Stainless Steel - Grade 303Se (UNS S30323)

Topics Covered

Chemical Composition
Mechanical Properties
Other Designations
Manufacturing Process


Grade 303Se stainless steel is a modified version of the basic grade 303, where selenium is substituted for sulfur to enable machining. Grade 303Se offers excellent machinability, good strength, and corrosion resistance. It has the capacity to resist scaling at temperatures up to 871°C (1600°F). This stainless steel is commonly used in parts requiring cold forming after machining.

The following datasheet provides an overview of grade 303 Se stainless steel.

Chemical Composition

The chemical composition of grade 303Se stainless steel is outlined in the following table.

Element Content (%)
Chromium, Cr 17-19
Nickel, Ni 8-10
Manganese, Mn 2
Silicon, Si 1
Phosphorous, P 0.2
Carbon, C 0.15
Selenium, Se 0.15 (min)
Sulfur, S 0.06
Iron, Fe Balance

Mechanical Properties

The mechanical properties of grade 303Se (annealed) stainless steel are displayed in the following table.

Properties Metric Imperial
Tensile strength 620 MPa 89900 psi
Yield strength (@strain 0.200%) 240 MPa 34800 psi
Elastic modulus 193 GPa 28000 ksi
Shear modulus 77.2 GPa 11200 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Elongation at break (in 50 mm) 50% 50%

Other Designations

Equivalent materials to grade 303 Se stainless steel are given below:

AMS 5640 (Type 2) AMS 5641 AMS 5738 ASME SA194
ASTM A194 ASTM A194 (grade 8F) ASTM A314 ASTM A320
ASTM A581 ASTM A582 MIL SPEC MIL-S-862 SAE 30303Se



SAE J405

Manufacturing Process

Analyze Your Metals | Request a Quote

The machinability of grade 303Se can be performed at excellent speeds and feeds. Selenium gives this material a very brittle chip. Welding at high temperature is not recommended as the selenium in this material tends to precipitate at the weld boundary causing weak and brittle joints; however welding can be performed at low temperatures with the AWS E/ER312 as the recommended filler metal.

Annealing of the grade 303Se can be performed at 1010-1066°C (1850-1950°F) followed by rapid cooling. Cold working can be used to raise the hardness and strength characteristics of this material. Hot working treatments such as forging and upsetting can be performed when the material is well heated to 1149-1260°C (2100-2300°F). Hot working below 927°C (1700°F) is not advisable. Rapid cooling after working enhances corrosion performance.


Grade 303Se stainless steel is widely used in screw and general machining industries.

The following are the other applications of grade 303Se stainless steel:

  • Hardware
  • Fasteners
  • Valve parts
  • Nozzles
  • Trim

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Your comment type

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.