Martensitic stainless steels were the first stainless steels commercially developed (as cutlery) and have relatively high carbon content (0.1 - 1.2%) compared to other stainless steels. They are plain chromium steels containing between 12 and 18% chromium.
Basic properties
- moderate corrosion resistance
- can be hardened by heat treatment and therefore high strength and hardness levels can be achieved
- poor weldability
- magnetic
Common uses
- knife blades
- surgical instruments
- shafts
- spindles
- pins
Common martensitic stainless steel grades and their applications
Common Name | UNS No | Forms Available* | Typical Compositions (%) | Typical Applications | ||||
|
|
| C | Cr | Ni | Mo | Other |
|
410 | S41000 | Bars | 0.10 | 12.5 | - | - | - | General purpose grade for use in mildly corrosive environments. |
416 | S41600 | Bars | 0.10 | 12.5 | - | - | 0.20S | Free machining variation of 410. |
420 | S42000 | Bars | 0.25 | 12.5 | - | - | - | General engineering uses, such as pump and valve shafts. |
420C | - | Sheet and Coil, Plate and Bars | 0.30 | 12.5 | - | - | - | Developed for high hardness after heat treatment. Used for cutting tools, surgical knives etc. |
431 | S43100 | Bars | 0.18 | 16.0 | 2.0 | - | - | Hardenable steel with corrosion resistance approaching 304. Used for pump shafts etc. Should be double tempered after hardening. |
440C | S44004 | Bars | 1.10 | 17.0 | - | 0.40 | - | Capable of being hardened to 60HRC. Highest hardness and abrasion resistance of all the stainless steels. Corrosion resistance similar to 410. |
* Compatible or equivalent grades also available in castings. | ||||||||