Moog Flo-Tork: Applying Rack and Pinion Actuators in the Steel Industry

Moog has grown rapidly both in size and breadth of technology options due to a smart and progressive acquisition strategy. We have found that not all of our customers are aware of these acquisitions and the new solutions that will make their machine performance better. This issue is focusing on a new member of the Moog organization named Moog Flo-Tork that offers an important technology for the industrial marketplace – rack and pinion actuators.

Background on Moog Flo-Tork

Flo-Tork has long been known for the portion of its business devoted to the naval market but its capabilities in the industrial market are now open to a wider audience due to its acquisition by Moog in 2005. The markets served include fluid power and valve actuation. As a manufacturer of rack & pinion actuators, Flo-Tork is a perfect complement to Moog’s servovalve, pump, manifold and controls product line. Torque range capabilities up to 5,650,000 Nm (50,000,000 lb-in) allow the ability to custom design actuation packages to meet motion control requirements for our customers in a multitude of industries.

While Moog Flo-Tork sells into a variety of industrial applications, such as firefighting, solid waste processing, offshore, gas/oil pipelines, renewable energy and rail, this case study is focusing on the steel industry. Moog is a trusted solutions provider on a global basis to the steel industry for high performance solutions such as Servovalves and Servo-Proportional Valves, motion controllers and linear actuators. It now expands its offering to include rack and pinion actuators.

Please also see the Did You Know article for more information on Moog Flo-Tork.

Case Study – Steel Industry Applications for Rack and Pinion Actuators

Moog Flo-Tork prides itself on the ability to solve many unique motion control problems. The steel industry has offered a number of opportunities which demonstrate these problem solving capabilities.

The first application came to our attention due to the mill experiencing excessive down time in the rolling mill area because of shock loading on the electric drives used to operate the edge guides on the slab mill. In this application the slabs are heated in a re-heat furnace. As a slab exits the re-heat furnace it slides onto a conveyor system. It is necessary to align the slab to ensure it enters the first stage in a straight-on alignment. To accomplish this alignment, the rolling mill conveyor is equipped with a set of guide bars (edge guides) which move laterally and therefore, align the slab correctly.

When the equipment was initially built, an electric motor and gear box were used to drive the edge guides. The slabs exiting the re-heat furnace slammed into the edge guide and the resulting shock loads were transferred to the motor and gear box. Over time this shock loading caused high maintenance costs for replacements.

Photo #2 shows an 112,979 Nm (1,000,000 lb-in) hydraulic rack & pinion actuator Flo-Tork designed to fit into the existing mounting pad. The system was equipped with proportional valves which mitigated the shock loading. The 360º rotation of the actuator drives the edge guide pinions and positions the edge guides by a 4-20 mA control.

The result is ten years of uninterrupted operation

Photo #3 illustrates an application common in the continuous casting process.

In this process a tundish is used to hold the molten steel. Visualize this as a large trough used to hold a volume of steel and allow for continuous operation. There are 4-6 openings in the bottom of the tundish that feed into the continuous caster machine.

At the end of a casting run it is necessary to empty sculls (hardened steel and slag) and the fire brick from the tundish. To do this the tundish must be rotated and dumped. Flo-Tork actuators in torque ranges from 85,000 Nm (750,000 lb-in) to 176,000 Nm (1,500,000 lb-in) are being used throughout the steel industry to operate the dumping mechanism.

Photo #4 shows the cooling bed of an I-Beam casting machine. The I-Beams must be lifted into the upright position to promote rapid cooling. The initial design made use of clevis mounted cylinders which lifted the arms that stand up the beams. These cylinders were a constant maintenance problem because they were continuously out of alignment.

The customer approached Moog Flo-Tork for a solution and six 112,943 Nm (1,000,000 lb-in) actuators were provided to solve the problem. A unique feature of using multiple actuators in this type of application is that all six actuators were interconnected through the pinion shafts to ensure a simultaneous sequence thus eliminating uneven loading. The synchronization of multiple hydraulic cylinders, where there is an uneven distribution of load, has been a perennial problem since the inception of hydraulics. In this particular example, where all Moog Flo-Tork actuators are mechanically linked on a common pinion shaft, a very elegant solution is provided that overcomes this problem.

Additional steel applications include:

  • Degassing Hood Rotator – Actuator used to position hood over ladle for degassing heat
  • Roll Changing Table – Actuator replaces gear box and electric motor
  • Butterfly Valves on BOF Exhaust – Replaced cylinders for more compact system with better control
  • Up Enders – Rotary actuator used to position coils – standup or lay down
  • Walking Beam Furnace – Using rotary actuator and harmonic motion to advance slabs in furnace – Replaces cylinders for even motion control
  • Furnace door operator – Replaces cylinders to provide smoother operation


Customers are increasingly finding that no matter what their motion control challenge is, the partnership of Moog's technology and application expertise is a powerful combination in the Steel Industry. Because we specialize in motion control across a wide variety of industrial, aerospace and medical applications with some of the world’s most demanding customers, we readily take the experience learned throughout our company by our top engineers to new applications where customers are facing similar challenges. Like this article about Moog Flo-Tork, in future issues we will try to share with you more about the dynamic technologies, products and applications that are available through our other divisions and newly acquired companies.

For More Information

Please check with our regional experts to learn more.

Europe: Bernhard Zervas, telephone +49-7031-622-219, e-mail

Americas: Allen Ruef, telephone +1-330-682-0010 x222, e-mail:

Asia Pacific: Peter Clements, telephone +61-7-38423134, e-mail:


Thomas M. Leaver has been with Flo-Tork for the past 20 years, first working in inside sales and progressing to his current position as Sales Manager and Department Head. He started his career as a Production Supervisor at J & L Steel and worked a sales person with Koppers Co. Duff-Norton and Alliance Machine Co. prior to joining Flo-Tork in 1987. He has a B.S. in Commerce from Rider University in Trenton, NJ.

Allen Ruef has been with Moog Flo-Tork for 5 years as an Application Engineer and currently as a Senior Sales Engineer. Allen has a Bachelors of Science in Mechanical Engineering and 15 years experience in Industrial Automation utilizing pneumatics and hydraulics.