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Title:Effects of repeated loading and moisture on fracture toughness of S A E 4340 steel
Author(s):Van Der Sluys, William Alan
Fracture Toughness
Abstract:This investigation determined the combined effect of water vapor and repeated loading on slow crack growth and fracture toughness. Round notched bars of SAE 4340 steel with a Rockwell C hardness of 48 were tested in tension, in a controlled environment, and at room temperature. The compliance of the specimen was measured on each cycle and was used to determine the amount of crack growth. It appears that the GIc values (fracture toughness) may be lowered slightly as the moisture content of the atmosphere increases. It was also found that water vapor alone assists slow crack growth but that water vapor combined with repeated loading has a greater effect. The effect can be easily seen by looking at the ratio ((σ_n^1)/σ_yp ) where σ_n^1 is the stress level sufficient to cause either slow crack growth or failure in less than 100 cycles. The amazing result is that if a specimen was cycled in the 100% relative humidity condition and with a natural crack present, the ((σ_n^1)/σ_yp ) ratio was found to be about 0.30 while it was about 0.55 if no moisture was present.
Issue Date:1963-05
Publisher:Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report:TAM R 245
Genre:Technical Report
Sponsor:U.S. Naval Research Laboratory, Contract No. Nonr 2947 (01) (x), SP Task Assignment 71402, Project Order 970
Rights Information:Copyright 1963 Board of Trustees of the University of Illinois
Date Available in IDEALS:2021-11-04

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  • Technical Reports - Theoretical and Applied Mechanics (TAM)
    TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.

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