Method and device for preventing edge cracking of magnesium alloy sheet rolling by induction heating

Abstract

The present application relates to a kind of induction heat supplementing method and its device for preventing magnesium alloy plate rolling from producing edge crack, comprising the following steps, step 1: according to numerical control console control rectangular coil position;Step 2: obtain the power required for induction heat supplementing magnesium alloy plate;Step 3: start power supply, complete the induction heat supplementing and rolling of magnesium alloy plate.The present application controls rectangular induction coil position and power according to the detected heat supplementing parameters, can realize the accurate control of magnesium alloy plate temperature;The device proposed in the present application realizes the cross-over superposition structure of induction coil by controlling the movement of ram in the width direction and thickness direction of magnesium alloy plate, can heat supplement magnesium alloy plate of different width and thickness;The present application effectively solves the situation that magnesium alloy plate appears crack due to low temperature at edge during rolling by induction heat supplementing, improves yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of induction heating slab, in particular to an induction heating method for preventing edge cracks of magnesium alloy plate rolling and a device thereof. BACKGROUND

[0002] Magnesium alloy is known as a green engineering material with development prospects due to its small density and high specific strength. However, the edge temperature of magnesium alloy plate drops a lot during the conveying process of heating to rolling and the multi-pass rolling process. When the edge temperature is low, the magnesium alloy plate prepared in the traditional hot rolling process will have serious edge cracking, resulting in low rolling yield of magnesium alloy plate. Therefore, it is necessary to develop a processing technology to prevent edge cracking during magnesium alloy plate rolling.

[0003] Currently, the traditional rolling process of magnesium alloy mainly relies on improving the rolling temperature to improve the processability of magnesium alloy plate to control the edge cracks of magnesium alloy plate. However, during long-time conveying or multi-pass rolling, the edge cracking problem of magnesium alloy plate is still serious due to the large temperature drop. Therefore, the electromagnetic induction heating method is selected to generate eddy current to generate Joule heat as a heat source to heat the edge of the magnesium alloy plate. During rolling, the edge crack can be inhibited, and the edge crack area and crack depth can be greatly reduced, thereby improving the yield. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application calculates the induction heating power according to the heating parameters by formula, realizes the accurate control of the temperature of the magnesium alloy plate, and controls the magnesium alloy plate of different widths and thicknesses by the cross-over structure of the induction coil. The present application effectively controls the edge cracking problem of the magnesium alloy plate, solves the crack problem of the magnesium alloy plate due to low edge temperature during rolling, and greatly improves the yield.

[0005] To achieve the above purpose, the solution adopted by the present application is as follows:

[0006] An induction heating method for preventing edge cracks of magnesium alloy plate rolling, comprising the following steps:

[0007] Step 1: adjusting the position of the rectangular coil according to the numerical control operation table;

[0008] Adjusting the relative position of the rectangular induction coil and the magnesium alloy plate according to the numerical control operation table, wherein the rectangular induction coil comprises a first rectangular induction coil and a second rectangular induction coil;

[0009] The numerical control console controls the first ram device to adjust the distance between the first rectangular induction coil, the second rectangular induction coil and the magnesium alloy plate according to the thickness of the magnesium alloy plate; controls the second ram device to adjust the distance from the left end of the second rectangular induction heating coil to the right end of the first induction heating coil according to the width of the magnesium alloy plate, so that the left and right edges of the magnesium alloy plate are aligned with the inner sides of the left side of the first rectangular induction coil and the right side of the second rectangular induction coil respectively; the length of the rectangular induction coil is not less than the length of the magnesium alloy plate.

