Technical guide · 2026-08-03
Martensitic Stainless Steel
Martensitic stainless steels are chromium steels with sufficient carbon and hardenability to transform during heat treatment. They are selected when hardness, edge retention, wear resistance or high strength is more important than the corrosion resistance and formability available from common austenitic grades.
01
Definition and boundary
Grade name alone does not define performance: annealed machinable stock, hardened product and tempered component can have completely different properties.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Austenitizing and quenching form martensite; tempering balances hardness and toughness.
Carbon level strongly influences achievable hardness and weldability.
Chromium supports moderate corrosion resistance but surface finish and tempering condition remain important.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| General martensitic grade balancing heat treatability, strength and moderate corrosion resistance. | Verify the ordered product specification, condition and dimensions before substitution. | |
| Higher-carbon family used where increased hardness and polished edges are important. | Verify the ordered product specification, condition and dimensions before substitution. | |
| Higher-strength or high-hardness choices requiring careful heat treatment and toughness review. | Verify the ordered product specification, condition and dimensions before substitution. |
04
Properties and trade-offs
Heat-treatment condition controls hardness, strength and toughness.
Corrosion resistance is generally below common 304/316-type grades.
Magnetic response is expected in annealed and hardened conditions.
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Cutlery, blades and surgical instruments
- Valve, pump and turbine components
- Shafts, fasteners and wear-resistant parts
Properties and trade-offs
- Start with required hardness/toughness after final temper, not nominal grade alone.
- Check corrosion environment and cleaning because increased carbon does not improve passivity.
- Review section size, quench route, distortion and cracking risk with the heat treater.
07
Fabrication, durability and inspection
Machine in the specified soft condition and leave allowance for heat-treatment distortion.
Control decarburization, austenitizing, quench and temper parameters by qualified procedure.
Welding may require preheat, controlled consumables and post-weld treatment; assess case by case.
08
Procurement checklist
- State annealed, hardened-and-tempered or final hardness condition.
- Specify cleanliness, decarburization, straightness, machining allowance and NDE where critical.
- Require heat-treatment records and hardness/toughness tests matched to the component.
09
Standards, sources and review
Standards and designation context
- ASTM A276/A276M for applicable bar and shape products
- ASTM A240/A240M for applicable flat products
- Component and heat-treatment specifications control final mechanical acceptance
Authoritative research sources
worldstainless · Technical overview, accessed 2026
Nickel Institute · Technical Guide 9014, 2020
ASTM International · A240/A240M-26 scope page