Martensitic stainless steel have the highest strength but also the lowest corrosion resistance of the stainless steel. Martensitic steels with high carbon contents are used for tool steel. Due to their high strength in combination with somecorrosion resistance, martensitic steels are suitable for applications where the material is subjected to both corrosion and wear. An example is in hydroelectric turbines.
Martensitic grades of stainless steel were developed in order to provide a group of stainless alloys that would be corrosion resistant and hardenable by heat treating. The martensitic grades are straight chromium steels containing no nickel. They are magnetic and can be hardened by heat treating. The martensitic grades are mainly used where hardness, strength, and wear resistance are required.
Martensitic stainless steel has a relatively high carbon content (0.1% – 1.2%) compared to other stainless steel. The martensitic steels are plain chromium steel containing between 12% and 18% chromium, can be heat treated to obtain high strength with good ductility. Martensitic stainless steel has very high hardenability. When only limited corrosion resistance or resistance to moderately elevated temperature scaling is required, can be used in the annealed condition, but its highest corrosion resistance is attained in the hardened and stress relieving (low temperature tempered) condition.
Basic martensitic grade, containing the lowest alloy content of the three basic stainless steels (304, 430, and 410). Low cost, general purpose, heat treatable stainless steel. Used widely where corrosion is not severe (air, water, some chemicals, and food acids. Typical applications include highly stressed parts needing the combination of strength and corrosion resistance such as fasteners.
Contains lower carbon than Type 410, offers improved weldability but lower hardenability. Type 410S is a general purpose corrosion and heat resisting chromium steel recommended for corrosion resisting applications.
Has nickel added (2%) for improved corrosion resistance. Typical applications include springs and cutlery.
Contains added phosphorus and sulfur for improved machinability. Typical applications include screw machine parts.
Contains increased carbon to improve mechanical properties. Typical applications include surgical instruments.
Contains increased chromium for greater corrosion resistance and good mechanical properties. Typical applications include high strength parts such as valves and pumps.
Further increases chromium and carbon to improve toughness and corrosion resistance. Typical applications include instruments.
|Stainless Steel – Martensitic|
|End Use|| Composition|
| 0.2% Yield|
| AL 403|
|Turbine blades, banding, strapping and hose clamps||C 0.15 max, Mn 1.0 max, Si 0.5 max, Cr 11.5-13.0, Ni 0.6 max, P 0.04 max, S 0.03 max, Fe Balance||ASTM A176 AMS QQ5763|| 0.280|
| 70 min|
| 30 min|
|25 min||96 Rockwell B max|
| 410 |
|Cutlery, dental and surgical instruments, nozzles, valve parts, hardened steel balls and seats for oil well pumps, separating screens and strainers, springs, shears, and wear surfaces||C 0.08-0.15, Mn 1.0 max, P 0.04 max, S 0.03, Si 1.0, Cr 11.5-13.5, Ni 0.75 max, Fe Balance||ASTM A240|| 0.276|
| 65 min|
| 30 min|
|20 min||96RockwellB max (Annealed) 38-45 RC (Hardened)|
| 416 |
|Cutlery, dental & surgical instruments||C 0.15 max, Mn 1.25 max, Si 1.0 max, Cr 12.0-14.0, P 0.06 max, S 0.15 min, Mo 0.60 max, Fe Balance||ASTM A895 ASTM A194 AMMS 55610 SAE J405|| 0.280|
|15-30||38-45 Rc (Hardened)|
| AL 418 SPL|
|Engine braces, turbine exhaust components, exhaust struts, stiffeners, ducts||C 0.15-0.20, Cr 12.0-14.0, Mn 0.50 max, Ni 1.8-2.2, P 0.04 max, S 0.03 max, Si 0.50 max, W 2.5-3.5, Fe Balance||AMS 5508|| 0.284|
|20||25-50 Rockwell C (Hardened)|
|Cutlery, Dental and surgical instruments, nozzles, valve parts, hardened steel balls and seats for oil well pumps, separating screens and strainers, springs, shears, and wear surfaces||C 0.15 min, Mn 1.0 max, Si 1.0 max, Cr 12.0-14.0, Ni 0.75 max, Mo 0.5 max S 0.03 max, P 0.04 max, Fe Balance||ASTM A176|| 0.280|
|29||53-57 Rockwell C (Hardened)|
|Cutlery, dental and surgical instruments, nozzles, valve parts, hardened steel balls and seats fro oil well pumps, separating screens and strainers, springs, shears, and wear surfaces||C 0.60-0.75, Mn 1.0 max, Si 1.0 max, Cr 16.0-18.0, Mo 0.75 max, S 0.03 max, P 0.04 max, Fe Balance||ASTM A276|| 0.279|
|20||57-60 Rockwell C (Hardened)|
|Bearings, valve parts, cutlery and industrial knives||C 0.95-1.20, Mn 1.0 max, Si 1.0 max, Cr 16.0-18.0, Mo 0.75 max, S 0.03 max, P 0.04 max, Fe Balance||ASTM A276 AMS 5630 QQ-S-763|| 0.277|
|15||58-61 Rockwell C (Hardened)|
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)