ALAS Industrial Circular Slitter Knives: Complete Product Guide
Introduction: Precision is measured in microns, and downtime costs thousands in the metal processing and metal service industry. ALAS manufactures premium circular slitter knives and rotary slitting blades built for heavy-duty metal coil slitting under extreme shear load. Our industrial blades deliver burr-free cuts and minimal edge deformation, ideal for processing ultra-thin copper foil, high-grade silicon steel, and high-tensile automotive alloy steel.
What Are Circular Slitter Knives?
Slitter knives, also known as circular slitter blades, rotary shear blades or strip slitting blades, are core components for metal coil slitting lines. Working Principle: Two sets of circular blades installed on upper and lower cutter shafts shear longitudinally like scissors, cutting wide metal coils into customized narrow strips or trimming coil edge scraps. Metal slitting requires blades with high precision, wear resistance and structural strength for stable operation.
Core Application & Service Industries
Main Functions
Slit carbon steel, stainless steel, aluminum, copper, brass and various alloy metal coils into standard narrow strips
Form flat, smooth cutting edges to eliminate secondary edge finishing processing
Adapt to high-speed, uninterrupted automated coil slitting production lines
Guarantee uniform strip width tolerance to stabilize subsequent stamping, molding and assembly processes
Applicable Industries
Metallurgy, metal fabrication, automotive parts manufacturing, home appliance production, hardware processing, special alloy deep processing
Advanced Metallurgy Formulated for Metal Shearing Stress & Material Matching
Metal slitting requires balanced performance: sufficient hardness for abrasion resistance, and reliable toughness to avoid edge chipping under heavy shear pressure. Blade material determines service life and finished cut quality. ALAS selects, forges and heat-treats raw materials in-house to match diverse slitting working conditions. Below are four mainstream blade raw materials for industrial slitting, plus targeted blade solutions for common metal coils:
Four Main Raw Materials for ALAS Circular Slitter Knives
High-Alloy Tool Steel & Die Steel: The most widely used material grade, including Cr12MoV, 6CrW2Si, H13 (DIN 1.2344 / JIS SKD61) and LD grade. It balances hardness, wear resistance and impact toughness for general-purpose metal slitting.
High-Speed Steel (HSS): Standard grades: W18Cr4V, W6Mo5Cr4V2 (M2). Featuring excellent red hardness, it fits continuous high-speed metal shearing production.
Cemented Tungsten Carbide: Extremely high hardness and abrasion resistance, designed for high-volume, high-wear slitting jobs, with far longer service life than standard steel blades.
Powder Metallurgy High-Speed Steel: Industry standard grades: CPM 10V, ASP 2030, Premium PM-3 Series. Produced via Hot Isostatic Pressing (HIP) process, it delivers uniform carbide microstructure, higher strength and fracture toughness for heavy-duty long-run slitting.
Classified Blade Solution for Different Metal Coils
1. Ordinary Cold-Rolled & Hot-Rolled Carbon Steel Strips
Blade material: Cr12MoV / SKD-11
Blade type: Standard round blades, paired shear blades
Hardness: HRC 58–60
Performance benefits: Good toughness and wear resistance, long service life, cost-effective for daily high-volume continuous slitting
2. Stainless Steel Strips (304, 316, 430 Grade)
Blade material: Cr12Mo1V1 / D2 / 1.2379
Blade type: Round blades, paired upper-lower shear blades
Hardness: HRC 60–62
Performance benefits: Superior wear resistance and anti-chipping performance, delivers clean, burr-free mirror cuts for corrosion-resistant metal strips
3. Soft Non-Ferrous Metals (Aluminum, Copper, Brass, Copper Foil)
Blade material: M2/W6Mo5Cr4V2 High-Speed Steel, premium alloy tool steel, cobalt-bonded tungsten carbide
Blade type: Precision-ground round blades
Performance benefits: Smooth cutting face reduces metal adhesion and surface scratches on soft non-ferrous materials; tungsten carbide blades offer up to 10x longer service life than conventional steel blades
4. Galvanized & Color-Coated Steel Strips
Blade material: Cr12MoV
Blade type: Mirror-polished round blades
Hardness: HRC 58–60
Surface treatment: Nitriding treatment, mirror super-finish polishing
Performance benefits: Protective blade surface prevents zinc flaking and coating delamination, keeping coated strip surfaces intact after slitting
Processing Thickness & Width Scope
ALAS circular slitter knives cover wide processing ranges: it processes ultra-thin sheets from 0.1mm up to 10mm thick steel plates. Heavy-duty large-diameter blades (max OD 500mm) are available for extra-thick plate slitting. Finished strip width is adjustable based on slitter model and cutter group layout.
