CN115555525A - Device and measurement method for real-time measurement of solidification speed of fast solidification ribbon - Google Patents

Abstract

The invention discloses a device and a method for measuring the solidification speed of a rapidly solidified thin strip in real time, comprising a main roller of a quenching roller, wherein the main roller of the quenching roller is arranged on a bracket through a central shaft; the bracket is movably arranged on the base; the central shaft is connected with an output shaft of the motor; a nozzle for spraying molten metal is arranged above the main roller of the quenching roller; the surface of the main roller of the quenching roller is provided with an auxiliary roller; the device also comprises a signal generator embedded in the secondary roller and a thermocouple which is arranged on the surface of the secondary roller and is communicated with the signal generator; the thermocouple temperature sensor also comprises a signal receiving device which is in communication connection with the signal generator and the thermocouple, and the signal receiving device is connected with the processing device; the method does not need additional equipment for measurement, can realize synchronous measurement of the solidification speed, ensures the instantaneity and reliability of the measurement of the solidification speed, can display in real time, and better controls the rotating speed to ensure the consistency of the rapidly solidified strip.

Description

A device and measurement method for real-time measurement of the solidification speed of a rapidly solidified thin strip

technical field

The invention relates to the technical field of casting alloys, in particular to a device and a measuring method for real-time measuring the solidification speed of a rapidly solidified thin strip.

Background technique

Conventional casting alloys are prone to serious defects such as coarse grains, severe segregation, and poor casting performance. The main reason is that the degree of undercooling and solidification speed of the alloy during solidification are very small. To eliminate the above-mentioned defects in cast alloys, the main method is to increase the degree of supercooling of the melt during solidification to increase the solidification speed.

Copper rollers with good thermal conductivity are mostly used in traditional alloy quenching, and the cooling rate is only roughly regulated by controlling the surface linear velocity of the rollers. The solidification speed of the alloy during solidification cannot be obtained accurately. There are mainly two methods to determine the solidification rate: theoretical calculation and actual measurement; the direct measurement method is to simultaneously measure the cooling rate during the rapid solidification process, such as thermocouple method and optical temperature measurement method. Due to the rapid solidification process of the alloy, these methods are difficult and inaccurate in practice. The size of the solidification rate directly determines the microstructure and properties of the alloy, so it is of great significance to accurately measure the solidification rate.

Contents of the invention

Aiming at the problems in the prior art, the present invention provides a device and a measuring method for real-time measurement of the solidification rate of a fast-solidified strip that can precisely control the solidification rate of metal and solidification structure.

The technical scheme adopted in the present invention is:

A device for real-time measurement of the solidification speed of fast-solidified thin strips, including a quenching roller main roller, which is set on a support through a central shaft; the support is movable on a base; the central shaft is connected to the output shaft of a motor; the quenching roller There is a nozzle for spraying molten metal above the main roller;

The surface of the main roll of the quenching roll is provided with an auxiliary roll; it also includes a signal generator embedded in the auxiliary roll and a thermocouple connected to the signal generator on the surface of the auxiliary roll; it also includes a signal receiver connected to the signal generator and the thermocouple. device, and the signal receiving device is connected to the processing device.

Further, the secondary roller includes a first secondary roller and a second secondary roller which are stacked, and the signal generator is buried between the first secondary roller and the second secondary roller.

Further, there are two signal generators, which are respectively arranged in the secondary rollers on opposite sides of the quenching roller in the axial section, and each signal generator is connected to two thermocouples with a distance of 1 mm.

Further, two supporting parts are arranged opposite to each other on the bracket, and the two ends of the central axis are respectively arranged on the supporting parts and can rotate relative to the supporting parts.

Further, the first sub-roll and the second sub-roll are arranged on the surface of the quench roll main roll through bolts.

Further, the nozzle is provided with an electromagnetic coil for continuous heating and heat preservation of the molten metal.

A method for measuring a device for real-time measuring the solidification speed of a fast-solidified thin strip, comprising the following steps:

Step 1: Adjust the base so that the nozzle corresponds to the position of the thermocouple; start the motor;

Step 2: When the molten metal is sprayed from the nozzle and touches the thermocouple on the main roller of the rotating quenching roller, the circuit is turned on, the signal receiving device receives the signal generated by the signal generator, and records the time _t1 and the corresponding temperature T ₁ ;

Step 3: When the molten metal is separated from the thermocouple after solidification, the circuit is disconnected at this time, and the signal receiving device cannot receive the signal generated by the signal generator, and record the time t ₂ and temperature T ₂ at this time;

Step 4: Get the solidification time according to t ₂ and t ₁ , get the temperature change according to T ₁ and T ₂ , and calculate the solidification speed according to the solidification time.

The intentional effect of the present invention is:

(1) The present invention can realize the measurement of coagulation time without additional equipment;

(2) The present invention accurately measures the solidification speed by switching on and off the circuit;

(3) The present invention can display the solidification time in real time through the control device, and can better control the rotation speed to ensure the consistency of the rapidly solidified strip.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the device of the present invention.

Fig. 2 is a schematic cross-sectional view of the quenching roll in the present invention.

