303 Stainless Steel Plate - ASTM A 895 - For Cutting and Machining

303 SS is a free-machining, austenitic stainless steel that is used primarily for parts requiring machining, grinding or polishing. The additional sulfur present in 303 assists in breaking up turnings which reduce drag on the cutting tool. This alloy offers good corrosion resistance in mild environments and good forming properties. It is non-magnetic in the annealed condition, is not hardenable by heat treatment, and can only be hardened by cold working. It is also difficult to weld, and may require filler rods and annealing.

The improved machinability of 303 stainless (UNS S30300) makes it ideal for screw machine applications, aircraft fittings, and fasteners. The additional sulfur that allows this product to be readily machinable also lowers its corrosion resistance compared to a grade like 304. Overall toughness is lower but still good despite the inclusion of sulfur, and is comparable to other austenitic grades of stainless steel. We offer 303 stainless in plate from 0.1875” to 4.000” thicknesses.

303 Inventory Size Ranges


0.1875" - 4.000"

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Standard Inventory Specifications

  • UNS S30300
  • AMS 5640 Chem Only
  • ASTM A 895

Common Trade Names

  • AISI 303

Common Applications of 303

  • Aircraft applications including fittings, shafts and spindles
  • Automatic screw machine applications
  • Medical devices with screw threads, drilled or tapped holes
  • Pump and valve parts
  • Architectural applications
  • Nuts and bolts
Chemical Composition of 303 Stainless Steel
Element Percent by Weight
Cr Chromium 17.0 min - 19.0 max
Ni Nickel 8.0 min - 10.0 max
C Carbon 0.15 min
Mn Manganese 2.00 min
P Phosphorus 0.20 max
S Sulfur 0.15 min - 0.35 max
Si Silicon 1.00 max
Mo Molybendum 0.60 max

Physical Properties of 303 Stainless Steel


Density lb/in?


Density g/cm?


Melting Point


Thermal Conductivity at 212°F (100°C)

112 BTU/hr/ft²/ft/°F

Thermal Conductivity at 212°F (100°C)

16.2 W/m-°K

Electrical Resistivity

28.3 Microhm-in at 68°C

Electrical Resistivity

72.0 Microhm-cm at 20°C

Mechanical Properties of 303 Stainless Steel



(max) 202 (HBN)

303 and 304 have similar chemistry and both are iron alloys, however Alloy 303 was purposefully developed for ease of machining. The additional sulfur present in 303 assists in breaking up turnings which reduces drag on the cutting tool and increases machining speeds. AISI 303 is not weldable and has limited formability due to its sulfur content. AISI 304 is weldable and machinable. It has very good drawability as well. Its low yield strength and high elongation allow it to be formed into complex shapes.

The technical data provided is for information only and not for design purposes. It is not warranted or guaranteed.