Abstract
dc:description.abstractDespite the significant progress in understanding the wear mechanisms and associated factors, steels for components susceptible to wear are developed primarily based on their hardness. The hardness often is achieved by martensitic transformation. Increasing the carbon concentration and substitutional solute content may also help. Hardness certainly helps to improve the wear properties, but it is known in the context of lifting and excavation equipment that other properties, such as toughness, may also play a role. In any event, it always is necessary to optimise a basket of properties rather than a single parameter, because the manufacture of a component requires a combination of performance criteria. It also is clear that a variety of microstructural features can influence the overall wear properties, although the results are not quantitative and the relationships claimed can be uncertain. The aim of work presented in this thesis is to study of role of toughness in increasing wear resistance in impact-abrasion conditions, in an experiment that, for the first time, decouples toughness from microstructure- and hardness-induced effects. The relevant literature has been critically examined to highlight the roles of properties other than hardness, such as fracture toughness, the work hardening rate and microstructural considerations in determining wear resistance of steel. In the work presented in the thesis, a remarkable new steel has been studied to reveal the role of toughness on a particularly dramatic wear scenario involving both abrasion and impact. The steel has very high toughness, (72.0 ± 1.5)MPa√m, and yet is hard, 561 ± 23 HV. The same steel was heat-treated to produce another variant with poor toughness but similar microstructure. It is demonstrated with clarity that the toughness becomes incredibly important in impact-abrasion, though not during abrasion on its own. The steel with high fracture toughness performed better during impact-abrasion wear tests compared to the other variant with poor toughness but high hardness and similar microstructure. Detailed microscopy and other characterisation techniques have revealed explanations for these observations. Based on the laboratory test results, full scale trials were undertaken in an integrated steel plant and the performance of a novel steel has been satisfactory thus far.
Degree
thesis:*- Name dc:type.qualificationname
- Doctor of Philosophy (PhD)
- Level dc:type.qualificationlevel
- Doctoral
- Grantor dc:publisher.institution
- University of Cambridge
- Year dc:date.issued
- 2021
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Chintha, Appa Rao
- Advisor dc:contributor.advisor
-
- Bhadeshia, HKDH
Subjects
dc:subject × 8Rights
dc:rights- Licence
- Language dc:language
- eng
Identifiers
dc:identifier.*- DOI dc:identifier.doi
- https://doi.org/10.17863/CAM.64115
- OAI identifier oai:identifier
- oai:www.repository.cam.ac.uk:1810/317004