Fig. 3 is a schematic diagram of signal changes received by the processing device in the present invention.

Fig. 4 is a schematic diagram of the side structure of the rapidly solidified strip of magnesium alloy under different solidification speeds in the present invention.

In the figure: 1-quenching roll main roll, 201-first secondary roll, 202-second secondary roll, 203-bolt, 204-signal generator, 205-thermocouple, 3-electromagnetic coil, 4-motor, 5- Support part, 6-central shaft, 7-support, 8-base, 9-nozzle.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1 and 2, a device for real-time measurement of the solidification speed of a fast-solidified thin strip includes a quenching roll main roll 1, and the quenching roll main roll 1 is arranged on a support 7 through a central shaft 6; the support 7 is movable On the base 8; the central shaft 6 is connected to the output shaft of the motor 4; a nozzle 9 for spraying molten metal is arranged above the quenching roll main roll 1;

The surface of the quench roll main roll 1 is provided with a sub-roll; it also includes a signal generator 204 embedded in the sub-roll and a thermocouple 205 communicated with the signal generator 204 on the surface of the sub-roll; it also includes a signal generator 204 and a thermocouple 205 A signal receiving device connected by communication, and the signal receiving device is connected to a processing device.

The secondary rollers include a first secondary roller 201 and a second secondary roller 202 stacked on top of each other, and a signal generator 204 is embedded between the first secondary roller 201 and the second secondary roller 202 . There are two signal generators 204, which are respectively arranged in the auxiliary rolls on opposite sides of the quenching roll 1 in the axial section, and each signal generator 204 is connected to two thermocouples 205 with a distance of 1 mm. Two supporting parts 5 are arranged oppositely on the bracket 7 , and the two ends of the central shaft 6 are respectively arranged on the supporting parts 5 and can rotate relative to the supporting parts 5 .

The first sub roll 201 and the second sub roll 202 are arranged on the surface of the quench roll main roll 1 through bolts 203 . The nozzle 9 is provided with an electromagnetic coil 3 for continuous heating and heat preservation of the molten metal, and the electromagnetic coil 3 is connected to a power source.

During specific use, two side-by-side small holes with a distance of 1mm are drilled around the periphery of the quenching roll main roll 1, and the thermocouple 205 protrudes slightly from the surface of the quenching roll main roll 1 through the small holes. The other end is connected to the signal generator 204 (the signal generator selects a wireless high-frequency signal transmitting device), and is received by a signal receiving device. When the alloy touches the two hot couples 205 during the rapid solidification process, the circuit is connected and an electrical signal is generated. The metal solidifies and leaves the roller surface, the circuit is disconnected, and the signal is interrupted. In order to ensure that the rollers are relatively balanced during rotation, two sets of temperature measuring devices (the temperature measuring devices include thermocouples and signal generators) are installed symmetrically on the upper and lower sides of the rollers, wherein the first secondary roller 201 and the second secondary roller 202 can be separated, It is convenient to replace the signal generator and thermocouple. The quench roll main roll 1 rotates under the drive of the motor 4, and the support 7 and the base 8 can move left and right to adjust the relative position of the nozzle 9 and the quench roll main roll 1, and to measure the solidification speed and actual production.

A method for measuring a device for real-time measuring the solidification speed of a fast-solidified thin strip, comprising the following steps:

Step 1: adjust the base 7 so that the nozzle 9 corresponds to the position of the thermocouple 205; start the motor 4;

Step 2: The molten metal is ejected from the nozzle 9, and when it touches the thermocouple 205 on the main roll 1 of the quenching roll that rotates, the circuit is turned on, and the signal receiving device receives the signal generated by the signal generator (204), and records the current Time t ₁ and corresponding temperature T ₁ ;

Step 3: When the molten metal is solidified and separated from the thermocouple 205, the circuit is disconnected at this time, and the signal receiving device cannot receive the signal generated by the signal generator 204, and record the time _t2 and temperature T2 at this time _;

Step 4: Get the solidification time according to t ₂ and t ₁ , get the temperature change according to T ₁ and T ₂ , and calculate the solidification speed according to the solidification time. From the solidification time and temperature change, the solidification rate of the alloy (temperature change/solidification time) is obtained.

The quenching roll main roll 1 can move laterally, which can ensure continuous production after debugging to the appropriate parameters in actual production. The solidification parameters of the rapid solidification alloy strip in the production process can be monitored in real time, so that the process parameters can be adjusted in time to ensure the stability and consistency of the strip itself. If you want the structure of the strip to have little difference before and after, you must ensure that its solidification speed is consistent. The solidification speed is closely related to the flow rate of molten metal and the speed of the quenching roll. Since the stability of the flow rate in the production process may not always be controllable, it is necessary to adjust the speed of the rollers in time to ensure that the solidification speed of the molten metal is consistent, thereby ensuring product quality.

It can be seen from the previous research results that the solidification process of the molten metal through the quenching roller generally takes 10 ^-4 s. The recording time requirements can be fully met by a high-frequency wireless signal generator (1MHz). When the molten metal contacts the thermocouple on the roller surface, the signal generator is connected to display data, and the signal received by the signal receiving device is shown in Figure 3.

