Dissertation/Thesis Abstract

Effects of silicon content and cooling rate on mechanical properties of heavy section ductile cast iron
by Haycock, Meghan, M.S., Michigan Technological University, 2011, 128; 1500154
Abstract (Summary)

The effects of Si and cooling rate are investigated for their effect on the mechanical properties and microstructure. Three alloys were chosen with varying C and Si contents and an attempt to keep the remainder of the elements present constant. Within each heat, three test blocks were poured. Two blocks had chills—one with a fluid flowing through it to cool it (active chill) and one without the fluid (passive)—and the third block did not have a chill. Cooling curves were gathered and analyzed. The mechanical properties of the castings were correlated to the microstructure, cooling rate and Si content of each block. It was found that an increase in Si content increased the yield stress, tensile strength and hardness but decreased the impact toughness, elongation and Young's modulus. The fast cooling rates produced by the chills caused a high nodule count in the castings along with a fine ferrite grain size and a high degree of nodularity. The fine microstructures, in turn, increased the strength and ductile to brittle transition temperature (DBTT) of the castings. The fast cooling rate was not adequate to overcome the dramatic increase in DBTT that is caused by the addition of Si.

Indexing (document details)
Advisor: Sanders, Paul
Commitee: Rundman, Karl, Sutter, Lawrence, Swenson, Doug
School: Michigan Technological University
Department: Materials Science & Engineering
School Location: United States -- Michigan
Source: MAI 50/02M, Masters Abstracts International
Subjects: Mechanical engineering, Materials science
Keywords: Cooling rate, Ductile iron, Heavy section ductile iron, Mechanical properties, Silicon, Wind turbines
Publication Number: 1500154
ISBN: 978-1-124-91333-9
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