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Fatigue behaviour of nickel- and cobalt-based laser cladded coatings on steel bars

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Details

Original languageEnglish
Title of host publicationSurface Modification Technologies XXVIII
Subtitle of host publicationProceedings of the 28th International Conference on Surface Modification Technologies
EditorsT.S. Sudarshan, P. Vuoristo, H. Koivuluoto
PublisherValardocs
Pages129-138
Number of pages10
ISBN (Electronic)978-81-926196-1-3
Publication statusPublished - Jan 2015
Publication typeA4 Article in a conference publication
EventInternational Conference on Surface Modification Technologies - , Finland
Duration: 1 Jan 2000 → …

Conference

ConferenceInternational Conference on Surface Modification Technologies
CountryFinland
Period1/01/00 → …

Abstract

Laser cladding allows the manufacturing of thick, dense and fusion bonded low diluted coatings, permitting its application in industry fields that require wear and corrosion protection. On the other hand, large residual stresses on the coating layer and noticeable changes in the substrate material may affect mechanical properties and fatigue strength. In this study, high load four-point bending fatigue tests were conducted, comparing the results to those of the substrate material alone and post-weld heat treated components. The fatigue test results were displayed with Wöhler curves. Two different substrate/coating couples are studied in this work: mild steel S355-J2 coated with Stellite21cobalt based hard-facing alloy, and low-alloy steel 42CrMo4 coated with Inconel625 nickel based super alloy. In order to better define how the features of the materials change with the cladding direction and the post weld heat treatment, the specimens were analysed by SEM/EDS; verifying the presence of defects, and how dilution changes along the cladding direction. Chemical etched samples were observed by optical microscope to assess the effect of the laser treatment on materials microstructures. Hardness measurements and depth sensing nanoindentations are performed to evaluate mechanical properties of coatings, HAZ and substrate. After fatigue failure, every fractured surface was separated from the fatigue specimen and analysed by stereo microscope, SEM and EDS in order to identify the reasons and the mechanisms of the failure.

Keywords

  • Laser cladding, Fatigue, Ni-based superalloy, Co-based hardfacing alloy

Publication forum classification

Field of science, Statistics Finland