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Welder’s Handbook
Corrective Action
Weld metal cracks are removed by gouging and grinding followed by re-welding with the correct welding procedure. HAZ cracks are more difficult to repair. Extensive gouging and grinding may be required with magnetic particle inspection or dye penetrant inspection to ensure complete removal. Butter layers of weld metal may be required to build up locally to the best weld geometry. A weld procedure specific to the individual joint is advisable. Repair using a qualified low hydrogen weld procedure. May require weld procedure utilizing very low (H5) consumables. May need hydrogen to be removed by heat treatment. Inspection & Standards Surface opening cracks can be detected by magnetic particle inspection or dye penetrant inspection. Sub-surface defects can be found by ultrasonic examination and/or radiography depending on the size and orientation of the defect.
Throat cracks are longitudinal cracks that start in the middle of a weld and extend through the weld as more layers are added. They can appear on the surface after cooling. Throat Cracks
Underbead Cracks Underbead cracks are cracks in the HAZ, under the surface of the metal. They can be longitudinal or transverse. Underbead cracks are small and usually don't go all the way through the metal.
Underbead Cracks
Throat Cracks
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