AISI 420 Martensitic Stainless Steel: Hardenable Cutlery Grade
ASTM A276 · Published: 2026-06-03 · Updated: July 2026
AISI 420 is a martensitic stainless steel that can be hardened by heat treatment to achieve high hardness (50-55 HRC) while retaining moderate corrosion resistance. It is the standard material for cutlery, surgical instruments, valve parts, and...
AISI 420 is a martensitic stainless steel that can be hardened by heat treatment to achieve high hardness (50-55 HRC) while retaining moderate corrosion resistance. It is the standard material for cutlery, surgical instruments, valve parts, and pump shafts.
Quick Facts
| Category | Stainless Steel |
| Standard | ASTM A276 |
| Density | 7.75 g/cm³ |
| Yield Strength | 345 MPa (annealed) |
| Tensile Strength | 700-1,930 MPa (hardened) |
Global Equivalents & Cross-Reference
Related Materials
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Frequently Asked Questions
Can 420 stainless rust?
Yes, 420 has lower corrosion resistance than 304 or 316 — approximately similar to 410. It will develop surface rust in chloride-rich environments. The tradeoff is its hardenability: 420 can achieve >50 HRC while 304 cannot be hardened by heat treatment.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu