Doctoral Dissertations

Jie Wan

Keywords and Phrases

Alloy design; Graphitic white iron; Metal-to-metal; Wear system

Abstract

"This research addressed heat dissipation issues related to the adhesive wear observed in metal-to-metal wear systems, by developing a graphitic white iron to increase thermal diffusivity of the wear components. One of the premium materials commonly used in current metal-to-metal wear systems is Fe15Mo18Cr and field returned parts were characterized as part of this study. Failure analysis showed that white layers were formed on the wearing surface due to frictional heating and surface deformation. These white layers were extremely brittle and could be fractured easily during use, which in turn led to micro-galling defects that caused parts leakage. Increasing thermal diffusivity of the material was recommended to improve the performance of wear components.

A new alloy, graphitic white iron, was developed for metal-to-metal wear systems by introducing 3.2-9.6 vol.% graphite flakes into white irons, to increase thermal diffusivity and reduce friction and frictional heating. Graphite volume percent was quantitatively investigated. It turned out that, at 200 °C, thermal diffusivity increased by ~114% with increasing graphite to 7.6 vol.%. Abrasive and adhesive wear resistance was measured by dry sand/rubber wheel test and block on ring test, respectively. Empirical models were established to predict graphite volume percent for any given composition, and a Hashin-Shtrikman model was used to predict the thermal diffusivity of the multiphase alloy. Abrasive and adhesive wear resistance was found to depend upon composite hardness and graphite volume percent. It was found that 1 vol.% graphite was equivalent to an increase of 2.33 HRC and 2.66 HRC in composite hardness with respect to abrasive wear resistance and adhesive wear resistance, respectively”--Abstract, page iv.

Advisor(s)

Xu, Mingzhi

Committee Member(s)

Van Aken, David C.
Wen, Haiming
Qing, Jingjing
Medvedeva, Julia E.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering

Comments

This work has been financially supported by Caterpillar Inc. through the APEC-Caterpillar Fellowship.

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2019

Journal article titles appearing in thesis/dissertation

  • Microstructural characterization and failure analysis of a wear resistant, high molybdenum and chromium white iron
  • Designing a novel graphitic white iron for metal-to-metal wear systems
  • Developing a graphitic white iron for abrasive wear application: thermal and wear properties
  • Adhesive wear property of a graphitic white iron designed for metal-to-metal wear systems

Pagination

xviii, 151 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2019 Jie Wan, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12099

Download

Share

 
COinS