Stainless Steel / 303 SEL "B" (HI TENSILE)

303SE Condition B is cold worked to obtain increased tensile strength and hardness. This grade is a modified version of 303 with a selenium addition in place of sulfur which allows for excellent machinability. Selenium produces a better surface finish. The material is a 18-8 chromium-nickel stainless steel modified by the addition of selenium or sulphur, as well as phosphorus, to improve machinability and non- seizing properties. 303 is not hardenable by heat treatment. 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. (UNS:S30323)

Chemical Makeup

Element Min Max
Carbon, C 0.15
Manganese, Mn 2
Silicon, Si 1
Sulfur, S 0.04
Phosphorus, P 0.12 0.17
Chromium, Cr 17 19
Nickel, Ni 8 10
Copper, Cu - 1
Molybdenum, Mo - 1
Selenium, Se 0.15 0.4

Common Applications

  • Aerospace Aerospace
  • Industrial Industrial


  • Increased Tensile Strength & Hardness
  • Good Machinability
  • Corrosion Resistance
  • Nongalling Properties

We stock 303 SEL "B" (HI TENSILE) to the following specifications:

  • AMS-5738
  • ASTM-A-320 GRD B8F CL 2 (EXC. FLTS)
  • ASTM-A-484
  • MIL-S-7720
  • MIL-W-52263
  • QQS-763C
  • QQS-764

Click on a cross-section to see the sizes we stock:

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