Chemical plant may suffer from similar damage depending on the operating environment but, generally,
the failure mode would tend to be either mechanical or corrosive. Wherever damage arises from thermal
degradation or corrosion, suitable precautions should be taken to ensure that the existing material is capable
of responding successfully to the repair process and that all damaged material is removed as required.
Generally, material suffering mechanical damage, either from direct physical abuse, brittle fracture or
fatigue, does not suffer severe metallurgical damage. Provided that any physical defects, such as cracks or
laps, are removed a satisfactory welding repair can be made. If the cause of the initial failure such as the
surface profile or stress level and pattern, can be identified and corrected before return to service, a
satisfactory and lasting repair is possible.