AISI 420 / UNS S42000 (Martensitic) Stainless Steel
Chemistry, mechanical properties, physical properties, and practical selection notes for rolled AISI 420 products.
- Higher-carbon martensitic stainless; heat treatable to higher hardness; magnetic.
- Often used for blades, instruments, wear parts; corrosion resistance improves when hardened and polished.
Standards & Designations
ASTM A240 ♦ UNS S42000
Data Tables
- Higher-carbon 410; capable of high hardness; commonly used for blades and surgical instruments.
- Hardenable by heat treatment; corrosion resistance best in hardened + polished condition.
| Chemical composition (wt%) | Specification limits |
|---|---|
| C | 0.15 min |
| Mn | 1.00 max |
| Si | 1.00 max |
| P | 0.040 max |
| S | 0.030 max |
| Cr | 12.00–14.00 |
| Mechanical (typical / specified values) | Examples from Atlas 420 datasheet |
|---|---|
| Annealed | UTS 655 MPa; YS 345 MPa; Elong 25%; Hardness 255 HB max |
| Tempered 204°C | UTS 1600 MPa; YS 1360 MPa; Elong 12%; ~444 HB |
| Tempered 650°C | UTS 895 MPa; YS 680 MPa; Elong 20%; ~262 HB |
Values shown are typical/spec limits at room temperature unless noted; requirements vary by product form, size, and specification.
420 stainless steel from Source21 is a high carbon martensitic stainless steel grade recognized for its ability to achieve high hardness excellent edge retention and a refined polished finish. Often known as classic knife steel Type 420 stainless steel combines high chromium content with heat treatable strength offering moderate corrosion resistance alongside superior wear performance. It is widely used in cutlery surgical instruments dies gauges and precision tooling where sharpness durability and surface finish are essential.
Source21 supplies 420 stainless steel in coil, strip, sheet, foil, and bar, all manufactured to meet ASTM A240, ASTM A276, AMS 5506, and ASTM F899 standards.
Contact the Source21 team to place an order discuss material availability or receive expert guidance for precision and cutting applications backed by reliable supply and responsive service.