• Neil Ide

The 316L Stainless steel is corroding, engineer's guide to material compatibility.

Updated: Aug 4

Have you ever used that oh so sweet stainless steel on your chemical line because its soooo corrosion resistant only to discover rusty brown discoloration of your fluid or corrosion around pipe/tube fittings?

Good, me neither...

Okay maybe once or twice...

This is an extra easy problem to solve. Before you start combining Acetone fluid with Viton seals check a "chemical compatibility database". Google that shit.

Cole Parmer has a great one here.

Pro tip: if the chemical compatibility is not listed as "Excellent, no effect" then the material is a no. Don't go picking a material that is listed anything other than excellent. Most compatibility data bases have 4 grades: Excellent, ok, moderate, severe. I'll make it easy for you.

They actually have 2 grades: compatible, not-compatible.

Use of a material graded "ok" resulted in me once blowing toxic ammonia all over my lab. Don't be like me.

Before you specify a component in your system check its list of wetted materials in that component for chemical compatibility. If a part doesn't have all wetted materials listed in the spec sheet its an automatic fail.

Pro tip: Corrosives that eat stainless steel don't tend to eat PTFE or PFA. Don't go reaching for 20x more expensive inconel just because you have rust spots on the stainless.

If you must flow a corrosive at a temperature that will make PTFE or other plastics fail then consider a corrosion barrier on your stainless steel such as this.

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