Process Automation System (Level II) of Continuous Casting

In continuous casting unit, a system that could coordinate the control of all casting machine processes is necessary and without it an access to high-quality products with minimum scrap, would not be possible.

For this reason, in level 2 automation system for casting, all the data from the downstream automation levels (level 1 and level 2) has received and processed, then the control amount of automation system for level 1 to be applied to PLC, and the data to coordinate production system for long-term storage are sent to the information management system.

IRISA relied on more than 20 years of experience in the field of Level 2 casting and cooperation with renowned foreign companies in engineering, implementation, installation, commissioning and maintenance of these systems, proceeds with the localization of this system.

This system is currently going through the formalities for the registration in the Supervision of Strategic Planning Department of Presidency and will be an exclusive s product of IRISA. All intellectual and materialistic property rights are at IRISA’s Ownership.

Algorithms and complex mathematical and metallurgical models in this automation system tasks do all the calculations and managerial responsible for all activities. The most important of these models include:

Monitoring Model of Casting: (Tracking)

This is the core of the system and is responsible for communication with level three and level one and other communications of level two models all together.

The main tasks of this model are:

– Calculate the remaining time of the melt and constantly sending them for the level 3 automation system.

– Indication of the temperature measurement time and sampling to the operator.
– Data storage
– Primary planned production of billets according to the production plan.
– Localization and segment boundary of casting machines for each billet for quality control model calculations.

Detecting the start and end boundaries of cooling according to the Steel Grade for the calculation of cooling model.

 Production Prediction Model:

In this model, according to the amount of melting in the ladle and tundish, dimensions and speed of each line, billets which will be produced are predicted and displayed to the operator. Detection of the exact limits of coming billets and diagnosis of accurate closing positions of lines which will be reduces the line losses processed in each of the primary tasks of this model.

Cutting Length Optimization of billets:

Level 2 casting system with respect to the virtual boundaries for each melt, follow the changes that happen to a melt and react to it and make the best of the length of the billets and reducing waste.

These changes may include oxygen injection; moving the tundish, and opening or closing the lines. In order to optimize the length of the billets, this model is using complex mathematical algorithms to reduce the length of billets, elongation billets, and scrap management.

Cooling Model:

The model assumed the task of cooling billet along the line and is considered as one of the most important models of the system. Cooling district is divided into a number of sections and each must absorb some of the heat energy from the billets, leading to and temperature loss of billet during their passage through the area.

This temperature lost must be gradually and ongoing to prevent the occurrence of cracks in the surface of the billets. The model accurately calculates the flow rate of water splashing Steel and is performed according to the steel grade and dimensions of billets for the entire cooling loop. This model uses two methods for cooling billet.

In Static Cooling method, according to cooling table of the alloy, once the system is changing rapidly with the interpolation method, the amount of water needed for cooling is quickly calculated and gradually from the old currents tend to the new one to severe changes in the cooling water output to prevent cracks.

 

In Dynamic Cooling method, the system due to the melting temperature of the tundish and based on heat absorbs factors such as spraying water, contact with rollers, radiation, area temperature and absorbs heat from the mold, the billets are divided into small elements along the path and the differential equations of heat transfer between the billet and the heat absorbance factors, the billet surface temperature is calculated for different parts.

With this method, a mathematical model to estimate the temperature of the product will be formed and we can decide to use it to raise the temperature of anywhere from one value to another value, with changes in water flow in different areas. In this method, the thermal history of each element stored in the database and is updated regularly and continuously improves the system performance based on the achieved actual results.

Speed Optimization:

The calculation of metallurgical immediately after measuring the temperature of the tundish, the temperature Liquids of that alloys procedures on the latest analysis of the melt flow is calculated and then at Super Heat, based on the temperature of Liquids will be calculated by using the temperature of the Super Heat obtained. Width and thickness of bars and equivalent carbon which is developed to calculate the melting analysis is performed to determine the speed of the machine and the operator is notified.

In order to calculate the speed of sequencing, automation system level 3, the time to reach the next melt casting is announced, speed model, finishing time of the current melting calculation, this time must have common intersection path with the arrival melting time. If upcoming melt has not arrived at the right time to the casting machine, in order to maintain the continuity of the casting, the speed model for the current melt flow, calculates a new rate to reduce the rate of melting, therefore the later melt reaches casting machine before current melt. This speed is called Pacing rate.

Mix Zone Handling Model:

When opening a new ladle, it is possible that the new melt and casting melt different in the alloy and a mixture melt (new) is produced in the tundish. This part of the alloy ingot will be different from the desired alloy ingot and must be removed from casted billet. This model, combination of the two alloys, amount of mixed melt, the beginning and ending point of this alloy is calculated and notifies the other models.

Quality Control Model:

This model divides the entire route into virtual segment and from the production time in the cast until Cutting, all entries are saves in that segment. At the end, by comparing the data and quality values, quality evaluation would available for management and system experts.

 

Re-melt Model:

The purpose of this program is to collect information about the machine, and reprogramming each line and their machines so that the system will be able to have a proper planning for the next melting.

 

Equipment Life Tracking Program:

This model with a database that includes all parts of mashie such as rollers and the frames, the lifecycle is identified from the installation on the machine into the taken number of melts. Depending on the length of life, which is set for completion in time for the lifetime of the equipment, the operator notified to replace the pieces.

Delay Handling Program

The system can recognize the elongation of melting time comparing to the required time for standards casting to identify and record the amount of time for the operator to stop the interval. In this case the system user is required in the related mask notifies the causes of the delay of the machine and specify the code and enter the start and end time of delay so that the cause could be identified.