By adjusting the base 7, the nozzle 9 is aligned with the position of the thermocouple 205, and the quench roll 1 is started. When the molten metal flows out from the nozzle 9 and touches the rotating quench roll main roll 1, since the molten metal is continuously sprayed, the molten metal has Conductivity, the circuit is connected. The signal generator 204 generates a signal, and the signal receiving device receives the signal. Due to the rapid cooling of the molten metal, the resistance of the thermocouple 205 also changes accordingly. Therefore, the signal generated by the signal generator 204 also changes accordingly, and when the molten metal is completely solidified, the entire circuit is disconnected from the thermocouple 205 . The signals emitted by the signal generator 204 are shown in FIG. 3 . By calibrating the thermocouple 205 and the signal generator 204, the real-time temperature corresponding to different electrical signals is obtained, and the solidification time is obtained at the sudden change time interval of the collected signal, so as to obtain the solidification speed of the molten metal. In order to maintain the balance of the quenching roller during the rapid rotation, two sets of temperature measuring devices are set. When the desired solidification speed is reached, the position of the base 7 can be adjusted to stabilize production.

Figure 4 shows the microstructure of the side surface of rapidly solidified strips of magnesium alloy prepared by different solidification speeds. The above solidification speed increases sequentially from left to right to the following drawings. It can be seen that with the increase of solidification speed, the thickness of the strip decreases significantly, its grains are finer, and the structure is more uniform. In subsequent performance tests, we found that the solidification speed has a significant effect on the strip. The properties of the metal strip are greatly influenced.

Compared with the existing thermocouple method and optical temperature measurement method, due to the fast speed of the alloy in the solidification process, these methods are difficult to operate and the accuracy is not high. The invention does not need additional equipment for measurement, can realize synchronous measurement of the solidification speed, ensures the instantaneity and reliability of the solidification speed measurement, can display in real time, and better controls the rotation speed to ensure the consistency of the rapid solidification strip.

Claims (7)

1. The device for measuring the solidification speed of the rapidly solidified thin strip in real time is characterized by comprising a quenching roller main roller (1), wherein the quenching roller main roller (1) is arranged on a bracket (7) through a central shaft (6); the bracket (7) is movably arranged on the base (8); the central shaft (6) is connected with an output shaft of the motor (4); a nozzle (10) for spraying molten metal is arranged above the main roller (1) of the quenching roller;

the surface of the quenching roller main roller (1) is provided with an auxiliary roller; the device also comprises a signal generator (204) embedded in the secondary roller and a thermocouple (205) which is arranged on the surface of the secondary roller and is communicated with the signal generator (204); the thermocouple junction box further comprises a signal receiving device which is connected with the signal generator (204) and the thermocouple (205) in a communication mode, and the signal receiving device is connected with the processing device.

2. The device for measuring the solidification speed of the rapidly solidified thin strip in real time as claimed in claim 1, wherein the sub-rolls comprise a first sub-roll (201) and a second sub-roll (202) which are overlapped, and the signal generator (204) is embedded between the first sub-roll (201) and the second sub-roll (202).

3. The apparatus for measuring the solidification rate of thin rapidly solidified strip in real time as claimed in claim 1 wherein two signal generators (204) are provided, each being disposed in the sub-roll on the opposite side of the axial section of the main roll (1) of the chill roll, each signal generator (204) being connected to two thermocouples (205).

4. The device for measuring the solidification speed of the rapidly solidified thin strip in real time as claimed in claim 1, wherein the two support parts (5) are oppositely arranged on the support (7), and both ends of the central shaft (6) are respectively arranged on the support parts (5) and can rotate relative to the support parts (5).

5. The apparatus for real-time measurement of solidification rate of thin strip of rapidly solidified material as claimed in claim 2 wherein the first sub roll (201) and the second sub roll (202) are disposed on the surface of the chill roll main roll (1) by bolts (203).

6. The device for measuring the solidification speed of the rapidly solidified thin strip in real time as claimed in claim 1, wherein an electromagnetic coil (3) for keeping the molten metal heated and kept warm is arranged outside the nozzle (9).

7. The method of any of claims 1-6, comprising the steps of:

step 1: adjusting the bracket (7) to enable the nozzle (9) to correspond to the thermocouple (205); starting the motor (4);

step 2: when molten metal is discharged from a nozzle (9) and comes into contact with a thermocouple (205) on a rotating main roller (1) of a chill roll, an electric circuit is turned on, a signal receiving device receives a signal generated by a signal generator (204), and the time t at that time is recorded ₁ And corresponding temperature T ₁ ；

And step 3: when the molten metal is separated from the thermocouple (205) after solidification, the circuit is disconnected, the signal receiving device cannot receive the signal generated by the signal generator (204), and the time t at the moment is recorded ₂ And temperature T ₂ ；

And 4, step 4: according to t ₂ And t ₁ Obtaining a setting time according to T ₁ And T ₂ The temperature change is obtained, and the solidification speed can be calculated according to the solidification time.

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