[0010] Step 2: Obtain the power required for the induction heat compensation of the magnesium alloy plate;

[0011] The induction heat compensation power is matched with the physical properties, size variables and the vertical distance between the coil and the magnesium alloy plate of the magnesium alloy plate, including the thermal conductivity coefficient, resistivity, length, width and thickness of the magnesium alloy plate; the obtaining method is as follows:

[0012]

[0013] In the formula, P represents the power of the rectangular induction coil, unit W; λ represents the thermal conductivity coefficient, unit W / (m·℃); h represents the vertical distance between the rectangular induction coil and the magnesium alloy plate, unit m; ρ1 represents the resistivity of the rectangular coil, unit Ω·m, ρ2 represents the resistivity of the magnesium alloy plate, unit Ω·m; B represents the width of the magnesium alloy plate, unit m; L represents the length of the magnesium alloy plate, unit m; H represents the thickness of the magnesium alloy plate, unit m; the edge temperature T of the magnesium alloy plate during induction heat compensation, unit ℃; T0 represents the conventional heating temperature of the aluminum alloy plate, unit ℃; k represents the heating coefficient, the value range is 0.4-0.9;

[0014] Step 3: Start the power supply to complete the induction heat compensation and rolling of the magnesium alloy plate;

[0015] When the temperature difference between the edge temperature of the magnesium alloy plate during induction heat compensation and the conventional heating temperature value of the magnesium alloy plate satisfies T0-T≥30℃, the induction heating device stops heating and the magnesium alloy plate is rolled.

[0016] Preferably, the distance h between the rectangular induction coil and the magnesium alloy plate in step 2 is specifically:

[0017] The heat compensation effect of the rectangular induction coil on the magnesium alloy plate depends on: when the inner diameter of the induction coil is fixed, the vertical distance between the induction coil and the magnesium alloy plate satisfies H / 2<h<H.

[0018] The second aspect of the present application proposes an induction heating device using the aforementioned induction heating method for preventing edge cracks of magnesium alloy plates during rolling, characterized in that the induction heating device comprises a first rectangular induction coil, a second rectangular induction coil, a first rectangular induction coil cover, a second rectangular induction coil cover, a numerical control operating table, a support column, a first ram, a second ram, a cooling device, a cooling liquid pipe, an infrared temperature measuring instrument, a base, a first ball screw, a second ball screw, a first coupling, a second coupling, a first servo motor, a second servo motor, and a magnesium alloy plate.

[0019] Preferably, the first rectangular induction coil is wrapped by the first rectangular induction coil cover; the second rectangular induction coil is wrapped by the second rectangular induction coil cover; and the infrared temperature measuring instrument is arranged at the edge of the first ram below the first rectangular induction coil cover.

[0020] Preferably, the numerical control operating table controls the rotation of the first servo motor and the second servo motor, the first servo motor and the second servo motor are connected to the first ball screw and the second ball screw through the first coupling and the second coupling respectively, and the first servo motor and the second servo motor are fixedly connected through the support column and the base; the first ball screw and the second ball screw can drive the first ram on the support column to move in the longitudinal sliding groove and the second ram on the base to move in the transverse sliding groove; and the first rectangular induction coil and the second rectangular induction coil are connected to the rams, so that the rectangular induction coils can move when the servo motors rotate.

[0021] Preferably, the cooling liquid device circulates the cooling liquid into the first rectangular induction coil and the second rectangular induction coil through the cooling liquid pipe to avoid malfunction of the first rectangular induction coil and the second rectangular induction coil due to high temperature.

[0022] Preferably, the base is fixedly arranged with the numerical control operating table, the second servo motor, the second ball screw, the second ram, the second rectangular induction coil, and the second rectangular induction coil cover; and the cooling device is fixedly installed on the left side of the base, and the upper end of the cooling device is connected to the cooling outer ports of the outer ends of the two induction coils.

