Nondestructive Evaluation of Metal Fatigue,
Abstract
The benefit of a multi-disciplined approach to the investigation of nondestructive evaluation (NDE) techniques for the detection of fatigue damage in engineering materials is established. The results of continued fatigue crack nucleation and propagation investigations in the vicinity of inclusions in 4340 steel are presented. NDE results using ultrasonic and magnetic perturbation methods are illustrated and discussed. Certain characteristics of magnetic signals from a fatigue crack are examined with regard to the plastic zone in the vicinity of the crack. Other features of magnetic signal response from an inclusion as a function of stress cycling indicate that significant improvements in the magnetic detection of fatigue cracks appear possible. Using analytic approaches, estimates of the shape and extent of plastic yielding in the vicinity of a surface inclusion have been made and have shown qualitative agreement with metallurgical results. Important metalurgical findings related to crack initiation and propagation are also presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1971
- Accession Number
- AD0728637
Entities
People
- F. N. Kusenberger
- J. Lankford Jr.
- Joshua R. Barton
- Philip H. Francis
Organizations
- Southwest Research Institute