Key Factors for Blade Selection
Four key factors to select matched slitter knives for stable production:
Workpiece Material: Confirm metal type (cold/hot rolled steel, stainless steel, silicon steel, aluminum, copper etc.), material thickness, surface hardness and tensile strength.
Slitting Precision Standard: Different finished products have different limits on burr height and width tolerance. High-precision manufacturing requires premium-grade blades with thickness tolerance up to ±0.001mm.
Production Speed & Output: High-speed and mass production needs blades with upgraded wear resistance, thermal stability and professional surface coating treatment.
Blade Dimension & Edge Angle: Confirm blade outer diameter (OD), inner diameter (ID), thickness matching machine parameters. Edge angle is critical: small edge angle for thin sheets to improve sharpness; large edge angle for thick sheets to strengthen cutting edge anti-break performance.
Why Circular Slitter Knives Precision Matters for Metal Slitting
Precision defines qualified metal slitting. Standard premium circular slitter knives keep thickness and flatness tolerance within 0.003mm (3 microns); Precision-engineered ALAS circular slitter knives achieve ultra-tight tolerance down to ±0.0005mm. Poor blade precision brings major production risks: uneven blade thickness causes inconsistent knife clearance, leading to burrs, uneven cuts and edge damage. Oversized inner diameter triggers high-speed blade vibration and abnormal slitting failure.
Common Circular Slitter Knives Faults & Failure Causes
Blade Abrasion: Normal wear; accelerated by fast feeding speed and insufficient cutting lubrication
Edge Chipping & Breaking: Caused by improper knife clearance, deep cutting depth, ultra-hard workpiece material or wrong blade installation
Excessive Cutting Burrs: Mainly caused by overlarge knife clearance or dull cutting edge
Blade Vibration & Noise: Resulted from loose assembly, damaged bearing or unbalanced cutter shaft
Daily Circular Slitter Knives Maintenance & Maintenance Guidelines
Proper daily maintenance extends blade life and cuts overall production cost:
Accurate Installation & Gap Adjustment: Clean blades and cutter shafts before assembly. Adjust upper-lower knife clearance with feeler gauge; standard clearance ranges 0.03mm-0.1mm according to sheet thickness
Adequate Lubrication & Cooling: Use dedicated metal cutting fluid to reduce friction and cutting heat, avoiding blade thermal softening
Regular Surface Cleaning: Clear metal chips and oil residue after each production run to prevent corrosion and abrasive wear
Routine Inspection & Timely Grinding: Check edge wear regularly. Grind blades before edge fillet R reaches 2mm. Delayed grinding ruins cutting quality and wastes blade material
Standard Storage: Apply anti-rust treatment on idle blades, store separately to avoid edge collision damage
Blade Surface Coating Technology & Benefits
Blade coating applies micron-level hard protective films via PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition). Common coatings include TiN (Titanium Nitride) and AlTiN (Aluminum Titanium Nitride).
Coating improves surface hardness, lowers friction coefficient, and boosts wear and corrosion resistance. Coated blades perform better on stainless steel and high-strength alloy slitting, extending service life and delivering mirror burr-free cuts.
