The Introduction of Continuous Casting Products

The Introduction of Continuous Casting Products

 

 

 

1	Ladle slag detection system
2	Continuous temperature measuring system for molten steel in tundish	Tundish molten steel level control system
	Tundish stopper control system
3	Mold breakout prediction system	Mold taper measurement
	Mold oscillation detection	Online width adjustment for mold
	Mold expert system	Mold CNC Non-sinusoidal Oscillation System
	Mold molten steel level detection	Automatic mold flux feeding system
4	Multifunctional strand condition monitor
5	Online continuous temperature measuring system for the end of continuously cast product	Online shape inspection system for continuously cast product
	Cutting to length and optimization system	Dynamic secondary cooling water model for continuously cast product
	Online surface quality inspection system for continuously cast product

 

1. Ladle slag detection system

There are mainly two kinds of slag detection systems.

 

1.1 Ladle slag detection (vibration type)

It is composed of a vibration detection sensor, a signal preamplifier, a slag detection operation unit, a tundish liquid level control unit, an on-site operation indicator box, and a process control cabinet etc. The system detects the slag content in molten steel by collecting the vibration signal of the mechanical operating arm. The vibration signal is connected to the electrical control unit of the control cabinet through the pre-conditioning and amplification module and the sensor installed in the middle of the operating rod, and after processing, it is output to the industrial control compute for calculation and analysis. The slag signal detected by the system is output from the system control cabinet to the front-end control unit, and then the ront-end control unit control the alarm horn and alarm light to work, or issue an instruction to close the ladle nozzle.

The vibration detection sensor is installed on the mechanical operating arm for the protection and pouring of the ladle, and is used to detect the vibration signal of the whole pouring process of the ladle; the signal preamplifier is used to amplify, convert and transmit the weak vibration signal detected by the vibration detection sensor. The slag detection and calculation unit analyzes, judges and discriminates the vibration signal, realize the discrimination of all steel, mixed slag, and all slag, and outputs a slag alarm signal. The tundish liquid level control unit receives the control signals of the tundish and the ladle nozzle, and realizes automatic or manual control of the ladle casting stream according to the requirements. The on-site operation instruction box provides man-machine exchange for slag alarm indication, fault indication, system activation mode selection, and control mode selection. Process control cabinet, providing power management, the display of man-machine interface and setting management.

1.2 Ladle slag detection (eddy current type)

The sensor uses the electromagnetic principle to detect the signal, and its typical structure is two concentric coils. When the primary coil is supplied with an intermediate frequency excitation current, an eddy current is generated in the steel flow due to the action of the magnetic field. Because the conductivity of slag is much lower than that of molten steel at high temperature, the eddy current generated in slag is much smaller than that generated in molten steel. In the process of pouring, all the molten steel flows out at the beginning of pouring. At the later stage of pouring, the molten steel and slag mix out, which reduces the conductivity of the solution and enhances the electromagnetic field. This signal is measured by the secondary coil.

Schematic diagram of the ladle slag detection principle (eddy current)

The eddy current ladle slag detection has the advantages of high detection accuracy, full detection of the actual amount of mixed slag in molten steel, and it is also widely used to close the nozzle in advance.

 

1.3 Slag coil and signal amplifier

 

 

 

1. General introduction of tundish measurement and control system

   The continuous temperature measuring system of the molten steel in tundish consists of continuous temperature measuring, level control, tundish stopper.

 

2.1 Continuous temperature measuring system for the molten steel in tundish

The continuous temperature measurement system of molten steel in the tundish includes temperature measurement components, temperature measurement detectors, signal transmission, signal processor and cooling air system.

The system is controlled by the tundish stopper. A black cavity is designed on the tundish stopper, and a heat transfer conductor is installed at the bottom of the cavity. The depth of the cavity is about 2/3 of the length of the tundish. The bottom need to be completely immersed in molten steel during use.

