Rolling Mill Process
The primary function of a Rolling Mill is to reheat semi-finished steel billet/ Ingot nearly to their melting point, then roll them thinner and longer through successive rolling mill stands driven by motors
Sample Layout
RMT Tools is reshaping the steel industry and influencing the direction of the area’s industrial development as the best Steel Mill in Saudi Arabia. The name RMT Tools is a symbol of quality in the steel sector. Our goal when we first arrived in Saudi Arabia was to improve the productivity and quality standards of the regional steel mills by providing them with cutting-edge equipment and technology. We have accomplished this goal by continuously providing creative solutions that address particular requirements.
- Critical to Rolling Mill is its reheat furnace,
- Billets and Ingots are stacked on the Hot charging area of the plant with the help of overhead cranes.
- Billets placed parallel to each other on the CI lines in the furnace are continuously pushed inside the Reheating furnace with the help of mechanical or Hydraulic pusher depending on the quantity.
- The furnace is divided into number of zones (preheat, top-and-bottom; heating, top-and-bottom; and soak, top-and-bottom, east-and-west )depending on the hourly heating capacity of the Reheating furnace for temperature control.The preheat and heating zones combust a mixture of natural gas and preheated combustion
- Air with massive burners on the side walls of the furnace heat the billets nearly to its discharge temperature.
- Incoming combustion air to is heated before its fired into the furnace using the heating blowers and reccuperators
- Computer models calculate the targeted roughing mill exit temperature of the Billet to obtain a furnace discharge (‘drop-out’) aim temperature. Estimating the temperature profile through the thickness of Billet feeded in the furnace on an ongoing basis, the computer aids the operator in selecting the production rate and zone set-points that will maximize production of Billets uniformly heated to as close to the target temperature as possible
- When the Billet reaches the ‘discharge door’ at the exit end of the furnace, and the computer has determined that the Billet has been sufficiently heated, the door opens and the material is drawn out of the furnace with the help of Ejectors. The intensely hot Billet is placed on a roller table which carries it into the roughing mill.
Descaling
After exiting the reheat furnace, the Billet passes through a descaling unit, an enclosure employing two pairs of spray headers that blast the intensely hot Billet with 1,500 psi pressurized water to remove the thick layer of oxidized iron that forms at the surface of the Billet in the oxygen-rich atmosphere of the reheat furnace.
Slitting systems
Slitters manufactured by Rmt are highly accurate and consistent dividing. Slitters are basically used to allow rebars to be rolled in multiple strands, significantly improving the productivity of small size rebars, without increasing their finishing speeds.
Roughing
- The roughing mill is made up of Multiple independent rolling mill stands, Billets heated in the furnace until they glow bright orange-yellow are rolled through one stand at a time to produce transfer bars suitable for finish rolling. High-pressure water-jet nozzles clean the oxidized iron, or scale, from the surface along the way.
- As the transfer bar exits the last roughing mill stand, the thickness of the leading edge of the bar is estimated. Similarly, a pyrometer measures the temperature profile of the bar from head to tail. Depending on the gauge, width, and grade of the product to be rolled. This data is collected in anticipation of finish rolling.
Cropping
- Because a square head-end is critical to properly threading the finish mills, and because an uneven tail can bruise work-roll surfaces or cause threading problems for the next production process, the head- and tail-ends of nearly every transfer bar are cropped by using crop shear, and Snap shear.
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Rolling Mill Process Flow
Our rolling mill process integrates finishing mills, flying shears, cooling beds, coilers, bundling units, and slitting systems into one streamlined line. Each stage is engineered for dimensional accuracy, consistent quality, and efficient handling, ensuring rebars are delivered ready for storage, transport, and downstream processing.
Finishing
01. Hot Rolling Mills includes multiple finishing mills to reduce the thickness of the transfer bar down to the gauge according to customer’s requirement.
Flying Shear
01. Flying shears are used for shearing of Reinforcement bars on the fly by synchronizing its circular speed with the linear speed of the incoming rebars on given axis. 02. Flying shears are digitally operated and controlled to ensure accurate cutting as well as a digital output for providing management of the cutting mechanism.
Cooling Bed
01. Used for Cooling and cross transferring the finished product towards the discharge end.
COILING or BUNDLING
01. Rmt designed Edenborune type and Garret type coilers are used for obtaining a compact coil of Hot rolled bars rolled upto size of 12 mm .The hot rolled condition of the compact coil makes it suitable for direct cold working with high ductility during elastic deformation and low energy demand for final forming while while protecting the bearings from heat radiation .
02. The speed of the coiler is upto 40m/sec.Bundling
01. Bundling machines are used to make bundles of the Rebar so that it could be easily lifted with the help of overhead or Mobile crane and transported
Slitting systems
01. Slitters manufactured by Rmt are highly accurate and consistent dividing. Slitters are basically used to allow rebars to be rolled in multiple strands, significantly improving the productivity of small size rebars, without increasing their finishing speeds.
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Common Rolling Mill Problems and Solutions
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Problem
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Likely Cause
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What To Check or Do
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Cobbles (bar jams in the mill)
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Cold or uneven billet, bad guides, speed mismatch, bad head end
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Check furnace temperature, guide setting, stand speeds and crop shear performance.
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Uneven or low heating
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Burner imbalance, poor zone control, billets pushed too fast
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Rebalance burners, review zone set-points and pusher rate.
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Surface pitting or scale marks
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Weak descaling, long delay after discharge
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Check descaler nozzles and water pressure, shorten billet delays.
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Size out of tolerance
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Roll wear, loose stand settings, temperature swings
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Change worn rolls, re-set gaps, stabilise bar temperature.
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Weak or inconsistent TMT strength
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Wrong quench pressure or flow, bar temperature too low at entry
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Tune quench water settings and finishing temperature, then re-test samples.
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Bent bars on the cooling bed
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Uneven cooling, bed transfer problems
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Check bed alignment and transfer mechanism, then add or tune straightening.
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Frequent gearbox or coupling failure
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Misalignment, overload, poor lubrication
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Frequently Asked Questions
Steel billets are reheated in a furnace, descaled, and passed through roughing and finishing stands that make the bar thinner and longer. The bar is then cut by shears, cooled on a cooling bed, and bundled or coiled. Each step is explained in detail above.
Billets are usually heated to about 1,100–1,200 °C before they enter the roughing mill. The exact temperature depends on the steel grade, the section being rolled and the mill design.
Hot rolling is done above the steel’s recrystallisation temperature, so the metal is easy to shape. It is used for rebars, wire rods and sections. Cold rolling is done at room temperature on already hot-rolled material. It gives tighter tolerances and a smoother surface.
TMT means Thermo-Mechanically Treated. After the last rolling stand, the bar is quenched with water so the outer layer hardens while the core stays softer. This gives a strong surface and a ductile core. See our Rebar Mill.
A typical plant needs a reheating furnace with pusher and ejector, roughing and finishing mill stands, shears, gearboxes and couplings, a cooling bed, and straightening and bundling equipment. Browse them on our Our Products page.
The cost depends on plant capacity, the products you want to roll, the level of automation and the scope of supply. Send us your requirement and we will prepare a quotation. Request a quote.
Yes. RMT Tools supplies turnkey rolling mill projects as well as single machines. See our Turnkey Projects and Clientele pages.
Planning a new rolling mill?
Tell us your product, capacity and location. Our team will suggest a mill layout.