When strength, wear resistance, and appearance are equally important, ASTM A240 420 stainless steel cold-rolled plate is the material of choice. Also known as AISI 420 / UNS S42000, this grade is a martensitic stainless steel that offers excellent hardness, polishability, and moderate corrosion resistance. It's commonly used in cutlery, molds, surgical instruments, and machinery where a smooth surface finish and durability are crucial.
What is ASTM A240 420 stainless steel plate?
ASTM A240 is the standard specification for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and general applications. Type 420 stainless steel contains approximately 12-14% chromium and a small amount of carbon, making it hardenable through heat treatment-a key difference from austenitic stainless steel grades like 304 or 316. The cold rolling process further enhances surface finish, flatness, and dimensional accuracy, making it ideal for decorative or precision engineering applications.
ASTM A240 Type 420 stainless steel plate Specification
| Property | Specification / Typical Value |
|---|---|
| Standard | ASTM A240 / A240M |
| Grade | 420 (AISI 420 / UNS S42000 / EN 1.4021) |
| Chemical Composition (%): | C 0.15 max, Cr 12–14, Mn ≤ 1.0, Si ≤ 1.0, Ni ≤ 0.75 |
| Density | 7.74 g/cm³ |
| Tensile Strength (Annealed) | 655–860 MPa |
| Yield Strength (0.2%) | 345 MPa (typical) |
| Elongation | 15–20% |
| Hardness (Annealed) | 200 HB max |
| Hardness (Hardened + Tempered) | up to 500 HB |
| Heat Treatment Range | 980–1050°C, air or oil quench, temper at 150–370°C |
| Surface Finish | 2B, BA, Mirror, No.4, HL |
| Thickness Range | 0.3 – 6.0 mm (cold rolled) |
Available Dimensions and Finishes
| Thickness (mm) | Width (mm) | Length (mm) | Surface Finish |
|---|---|---|---|
| 0.3 – 3.0 | 1000 / 1219 / 1500 | 2000 – 6000 | 2B, BA, Mirror, HL |
| 3.0 – 6.0 | 1000 / 1500 | 2000 – 6000 | No.1, No.4, Satin, Polished |
Tolerances: According to ASTM A480 and EN ISO 9445 standards.
Edge: Mill edge or slit edge as requested.
What is the difference between 420 stainless steel and 410 stainless steel?
420 stainless steel has a higher carbon content and is harder after heat treatment. 410 stainless steel is better weldable but slightly less hard.
Can 420 stainless steel be used outdoors?
Yes, but it is more suitable for dry or mildly corrosive environments. For marine or acidic environments, 316 or 904L stainless steel is recommended.
Can 420 stainless steel be mirror polished?
Of course. After fine grinding and polishing, 420 stainless steel can achieve a highly reflective mirror finish, which is common in decorative or surgical applications.
Why Choose Gnee for ASTM A240 420 Cold Rolled Plates
18+ years of export experience to 60+ countries
Full-size inventory of 0.3–6.0 mm cold rolled plates
SGS / BV / ISO 9001 certified production lines
In-house cutting, slitting, polishing, and packaging services
Competitive factory price and fast delivery within 15 days
Packaging and Delivery
PE film protection on both sides for polished plates
Packed in wooden pallets or fumigation-free boxes
Seaworthy export packaging with corner and edge protection
Delivery time: 7–15 days for stock, 25–35 days for custom sizes
