional method is adopted:
1) opening the conveying roller way and closing the temperature compensating device;
2) placing a ZK60 plate with the thickness of 10mm in a roller conveyor for conveying, wherein the temperature of the initial ZK60 plate is 350 ℃;
3) the infrared sensors respectively test the temperatures of the upper surface and the lower surface of the ZK60 plate when the plate just enters the conveying roller way;
4) continuously testing the temperatures of the upper surface and the lower surface of the ZK60 plate by using an infrared sensor in the conveying process;
5) entering a rolling mill to generate thickness reduction deformation. The temperature profile of the upper and lower surfaces of the ZK60 sheet during the above process is shown in fig. 7 b.
As can be seen from fig. 7, when the temperature compensation tool on the roller conveyor is opened, the temperature difference between the upper surface and the lower surface of the ZK60 plate strip is small and is within 3 ℃ (fig. 7a), and when the temperature compensation tool on the roller conveyor is closed, the temperature difference between the upper surface and the lower surface of the ZK60 plate strip can reach 12 ℃ (fig. 7 b). Due to the temperature difference between the upper and lower surfaces during the transportation process, the microstructure and mechanical properties of the upper and lower surfaces after plastic deformation show a large difference, as shown in fig. 8 and 9, respectively. As can be seen from fig. 8 and 9, when the temperature compensation tool in test 2 is opened, the microstructure of the upper and lower surfaces after plastic deformation is mainly a fine equiaxial dynamic recrystallization structure, and the structure difference and the mechanical property difference are small (fig. 8); in contrast experiment 2, when the temperature compensation tool is closed, the upper surface is dynamically recrystallized and has a dynamic recrystallization structure, while the lower surface is not obviously dynamically recrystallized due to lower temperature, so that an elongated grain morphology structure is shown, the mechanical property difference is large, and the yield strength difference is 15MPa (fig. 9). The temperature changes generated on the upper surface and the lower surface in the conveying process generate shape differences (figure 10) on the plastically deformed ZK60 plate strip, wherein when the temperature compensation tool in the test 2 is opened, the ZK60 plate strip is straight and has no warpage, while the ZK60 plate strip without the effect of the temperature compensation tool in the comparison test 2 has severe warpage, and the shape of the plate strip is very poor. Therefore, the temperature compensation tool on the conveying roller way not only has a great improvement effect on the microstructure and the mechanical property of the deformed plate, but also has a great improvement effect on the shape of the deformed plate.
Comparative experiment example III,
Taking Mg-Nd-Zn-Zr series plates as an example, the method and the device are used for carrying out online temperature compensation on the plates to be processed by using the method and the device and carrying out online temperature compensation without using the method, and the microstructure observation and the mechanical property test are respectively carried out on the upper surface and the lower surface temperature change in the plate conveying process and the deformed Mg-Nd-Zn-Zr series plates.
1) starting the conveying roller way and opening the temperature compensating device;
2) placing Mg-Nd-Zn-Zr series plates with the thickness of 30mm in a conveying roller way for conveying, wherein the temperature of the initial Mg-Nd-Zn-Zr series plates is 450 ℃;
3) respectively testing the temperatures of the upper surface and the lower surface of the Mg-Nd-Zn-Zr plate when the Mg-Nd-Zn-Zr plate just enters the conveying roller way by using an infrared sensor;
4) continuously testing the temperatures of the upper surface and the lower surface of the Mg-Nd-Zn-Zr plate by using an infrared sensor in the conveying process;
5) entering a rolling mill to generate thickness reduction deformation. The temperature change curves of the upper and lower surfaces of the Mg-Nd-Zn-Zr based sheet in the above process are shown in FIG. 11 a.
In contrast test 3, the temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller bed is not used, namely, the conventional method is adopted:
1) opening the conveying roller way and closing the temperature compensating device;
2) placing Mg-Nd-Zn-Zr series plates with the thickness of 30mm in a conveying roller way for conveying, wherein the temperature of the initial Mg-Nd-Zn-Zr series plates is 450 ℃;
3) respectively testing the temperatures of the upper surface and the lower surface of the Mg-Nd-Zn-Zr plate when the Mg-Nd-Zn-Zr plate just enters the conveying roller way by using an infrared sensor;
4) continuously testing the temperatures of the upper surface and the lower surface of the Mg-Nd-Zn-Zr plate by using an infrared sensor in the conveying process;
5) entering a rolling mill to generate thickness reduction deformation. The temperature change curves of the upper and lower surfaces of the Mg-Nd-Zn-Zr based sheet in the above process are shown in FIG. 11 b.
