Oct 6, 2026
Circular Metal Slitter Blades: Tolerances, Steels and Line Matching
How to spec circular metal slitter blades: 6CrW2Si/D2/LD/H13/HSS grades, ±0.001 mm thickness tolerance, flatness and concentricity limits, plus slitting line matching.
What a Slitter Blade Has to Survive
Circular metal slitter blades work at the heart of the slitter tool apron: they unwind metal coils and slit them into strips — silicon steel, hot-rolled and cold-rolled stainless, galvanized iron, strip steel, aluminum and copper coil, even rubber tire components. The two failures buyers complain about most are fast edge wear and edge cracking under high-torque slitting, and both trace back to raw material selection and heat treatment.
Which Steels We Recommend
Common grades include 6CrW2Si, SKD-11 (D2), LD (7CrSiMnMoV), H13 and high speed steels such as SKH-51/M2. For thick, high-strength coil we favor fine-grain alloy steels with deep vacuum heat treatment and multiple tempers, which raise abrasion resistance while keeping enough ductility to stop the edge from micro-cracking. Hardness ranges from HRC 55 up to 70 depending on the material being slit.
The Tolerances That Matter
• Outer diameter tolerance: ±0.01 mm
• Inner diameter: 0.01–0.04 mm for a precise knife-shaft fit
• Thickness: ±0.001 mm, so knife and separator clearances hold across the whole set
• Flatness ≤ 0.003 mm, parallelism ≤ 0.002 mm, concentricity ≤ 0.02 mm
• Surface roughness Ra 0.1 µm to reduce burrs on the slit edge
Custom Sizes and Line Matching
Slitting capability, material and shaft diameter define the knife: outer diameters from 70 mm to 1050 mm, slitting thickness 0.1–16 mm, material tensile strength up to 1200 N/mm², and line speeds of 60–150 m/min are all workable ranges for OEM production. Knives are routinely matched to slitting and cut-to-length equipment from builders such as TCSF, GEORG, Butech Bliss and CAMU.
Buying Slitter Blades from ZHONGJIAN TECH
ZHONGJIAN TECH produces circular metal slitter blades and rotary slitter knives to drawing, with forging, vacuum heat treatment and precision grinding controlled in-house. Read our guide to slitter blade materials for grade comparisons, or send us your knife drawing for a factory-direct quotation with hardness certificates.