How Does the Coil Slitting Process Work?

  • /
  • /
  • How Does the Coil Slitting Process Work?

What is Coil Slitting?

Coil Slitting is the process of taking a wider master coil and slitting (cutting) it into a series of narrower coils by running the material through a set of rotary slitting knives. Each smaller coil is called a mult. Mults can be customized to your specific width and/or weight and packaged accordingly.

What is Coil Slitting

What Materials Can I Slit?

Alliance Steel can slit coils with material thickness ranging from .010” - .500” under one roof. We can slit hot roll, hot roll black, hot roll pickled and oiled, cold roll, coated steel (hot-dipped galvanized, electrogalvanized, galvannealed, and galvalume).

What is the Coil Slitting Process?

There are three main parts to a slitter: the uncoiler, slitter arbors/rotary knives, and a recoiler.

Uncoiler: The master coil is loaded onto the uncoiler at the entry of the machine. Then the uncoiler uses an expandable mandrel to grip the master coil on its inside diameter. The coil rotates off the mandrel, and the head of the coil is threaded into the machine’s edge guides.

Slitter: The material is fed length-wise into the slitter head, which consists of two parallel arbors. These parallel arbors are mounted with a customized set of rotary slitting knives and rubber stripper rings. Rubber rings help pull the material through the slitter arbors, while the knives penetrate the steel causing the material to break or fracture.

The key to running an efficient precision coil slitting job is in the setup. Alliance Steel uses precision tooling and knives to ensure the best slit edges and a computer-automated system to assure spacing and horizontal knife clearances.

Rule of thumb: the harder the material, the less the slitting knives must penetrate. The softer the material, the deeper the knives need to go before the material slits/breaks.

Recoiler: The recoiler’s primary purpose is to wrap the slit coils back into a coil form for packaging and shipment.

Heavy Gauge Coil Slitting:

Are you looking for a partner to slit your heavy gauge material? Our heavy-gauge line can slit .043” - .500” x 84”, with an 80,000 – max coil on entry, corrective leveling up to .187” and narrow heavy slitting to a width of 1.250”.

Alliance Steel is a flat roll and coil processing - steel service center in Gary, Indiana. We have been a leader in flat-roll steel supply and coil processing for over 20 years. In May of 2020, we relocated to Gary, Indiana, strategically placing ourselves near significant highways, mills, and ports. There are also two sales locations in the Mid- South (Atlanta and Memphis).

Our temperature-controlled 300,000 square foot facility is equipped with full rail service, multiple slitters, including a heavy-gauge line, numerous fiber lasers, multi–blanking, cut to length, stretcher leveling, and metallurgical capabilities.

Alliance Steel is prepared to support your steel needs with an extensive inventory of flat-rolled sheet and coil products.

We maintain a selection of hot rolled steel, hot rolled pickled and oiled, hot rolled pickled dry, cold-rolled steel, motor lam, all coated products steel products. For more information, please call 219-427-5400 or visit us at