Line 06
Slitting Lines
One wide coil into many narrow coils — slit width, burr and coil shape held by the slitter head, the tension section and the recoiler working together.
- 30,000 - 250,000 t/yr
- Width tolerance within ±0.05 mm
- 2 - 30 strips per coil
- Thickness 0.08 - 12 mm
From one wide coil to many narrow coils
The slitting line cuts a wide coil longitudinally into several narrower coils of precise width. Along with cut-to-length, it is one of the two basic processing routes in a service centre: CTL produces sheets, slitting produces narrow coil.
The value is in the width. Instead of buying narrow coil in fixed sizes, the plant slits to the width the next process needs, which changes both material cost and the product range it can serve.
Width on demand
Any width inside the line range, without holding stock in every narrow size.
Many strips at once
A single wide coil is slit into several widths in one pass.
Feeds the next process
Slit coil goes directly to tube mills, presses and roll forming lines.
Trim recovered
Edge trim is wound or chopped for recycling instead of being lost on the floor.
Where slit coil goes
| Industry | Products |
|---|---|
| Tube and pipe | Round, square, rectangular and spiral welded pipe feedstock |
| Roll forming | C and Z purlins, U-channels, angles, studs, shelving posts |
| Automotive | Door frames, seat rails, seat belt springs, weatherstrip carriers |
| Hardware and stamping | Hinges, locks, washers, electrical terminals, heat sinks |
| Appliances | Door gasket carriers, AC fins, motor laminations |
| Packaging | Strapping, steel banding, packaging strip |
| Solar and new energy | PV mounting rails, battery shell strip |
| Service centres | Cut-to-width coil distribution to fabricators |
Thickness, capacity and recoiling options
Three decisions shape the line: the thickness range it has to cut, the output it has to reach, and whether the strips are recoiled together or separately.
By strip thickness
| Type | Thickness range | Typical applications | Equipment features |
|---|---|---|---|
| Thin-gauge line | 0.08 - 1.5 mm | Silicon steel, thin-gauge stamping, appliances | High-precision slitter head, fine tension control |
| Medium-gauge line | 0.3 - 3.0 mm | CR, GI and CCL slitting, tube feedstock | Most versatile configuration |
| Heavy-gauge line | 1.0 - 6.0 mm | HR slitting, structural steel | High cutting force, rigid arbor design |
| Extra-heavy line | 3.0 - 12.0 mm | HR plate slitting, large-diameter pipe feedstock | Heavy-duty slitter, high-tension recoiler |
By capacity
| Tier | Line speed | Annual capacity | Application |
|---|---|---|---|
| Economy | 30 - 80 m/min | 20,000 - 60,000 t/yr | Small processors, multi-product, short runs |
| Standard | 80 - 150 m/min | 60,000 - 120,000 t/yr | Regular service centres with a stable order book |
| High speed | 150 - 250 m/min | 120,000 - 250,000 t/yr | Large service centres, high-volume production |
By recoiling method
| Method | Principle | Best for | Key feature |
|---|---|---|---|
| Synchronous, single arbor | All narrow strips wound on one recoiler shaft | Few strips, up to six, wider widths | Simple structure, lower cost |
| Separate, multi-arbor | Strips wound on separate recoiler arbors | Many strips, eight or more, high speed | No inter-strip friction, higher efficiency |
| Expanding mandrel with pressure roll | Mandrel expands inside the coil, pressure roll holds the wrap | General-purpose applications | Straight-sided coils with tower control |
Process sequence and specifications
The strip is centred before the slitter, cut by matched circular blades, then separated and recoiled under controlled tension.
Process sequence
| Stage | Operation |
|---|---|
| Coil handling | Overhead crane to uncoiler |
| Entry | Pinch leveler with rough levelling, crop shear for head and tail |
| Looping | Entry looper buffers the line for coil change |
| Centring | Side guide positions the strip against the slitter |
| Slitting | Circular slitter cuts the strip longitudinally |
| Trim handling | Edge trim separation and winding or chopping |
| Tension | Tension bridle sets back tension before recoiling |
| Separation | Dividing discs keep the strips apart |
| Recoiling | Single or multi-arbor recoiler winds the narrow coils |
| Exit | Coil car, strapping and transfer to finished goods |
Technical specifications
| Parameter | Range | Notes |
|---|---|---|
| Annual capacity | 30,000 / 50,000 / 80,000 / 100,000 / 150,000 / 200,000 / 250,000 t | Speed and utilisation dependent |
| Strip thickness | 0.08 - 1.5 thin / 0.3 - 3.0 medium / 1.0 - 6.0 heavy / 3.0 - 12.0 extra-heavy | Sets the equipment specification |
| Strip width | 300 - 1,250 mm standard, up to 1,600 or 2,000 mm | Wider lines need larger equipment |
| Number of strips | 2 - 30 | Thin gauge allows more strips |
| Slit width | 20 - 600 mm per strip | Minimum slit width 20 mm |
| Width tolerance | ± 0.05 - ± 0.15 mm | With servo control |
| Burr height | 0.02 - 0.05 mm | Material and blade clearance dependent |
| Maximum line speed | 60 / 100 / 150 / 200 / 250 m/min | Configuration dependent |
| Recoil inner diameter | 508 / 610 mm | Other sizes available |
| Finished coil weight | up to 10 - 20 t | Substrate and width dependent |
| Installed power | approx. 150 - 800 kW | Capacity and configuration dependent |
| Approx. footprint | 800 - 2,000 m² | Includes raw material and finished goods storage |
The circular slitting unit
Slit quality is decided at the slitter head. Arbor rigidity, blade material and clearance setting determine burr, edge condition and blade life, so these are specified as one system.
