UNS Number S30323
303Se Stainless Steel is a free machining 18-8 chrome-nickel steel. Selenium, added to an 18-8 stainless steel that is tough and difficult to machine, makes it so easily and freely machinable that it can be readily be handled on automatic screw machines. It can be machined at about 75% of the speed of carbon C1212. This material has displayed nongalling properties that make disassembly of parts easy and help to avoid scratching or galling in its moving parts.
Type 303Se has somewhat better formability than Stainless Type 303 and should be considered for applications which involve cold-forming operations.
Type 303Se can been used for parts that are fabricated by machining, grinding and polishing. For example, all types of screw machine products, valves, valve trim, etc. However, it is not recommended for vessels containing gases or liquids under high pressure.
Stainless Type 303Se is resistant to atmospheric corrosion, foodstuffs, sterilizing solutions, many organic chemicals and dyestuffs, and a wide variety of inorganic chemicals.
Intergranular corrosion may be a problem if the material is heated between 800ºF (427ºC) and 1650ºF (899ºC) or cooled slowly through that range.
For optimum corrosion resistance, surfaces must be free of scale, lubricants, foreign particles, and coatings applied for drawing and heading. After fabrication of parts, cleaning and/or passivation should be considered.
