Doctoral Dissertations

Abstract

"Hot rolling is one of the most important and complex process that includes large material deformation, different contact conditions, complex geometries and different temperature gradients along with micro structural changes such as viscoplasticity, dynamic recrystallization, and static softening. In the present work, the viscoplasticity, damage evolution, static softening and void closure of alloyed metal during hot rolling process was numerically investigated. GleebleTM hot compression and double hit tests were performed to provide experimental stress-strain curves at recrystallization temperatures and at different strain rates. Johnson-Cook viscoplastic model was calibrated using experimental stress-strain curves. Static softening model was developed at varying interpass times, pre-strains, temperatures, and strain rates. Subroutine to include developed viscoplasticity and static softening were developed and implemented into a three-dimensional finite element model of slab hot rolling. Hydrostatic integration parameter was used to describe the healing of void defects. Subroutine accounting for viscoplasticity and hydrostatic integration parameter was developed and integrated into the finite element model. Void closure of low carbon steel plates in Steckel mill hot rolling process was investigated. Uni-axial tensile tests for industrial steel grade 15V38 was conducted. Plastic flow behavior and the failure were approximated using the Johnson-Cook strength and failure models. The developed material models were incorporated into finite element model to perform hot rolling simulations of 15V38 steel bars. The evolution of ductile failure in steel bars during the industrial square-to-round bar and round-to-round bar hot rolling schedule was investigated" -- Abstract, p. iv

Advisor(s)

Chandrashekhara , K.

Committee Member(s)

Dharani, Lokeswarappa R.
O'Malley, Ronald J.
Buchely, Mario F.
Corns, Steven

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2024

Pagination

xix, 120 pages

Note about bibliography

Includes_bibliographical_references_(pages 41, 77 & 116)

Rights

©2024 Siva Sai Krishna Dasari , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12422

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