Section VIII, Div 1 does not explicitly address weld undercut. However, if you carefully read UW-35, there is reference made to not having a reduction in thickness of a finished longitudinal or circumferential weld joint exceed 1/32" or 10% of the wall thickness, whichever is less. These reductions would be from the welding process.
if we want to visually inspect a pressure vessel what is the acceptance criteria for porosity. should we consider that because there is no idea about porosity acceptance in ASME SecVIII so the porosity in surface is not permitted?
I would perform a surface NDT of these welds if RT is not required, like Liquid Penetrant (PT) or Wet Fluorescent magnetic particle (MT)and follow the mandatory Appendix 8 or 6 requirements, respectively in Section VIII, Div 1.
fazel1 If NDT is not required, vissual inspection is sufficient, if the welds pass the vissual examination the weld is acceptable. vissual examination has to comply with the Code requirements. any surface porosity is not acceptable but if there is any at all you can invoke sect V and deal with the AI, It means that if the porosity is less than the accepted if RT was performed the weld will have to be accepted.- Ussually with vissual you can not assess the size of the porosity and the weld is automatically rejected and repairs have to be done per Code.
ER
