Intergranular Fracture in 4340-Type Steels: Effects of Impurities and Hydrogen.

Abstract

A study has been made of the conditions which lead to intergranular brittle fracture in 4340-type steels at an ultra high yield strength level (200 ksi, 1380 MPa) in both an ambient environment and gaseous hydrogen. By means of Charpy impact tests on commercial and high purity steels, and by Auger electron spectroscopy of fracture surfaces, it is shown that one-step temper embrittlement (OSTE or '500 F embrittlement'), and low K intergranular cracking in gaseous hydrogen are the result of segregation of P to prior austenite grain boundaries. Segregation of N also contributes to OSTE. Most, if not all, segregation apparently occurs during austenitization, rather than during tempering. These observations are discussed in terms of our understanding of the mechanisms of OSTE and hydrogen-assisted cracking.

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Document Details

Document Type
Technical Report
Publication Date
Jan 03, 1977
Accession Number
ADA054603

Entities

People

  • Charles J. Mcmahon Jr.
  • Howard C. Feng
  • Samir K. Banerji

Organizations

  • University of Pennsylvania

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Alloys
  • Auger Electron Spectroscopy
  • Auger Electrons
  • Austenite
  • Chemistry
  • Crystal Structure
  • Electron Spectroscopy
  • Elements
  • Embrittlement
  • Ferrium
  • Grain Size
  • Iron
  • Materials
  • Solid Solutions
  • Spectra
  • Tensile Strength
  • Yield Strength

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Metallurgy
  • Thin Film Deposition Science.

Technology Areas

  • Microelectronics