9 Unacceptable Welds for High Purity Applications

Have you ever wondered why welds fail? When welding in a high purity environment, several factors can render a weld unacceptable: heat tint, a lack of purge, extra purge, overlap and/or leaking, and even inadequate welding technique. The photos below show examples of what could make a weld unacceptable in a high purity environment.


  • No purge.
  • Purging is essential to remove oxygen from the air as it may react with the metal.


  • Too much purge.
  • If this is for a documented weld, it is not acceptable.


  • Lack of penetration.
  • Preheat is too low.
  • Travel speed is too fast.
  • Arc length is too short.


  • No purge.
  • Oxidation due to reaction with the metal.


  • No purge.



  • Leak or overlap — When there is a disconnect between the head and toe of the weld.
  • Inadequate welding technique.
  • Could be prime spots for corrosion.


  • Overlap.
  • When exposed to a corrosive atmosphere, can attack the weld.


  • Overlap, causing leak.
  • This creates more areas in which corrosion is more likely to happen.


  • No purge.
  • Heat tint.

While these are all examples of unsuitable welds, remember that this is not an exhaustive list. The severity of unusable welds ranges from a more acceptable level to a severely unacceptable level that should never be used in your system. If you’re not sure whether or not a weld is adequate for your application, always be sure to contact your alloys specialist for verification.


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