Ductile iron modelling and optimisation for mechanically and thermally loaded components

Jarkko Laine

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

Today, casting is an important part of mechanical engineering, especially in large engine manufacturing, where more than 60% of the components are castings. The spheroidal cast irons are significant materials, due to their good material and excellent castability properties. The technological development has increased the mechanical and thermal loads on the components, which can be seen as higher material requirements. At the same time, the requirements for the reliability and service life of the components have become even more critical. In this work, the thermal conductivity of different types of cast iron from room temperature to 400 ° C were studied. Based on those results, the thermal conductivity and mechanical properties of spheroidal graphite cast iron at elevated temperatures with different silicon concentrations and ferrite-pearlite ratios were further investigated. The effect of thermal conductivity and mechanical properties was also modelled. At elevated temperatures, there is a dynamic strain ageing present and that effect to ferritic-pearlitic cast irons were also investigated. The results were used to optimize the material of the mechanically and thermally loaded component. The choice of the cast iron type with spherical graphite was significant to the predicted life of the part. This work expands the knowledge about the behaviour of cast irons, especially of the spheroidal graphite cast iron at elevated temperatures. The use of the information in the optimization of thermally and mechanically stressed components enables the selection of the most suitable type of spheroidal graphite cast iron for the particular load case. That has a significant impact on the service life and reliability of the component.
Translated title of the contributionPallografiittivaluraudan mallinnus ja optimointi mekaanisesti ja termisesti kuormitetuille komponenteille
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Orkas, Juhani, Supervising Professor
Publisher
Print ISBNs978-952-64-0221-5
Electronic ISBNs978-952-64-0222-2
Publication statusPublished - 2020
MoE publication typeG5 Doctoral dissertation (article)

Keywords

  • cast iron
  • thermal conductivity
  • dynamic strain ageing
  • mechanical properities
  • elevated temperatures
  • material optimisation

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