| Component | Function | Detail |
|---|---|---|
| Slitter arbors | Carry blades and spacers on parallel upper and lower shafts | Precision ground, 40Cr or 42CrMo, shaft diameter 120 - 280 mm |
| Circular blades | Matched pairs shear the strip as they rotate | SKD-11, Cr12MoV or powder metallurgy HSS, hardness HRC 58 - 62 |
| Spacers | Set the blade spacing that fixes slit width | Precision ground, thickness tolerance ± 0.005 mm |
| Clearance adjustment | Sets axial gap and overlap for each thickness | Servo or worm gear adjustment |
| Side guide | Keeps the strip centred entering the slitter | Servo centring to prevent wandering |
Blade clearance settings
| Parameter | Principle | Typical value |
|---|---|---|
| Axial clearance | 5% - 10% of strip thickness | 0.02 - 0.15 mm |
| Overlap | 30% - 50% of strip thickness | 0.05 - 0.5 mm |
| Clearance too large | Burr increases and the cut edge roughens | — |
| Clearance too small | Blade wear accelerates and chipping risk rises | — |
A blade change cart and spacer library are supplied so a full blade change can be planned within a shift rather than as a day-long stoppage.
Tension and trim handling
After slitting, each narrow strip needs back tension before it is wound. Without it the coil telescopes, winds loose or wanders, and the defect only appears at the customer.
Tension methods
| Method | Principle | Application |
|---|---|---|
| Tension bridle rolls | Two sets of pinch rolls run at a speed differential | General purpose, thin to medium gauge |
| Looper tension control | Loop sag holds a constant low tension | Thin gauge and aluminium, tension-sensitive material |
| Brake tension | Brake before the slitter | Economy configuration |
Tension sensors with VFD adjustment close the loop, so recoil tension is held as the coil builds rather than set once at the start.
Edge trim handling
| Equipment | Function | Detail |
|---|---|---|
| Trim separation rolls | Separates trim scrap from the finished strips | Guide wheels direct trim to the winder |
| Trim winder | Winds trim into coils for recycling | Expanding mandrel, speed matched to the line |
| Scrap chopper (optional) | Chops trim into small pieces for remelting | Saves floor space and trim coil handling |
Separation, recoiling and automation
Strips must stay apart and wind straight. The separator, recoiler and pressure roll are therefore selected with the strip count, not after the line layout is fixed.
Separator and recoiler
| Equipment | Function | Detail |
|---|---|---|
| Separator discs | Keep individual strips apart before the recoiler | Disc count matches strip count, micro-adjustable spacing |
| Recoiler | Winds the narrow strips into coils | Single, dual or multi-arbor with pressure roll |
| Coil car | Removes finished coils from the mandrel | Hydraulic lift, V-saddle |
| Strapping | Circumferential strapping of narrow coils | Manual, semi-automatic or automatic |
Automation
| Level | Function | Key components |
|---|---|---|
| Line PLC | Speed synchronisation, tension loop, width logic, coil change sequence | Platform agreed with the plant standard |
| HMI | Recipe management, parameter setting, monitoring and diagnostics | Touch screen, multi-language |
| Servo and VFD drives | Independent drives per section with speed synchronisation | Bus communication |
| Width measurement | Real-time slit width verification | Laser or vision inspection |
Materials and finished products
Silicon steel and stainless need harder blades and tighter burr control than carbon steel, while aluminium needs gentler tension. The material list is reviewed before the slitter is specified.
