Fractographic investigation and microstructural characterization of a diffusion-bonded sinter-hardened steel: A case study

Fractographic investigation and microstructural characterization of a diffusion-bonded sinter-hardened steel: A case study

•Case study of a sinter-hardened steel component fractured during bench-testing.•Microstructural features were related to critical aspects of Press & Sinter process.•Low density and superficial carburization were identified as the failure's root causes.•Positioning on the conveyor belt can...

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Bibliographic Details
Published in:Engineering failure analysis Vol. 152; p. 107442
Main Authors: Vezzani, O., Fortini, A., Blum, A., Morales, C., Soffritti, C., Merlin, M.
Format: Journal Article
Language:English
Published: Elsevier Ltd 01-10-2023
Subjects:
Endogas atmosphere
Failure analysis
Microstructure
Sinter-hardening
Sintered steel
Sintered steel
Endogas atmosphere
Sinter-hardening
Microstructure
Failure analysis
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Summary:•Case study of a sinter-hardened steel component fractured during bench-testing.•Microstructural features were related to critical aspects of Press & Sinter process.•Low density and superficial carburization were identified as the failure's root causes.•Positioning on the conveyor belt can affect the sintering atmosphere exposure. This study analyzes the fracture on a sinter-hardened steel component during bench-testing. The component was made from a Fe-base powder with pre-alloyed Mo (1.5 %), diffusion-bonded Cu (2.0 %) and mixed C (0.7 %), cold-compacted and sinter-hardened in an endogas atmosphere. The fractured surface was analyzed by scanning electron microscopy to investigate the failure mechanism. The same fractured component and a new one, taken as a reference, were observed by optical microscopy to identify the metallographic features, which were compared through microhardness measures. The mean porosity and some morphological characteristics of pores were determined by image analysis. Density was measured using Archimedes' principle, carbon content was quantified by combustion analysis. Based on the results, the failure mode was related to microstructure, microhardness and porosity morphology. Critical aspects in the compaction phase and in the sintering process were identified: carburization due to endogas sintering atmosphere was related to the occurred failure.
ISSN:1350-6307
1873-1961
DOI:10.1016/j.engfailanal.2023.107442