Infrared temperature measurement technology is a non-contact measurement of temperature based on the principle of radiation temperature measurement. It has the advantages of short response time, good heat transfer performance, high sensitivity, and accurate measurement. It has been widely used in metallurgy, petrochemical, transportation, coal mining, electric power and other industries. For the environmental requirements, compared with the integrated infrared temperature measurement, the optical fiber temperature measurement has a much wider usage range.

Because the integrated infrared probe is very close to the nozzle of the tundish, it can also measure the baking preheating temperature of the tundish, which not only eliminates the cost of adding this function, but also saves manpower and ensures safety, and will not change the user's existing hardware.

In summary, the system can achieve: deep and stable measurement point; fast response; accurate measurement; low cost for temperature measurement

 

Schematic Diagram of Continuous Temperature Measurement of Central Package

 

2.2 Control system for molten steel level in a tundish

The Control system for molten steel level in a tundish is composed of the tundish weight weighing system, the ladle slag detection system, the infrared auxiliary measurement system, the control PLC and its model, the control execution unit and the operation indication unit.

 The tundish weight weighing system includes the weighing sensor and the sensor anti-heat and anti-impact protection device, which are evenly distributed in the tundish car to measure the actual weight of the tundish. The system is used to improve the cleanliness of the molten steel in the tundish and obtain the best yield of molten steel. The infrared auxiliary measurement system uses an infrared measurement probe to implement the online detection for the surface height of the molten steel in the tundish, and sends the measurement parameters to the PLC as a reference factor for system detection, and then evaluates and corrects the calculated data to ensure that the tundish level is accurate in the whole pouring process.

The control PLC adopts the same series PLC of the user as the main system, and is connected to the whole continuous casting PLC system to realize the data exchange of ladle casting strand control. According to the tundish volume model, the system calculates the level height of molten steel in the tundish in real time. In order to realize the above operation, the system needs to introduce the signal of the weight of the ladle molten steel, drawing speed and the position of the tundish car.

The control execution unit converts the control signal output by the control PLC into the drive signal of the servo control module through the drive conversion module board, so as to control the opening of the sliding nozzle of the ladle.

Finally, the system is equipped with a large-screen indicator to indicate the height of the liquid level in the casting process in real time.

Schematic diagram of liquid level control in tundish

2.3 The tundish stopper control system

If we adopt a black cavity for temperature measurement in the tundish stopper rod. The tundish stopper need to be immersed into the molten steel, and the temperature change of the inner cavity of the stopper rod is consistent with the temperature change of the molten steel. If we adopt infrared temperature measurement method to measure the temperature of molten steel, the temperature of tundish molten steel can be obtained by measuring the temperature change of the stopper rod cavity.

 

3. Mold measurement and control series

    They are roughly composed of detection, measurement and control.

3.1 Mold breakout prediction system

The mold breakout prediction system is designed according to the characteristics of the mold of the slab continuous casting machine to design the buried quantity and spacing of galvanic couples, uses online equipment for prediction and alarm and uses offline equipment for data verification and record, and uses industrial Ethernet to achieve the collection, storage and remote transmission of the on-site data. The system is based on NeuralWare's fuzzy neural network platform system, it has the functions of online self-learning and self-correction.

Typical breakout and forecasting process

 

3.2 Mold taper measurement

The hand-held taper measuring instrument is an effective tool to complete mold taper measurement. For ZFY-018 taper measuring instrument, the advantages are shown below: self-supporting, easy to center, easy to operate; easy to calibrate, stable performance; high measurement accuracy; LED data reading; short response time, real-time display reading; intelligent calibration function.

3.3 Mold oscillation detection

The mold oscillation detection includes: mold hydraulic oscillation (hydraulic cylinder pressure detection, hydraulic cylinder stroke detection); mold mechanical oscillation (mould oscillation amplitude detection, mold load current detection); mold CNC oscillation system; friction force measurement and calculations, etc.

