Using robots in industrial environments is far from a new idea. But while theyve been used in automotive assembly plants for years, they are rarely used in steel mills.
Austrias Siemens VAI Metals Technologies GmbH would like to see that change through the use of its Simetal LiquiRob flexible robot-aided measuring solution, which has already been installed in about 10 steelmaking facilities in Europe, Asia and South America, with three to four North American Free Trade Agreement (Nafta) producers reportedly considering the new technology.
Siemens, an international supplier of steel mill technologies, provides the automation for the Simetal LiquiRob using industrial robots from several European producers.
Phil Ponikvar, business segment manager for mechanical equipment at Siemens Industry Inc., Canonsburg, Pa., acknowledged that the steel industry has been somewhat reluctant to use robotics. However, he said, its a technology whose time has come, especially given the number of injuries and fatalities in the hot end of steelmaking facilities each year, as well as steelmakers desire to provide high-quality steel products that closely conform to increasingly stringent end-user requirements.
When the Simetal LiquiRob technology was developed about five years ago, Ponikvar said, it was mainly to improve safety in the hot end of steelmaking plants by having a robot do some of the normal day-to-day, heat-to-heat operations within the steel plant, such as taking temperatures or chemical samples in the furnace or in the casting machine tundish.
In a steel mill environment, particularly where liquid hot metal is produced or manipulated, operators are continually exposed to dangerous working conditions. This is true for workers both at electric-arc furnace (EF) and basic oxygen furnace (BOF) operations, as well as those at continuous casters, secondary metallurgical plants and converters.
Using a robot is unbelievably safer. There is no chance that sparking or boiling of steel will result in splashback on a worker, Ponikvar said. What we wanted to do was to eliminate the need of having humans doing some of these more dangerous jobs, but what we found afterwards was that we werent only able to assist in improving safety, but we were also able to allow steelmakers to have an operation that was more stable and controlled than it had been previously.
He said that with each temperature reading or chemistry sample being taken at the same depth at the same location in the furnace or the tundish, the steelmaker gets guaranteed consistency and repeatability in results.
Still, steelmakers have been slow to accept the use of robots such as the Simetal LiquiRob in their facilities. One factor contributing to this is that labor unions see them as eliminating personnel. The way that we look at it, though, is that you cant put a price on safety, and those people could be reassigned somewhere else in the facility, Ponikvar said.
Another major area of concern is the robustness of robotics in a steel plant, he said, but that is because 20 to 25 years ago there were various robotic manipulator arms used in steel mills that couldnt stand up to the harsh environment. Weve come a long way in making heavier, sturdier, stronger robots since then, Ponikvar said, evidenced by the number of robots doing welding in auto plants, which also have nasty environments.
The pricing of robots also is a concern, but Ponikvar said that robots like the Simetal LiquiRobÑwhich is able to perform many different functions in the mill in a very repeatable fashionÑcould help steelmakers cut costs as well as improve safety, leading to a higher return on investment. While the payback period varies on the specifications and functionality of a robot, it is a maximum of 24 months for the LiquiRob, he said.
Ponikvar said there will come a day when robots like the Simetal LiquiRob will be as common in steel mills as they are in automotive assembly plants, although it could take another 15 to 20 years, with acceptance likely to come elsewhere in the world before North America. Right now, while some other robots have found some limited use in steel mills, performing one or two functions at the most, as far as he is aware the LiquiRob is the only such robot being used to perform operations in the EF, BOF and continuous caster.
The Simetal LiquiRobs worldwide installations include the EF at Riva Fire SpA in Neuves Maisons, France; BOFs at ThyssenKrupp CSA in Brazil and JSC Zaporozhstal, Ukraine; and continuous casters at Brazils Cia. Siderurgica Paulista (Cosipa), Poscos Gwangyang, South Korea, facility and Voestalpine Stahl GmbHs Linz, Austria, steelmaking complex. While three or four North American companies have expressed interest in the Simetal LiquiRob for several of their operations, none has pulled the trigger yet.
About half of the Simetal LiquiRob installations were retrofits, with the rest installed in new or expanded steelmaking facilities. Provided they have the room, it is easy to install, wire up, program and operate, Ponikvar said, adding that size depends on the available options. It could take up as little space as 6 feet by 6 feet or as much as 15 feet by 25 feet.
In the furnace area of the melt shop, Ponikvar said, the Simetal LiquiRob is able to take both temperature and chemical samples in a repeatable fashion to ensure uninterrupted, fail-safe and controlled steel production. This, Siemens said, could have a direct influence on the quality of the steel being produced as well as productivity, thanks to faster cycle times and fewer measurement errors.
The same is true of EF oxygen lancing or BOF sublancing, hazardous tasks the LiquiRob is able to perform with an operator supervising it from the safety of the control room.
With its six-axis movement, the Simetal LiquiRob can be used in extremely tight conditions. This means that very short cycle times can be achieved, and it can be used for handling various kinds of cartridges without any major modifications. In fact, the LiquiRob recognizes defective cartridges and sorts them out before taking any measurements, therefore minimizing measurement errors.
In the continuous caster area of the steelmaking plant, the Simetal LiquiRob can perform tasks in three areas: the ladle area, the tundish area and the mold area. In the ladle area, operations such as media and signal connections could be implemented. Connection of the ladle slide gate cylinder also can be performed.
In the tundish area, not only can the Simetal LiquiRob perform similar temperature and probe-handling operations as it does in EFs and BOFs, it also can feed an insulation powder used to prevent any oxidation from occurring in the tundish, as well as carrying out ladle shroud manipulations. The ladle shroud is placed on the ladle to prevent reoxidation from occurring when steel flows from the tundish and needs to be inserted and retracted at appropriate times. Ponikvar said that when the ladle shroud needs to be exchanged or cleaned, the Simetal LiquiRob is able to do that. It takes an oxygen lance and cleans the steel or slag buildup so the shroud can be reused instead of being discarded, he said.
In the mold area, the LiquiRob could dose the casting powder, as well as exchange submerged entry nozzles, remove slag and insert separator plates.
Siemens said the centerpiece of the Simetal LiquiRob for many applications is its optional position detection system, a twin video camera sensor mounted on the robot arm. From a reference plate mounted on the ladle or tundish, the system analysis position moves in three deviations in all three axial directions in addition to rotations. The deviation parameters are automatically transferred to the robot control system, allowing for a high degree of measuring accuracy and observational flexibility as well as excellent position measuring results in many adverse conditions.
Ponikvar said the Simetal LiquiRob and other robots have a bright future in steel mills. I think that everyone is continuing to not only look at their safety records, but at what they can do to improve their costs and profitability. If they could have a piece of equipment that provides this type of repeatability and that also improves safety, productivity and the quality of their end product, then they are all for it.