Rotary Kiln Fabrication

Massive Rotary Kiln Fabrication for the Araguaia Project

Rotary kilns are the workhorses of the mineral processing and cement industries. Representing some of the largest moving industrial machinery in the world, these massive rotating cylinders operate at extreme temperatures and carry incredible internal weight. To prevent structural fatigue, vibration, or premature failure of the riding rings (tires) and drive gears, the shell of the kiln must be fabricated with near-perfect cylindricity.

The Manufacturing Challenge

The customer required the fabrication of a massive rotary kiln shell split into 11 transportable sections. The key manufacturing challenges included:

• Strict Cylindricity: Even millimeters of out-of-roundness on sections this large can cause catastrophic eccentric loads during field operation.
• Extreme Plate Thickness: Rolling heavy shell sections thick enough to handle the thermal expansion without compromising dimensional tolerance.
• Deep Weld Penetration: Continuous, defect-free welding along the massive longitudinal seams capable of passing 100% UT and RT non-destructive testing.
• Factory Fit-Up: Assembling the entire structure within the factory before breaking it down for global logistics to guarantee flawless on-site installation.

The Openex Solution

We deployed our massive 3-roll and 4-roll plate bending machines to smoothly shape the heavy metal plates. Plate rolling at this scale requires masterful operator calculation to prevent "fluting" or flat spots along the edges of the roll. Once the semi-cylinders were formed, we utilized heavily automated Submerged Arc Welding (SAW) booms to run full-penetration seams down the shells.

Following the weld phase, sections underwent intensive Thermal Stress Relief in our massive heat treatment furnaces. Finally, taking advantage of our 180-acre facility, our engineers staged and completely dry-fitted the 11 shell sections indoors on large rotators to ensure perfectly matching tolerances prior to shipment.