[0023] Compared with the prior art, the present application has the following advantages:

[0024] (1) The present application effectively controls the edge crack problem of magnesium alloy plates through induction heating, solves the crack problem of magnesium alloy plates due to low edge temperature during rolling, and greatly improves the yield;

[0025] (2) The device proposed by the present application realizes the cross-overlapping structure of the induction coils by controlling the movement of the rams in the width direction and the thickness direction of the magnesium alloy plate, and can realize the heating of magnesium alloy plates with different widths and thicknesses. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The control block diagram of the induction heat compensation method for preventing edge cracks of magnesium alloy plate rolling in the embodiment of the present application;

[0027] Figure 2 The flow chart of the induction heat compensation device for preventing edge cracks of magnesium alloy plate rolling in the embodiment of the present application;

[0028] Figure 3 The structural schematic diagram of the induction heat compensation device in the embodiment of the present application;

[0029] Figure 4 The left view of the induction heat compensation device in the embodiment of the present application;

[0030] Figure 5 The axial side view of the induction heat compensation device in the embodiment of the present application;

[0031] Figure 6 The experimental result diagram of the magnesium alloy plate after traditional rolling in the embodiment of the present application;

[0032] Figure 7 The experimental result diagram of the magnesium alloy plate after induction heat compensation rolling in the embodiment of the present application.

[0033] Main reference signs:

[0034] 1, second servo motor; 2, second ram; 3, second rectangular induction coil cover; 4, numerical control operating platform; 5, cooling device; 6, first rectangular induction coil cover; 7, first ram; 8, first servo motor; 9, support column; 10, first rectangular induction coil; 11, second rectangular induction coil; 12, magnesium alloy plate; 13, first coupling; 14, first ball screw; 15, infrared temperature measuring instrument; 16, cooling liquid pipe; 17, second coupling; 18, second ball screw; 19, base; F-rectangular coil and magnesium alloy plate front end. DETAILED DESCRIPTION

[0035] Hereinafter, the embodiments of the present application will be described with reference to the accompanying drawings.

[0036] The embodiment of the present application can prevent the edge crack problem of magnesium alloy plate rolling, and the induction heat compensation power is calculated according to the heat compensation parameters through a formula, so that the temperature rise of the magnesium alloy plate can be effectively controlled. The device proposed in the embodiment of the present application can realize the cross-overlapping structure of the induction coil by controlling the movement of the ram in the width direction and the thickness direction of the magnesium alloy plate, so that the heat compensation of the magnesium alloy plate with different width and thickness can be realized, and the adaptability and flexibility of the device are stronger. It can be proved by comparing the traditional rolling and the rolling after induction heating that the case solves the crack problem of the magnesium alloy plate due to low edge temperature during rolling, and greatly improves the yield rate. Figure 1The control block diagram of the induction heat compensation method for preventing edge cracks of magnesium alloy plate rolling is shown.

[0037] The induction heat compensation method for preventing edge cracks of magnesium alloy plate rolling is provided. Figure 2 The flow chart of the induction heat compensation method is shown. In order to illustrate the applicability of the present application, it is applied to an example, which specifically includes the following steps:

[0038] S1: The position of the rectangular coil is controlled according to the numerical control console.

[0039] The relative position of the rectangular induction coil and the magnesium alloy plate is controlled according to the numerical control console, wherein the rectangular induction coil includes a first rectangular induction coil and a second rectangular induction coil.

[0040] The numerical control console controls the first ram device to adjust the distance between the first and second rectangular induction coils and the magnesium alloy plate according to the thickness of the magnesium alloy plate, and controls the second ram device to adjust the distance between the left end of the second rectangular induction coil and the right end of the first induction coil according to the width of the magnesium alloy plate, so that the left and right edges of the magnesium alloy plate are aligned with the inner sides of the left side of the first rectangular induction coil and the right side of the second rectangular induction coil, respectively. The length of the rectangular induction coil is not less than the length of the magnesium alloy plate.

[0041] S2: Obtain the power required for induction heat compensation of the magnesium alloy plate.

