| Analysis | Mechanical_Properties | Applications | Machineability_and_Weldability | Heat_Treating | Tolerances | Speedy Metals items |
303 is an “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. It is the most readily machinable of all the chromium-nickel stainless grades and has good corrosion resistance, although less than other chromium-nickel grades, such as 304 or 316. It is non-magnetic in the annealed condition and not hardenable by heat treatment. Tensile strength and hardness can be increased by cold working. Slight magnetism can be detected by cold working. 303 has excellent scale resistance at temperatures up to 1600° F in continuous service. It is manufactured by the electric-furnace process and meets the exacting requirements of the aircraft industry.
Stainless Plate conforms to ASTM A895, SAE J405
The above values are average and may be considered as representative of 303 stainless
303 is used almost exclusively for parts requiring machining, grinding, or polishing where good corrosion resistance is also required. It’s non-seizing and non-galling properties make it ideal for moving parts. Being austenitic steel, it is useful where low magnetic permeability is desired. 303 has fairly good forming properties. Used for aircraft parts, valves, valve trims, all types of screw machine products, bolts, screws, and machine parts, as well as architectural purposes. It is not recommended for vessels containing liquids or gases under high pressure
Machinability is rated at 78% of B1112. Average cutting speed 130 ft/min.
303 has only low to fair welding properties.
303 can be forged between 2100°-2350° F. Do not forge below 1700° F.
303 is not hardenable by heat treatment. Cold working increases tensile strength and hardness.
Annealing range is between 1850° and 2050°F. Cool rapidly. Water should be used for heavier sections; air for lighter sections. The stress relieving range is between 400° and 750°F.
| Plate Thickness (in) | Tolerance (in)* |
| 3/16 to 5/16 | +.045 / -.010 |
| 3/8 to 11/16 | +.055 / -.010 |
| 3/4 to 15/16 | +.060 / -.010 |
| 1 to 1-3/4 | +.070 / -.010 |
* Standard mill widths to 48"
Flatness Tolerance: Commercial flatness and camber per ASTM A480