EDDY CURRENT INSPECTION OF TURBINE BLADES

The report presents the results of a program to find a nondestructive field inspection technique which will detect cracks in the leading and trailing edges of jet engine turbine blades. Such an inspection is required because the presence of cracks causes blade failures and can cause the loss of an engine or entire aircraft. Various nondestructive inspection methods were considered and experimentally evaluated in the laboratory. One was found suitable for field testing. This method, which uses eddy currents, is described in detail. Field and lab test data is presented. It includes response characteristics, speeds of inspection, and micrographs of typical cracks detected in the turbine blades of built up rotors from various engines. The system is capable of detecting cracks down to 0.020 in. in length, 0.0005 in. wide, and 0.005 in. deep. On built up rotors of an engine having 108 cleaned blades per stage cracks could be detected at an inspection rate of one stage in 15 minutes. The penetrant system could detect cracks at an inspection rate of one stage in 1 hour and 50 minutes.

• Corporate Authors:

  General American Transportation

  ,    
• Authors:
  • KRASKA, I R
  • Kamm, H W
• Publication Date: 1971-10

Media Info

• Pagination: 41 p.

Subject/Index Terms

• TRT Terms: Blades (Machinery); Equipment maintenance; Gas turbines; Maintenance; Nondestructive tests
• Subject Areas: Maintenance and Preservation; Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00035592
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: AFML-TR-70-266 Tech Rpt
• Contract Numbers: F33615-68-C-1429
• Files: TRIS
• Created Date: Dec 6 1973 12:00AM