Combining hardness measurements of a heat-treated crankshaft bearing with cross-sectional residual stress and retained austenite distributions measured by HEXRD

Daniel G. Mevec, Vince Jászfi, Petri Prevedel, Juraj Todt, Emad Maawad, Jozef Keckes, Peter Raninger

Research output: Contribution to journalArticleResearchpeer-review


Surface hardening is commonly used to modify mechanical properties of crankshaft bearings. In this work, residual stress and hardness distributions across the crankshaft bearings cross-sections are evaluated using synchrotron high-energy X-ray diffraction and hardness testing. It is shown that the measured hardening depth correlates with a point of sudden sharp reversal of the stress gradient from compressive to tensile. This point is linked to the microstructure and does not shift with subsequent tempering or trimming of the sample. The superimposed data is used to interpret the evolution of stresses during the quenching and tempering cycle and gain understanding of the hardening process for such complex geometries. Within the hardened zone retained austenite is found to increase with depth to over 15 %, which is attributed to reduced quenching effects as the material is further away from the surface. All measured properties agree in the determined hardening depth of 3.5 mm to 4.5 mm, which in turn fits well with optical evaluation of metallographic microsections.
Original languageEnglish
Article number104267
Number of pages8
JournalMaterials Today Communications
Issue numberDecember
Publication statusE-pub ahead of print - 19 Aug 2022

Bibliographical note

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  • High energy X-ray diffraction
  • Induction hardening
  • Residual austenite
  • Residual stress
  • Surface hardening
  • Synchrotron

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