1.) Overheating may cause irreversible effects, so a repair may not be possible without material replacement. Physical properties of heated areas must be assessed to determine if material is still acceptable for incorporation in structure. Possible indicators include hardness checks (Brinell, Knoop, Vickers, or Rockwell), which can be done in-situ. Also, yield, ductility or Charpy V-notch tests can be done which require removing material for specimens. Metallographic analysis can determine if microstructure has changed, but this is very sophisticated and site-specific for this situation. Tests should be conducted by a qualified testing agency at the fabricator’s expense. If hardness testing provides adequate assurance, the material may then be accepted. Otherwise, either the material must be completely replaced or an adequate number of specimens must be extracted and tested to verify properties. If tests are acceptable, the fabricator must develop a method to replace the extracted areas of the material.
2.) Other solutions involve replacement of material; extensive non-destructive evaluation, including wet-particle MT, through thickness and surface wave UT, and hardness testing; stress relief of heated areas (difficult, and unwanted distortion is possible); or addition of reinforcing plates.
3.) For additional information associated with heat treatment of structural materials, the engineer is directed to ASTM A6 section 7. Also, refer to section 19 for information regarding retreatment of material.