University of Illinois Urbana-Champaign

Effects of repeated loading and moisture on fracture toughness of S A E 4340 steel

Van Der Sluys, William Alan

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https://hdl.handle.net/2142/111964

Description

Title
Effects of repeated loading and moisture on fracture toughness of S A E 4340 steel
Author(s)
Van Der Sluys, William Alan
Issue Date
1963-05
Keyword(s)
  • Loading
  • Moisture
  • Fracture Toughness
  • Steel
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.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 245
  • 1967-0541
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/111964
Sponsor(s)/Grant Number(s)
U.S. Naval Research Laboratory, Contract No. Nonr 2947 (01) (x), SP Task Assignment 71402, Project Order 970
Copyright and License Information
Copyright 1963 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
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.