THE EFFECT OF MICROSTRUCTURE AND AGING CONDITION ON THE FATIGUE CHARACTERISTICS OF THE 18% NI MARAGING STEELS

Abstract

Smooth and notched rotating beam fatigue characteristics at various strength levels are presented over the range of 1000-100000 cycles-to-failure for 250 and 300 grade 18% Ni maraging steels and a modified 4330 alloy. Two different heats of each of the maraging steels having large differences in ductility and toughness due to microsegregation are examined. In addition, the effects of under- and over-aging on fatigue properties are also studied. The microstructural segregation in the maraging steel showed no detrimental effect on the smooth or notched fatigue properties even though the ductility and toughness values were greatly reduced. Underaging the maraging steels was found to drastically impair the notched fatigue behavior. No correlation was found between notched fatigue behavior, as expressed by notched strength reduction factor, and the standard engineering mechanical properties of ductility and toughness.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
May 01, 1965
Accession Number
AD0617320

Entities

People

  • J. M. Barranco
  • R. V. Milligan
  • T. E. Davidson

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Bending Stress
  • Blood Coagulation Factors
  • Chemical Composition
  • Ductility
  • Engineering
  • Heat Treatment
  • Materials
  • Mechanical Properties
  • Mechanical Working
  • Microstructure
  • Notch Sensitivity
  • Statistical Data
  • Steel
  • Tensile Properties
  • Tensile Strength
  • Toughness

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Metallurgy