• Name: SS303 / W.Nr. 1.4305
  • Code: 303
  • Time: 2015-02-08
  • Views : 459
  • Sold amount: 0Piece

Alloy 303 (UNS S30300) is an austenitic stainless steel developed for applications requiring extensive machining operations. The alloy has a sulfur addition which assists in breaking up turnings while reducing drag on the cutting tool when compared to the machining characteristics of the conventional 18-8 stainless steels.

The alloy is nonmagnetic in the annealed condition , but may become slightly magnetic as a result of cold working. The addition of sulfur negatively impacts the corrosion resistance of 303 making it less resistant than 304 to mildly corrosive environments.

Back to top


  • Aerospace Parts
  • Fittings
  • Pump and Valve Components
  • Screw Machine Products

Back to top

ASTM .......... A 895

Back to top

Corrosion Resistance
Alloy 303 is resistant to mildly corrosive environments. However, the alloy’s corrosion resistance is inferior to 304 in most applications. Its corrosion resistance is superior to 416, another free-machining grade, but is somewhat inferior to other 400 series stainless steels which do not contain higher sulfur levels. In order to obtain optimal corrosion resistance, it is recommended that Alloy 303 be chemically treated to remove sulfides from the final surfaces.

Back to top

Chemical Analysis

Back to top

Physical Properties

0.285 lbs/in3
7.89 g/cm3
  Specific Heat
0.12 BTU/lb-°F (32 – 212°F)
502 J/kg-°K (0 – 100°C)

Modulus of Elasticity
28.0 x 106 psi
193 GPa

Thermal Conductivity 212°F (100°C)
112 BTU/hr/ft2/ft/°F
16.2 W/m-°K

Melting Range
2500 – 2590°F
1480 – 1530°C


Electrical Resistivity
28.3 Microhm-in at 68°C
72.0 Microhm-cm at 20°C

Back to top

Mechanical Properties
Typicals Values at 68°F (20°C)

Back to top

Fabrication Data
Heat Treatment

Annealing – Heat to a minimum temperature of 1900oF (1038oC) and water quench or rapid cool by other means.

Hardening – Alloy 303 cannot be hardened by thermal treatment, it can only be hardened by cold working.

Cold Forming
The cold formability of Alloy 303 is adversely impacted by the high sulfur content. The alloy may be bent with a generous bend radius, however, when cold forming is required, 304 should be utilized.

Hot Forming
The high sulfur content of Alloy 303 also has a detrimental impact on hot workability. If hot forming is required, once again, 304 should be considered as an alternate selection.

Alloy 303 was developed specifically for ease of machining. The sulfur addition assists in breaking up turnings which reduces drag on the cutting tool. It produces small brittle chips and may be machined at high speeds with deep cuts and heavy feeds.

The table below suggests speeds and feeds for various machining operations for 303.

Alloy 303 is not recommended for applications requiring welding. If it is necessary to weld the alloy, AWS E312 filler metal may be considered.

The information and data in this product data sheet are accurate to the best of our knowledge and belief, but are intended for informational purposes only, and may be revised at any time without notice. Applications suggested for the materials are described only to help readers make their own evaluations and decisions, and are neither guarantees nor to be construed as express or implied warranties of suitability for these or other applications.