Stainless Steel 303 / Alloy 303Se / Alloy 303 Sulf

Technical Data Sheet


Chemical Composition Limits
Weight% C Mn Si P S Cr Ni Mo Se Cu
Alloy 303 Se
AMS 5640 Ty 2
0.15 max 2 max 1 max 0.12-0.17 0.04 max 17-18 8-10 1 max 0.15 - 0.40 1.00 max
Alloy 303 Sulf
AMS 5640 Ty1
0.15 max 2 max 1 max 0.15 max 0.15 min 17-19 8-10 1 max - 1 max

Stainless Steel 303 is a free machining stainless steel. Due to the addition of sulfur this 18-8 chrome nickel stainless steel has enhanced machinability where before it was tough and difficult to machine.   Stainless Steel 303 is widely used in the screw machine industry, as well as for use in shafts, valves and fittings. Stainless Steel 303 is not recommended for vessels containing gases or liquids under high pressure.

Typical Mechanical Properties


Alloy Ultimate Tensile Strength (ksi) Yield Strength 0.2% (ksi)
Elongation 2" (%) Reduction of Area (%) Brinell Hardness
Alloy 303 90 35 50 55 160
Typical Properties for 1" diameter round bar, annealed 1900°F

Alloy 303 (Stainless Steel) is available in Bar (Round, Flats, Hexagon, Squares), Plate, Wire. View stock list for further information Plate Stock List. For all other stock availability contact Sales.

AMS 5635 303Pb Bar / forging
AMS 5638 Bar / wire / forging
AMS 5640 Type 1 303Sulf Bar
AMS 5640 Type 2 303Se Bar
AMS 5641 303Se Free machine Bar
ASM 5738 Free mach, High yield str
ASTM A320 Grade B8F Cl1
ASTM A320 Grade B8F Cl2
ASTM A484 / ASME SA484
AISI 303
BS 970; 303S21
BS 970; 303S41
WS 1.4305

At Aircraft Materials we specialise in the rapid turn-around of orders, with most stock items ready for shipping out the same day to anywhere in the world. For time-critical orders, such as AOGs use our AOG service desk (, the team are dedicated to processing and dispatching orders on the same day, even for cutting orders on bar and sheet products.

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Every effort is made to ensure that technical specifications are accurate. However, technical specifications included herein should be used as a guideline only. All specifications are subject to change without notice.