[0042] The induction heat compensation power is matched with the physical properties, size variables and the vertical distance between the coil and the magnesium alloy plate of the magnesium alloy plate, including the thermal conductivity coefficient, resistivity, length, width and thickness of the magnesium alloy plate. The obtaining method is as follows:

[0043]

[0044] In the formula, P represents the power of the rectangular induction coil, unit W; λ represents the thermal conductivity coefficient, unit W / (m·℃); h represents the vertical distance between the rectangular induction coil and the magnesium alloy plate, unit m; ρ1 represents the resistivity of the rectangular coil, unit Ω·m, ρ2 represents the resistivity of the magnesium alloy plate, unit Ω·m, B represents the width of the magnesium alloy plate, unit m; L represents the length of the magnesium alloy plate, unit m; H represents the thickness of the magnesium alloy plate, unit m; T represents the edge temperature of the magnesium alloy plate during induction heat compensation, unit ℃; T0 represents the conventional heating temperature of the aluminum alloy plate, unit ℃; k is the heating coefficient, the value range is 0.4-0.9. In one preferred embodiment, the conventional heating temperature of the magnesium alloy plate is 200℃.

[0045] The distance h between the rectangular induction coil and the magnesium alloy plate depends on the heat compensation effect of the rectangular induction coil on the magnesium alloy plate: when the inner diameter of the induction coil is fixed, the vertical distance between the induction coil and the magnesium alloy plate satisfies H / 2

[0046] S3: start power supply, complete induction heat compensation and rolling of the magnesium alloy plate;

[0047] When the temperature difference between the edge temperature of the magnesium alloy plate after induction heat compensation and the conventional heating temperature value of the magnesium alloy plate satisfies T0-T≥30℃, the induction heating device stops heating and the magnesium alloy plate is rolled.

[0048] The second aspect of the present application provides an induction heat compensation device for preventing edge cracks during magnesium alloy rolling, which can complete the induction heat compensation of the edge of the magnesium alloy plate. Figure 3 As shown in the structural schematic diagram of the embodiment of the present application, the induction heat compensation device comprises a first rectangular induction coil 10, a second rectangular induction coil 11, a first rectangular induction coil cover 6, a second rectangular induction coil cover 3, a numerical control operation table 4, a support column 9, a first ram 7, a second ram 2, a cooling device 5, a cooling liquid pipe 16, an infrared temperature measuring instrument 15, a base 19, a first ball screw 14, a second ball screw 18, a first coupling 13, a second coupling 17, a first servo motor 8, a second servo motor 1 and a magnesium alloy plate 12, wherein the letter F represents the position direction of the rectangular coil and the front end of the magnesium alloy plate.

[0049] The first rectangular induction coil 10 is wrapped by the first rectangular induction coil cover 6; the second rectangular induction coil 11 is wrapped by the second rectangular induction coil cover 3; the edge of the first ram 7 below the first rectangular induction coil cover 6 is provided with the infrared temperature measuring instrument 15; the length of the first rectangular induction coil 10 and the second rectangular induction coil 11 is not less than the length of the magnesium alloy plate 12.

[0050] The first servo motor 8 and the second servo motor 1 rotate, the first servo motor 8 and the second servo motor 1 are connected with the first ball screw 14 and the second ball screw 18 through the first coupling 13 and the second coupling 17 respectively, and the first servo motor 8 and the second servo motor 1 are fixedly connected through the support column 9 and the base 19; the first ball screw 14 and the second ball screw 18 can drive the first ram 7 on the support column 9 to move in the longitudinal sliding groove and the second ram 2 on the base 19 to move in the transverse sliding groove; the first rectangular induction coil 10 and the second rectangular induction coil 11 are connected with the first ram 7 and the second ram 2 respectively, so that the rectangular induction coil can be moved when the servo motor rotates.

[0051] The cooling device 5 circulates the cooling liquid into the inside of the first rectangular induction coil 10 and the second rectangular induction coil 11 through the cooling liquid pipe 16 to avoid faults caused by high temperature of the first rectangular induction coil 10 and the second rectangular induction coil 11.

