Stainless Steel - Grade 303Se (UNS S30323)

Topics Covered

Introduction
Chemical Composition
Mechanical Properties
Other Designations
Manufacturing Process
Applications

Introduction

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
ASTM A276

ASME SA320

ASTM A473

SAE J405

Manufacturing Process

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.

Applications

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
     

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