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An online monitoring system for mould processes would not only provide early alarms for potential breakouts but also prevent casting defects in the downstream processes. Identification of aberrations in the solidification process of steel inside the mould would make information available for immediate problem analysis & prevention and would aid continuous quality improvement.
Overview
Casting is a critical step in steel making. Conversion of molten steel into slabs while casting may lead to spill out of molten steel around the mould bottom. This phenomenon is known as breakout. Breakouts can cause the damage of the caster ,loss of production and poor safety records.
To prevent breakouts, Automation Division, Tata Steel has developed a Casting Online Diagnostics System (CODS). Breakouts can be detected while the molten steel is inside the mould .It has been observed that 90% of the breakouts happen due to sticker and such breakouts are known as sticker breakouts.
Working Principle
Casting Online Diagnostics System (CODS) reads the temperature signals from an array of thermocouples embedded in the mould horizontally in four layers. It is able to predict the tendency towards the sticking of solidifying shell inside the mould and take automatic preventive action when necessary. It also reads the non TC field inputs and provides indication of the casting health with a continuous performance indicator called "Breakoutability".
Features
- Prediction of all types of breakouts-stickers, cracks, thin shells, start-ups, slag entrapment, etc.
- Handling all steel grades and casting speeds up to 2.2 meters/min.
- Predicting a value of 'breakoutability'- inverse of 'normality'- in real time on a continuous scale of 0-100, rather than a binary response in terms of breakout/no-breakout; thus providing a view of the health of casting rather than just indicating the failure whenever it occurs.
- Fuzzy systems convert thermal and casting conditions into breakoutability along with identification of the cause of highest breakout-ability, the location in the mould, of the point of highest breakoutability (or farthest from 'local normal') and the nature of evolution of this fault point.
Benefits
- Very low number of false alarms.
- Prevents all possible types of breakouts-stickers, cracks, thin shells, start-ups, slag entrapment; a unique feature in the system.
- Provides online casting diagnostics along with real time mold thermograph.
- Facility to automatically modulate casting speed based on the nature and intensity of the fault thus ensuring higher efficiency of throughput along with higher quality of slabs.
- Avoids production losses due to breakouts
- Enables process improvement
- Provides relevant data for analysis
- Uses “ off the shelf ” hardware components & simple architecture.
- Easily configurable to the customer’s specified hardware
- User friendly HMIs providing visualisation of key casting parameters.
- Low maintenance cost
- Customer configurable graphical user interfaces