SEDL / STP / STP821-EB / STP34451S

Application of Ultrasonic Fatigue Testing Techniques to the Evaluation of the Corrosion-Fatigue Strength of Materials

Roth, LD
Materials Engineering Department, Westinghouse R&D Center, Pittsburgh, Pa.

Willertz, LE
Pennsylvania Power and Light Company, Allentown, Pa.

Pages: 16    Published: Jan 1984

Download this paper for $25 PDF (300K)          View License Agreement
Abstract

A corrosion fatigue testing system has been developed for examining the corrosion-fatigue strength of engineering materials in the very high cycle regime (10⁹ to 10¹⁰ cycles) typical of many design lifetimes. Central to this resonant fatigue testing system is a high efficiency, large displacement, piezoelectric transducer which operates at a frequency of 20 kHz, thus enabling the accumulation of large numbers of cycles in a reasonable amount of time. A description of apparatus, environmental controls, and testing method is presented. Experimental 20 kHz and low frequency corrosion fatigue results for a number of engineering materials, including a 12% chromium stainless steel, show similar reductions in fatigue limit at a specified number of cycles, despite the difference in frequency. This result holds for a variety of aqueous environments with and without electrochemical controls imposed during testing. The data illustrate the capabilities of the ultrasonic corrosion-fatigue technique and are analyzed to assess its advantages and limitations.