Stainless Steel - Martensitic

The major alloying addition in martensitic stainless steels is chromium in the range of 11 to 17%. The carbon levels can vary from 0.10 to 0.65% in these alloys. This radically changes the behavior of the martensitic alloys relative to the ferritic 400 Series alloys. The high carbon enables the material to be hardened by heating to a high temperature, followed by rapid cooling (quenching). Martensitic types offer a good combination of corrosion resistance and superior mechanical properties, as produced by heat treatment to develop maximum hardness, strength and resistance to abrasion and erosion. The martensitic grades are usually sold in the soft state. This allows the customers to cut or form the parts before they are thermally hardened. End uses include cutlery, scissors, surgical instruments, wear plates, garbage disposal shredder lugs, and industrial knives. The AL 403™ alloy is used to make vanes for steam turbines.

Stainless Steel - Martensitic
Alloy (UNS Designation)	End Use	Composition nominal wt%	Specifications	Density lb/in3 (g/cm3)	Tensile Strength ksi. (MPa)	0.2% Yield Strength ksi. (MPa)	Elong- ation %	Hardness

AL 403™ S40300	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 (7.75)	70 min (485 min)	30 min (205 min)	25 min	96 Rockwell B max

410 S41000	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 (7.65)	65 min (450 min)	30 min (205 min)	20 min	96 Rockwell B max (Annealed) 38-45 RC (Hardened)

416 S41600	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 (7.74)	75-90 (517-621)	40-50 (276-345)	15-30	38-45 Rc (Hardened)

AL 418 SPL™ S41800	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 (7.87)	130 (900)	105 (725)	20	25-50 Rockwell C (Hardened)

420 S42000	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 (7.74)	85 (586)	45 (310)	29	53-57 Rockwell C (Hardened)

440A S44002	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 (7.72)	104 (717)	62 (427)	20	57-60 Rockwell C (Hardened)

440C S44004	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 (7.68)	110 (760)	65 (450)	15	58-61 Rockwell C (Hardened)