420 Stainless Steel Cold Rolled Sheet Precision Dimension Bright Surface Finish
420 cold-rolled stainless steel sheet is a high-carbon martensitic stainless steel produced through precision cold rolling processes. The cold rolling operation imparts superior surface finish, tight dimensional tolerances, and enhanced mechanical properties compared to hot-rolled equivalents.
This grade offers high hardness (after heat treatment), good wear resistance, and moderate corrosion resistance. It is widely used in applications requiring a combination of sharp cutting edges, durability, and a smooth, bright surface.
| Feature | Benefit |
|---|---|
| Precise dimensional accuracy | Tight thickness tolerances (±0.03mm to ±0.05mm) |
| Excellent surface finish | Smooth, bright, or matte finishes (2B, BA, No.4, HL) |
| Improved mechanical properties | Higher strength and uniformity due to work hardening |
| Superior flatness | Suitable for precision stamping and forming |
| Consistent quality | Uniform microstructure and performance across the coil |
| Element | Content Range |
|---|---|
| Carbon (C) | 0.15% – 0.36% |
| Chromium (Cr) | 12.00% – 14.00% |
| Manganese (Mn) | ≤ 1.00% |
| Phosphorus (P) | ≤ 0.040% |
| Sulfur (S) | ≤ 0.030% |
| Silicon (Si) | ≤ 1.00% |
Note: The carbon content allows hardening by heat treatment to achieve HRC 50–55. Chromium provides moderate corrosion resistance.
| Parameter | Range / Details |
|---|---|
| Material Grade | 420 Stainless Steel (Martensitic) |
| Manufacturing Process | Cold Rolled (CR) |
| Thickness | 0.3 mm – 6.0 mm (typical cold rolled range) |
| Thickness Tolerance | ±0.03 mm to ±0.05 mm (depending on thickness) |
| Width | 500 mm – 1500 mm (slit or mill edge) |
| Width Tolerance | 0 / +3 mm (slit edge) |
| Length | Coil form: as required (typically 50–500 kg coils) Sheet form: 1000–4000 mm (cut-to-length) |
| Flatness | ≤ 3 mm per meter (or as agreed) |
| Surface Finish | 2B, BA, No.4, HL, Mirror (No.8), or custom |
| Delivery Condition | Annealed (soft) – suitable for further forming and heat treatment |
| Hardness (Annealed) | ≤ HB 235 |
| Hardness (Heat Treated) | HRC 50 – 55 |
| Density | 7.75 g/cm³ |
| Finish Code | Description | Typical Application |
|---|---|---|
| 2B | Smooth, matte grey finish produced by cold rolling, followed by annealing and pickling | General industrial, stamping, forming |
| BA (Bright Annealed) | Mirror-bright, reflective finish obtained by bright annealing in a controlled atmosphere | Decorative household appliances |
| No.4 | Brushed / satin finish (120-320 grit) | Architectural panels, kitchen equipment |
| HL (Hairline) | Long, continuous brush lines | Elevator panels, decorative trim |
| No.8 (Mirror) | Highly reflective mirror finish | Cosmetic packaging, high-end decoration |
Other finishes (including embossed, patterned, or coated) are available upon request.
| Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| Annealed (Cold Rolled) | 550 – 750 | 300 – 450 | 15 – 25 | ≤ HB 235 |
| Quenched & Tempered | 800 – 1000 | 600 – 800 | 8 – 12 | HRC 50 – 55 |
Note: Mechanical properties vary with carbon content and heat treatment parameters. Values shown are typical.
| Process | Temperature | Cooling Medium | Resulting Hardness |
|---|---|---|---|
| Annealing | 750 – 800°C | Furnace slow cool | ≤ HB 235 |
| Hardening | 980 – 1040°C | Oil or air | HRC 50+ |
| Tempering | 150 – 370°C | Air | HRC 50 – 55 (adjustable) |
Caution: Avoid tempering in the range of 400–600°C (temper embrittlement zone).
| Aspect | Cold Rolled Advantage |
|---|---|
| Surface Quality | Smooth, defect-free surface, ideal for decorative and precision applications |
| Dimensional Accuracy | Tight thickness tolerances (±0.03mm), suitable for high-volume stamping |
| Mechanical Consistency | Uniform hardness and strength across the entire coil |
| Work Hardening | Higher as-rolled strength (if supplied non-annealed, e.g., hard or half-hard tempers) |
| Formability | Annealed cold-rolled sheet offers excellent formability for bending, drawing, and stamping |
| Industry | Specific Application | Recommended Finish |
|---|---|---|
| Cutlery & Blades | Kitchen knives, scissors, surgical blades | 2B, No.4 |
| Medical Instruments | Forceps, retractors, dental tools | 2B, BA |
| Molds & Dies | Plastic injection molds, die-casting molds | 2B |
| Automotive Components | Trim panels, exhaust system hardware | No.4, HL |
| Household Appliances | Knife blades for food processors, blender blades | 2B, BA |
| Architectural & Decorative | Elevator panels, door hardware, decorative trim | HL, No.4, Mirror |
| Industrial Tooling | Saw blades, industrial knives, wear plates | 2B |
| Precision Stamping | Electronic components, spring clips, and washers | 2B, BA |
| Form | Thickness Range | Width Range | Weight (Coil) | Length (Sheet) |
|---|---|---|---|---|
| Coil | 0.3 – 6.0 mm | 500 – 1500 mm | 50 – 500 kg | — |
| Cut-to-length Sheet | 0.3 – 6.0 mm | 500 – 1500 mm | — | 1000 – 4000 mm |
| Slit Coil | 0.3 – 6.0 mm | 10 – 500 mm | 50 – 500 kg | — |
| Thickness Range | Thickness Tolerance (±) | Width Tolerance (Slit Edge) | Flatness (per meter) |
|---|---|---|---|
| 0.30 – 0.60 mm | 0.03 mm | 0 / +0.5 mm | ≤ 2 mm |
| 0.61 – 1.50 mm | 0.04 mm | 0 / +1.0 mm | ≤ 2 mm |
| 1.51 – 3.00 mm | 0.05 mm | 0 / +1.5 mm | ≤ 3 mm |
| 3.01 – 6.00 mm | 0.06 mm | 0 / +2.0 mm | ≤ 3 mm |
Each coil or sheet is subject to the following inspections:
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Chemical analysis – per heat
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Hardness test (Rockwell B or C, depending on condition)
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Tensile test (yield, tensile, elongation)
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Surface roughness measurement (Ra, Rz as required)
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Flatness inspection (using a straight edge or a laser)
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Dimensional check (thickness, width, length)
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Visual inspection (surface defects, scratches, oil spots)
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Eddy current or PMI (upon request)
Certificates Available:
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Mill Test Certificate (EN 10204 3.1)
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Third-party inspection report (SGS, BV, TUV – upon request)
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Heat treatment records (if applicable)
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NACE compliance (on request)
| Item | Method |
|---|---|
| Sheet Packaging | Paper interleaving between sheets, moisture-proof paper wrapping, steel strapping, wooden pallet |
| Coil Packaging | VCI paper + moisture-proof paper + galvanized steel outer wrapping + wooden skid |
| Edge Protection | Cardboard or plastic edge protectors for coils |
| Marking | Grade, dimensions, heat number, and weight are clearly labeled |
| Port of Loading | Major Chinese ports (Shanghai, Tianjin, Ningbo, etc.) |
| Shipping Terms | FOB, CFR, CIF (as agreed) |
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