3.4 Online mold width adjustment

In order to meet the needs of slabs with different widths, the width of the mold must be adjusted with the width of the slab. The on-line mold width adjustment is to change the width of the slab without stopping the drawing. The S-shape mode of mold width adjustment is adopted, and the S-shape is present when the width is adjusted. When casting carbon steel on the traditional slab continuous casting machine, the corresponding parameters are: the maximum casting speed is 2m/min, and the maximum width adjustment speed on each side is 50mm/min.

3.5 Mold expert system

The Mold expert system is a high-tech, complex system. It is also a modern system that integrates sensor technology, electrical automation technology, computer technology, visual display technology, and mathematical model technology. The system collects the technological parameters of the mold and displays the relevant data on the monitor after data processing, helping the producer to "intuitively" see the internal conditions of the mold, and instructing the operator to control the continuous casting machine.

3.6 Mold CNC Non-sinusoidal Oscillation System

The mold CNC non-sinusoidal oscillation system consists of a oscillating table, a base, a driving device and a buffer device; and the control unit (oscillation curve generation, setting, adjustment), driving unit, power driving and control unit in the monitoring operation station. 

 

Schematic diagram of a non-sinusoidal oscillation system

 

3.7 Mold molten steel level detection

The mold electromagnetic liquid level detector is used to measure the molten steel liquid level of the mold of the slab continuous caster. The mold liquid level detector includes an electromagnetic sensor including cables, connectors, a preamplifier and a calculator.

Mold level detection

 

3.8  Mould automatic mold powder feeding system

According to different steel grades, casting speed, vibration and other process parameters, the system can analyze and calculate the accurate mold flux addition amount through intelligent software. Then the system sends out signals to control the mold flux addition process and mold flux addition amount, and designs appropriate nozzles and propellers according to the fluidity of molten steel in the mold and the ductility of mold flux. After the system setting is completed, there is no manual intervention is required. It completely replaces the whole process of manual addition of mold flux and realizes the automation of mold flux addition.

The user can set the parameters from the operation box according to the actual needs, so as to change the length of the mold powder feeding time and the amount of the mold powder addiction, so as to be suitable for use under different sections and different drawing speed.

The system consists of three parts: storage bin, control operation box and actuator. It can be adapted to powder and granular mold flux. It has anti-clogging nozzle and back-flushing design to overcome the phenomenon of pipeline blockage.

Mould automatic mold powder feeding system

 

4. Multifunctional strand condition monitor

The functions of the multi-function strand condition monitor: roll gap measurement, arc condition inspection of guide roller, guide roller bending/wear detection, guide roller rotation measurement, segmented roll condition inspection, nozzle inspection, etc.

 

5. Casting billet measurement and control series

5.1 On-line temperature monitoring system for the end of the cast product

This system is aimed at the continuous detection of the temperature at the end of the casting slab of the continuous casting machine. The continuous casting billet and surrounding environmental factors, such as scale, steam, shielding and other factors, are taken into account in the scheme design and equipment selection. At the same time, the accurate detection and real-time transmission of temperature during the movement of the billet are also considered.

5.2 On-line shape inspection of billets

The CCD detection is to check whether the shape of the cast product is qualified or not.

5.3 Cutting-to-length and optimization system

Cutting and optimization of length include: optimization model of fixed-length, infrared fixed-length measurement, laser fixed-length.

5.4 Dynamic secondary cooling model of the cast product

The core of the online production system is the dynamic cooling model. The dynamic cooling model cyclically calculates cooling water flow in each zone according to the different cooling modes used. The calculation mode can be defined for each zone. The dynamic cooling model collects online real-time data and the cooling water meter which is used to meet the quality requirements for different steel grades, including: dynamic velocity model, dynamic temperature model, and dynamic shell model.

At the same time, each model can modify the set value of water volume in each area.

Dynamic Temperature Model

 

5.5 On-line surface quality inspection of billets

The online detection of slab surface quality is divided into: surface quality detection based on eddy current, surface quality detection based on machine vision, and automatic flame cleaning.

 

 

Schematic diagram of CCD surface quality inspection