As can be seen from FIG. 11, the results are similar to the above, and when the temperature compensation fixture on the rollgang is opened, the temperature difference between the upper and lower surfaces of the Mg-Nd-Zn-Zr system sheet is small and within 5 ℃ (FIG. 11a), and when the temperature compensation fixture on the rollgang is closed, the temperature difference between the upper and lower surfaces thereof can reach 15 ℃ (FIG. 11 b). This temperature difference also has different effects on the microstructure and mechanical properties of the upper and lower surfaces after plastic deformation (fig. 12 and 13). But differs from comparative test example 1 and comparative test example 2: due to the existence of rare earth elements of the Mg-Nd-Zn-Zr series plate, complete dynamic recrystallization occurs on the upper surface and the lower surface of the plastically deformed plate, equiaxial dynamic recrystallization textures are formed, but the difference of the temperature of the upper surface and the lower surface brings about the difference of grain sizes. Specifically, in test 3, when the temperature compensation tool is opened, the difference between the sizes of the grains on the upper surface and the lower surface of the plate is small; when contrast test 3 closed the frock of mending temperature, the lower surface of panel dispels the heat very fast in transportation process, and the temperature drop is great, and the crystalline grain is difficult for growing up, and the crystalline grain size is comparatively tiny, and the upper surface is because the temperature is higher, is changeed and grows up, and the crystalline grain size is thick slightly (fig. 12). Therefore, the temperature compensation tool has a more obvious influence on the grain size of the microstructure of the plastically deformed plate. The change of mechanical properties is also brought by the grain size difference, wherein the lower surface of the plate without the effect of the temperature compensation tool in the comparative test 3 shows higher yield strength (186.9MPa) and is obviously higher than the upper surface (169.1MPa) due to smaller grain size; experiment 3 the difference of the mechanical properties of the upper and lower surfaces of the plate with the temperature compensation tooling effect is small because the difference of the sizes of crystal grains is small (figure 13). As in comparative example 2, the temperature difference between the upper and lower surfaces of the sheet during the conveying process also had a large influence on the sheet after the flow deformation (fig. 14). Experiment 3 when the temperature compensation tool was opened, the Mg-Nd-Zn-Zr based panel was straight and without warpage, while the Mg-Nd-Zn-Zr based panel without the effect of the temperature compensation tool suffered severe warpage.
It can be seen from the above comparative examples that when the temperature compensation device was opened, the temperature difference between the upper surface and the lower surface of the magnesium alloy sheet strip was small and was within 5 ℃, and when the temperature compensation device was closed, the temperature difference between the upper surface and the lower surface of the magnesium alloy sheet strip was 15 ℃. Meanwhile, magnesium or magnesium alloy has the characteristic of narrow plastic deformation temperature window, so that obviously different plastic deformation behaviors can be generated under the influence of smaller temperature difference, and the shape and the performance of the magnesium plate strip are seriously influenced. Therefore, in order to prepare the magnesium or magnesium alloy plate strip with excellent formability, the temperature compensation device is added in the conveying roller way, so that the problem of large temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip caused by different contact media of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process is solved, and the method is very necessary.
Claims (10)
1. A temperature compensation method for a magnesium or magnesium alloy plate strip conveying roller way is characterized by comprising the following steps: the method is characterized in that an electric heating conveying roller is adopted, a temperature testing device and a temperature control and feedback system are arranged, the temperature of the conveying roller is adjusted, so that the contact environment temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process is the same, and the temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip in the conveying process of a conveying roller way is controlled within 5 ℃.
2. The method for supplementing the temperature of the magnesium or magnesium alloy plate strip conveying roller way according to claim 1, which is characterized by comprising the following steps:
(1) a conveying roller way temperature compensating device consisting of an electric heating system of a conveying roller, a temperature testing device, a temperature analysis module and an intelligent control system of a temperature control module is built; the intelligent control system can realize a closed-loop feedback system of temperature test, temperature analysis and temperature control;
(2) placing a magnesium or magnesium alloy plate strip to be processed on a conveying roller way; starting the conveying roller way and starting the temperature compensating device;
(3) the intelligent control system starts a temperature testing device to test the initial temperature of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip to be processed, and continuously tests the temperature of the upper surface and the lower surface of the plate in real time in the conveying process;
(4) calculating the temperature difference between the upper surface and the lower surface of the magnesium or magnesium alloy plate strip by a temperature analysis module in an intelligent control system, comparing the temperature difference with a preset tolerance temperature, and outputting a control instruction; and then the temperature control module controls the working state of the electric heating system of the conveying roller.