[0052] The base 19 is fixedly arranged with the numerical control operation table 4, the second servo motor 1, the second ball screw 18, the second ram 2, the second rectangular induction coil 11 and the second rectangular induction coil outer cover 3; the cooling device 5 is fixedly installed on the left side of the base 19, and the upper end of the cooling device 5 is connected with the two induction coil outer end cooling outer ports.

[0053] As Figure 4 shown is the left view of the induction heat supplementing device of the embodiment of the application; as Figure 5 shown is the axial view of the induction heat supplementing device of the embodiment of the application; the left view and the axial view are used to further show the structure of the device and the relationship between the components.

[0054] Finally, the case compares the traditional rolling mode and the rolling process after induction heating, as Figure 6 shown is the experimental result graph of the magnesium alloy plate after traditional rolling of the embodiment of the application; as Figure 7 shown is the experimental result graph of the magnesium alloy plate after induction heat supplementing rolling of the embodiment of the application. Figure 6 It can be seen that there are obvious defects after rolling, Figure 7 the defects in the magnesium alloy plate after traditional rolling have disappeared.

[0055] In summary, the application and the prediction results of the automatic induction heat supplementing method and device for the edge of the magnesium alloy plate can prove that the scheme of the application has good effects.

[0056] (1) The embodiment of the application effectively controls the magnesium alloy plate edge cracking problem through induction heat supplementing, and through the comparison between the traditional rolling and the rolling mode after induction heating in the drawings, it can be proved that the case solves the situation that the magnesium alloy plate cracks due to low edge temperature during rolling, and can greatly improve the yield.

[0057] (2) The device proposed in the embodiment of the application realizes the cross-overlapping structure of the induction coil by controlling the movement of the ram in the width direction and the thickness direction of the magnesium alloy plate, and can realize heat supplementing for magnesium alloy plates of different widths and thicknesses, and the adaptability and flexibility of the device are stronger.

[0058] The above-described embodiments are only used to describe the preferred embodiments of the application, and do not limit the scope of the application, and various modifications and improvements to the technical solutions of the application made by those skilled in the art without departing from the design spirit of the application shall fall within the protection scope of the claims of the application.

Claims

1. A method for induction heating to prevent edge cracking during the rolling of magnesium alloy plates, characterized in that, It includes the following steps: Step 1: Adjust the position of the rectangular coil according to the CNC operating panel; The relative position of the rectangular induction coil and the magnesium alloy plate is adjusted according to the CNC operating table, wherein the rectangular induction coil includes a first rectangular induction coil and a second rectangular induction coil. The CNC operating table controls the first sliding device to adjust the distance between the first rectangular induction coil, the second rectangular induction coil and the magnesium alloy plate according to the thickness of the magnesium alloy plate; according to the width of the magnesium alloy plate, it controls the second sliding device to adjust the distance from the left end of the second rectangular induction heating coil to the right end of the first induction heating coil, so that the left and right sides of the magnesium alloy plate are respectively aligned with the inner sides of the left side of the first rectangular induction coil and the right side of the second rectangular induction coil; the length of the rectangular induction coil is not less than the length of the magnesium alloy plate, and the cross-stacked structure of the induction coil is achieved by controlling the sliding device to move in the width and thickness directions of the magnesium alloy plate; Step 2: Obtain the power required for the induction heating magnesium alloy plate; The induction heating power is matched with the physical properties and dimensional variables of the magnesium alloy plate, as well as the vertical distance between the coil and the magnesium alloy plate; specifically, this includes the thermal conductivity, resistivity, and length, width, and thickness dimensions of the magnesium alloy plate; the method for obtaining these parameters is as follows: In the formula: P represents the power of the rectangular induction coil, in watts (W); represents the thermal conductivity coefficient, in W / (m·℃); h represents the perpendicular distance between the rectangular induction coil and the magnesium alloy plate, in meters. Represents the resistivity of a rectangular coil, in Ω·m. The resistivity of the magnesium alloy plate is expressed in Ω·m; B represents the width of the magnesium alloy plate in meters; L represents the length of the magnesium alloy plate in meters; H represents the thickness of the magnesium alloy plate in meters; T represents the edge temperature of the magnesium alloy plate during induction heating in degrees Celsius; T0 represents the conventional heating temperature of the aluminum alloy plate in degrees Celsius; k represents the heating coefficient, with a value ranging from 0.4 to 0.

