Observation of Microstructures in Carburized-Quenched SCM415 Steel under Rotating Bending Fatigue of 716 MPa

Shusuke Kita, Kei Ushizima, Takahiro Matsueda, Koshiro Mizobe, Katsuyuki Kida*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

Abstract

Carburized-quenched steel has a hard layer on the surface and a soft layer in the core. Internal fatigue cracks are observed around the boundary between these two layers under cyclic stress. In this research, we investigated the microstructures (carbon content, prior austenite grains and retained austenite) in the carburized-quenched chromium molybdenum steel bar (JIS-SCM415, diameter = 10 mm) failed by rotating bending test (RBT) at nominal stress amplitude of 716 MPa. After the investigations, we obtained three conclusions: the carbon content in the area from the surface to 0.1 mm depth was higher than other area; the prior austenite grain (PAG) sizes at 0.1 mm depth from the surface was almost the same as that of 0.6 mm depth; and the retained austenite which was indicated from the ratio of γ to α in the cross section ranging from the surface to 0.1 mm depth was decreased by rotating bending fatigue.

Original languageEnglish
Title of host publicationMaterials Science Forum
PublisherTrans Tech Publications Ltd
Pages97-102
Number of pages6
DOIs
StatePublished - 2023

Publication series

NameMaterials Science Forum
Volume1084
ISSN (Print)0255-5476
ISSN (Electronic)1662-9752

Keywords

  • SCM415 steel
  • carbon
  • carburizing
  • retained austenite
  • rotating bending fatigue

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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