BOF VARG

What is BOF VARG

Vesuvius Advanced Robotic Gunning (VARG) is a groundbreaking robotic platform meticulously engineered to revolutionise refractory maintenance in Basic Oxygen Furnaces (BOFs). The traditional methods of BOF refractory repair are inherently hazardous and demand significant time, exposing operators to extreme temperatures and molten metal, which can lead to inconsistent application and substantial production losses.

BOF VARG directly confronts these challenges by integrating state-of-the-art mechatronics, advanced laser technology, and specialised refractory materials. This innovative solution transforms refractory repair from a manual, unpredictable task into a repeatable, data-driven, and highly efficient workflow, ultimately ensuring maximum furnace availability and significantly enhancing safety in the steelmaking process.

Key Benefits

BOF VARG delivers transformative improvements across critical operational aspects for steelmakers:

Improved Safety

• BOF VARG removes personnel from hazardous environments, eliminating direct human exposure to extreme heat, molten metal splashes, and overhead crane movements during repairs.
• The system's laser-guided gunning ensures weak areas are identified and repaired, preventing breakouts and hotspots.
• Compared to manual gunning, which typically requires three operators, robotic gunning for BOF VARG often requires only one operator (though some plants may choose to use two), freeing up personnel for other high-value tasks.

Increased Productivity and Efficiency

• BOF VARG enables hot repair, significantly minimising downtime associated with traditional refractory maintenance that necessitates cooling and shutdown.
• It offers high-speed application rates of over 200 kg/min when required, with a documented average rate of 218 kg/min and a record of 243 kg/min during BOF trials. This high throughput translates to less time gunning and more time making steel.
• A potential time saving of 7.5 minutes in a 1-tonne application compared to standard methods has been observed.
• It offers a 40-60% increase in BOF availability compared to typical standard application rates, enabling more heats and reducing maintenance time.
• Overall, it can lead to an increase in annual tonne output of 1-2% by reclaiming downtime.

Extended Refractory Life and Cost Efficiency:

• The system allows for gunning ONLY areas that need repair, ensuring precise and uniform refractory application. This reduces gunning material consumption through accurate product placement and defined, even thickness on the furnace wall.
• It promotes consistency and repeatable gunning application across shifts, leading to longer campaign lives and reduced frequency of full refractory relining.
• It reduces refractory cost per tonne of steel.
• Increased product densification through high-speed application improves product durability, increasing the duration between repairs.

Data-Driven Decisions (Industry 4.0 System):

• BOF VARG integrates an Industry 4.0-compliant software system that supports predictive maintenance.
• It performs fast laser measurements to generate 3D wear maps and automatically generates customer reports on material consumption, gunning time, gunning rates, and water usage.
• This provides steel shop refractory managers with 100% clarity of consumption data 24/7/365, enabling informed, data-driven decisions and optimised repair protocols.

Automation Levels

1. Full-Automatic BOF VARG
   This version offers full functionality with wireless remote control and fully automatic gunning to worn areas. It integrates a PMC laser scanning system for precise measurements and automated gunning sequences, enhancing precision and reducing maintenance costs and downtime. The entire process is controlled by the machine with minimal operator intervention, using advanced robotics and integrated sensors.
2. Semi-Automatic BOF VARG
   This mode enables operators to set up the machine and initiate or supervise gunning cycles, utilising pre-defined or programmable sequences. It provides flexibility without sacrificing accuracy, enabling safer, faster manual touch-ups in known weak spots.

Features

ANTERIS 360™ Laser Contouring System
This state-of-the-art laser system captures over 1 million data points to create a high-resolution 3D model of the furnace's interior in under 60 seconds. It precisely identifies wear hotspots, skull build-up, and cracks, guiding the robotic repair. The system can scan the vessel after each heat in less than one minute, significantly minimising the risk of a BOF breakthrough.

Twin-Tank High-Flow System
A patented pressure-balance skid is integrated to sustain a record material rate of 200–243 kg/min. This twin-tank technology allows for non-stop gunning or the use of two different types of material, ensuring continuous operation and efficiency. It can also be configured with a dual-hopper or single-hopper enclosed system.

Water Dosing System
A proprietary system unique to VARG, it provides precise moisture control for higher durability and densification of the applied refractory material.

Improved Controller
A significantly improved controller for the industrialisation phase is undergoing rigorous testing at the Centre of Excellence. It offers features such as a flip function to prevent lance distortion, allows for offline reachability testing, implements continuous movement to prevent over-gunning due to velocity changes, and enables commissioning based on a CAD file of the furnace for improved initial installation.

Material Application
BOF VARG is designed to work with specifically developed materials, such as BASISGUN-B90VG, which features dual binder technology for high primary adhesion on very hot BOF furnaces, enabling immediate application after slag decanting.

Integrated Software
Utilises Vesuvius's Gunning Map Manager software for a fully controlled application process, from scanning to repair confirmation and automated report generation.

Customisation
Each BOF VARG unit is tailor-made and customised to individual furnace geometries, ensuring optimal performance and target-oriented gunning.

Gunning Arm
The system includes a 300-degree rotating arm with a 0-45-degree angle range. The gunning head's optimised angle enables effective gunning of lower banks.