Required Parameters for Accurate Blade Quotation
Provide the following parameters to ALAS engineering team for accurate customized blade quotation:
Workpiece info: Exact metal grade, thickness range, material tensile strength
Machine info: Slitter model, cutter shaft dimension parameters
Production demand: Running speed, expected blade lifespan, finished edge burr standard
Blade customized parameter: Required OD, ID, thickness and cutting edge angle
International Standard Material Grade Comparison Table
| China (GB) | USA(ASTM) | Japan (JIS) | Germany (DIN) | Germany (W-Nr) | France (NF) | Russia (ROCT) | U.K (BS) |
| Cr12MOV | - | SKD11 | X165CrMov12 | 1.2601 | - | X12M | - |
| Cr12Mo1V1 | D2 | - | X155Cr12Mo12 | 1.2379 | X160CrMoV12 | - | BD |
| 4Cr5MoSiVI | H13 | SKD61 | X40CrMoV5-1 | 1.2344 | X40CrMoV5 | 4X5MO1C | BH13 |
| LD | - | - | - | - | - | - | - |
| W18Cr4V | T1 | SKH2 | S18-0-1 | 1.3355 | HS18-0-1 | P18 | BT1 |
| W6Mo5Cr4V2 | M2 | SKH9 | S6-5-2 | 1.3343 | - | P6M5 | BM2 |
Ultra-Precise Tolerances for Flawless Metal Edges
Burrs, camber and slitting defects are determined by blade geometric precision. ALAS blades are processed on high-end CNC grinding machines and inspected via full-process HardnessMap quality control to achieve top-tier precision:
Thickness Tolerance: Up to ±0.001 mm (±0.00004”) to guarantee accurate horizontal clearance and knife gap setup
Flatness & Parallelism: Within 0.002 mm (0.00008”) to minimize axial runout and eliminate wavy edges on the slit strips
Super-Finish Surfaces (Ra < 0.1 μm): Mirror-polished faces reduce friction and metal-to-metal pickup, preventing scuffing or scratching on sensitive surfaces like pre-painted steel or polished aluminum
Full-Line Slitter Tooling Solutions
Beyond standalone blades, ALAS provides complete matched tooling systems for all slitter models, simplifying assembly and improving running stability:
Male & Female Circular Slitters: Precisely paired for clean scissor-action shearing, uniform cutting force and low edge deformation
Rubber Stripper Rings / Bonded Spacers: Made with premium polyurethane or perbunan rubber to eject slit metal strips smoothly without surface indentation
Steel Spacers & Shims: Quenched hardened steel accessories with unified precision tolerances, supporting accurate blade positioning and gap adjustment
Advantages of ALAS Engineering-Grade Circular Slitter Knives VS Generic Import Blades
1. Higher Manufacturing Precision
ALAS blades are engineered customized tooling, not generic commodity blades. We adopt in-house CNC machining and full HardnessMap quality inspection. Strict dimensional, flatness and hardness control minimizes edge chipping, material scratching and production downtime.
2. Lower Total Operation Cost (TCO)
We customize metallurgy formulas based on customer material type, thickness and running speed. ALAS blades feature longer service life and higher tonnage per sharpening. Fewer blade replacements and grinding cycles cut labor, accessory and shutdown costs.
3. One-Stop Professional Engineering Support
Customers gain full slitting solutions instead of single blades. Our engineering team offers customized knife gap setting, machine matching and speed optimization based on site conditions, material tensile strength and coil specs, reducing material waste and raising finished yield.
Core Strengths to Choose ALAS Slitter Knives
Direct OEM Manufacturer: In-house production workshop and full imported CNC & heat treatment equipment. Custom non-standard blades available, stable production lead time
Full-Process Quality Control: Traceable inspection from raw material incoming, forging, heat treatment, grinding to finished packing, guaranteeing stable blade accuracy and wear resistance
Full Model Compatibility: Complete blade range including standard round blades, special-shaped blades and paired upper/lower blades, compatible with global brand slitters for diverse metal processing demands
Full-Cycle After-Sales Service: One-stop support covering blade selection, on-site installation guidance, precision re-grinding and blade repair to solve on-site slitting problems
Partner with the Metal Slitting Experts
Never compromise metal slitting quality. Upgrade your slitting line with ALAS professional circular slitter knives to lower cost per ton. Send your material tensile strength, thickness and coil width data to our engineering team for customized quotation and tooling optimization layout.
