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.


Unacceptable Weld 1
  • No purge.
  • Purging is essential to remove oxygen from the air as it may react with the metal.


Unacceptable Weld 2
  • Too much purge.
  • If this is for a documented weld, it is not acceptable.


Unacceptable Weld 3
  • Lack of penetration.
  • Preheat is too low.
  • Travel speed is too fast.
  • Arc length is too short.


Unacceptable Weld 4
  • No purge.
  • Oxidation due to reaction with the metal.


Unacceptable Weld 5
  • No purge.


Unacceptable Weld 6
  • 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.


Unacceptable Weld 7
  • Overlap.
  • When exposed to a corrosive atmosphere, can attack the weld.


Unacceptable Weld 8
  • Overlap, causing leak.
  • This creates more areas in which corrosion is more likely to happen.


Unacceptable Weld 9
  • 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.

Expert Bio

Yogini Dhopade

Yogini Dhopade has three degrees, speaks four languages, and has traveled to ten different countries across the world. She has an unmatchable passion for metals and spends her time at CSI managing everything related to corrosion-resistant alloys.

Tom O'Connor - Quality Control Manager

Tom O'Connor has over two decades of experience as a Manufacturing and Tooling Engineer, with degrees in Manufacturing Engineering and Welding Technology. He is a member of the American Welding Society (AWS), American Society of Mechanical Engineers (ASME), and the ASME BioProcessing Equipment (ASME BPE) Committee.


Central States Industrial Equipment (CSI) is a leader in distribution of hygienic pipe, valves, fittings, pumps, heat exchangers, and MRO supplies for hygienic industrial processors, with four distribution facilities across the U.S. CSI also provides detail design and execution for hygienic process systems in the food, dairy, beverage, pharmaceutical, biotechnology, and personal care industries. Specializing in process piping, system start-ups, and cleaning systems, CSI leverages technology, intellectual property, and industry expertise to deliver solutions to processing problems. More information can be found at www.csidesigns.com.