Stress Rupture Cracks usually appear as:

• A. Large Transverse Cracks Along the Edge
• B. Tiny Hairline Cracks On or Across the Leading or Trailing Edge At Right Angles to the Edge Length
• C. Deep Longitudinal Cracks Along Blade Length
• D. Surface Pitting

Answer: (B)

Stress rupture cracks show up as very small, hairline cracks on or across the edge, and they run perpendicular to the edge length. This edge-centered, perpendicular orientation happens because the highest tensile stresses concentrate at the blade edges, so cracks initiate there and propagate across the edge rather than along the blade. Seeing large transverse cracks along the edge, deep longitudinal cracks along the blade, or surface pitting points to different damage mechanisms, not the typical edge-perpendicular hairline pattern of stress rupture.