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 all stock items can be shipped out within 24 hours, usually within the same day. Even cutting orders for bar or sheet can be processed and dispatched the same day, and for time-critical situations such as AOGs, we have a dedicated AOG service desk ready to help (

Thanks to our global logistics network we can source from anywhere in the world in just a few days. We use a range of transport partners to enable us to ship overnight within the U.K. and Europe and provide fast shipping solutions to the rest of the world. If your requirement is urgent we can offer a priority shipping service, but also if time is not so critical we can offer more cost-effective options to ensure you get the best value for money. To find out more about our services click here.

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.

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