SUS420J2 Cold Rolled Stainless Steel Sheet for Knife

What is SUS420J2 Stainless Steel?

SUS420J2 is a martensitic stainless steel grade under the JIS standard, known for its excellent hardness, wear resistance, and good corrosion resistance after heat treatment. It is widely used in the production of cutting tools, especially knife blades.

 

GNEE supplies high-quality SUS420J2 cold rolled stainless steel sheets specially designed for knife and cutting tool applications. Our products have been exported to more than 50 countries, including Europe, Southeast Asia, the Middle East, and the Americas, and have been widely used in hardware, kitchen knife, and industrial tool manufacturing, with hundreds of successful cases.

We hold authoritative certifications such as ISO 9001, SGS, and Mill Test Certificates (MTC), ensuring strict quality traceability and stable batch performance.

The chemical composition of SUS420J2 stainless steel sheets is strictly controlled, with carbon content of 0.26–0.35% and chromium content of 12.0–14.0%, providing excellent hardenability and edge retention. After proper quenching and tempering, the hardness can reach HRC 52–58, the tensile strength can reach 750–900 MPa, and the material maintains good toughness with low risk of chipping.

 

SUS420J2 sheets are produced using a cold rolling process, ensuring precise dimensional control. The thickness ranges from 0.4 mm to 6.0 mm, with tolerance controlled within ±0.02 mm. The sheets have minimal thickness variation, fully released internal stress, no deformation during laser cutting, and reduced grinding allowance. Surface finishes include 2B, BA, and No.4 polishing (Ra ≤ 0.6 μm), offering excellent grinding and polishing performance.Each sheet undergoes flatness testing, hardness testing, and ultrasonic inspection to ensure it is free from inclusions and cracks.

 

SUS420J2 Steel Coil Specifications

Item	Specification
Product Type	Cold Rolled Stainless Steel Coil / Sheet
Standard	JIS G 4305
Material Grade	SUS420J2
Surface Treatment	2B Finish
Protection Grade	With Paper Interleaving / Paper Lining
Max Coil Weight	2.5 tons
Width	1,000 mm
Thickness	1.0 mm
Inner Diameter (ID)	508 mm (20 inches)
Outer Diameter (OD)	Max. 1,200 mm
Edge Treatment	Slit / Deburred / Trimmed
Heat Treatment	Supplied in Annealed Condition
Application Field	Manufacturing of Kitchen Knives / Utensils
Quantity	20 tons per month
Lead Time	45–60 days

 

 Chemical Composition (Mass Fraction, wt.%)

Element	Carbon (C)	Silicon (Si)	Manganese (Mn)	Phosphorus (P)	Sulfur (S)	Chromium (Cr)	Nickel (Ni)*
Standard Value	0.26 – 0.40	≤ 1.00	≤ 1.00	≤ 0.040	≤ 0.030	12.00 – 14.00	≤ 0.60
Typical Value	0.33	0.45	0.50	0.025	0.002	13.20	0.15

*Nickel is a residual element unless otherwise specified.

 

Mechanical Properties (Annealed Condition  Delivery State)

The material is typically supplied in an annealed (soft) condition, making it suitable for blanking and laser cutting.

Property	Value	Unit
Tensile Strength (Rm)	≥ 520	MPa
Yield Strength (Rp0.2)	≥ 225	MPa
Elongation (A50mm)	≥ 18	%
Hardness (HV)	≤ 235	Vickers
Hardness (HRB)	≤ 99	Rockwell B

 

Heat Treatment Process of SUS420J2 Stainless Steel for Knife 

Process	Temperature Range	Cooling Method	Typical Hardness
Annealing	750 – 800°C	Furnace cooling	≤ 235 HV
Hardening (Quenching)	980 – 1050°C	Oil quenching or air cooling	52 – 55 HRC (as-quenched)
Tempering	150 – 250°C	Air cooling	50 – 54 HRC (final hardness)

 

SUS420J2 Stainless plate Physical Properties

Property	Value	Unit
Density	7.75	g/cm³
Modulus of Elasticity	200	GPa
Thermal Conductivity (at 100°C)	24.9	W/(m·K)
Specific Heat	460	J/(kg·K)
Magnetic Properties	Ferromagnetic	Strongly magnetic

 

Surface Finish Options

Finish Code	Description	Typical Use in Knives
2B	Smooth, cold-rolled, heat treated, pickled, skin passed	General purpose, semi-finished blades
BA	Bright Annealed (Mirror-like)	Decorative blades, high-end kitchenware
No.4	Polished with 150-180 mesh abrasive	Brushed finish for handles or utility blades
HL (Hairline)	Continuous linear polishing	Aesthetic architectural or tool surfaces

 

SUS420J2 Stainless sheets Dimensional Tolerance (Cold Rolled Sheet)

Thickness (mm)	Tolerance (mm)	Width Tolerance (mm)	Camber (mm/2m)
0.50 – 1.00	± 0.04	+ 0.30 / - 0	≤ 2.0
1.01 – 2.00	± 0.06	+ 0.50 / - 0	≤ 1.5
2.01 – 3.00	± 0.08	+ 0.70 / - 0	≤ 1.5

 

420J2 vs. 420J1 Sheets: Differences

The primary difference between 420J1 and 420J2 stainless steel sheets lies in their carbon content, which directly impacts their hardness, strength, and intended applications. Generally, 420J2 has a higher carbon content (0.26–0.40%) compared to 420J1 (0.16–0.25%), resulting in greater hardness and edge retention for the J2 grade.

 

420J2 vs 440C Stainless Steel Sheets: Knives

440C stainless steel is better suited for blades than 420J2. It has a higher hardness (58-60 HRC), better edge retention, and greater wear resistance, making it ideal for high-performance hunting knives or EDC (Everyday Carry) knives. 420J2 is an affordable, corrosion-resistant steel, but due to its poorer edge retention and easier sharpening, it's better suited for diving knives, kitchen knives, or entry-level tools.

 

For packaging and transportation, all stainless steel sheets are treated for moisture resistance and securely sealed using wooden crates, pallets, or bubble wrap. Standard containers or dedicated transport vehicles are used during transportation to ensure the integrity and safety of the goods during transit. We offer worldwide shipping, with a typical delivery cycle of 7-15 days from production to delivery, ensuring on-time delivery to our customers.

 

After bundling, the sheets are packed with waterproof paper and wooden pallets. The packaging is robust to prevent damage during transportation and can be customized according to regulations and customer requirements. Furthermore, clear labels are affixed to the exterior of the product packaging for easy identification of product and quality information.