Suitable materials
| Material | Representative grades | Thickness | Requirement |
|---|---|---|---|
| Cold-rolled steel | ASTM A1008 / EN DC01 / JIS SPCC | 0.15 - 2.5 mm | Burr and surface quality critical |
| Hot-rolled steel | ASTM A1011 / EN S235 / JIS SPHC | 0.8 - 12.0 mm | Heavy-duty slitter |
| Galvanized (GI / GL) | ASTM A653 / A792 / EN 10346 | 0.2 - 3.0 mm | Blade design protects the coating |
| Prepainted (CCL) | Colour coated coil | 0.2 - 1.5 mm | Surface protection during slitting |
| Stainless steel | ASTM 304 / 430 / 201 / 316 | 0.2 - 6.0 mm | Harder blade material |
| Silicon steel | Non-oriented / grain-oriented | 0.15 - 0.65 mm | Minimum burr, brittle material |
| Aluminium alloy | ASTM 1060 / 3003 / 5052 / 6061 | 0.08 - 4.0 mm | Gentle tension control |
| Copper and brass | C11000 / C26000 / C51900 | 0.08 - 2.0 mm | High precision and surface finish |
Finished product range
| Product | Width | Thickness | Application |
|---|---|---|---|
| Tube mill feedstock | 50 - 600 mm | 0.3 - 8.0 mm | Round, square and spiral welded pipe |
| Roll forming feedstock | 80 - 500 mm | 0.5 - 6.0 mm | C and Z purlins, studs, shelving |
| Stamping strip | 20 - 300 mm | 0.15 - 3.0 mm | Hardware stampings and terminals |
| Silicon steel strip | 30 - 200 mm | 0.15 - 0.65 mm | Motor laminations |
| Strapping | 20 - 50 mm | 0.3 - 1.2 mm | Packaging steel strap |
| Solar mounting strip | 100 - 400 mm | 1.5 - 3.0 mm | PV mounting rails |
Spare parts and retrofit
Blades, spacers and pressure rolls wear with tonnage. Spare supply and retrofit work continue after handover, whether or not we supplied the original line.
- Slit width accuracy, burr trend, line speed and downtime monitored in real time
- Blade wear prediction based on accumulated metres run
- Mobile app for production reports, line status and alerts
Typical spare parts
| Part | Application | Detail |
|---|---|---|
| Circular slitting blades | Circular slitter | Matched pairs, ground to arbor specification |
| Precision spacers | Slitter arbors | Thickness tolerance ± 0.005 mm |
| Slitter arbors | Circular slitter | Spare upper and lower shafts |
| Separator discs | Recoiler entry | Various widths |
| Pressure rolls | Recoiler pressure roll | Anti-slip, wear-resistant rubber sleeves |
| Trim guide wheels | Edge trim handling | Wear-resistant material |
| Tension sensors | Tension section | Matched to the existing system |
| Hydraulic seals | Hydraulic system | Full sets |
Retrofit options
| Retrofit | Scope | Typical driver |
|---|---|---|
| Blade material upgrade | Standard Cr12 to powder HSS | Frequent blade changes |
| Automatic clearance adjustment | Manual to servo adjustment | Frequent specification changes |
| Entry looper addition | Pit or tower looper | Frequent stops for coil change |
| Tension control upgrade | Open loop to closed loop | Poor narrow coil shape |
| Automation upgrade | HMI, recipes and data logging | Changeover time and consistency |
| High-speed upgrade | Line speed increase with new drives | Capacity bottleneck |
| Remote monitoring | Data acquisition, cloud platform and mobile app | Multi-site management |
Configuration inputs
What we need to specify this line
- 01Material types and thickness range
- 02Slit width range and width tolerance
- 03Strip count per coil and recoil inner diameter
- 04Capacity target and coil weight
Questions
Questions we hear on this line
Synchronous or separate recoiling?
Up to about six strips, synchronous recoiling on one arbor is simpler and cheaper. Beyond that, separate arbors keep the strips apart and prevent inter-strip friction at higher speed.
How is burr controlled?
Blade material, clearance and overlap are set against the thickness and strength of the strip, and measured during commissioning against the burr limit agreed in the specification.
Can an entry looper be added to an existing line?
Yes, where floor space or pit depth allows. A looper is the main difference between a line that stops for every coil change and one that runs continuously.
Related terms
What engineers search for on this line
- slitting line
- coil slitting
- steel coil slitting line
- slitting machine
- cut to width line
- precision slitting
- metal coil slitter
Other lines
Sections planned in the same scope
Pickling Lines (PPL & CPL)
Turnkey push-pull and continuous pickling lines for hot-rolled strip, covering scale breaking, acid pickling, rinsing, fume treatment and acid regeneration.
Reversing Cold Rolling Mills (CRM & TCRM)
Turnkey single-stand and tandem reversing cold rolling mills for carbon, silicon, stainless and HSLA strip, with hydraulic gauge and automatic flatness control.
Continuous Hot-Dip Galvanizing Line
Turnkey continuous hot-dip galvanizing lines for GI, 55% Al-Zn and Al-Zn-Mg coatings, from cleaning and annealing through the zinc pot, skin-pass and chemical treatment.
Planning a new line or an upgrade?
Send the product mix and target capacity, and we will review the configuration.