Dent Calling Scratches Score Cracks Burr Burn Damage repair (blend) Corrosion (putting) Figure 10-60.  Compressor blade damage.  Term Appearance Usual Causes • Smooth repair of ragged edge or surface into  the contour of surrounding area. • Bent blade. • Damage to surfaces evidenced by discoloration  or, in severe cases, by flow of material. • A ragged or turned out edge. • Breakdown of the surface; pitted appearance. • A partial fracture (separation). • Small, smoothly rounded hollow. • A transfer of metal from one surface to another. • Displacement of material from a surface; a  cutting or tearing effect. • Eleongation of blade. • (See corrosion). • Contour of a blade or surface. • Deep scratches. • Narrow shallow marks. • Blend • Bow • Burning • Burr • Corrosion (pits) • Cracks • Dent • Gall • Gouging • Growth • Pit • Profile • Score • Scratch • Foreign objects. • Excessive heat. • Grinding or cutting operation. • Corrosive agents—moisture, etc. • Excessive stress due to shock, overloading, or  faulty processing; defective materials;  overheating. • Striking of a part with a dull object. • Severe rubbing. • Presence of a comparatively large foreign body  between moving parts. • Continued and/or excessive heat and  centrifugal force. • Presence of chips between surfaces. • Sand or fine foreign particles; careless  handling. Figure 10-61. Blade maintenance terms. 10-48