When it comes to the visual inspection of tubing welds, the minimum acceptance criteria for the depth of porosity are quite stringent due to the critical nature of the welds in maintaining the structural integrity of the tubing. There are several possible criteria mentioned:
a. 1/64 in (0.4 mm) – This option suggests a specific measurable depth of porosity that might be acceptable.
b. Ok as long as the weld does not leak – This option allows for some porosity as long as it doesn't compromise the functionality of the weld by allowing leakage.
c. No porosity allowed – This option is the strictest, indicating that any visible porosity is unacceptable.
d. 25% of the base metal thickness – This option relates the acceptance criteria to the thickness of the base metal, allowing for some porosity proportional to this thickness.
Given these options, the most stringent and often used criterion for visual inspection is:
c. No porosity allowed.
This means that for a weld to pass visual inspection, any seen porosity is grounds for rejection. Porosity can lead to weaknesses in the weld that could affect the structural integrity and safety of the tubing, hence the requirement for zero tolerance in visual inspection settings. Therefore, the minimum acceptance criteria for the depth of porosity for visual inspection of tubing welds are:
Option c: No porosity allowed.