9. Step 3: Turn on the power to complete the induction heating and rolling of the magnesium alloy plate; When the temperature difference between the induction-heated edge temperature of the magnesium alloy plate and the conventional heating temperature of the magnesium alloy plate satisfies At ℃, the induction heating device stops heating and the magnesium alloy plate is rolled.

2. The induction heating method for preventing edge cracks during the rolling of magnesium alloy plates according to claim 1, characterized in that, The distance h between the rectangular induction coil and the magnesium alloy plate in step 2 is specifically as follows: The heating effect of a rectangular induction coil on a magnesium alloy plate depends on the following: when the inner diameter of the induction coil is fixed, the vertical distance between the induction coil and the magnesium alloy plate satisfies H / 2 < h < H.

3. An induction heating device for implementing the induction heating method for preventing edge cracking during the rolling of magnesium alloy plates according to claim 1 or 2, characterized in that, The induction heating device includes a first rectangular induction coil, a second rectangular induction coil, a first rectangular induction coil cover, a second rectangular induction coil cover, a CNC operating table, a support column, a first slide block, a second slide block, a cooling device, a coolant pipe, an infrared thermometer, a base, a first ball screw, a second ball screw, a first coupling, a second coupling, a first servo motor, a second servo motor, and a magnesium alloy plate. The first servo motor and the second servo motor rotate. The first servo motor and the second servo motor are respectively connected to the first ball screw and the second ball screw through the first coupling and the second coupling. The first servo motor and the second servo motor are fixedly connected through the support column and the base. The first ball screw and the second ball screw can drive the first slide block on the support column to move in the longitudinal groove and the second slide block on the base to move in the transverse groove. The first rectangular induction coil and the second rectangular induction coil are respectively connected to the first slide block and the second slide block, so that the rectangular induction coil can move when the servo motor rotates.

4. The induction heating device according to claim 3, characterized in that: The first rectangular induction coil is enclosed by a first rectangular induction coil cover; the second rectangular induction coil is enclosed by a second rectangular induction coil cover; an infrared thermometer is provided on the edge of the first sliding block below the first rectangular induction coil cover.

5. The induction heating device according to claim 3, characterized in that: The CNC operating table controls the rotation of the first servo motor and the second servo motor. The first servo motor and the second servo motor are respectively connected to the first ball screw and the second ball screw through the first coupling and the second coupling. The first servo motor and the second servo motor are fixedly connected through the support column and the base. The first ball screw and the second ball screw can drive the first slide block on the support column to move in the longitudinal groove and the second slide block on the base to move in the transverse groove. The first rectangular induction coil and the second rectangular induction coil are respectively connected to the slide block, so that the rectangular induction coil can move when the servo motor rotates.

6. The induction heating device according to claim 3, characterized in that: The cooling device circulates coolant through a coolant pipe into the first rectangular induction coil and the second rectangular induction coil for cooling, thus preventing the first rectangular induction coil and the second rectangular induction coil from malfunctioning due to high temperature.

7. The induction heating device according to claim 3, characterized in that: The base is fixedly equipped with a CNC operating table, a second servo motor, a second ball screw, a second slide block, a second rectangular induction coil, and a second rectangular induction coil cover; a cooling device is fixedly installed on the left side of the base, and the upper end of the cooling device is connected to the cooling port of the two induction coils.

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