Home » Boiler Tube Failure Handbook » Holes, Pits, Gouges » Material Defect » Porosity in weld Porosity in weld Click on images to enlarge. CommentsWeld porosity may be due to inadequate shield gas flow or contamination on the surface of the material. Issue Type:Holes, Pits, Gouges » Material DefectLocations:SuperheaterBoiler Type:PowerIndustry:Pulp and PaperMechanism:Weld DefectDownload a PDFPorosity in weld