3. The method for supplementing the temperature of the magnesium or magnesium alloy plate strip by the roller way as claimed in claim 2, which is characterized in that: if the temperature difference value of the upper surface and the lower surface of the magnesium or magnesium alloy plate strip exceeds the set tolerance temperature, starting an electric heating system of the conveying roller; if the temperature is less than or equal to the set tolerance temperature, the power supply is cut off, and the electric heating system of the conveying roller stops working.
4. The method for supplementing the temperature of the magnesium or magnesium alloy plate strip by the roller way as claimed in claim 2, which is characterized in that: the conveying roller way temperature compensation device in the step (1) comprises a conveying roller electric heating system and an intelligent control system; the conveying roller electric heating system comprises conveying rollers (2) arranged on a conveying roller way frame (1) and electric heating elements (5) positioned in the conveying rollers; the conveying roller (2) is a hollow roller, and a rotating shaft (4) with a hole is arranged in the roller; the electric heating element (5) is nested in the rotating shaft (4) with the hole, and the electric heating element and the rotating shaft are connected with the conveying roller (2) through the bearing (3) to form an electric heating conveying roller; the electric heating conveying rollers are arranged on the conveying roller way frame (1) side by side;
the intelligent control system comprises a temperature testing device and a control terminal; a temperature analysis module and a temperature control module are arranged in the control terminal; the temperature testing device comprises a plurality of infrared sensors (6) which are respectively arranged above and below the conveying roller way frame (1); the infrared sensor (6) is connected with the control terminal (10); the control terminal (10) comprises an LED display screen (7), a built-in temperature analysis module (8) and a temperature control module (9).
5. The method for supplementing the temperature of the magnesium or magnesium alloy plate strip by the roller way as claimed in claim 4, which is characterized in that: the intelligent control system is a closed-loop feedback system of temperature test, temperature analysis and temperature control.
6. A magnesium or magnesium alloy plate strip rollgang temperature supplementing device is characterized in that: the device comprises a conveying roller electric heating system and an intelligent control system; the conveying roller electric heating system comprises conveying rollers (2) arranged on a conveying roller way frame (1) and electric heating elements (5) positioned in the conveying rollers; the conveying roller (2) is a hollow roller, and a rotating shaft (4) with a hole is arranged in the roller; the electric heating element (5) is nested in the rotating shaft (4) with the hole, and the electric heating element and the rotating shaft are connected with the conveying roller (2) through the bearing (3) to form an electric heating conveying roller; the electric heating conveying rollers are arranged on the conveying roller way frame (1) side by side;
the intelligent control system comprises a temperature testing device and a control terminal; a temperature analysis module and a temperature control module are arranged in the control terminal; the temperature testing device comprises a plurality of infrared sensors (6) which are respectively arranged above and below the conveying roller way frame (1); the infrared sensor (6) is connected with the control terminal (10); the control terminal (10) comprises an LED display screen (7), a built-in temperature analysis module (8) and a temperature control module (9).
7. The magnesium or magnesium alloy plate strip conveying roller bed temperature supplementing device according to claim 6, wherein the control terminal (10) controls the switch of the electric heating system of the conveying roller.
8. The temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller way as claimed in claim 6, wherein the infrared sensors (6) are positioned 200-400 mm above and below the conveying roller.
9. The use of the temperature compensation device for the magnesium or magnesium alloy plate strip conveying roller way of claim 6 in the rolling, extrusion, forging and other plastic deformation processes of magnesium or magnesium alloy plate strips.
10. The use of the temperature compensation device for the magnesium or magnesium alloy plate and strip conveying roller way of claim 6 in the rolling, extrusion, forging and other plastic deformation processes of aluminum or aluminum alloy, titanium alloy and other metal materials.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115338282A (en) * | 2022-10-17 | 2022-11-15 | 南通长石科技有限公司 | Magnesium alloy forging product stamping forming system and stamping forming method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115338282A (en) * | 2022-10-17 | 2022-11-15 | 南通长石科技有限公司 | Magnesium alloy forging product stamping forming system and stamping forming method |
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