Title page for ETD etd-041310-122535

Document Type dissertation

Author Name Xiao, Bowang

URN etd-041310-122535

Title Numerical Modeling and Experimental Investigation for Optimization in Quenching Processes of Aluminum and Steel Parts

Degree PhD

Department Manufacturing Engineering

Advisors
Yiming Rong, Advisor
Richard D. Sisson, Jr., Committee Member
Diran Apelian, Committee Member
Makhlouf M. Makhlouf, Committee Member
Keyu Li , Committee Member
Qigui Wang, Committee Member

Keywords
experimental
CFD
finite element
residual stress
material modeling
heat transfer
quenching

Date of Presentation/Defense 2010-03-03

Availability unrestricted

Abstract
Aluminum and steel components are usually quenched in forced gas, oil or water flow to improve mechanical properties and improve product life. During the quenching process, heat is transferred rapidly from the hot metal component to the quenchant and the rapid temperature drop introduces phase transformation and deformation in the hot metal component. As a result, quenching problems arise such as distortion, cracking and high tensile residual stresses. To avoid or minimize these problems while improving mechanical properties, process optimization is needed for both part geometry and quenching process design.
A series of methods, including four existing methods and two new methods developed in this dissertation, were applied to obtain accurate thermal boundary conditions, i.e., the heat transfer coefficient (HTC) distribution. The commercially available material model DANTE was applied with finite element software ABAQUS to model the phase transformations and constitutive behavior of steel parts during quenching. A user material subroutine was developed for aluminum alloys based on a constitute model and tensile test data. The predicted residual stresses in the quenched parts agreed with those measured using the improved resistance strain gauge hole-drilling method and other methods, which validates the numerical models.

Files
Dissertation_Xiao.pdf

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Document Type	dissertation
Author Name	Xiao, Bowang
URN	etd-041310-122535
Title	Numerical Modeling and Experimental Investigation for Optimization in Quenching Processes of Aluminum and Steel Parts
Degree	PhD
Department	Manufacturing Engineering
Advisors	Yiming Rong, Advisor Richard D. Sisson, Jr., Committee Member Diran Apelian, Committee Member Makhlouf M. Makhlouf, Committee Member Keyu Li , Committee Member Qigui Wang, Committee Member
Keywords	experimental CFD finite element residual stress material modeling heat transfer quenching
Date of Presentation/Defense	2010-03-03
Availability	unrestricted
Abstract Aluminum and steel components are usually quenched in forced gas, oil or water flow to improve mechanical properties and improve product life. During the quenching process, heat is transferred rapidly from the hot metal component to the quenchant and the rapid temperature drop introduces phase transformation and deformation in the hot metal component. As a result, quenching problems arise such as distortion, cracking and high tensile residual stresses. To avoid or minimize these problems while improving mechanical properties, process optimization is needed for both part geometry and quenching process design. A series of methods, including four existing methods and two new methods developed in this dissertation, were applied to obtain accurate thermal boundary conditions, i.e., the heat transfer coefficient (HTC) distribution. The commercially available material model DANTE was applied with finite element software ABAQUS to model the phase transformations and constitutive behavior of steel parts during quenching. A user material subroutine was developed for aluminum alloys based on a constitute model and tensile test data. The predicted residual stresses in the quenched parts agreed with those measured using the improved resistance strain gauge hole-drilling method and other methods, which validates the numerical models.
Files	Dissertation_Xiao.pdf