Narrow-width martensitic stainless strip for disposable surgical and scalpel blades — 4Cr13 / SUS420J2, 0.10–0.40 mm × 6–25 mm, quenched to 50–54 HRC. Built for edge sharpness, corrosion resistance and biocompatibility per ISO 7153-1.
The table below is the working specification range for surgical blade strip. Exact values are agreed per order against the blade manufacturer's drawing and process.
| Parameter | Typical range | Why it matters |
|---|---|---|
| Material | 4Cr13 (GB/T 1220) or SUS420J2 (JIS G4304) | Martensitic stainless that hardens to 50–54 HRC and resists corrosion after passivation |
| Thickness | 0.10 – 0.40 mm | #10/#11 blades ~0.10–0.15 mm; #20–#25 blades ~0.25–0.40 mm |
| Width | 6 – 25 mm (narrow strip) | Matched to blade blank layout across the coil width for progressive dies |
| Thickness tolerance | ±0.005 – ±0.015 mm (typ.) | Blank weight and edge geometry depend on consistent gauge; confirmed per order |
| Width tolerance | ±0.05 – ±0.10 mm (typ.) | Feeds the progressive die; excess variation causes misfeed and scrap |
| Delivered hardness | ≤ 235 HB (annealed) | Soft enough for clean blanking or etching; final hardness achieved after customer quench |
| Final hardness (after Q&T) | 50 – 54 HRC | Balances edge sharpness and retention against chipping risk |
| Surface finish | Cold-rolled, bright / matte, defect-free | Rolled-in scale or scratches become weak points or cosmetic rejects on the blade face |
| Slitting burr | ≤ 5–10% of thickness (typ.) | Burr folded into the blank causes grinding defects and edge weakness |
| Camber | ≤ 1.0 mm / m (typ.) | Excessive camber causes misfeed in high-speed progressive lines |
Values are typical for surgical blade strip; exact tolerances and limits are confirmed at RFQ against your drawing and process. All delivered values documented on the MTC.
Most surgical blades use 4Cr13 or SUS420J2. SUS301 appears in spring-loaded instrument components, not the cutting edge itself. The table below maps grade to role.
| Grade | Type | C (%) | Cr (%) | Hardness | Role in surgical instruments |
|---|---|---|---|---|---|
| 4Cr13 | Martensitic | 0.36 – 0.45 | 12 – 14 | 50 – 54 HRC | Primary cutting edge — scalpel blades, surgical blades, dissecting knives |
| SUS420J2 | Martensitic | 0.26 – 0.40 | 12 – 14 | 50 – 53 HRC | Cutting edge + instrument bodies — razor blades, scissors, forceps jaws |
| 2Cr13 | Martensitic | 0.16 – 0.25 | 12 – 14 | 40 – 45 HRC | Instrument bodies & handles — tougher, lower hardness for non-cutting components |
| SUS301 | Austenitic | ≤ 0.15 | 16 – 18 | Work-hardened | Spring components — instrument latches, clips, return springs (not a cutting edge) |
Chemistry typical per GB/T 1220 / JIS G4304. 4Cr13 and SUS420J2 are the standard blade-edge grades; 2Cr13 and SUS301 support the instrument assembly. Final grade selection depends on the blade profile, production volume and the manufacturer's existing heat treat line.
Surgical blade production is unforgiving — a defect at the strip stage becomes a rejected blade at the end of the line. These are the four failure modes we engineer against.
Slitting 0.10–0.40 mm stainless to 6–25 mm widths with sharp, matched tooling and controlled tension. A burr that exceeds 5–10% of thickness folds into the blank, causing grinding burn or a weak edge. We verify burr height and direction on every coil before dispatch.
Thin, narrow strip distorts during oil quenching — flatness is critical for consistent edge grinding. Fixturing, press-quenching or controlled-atmosphere quenching manages distortion. We supply the annealed strip with flatness and camber controlled so your quench fixture works as designed.
The blade edge is ground after heat treatment. Inconsistent carbon across the coil causes inconsistent hardness, which causes inconsistent grind feel and edge geometry. Our chemistry control keeps carbon within a tight band so every blade grinds to the same edge.
After grinding, the blade must be passivated (nitric or citric acid) to restore the chromium oxide layer — this is what gives corrosion resistance and biocompatibility. Free iron from grinding or handling will rust if not removed. We advise on the passivation cycle and can supply pre-cleaned strip to reduce contamination risk.
A realistic walkthrough of the production route, from coil to packaged blade.
Step 1 — Coil receipt: 4Cr13 strip, 0.12 mm ± 0.005 mm × 12.5 mm wide, annealed to ≤220 HB, MTC documents chemistry (C 0.40%, Cr 13.2%) and surface inspection. Coil is rust-proof export packed on a wooden pallet.
Step 2 — Progressive blanking: The coil feeds a high-speed progressive die that blanks the blade profile (the #11's characteristic pointed tip and curved belly) at 200–400 strokes per minute. Burr from our slitting is oriented away from the cutting edge.
Step 3 — Heat treatment: Blanks are austenitized at 1030°C in a controlled-atmosphere furnace, oil-quenched, then tempered at 250°C. Hardness reaches 52 HRC across the batch. Flatness is maintained by fixturing.
Step 4 — Edge grinding: The cutting edge is ground to a hollow or double bevel profile. Consistent hardness from the coil means the grinding wheel removes material at a consistent rate — no soft spots that burn, no hard spots that chatter.
Step 5 — Passivation & clean: Blades are passivated in citric acid to restore the chromium oxide layer, then ultrasonically cleaned and inspected for edge defects under magnification.
Step 6 — Packaging & sterilization: Accepted blades are packaged in foil or plastic, then gamma-irradiated or autoclaved for sterile delivery. The strip's chemistry and corrosion resistance are what allow the blade to survive sterilization without rusting.
The entire route depends on the starting coil. A thickness variation of 0.01 mm changes blank weight and edge geometry. A carbon swing of 0.05% changes quench hardness by 1–2 HRC. A slitting burr of 0.015 mm on 0.12 mm stock is 12.5% of thickness — enough to cause a grinding defect. That is why we document every parameter on the MTC and verify before dispatch.
These grade families share material, processing or application territory with the topic on this page.
301 / 304 / 316 grades with excellent corrosion resistance and formability for springs, medical and food parts.
SK5 / SK7 / T8A / T10A grades with wear resistance and edge hardness for cutting tools.
Invar / Kovar / Elinvar / Nichrome precision alloys for electromagnetic, thermal-bimetal and resistance applications.
Include thickness × width, blade profile, annual volume and destination port. Our engineers reply within one working day.