How To Use Vacuum Oven for Best Results

Category: Educational Resource Center

Across various industries, vacuum purging is used to remove volatile substances/chemicals from the test item at low temperatures first before heating. Under vacuum, butane, propane, and other solvents convert into a gaseous form and evaporate, also known as “outgassing.” Vacuum purging works by lowering the atmospheric pressure in a vacuum oven chamber. Atmospheric pressure prevents “outgassing” from the surface area of the test specimen.

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Material Choices For Vacuum Chamber Construction

Category: Educational Resource CenterMaterials

Metals the most prevalent choice of vacuum chamber materials, with stainless steel (SS) far ahead of other metals such as mild steel. For example, deciding to use SS doesn’t mean any and all SS alloys. Free-machining alloys such as 303 SS contain sulfur (S), but the vapor pressure of the sulfur (S) is too high for high vacuum systems. 304 SS, though, is the most common choice. This helps narrow things down, but for ultrahigh vacuum (UHV)  the low-carbon 304L alloy is recommended.

Historically, the following three factors have made stainless steel the preferred material for the manufacture of vacuum chambers.

  • Ease of achieving vacuum leak-tight welds.
  • Ease of cleaning and bake out.
  • Availability of standard sealing systems.

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