Most chambers are adequately served by 304L. 316L is selected where the process atmosphere is corrosive or the drawing specifies SUS316L. Where the choice is unclear, state the operating conditions in the RFQ and the recommendation will be based on them.

What differs

Both are austenitic stainless steels. 316L contains molybdenum, which improves resistance to pitting and chlorides at higher material cost. For vacuum service and welding, both are suitable.

Verifying incoming stainless steel grade with a portable spectrometer
Incoming verification: every batch of stainless plate is grade-checked by spectrometer before cutting.

When to select 316L

Corrosive atmospheres in coating processes, contact with acids or chlorides, or a customer drawing that specifies SUS316L. For standard semiconductor chambers, 304L is the usual selection.

Material handling

Both 304L and SUS316L are kept in stock. Grade and surface finish follow the drawing. Certificates are dispatched with the unit, and incoming material is checked against specification before release.

Where the choice is unclear, include the process, atmosphere and temperature in the RFQ. The material recommendation is issued together with our DFM feedback.