WWeesstteerrnn MMiicchhiiggaann UUnniivveerrssiittyy SScchhoollaarrWWoorrkkss aatt WWMMUU Dissertations Graduate College 5-2010 OOppttiimmiizziinngg GGrreeeenn SSaanndd PPrrooppeerrttiieess ooff FFlluuiiddiizzeedd SSaanndd ffrroomm AAeerraattiioonn aanndd DDeevveellooppiinngg NNeeww GGrreeeenn SSaanndd TTeessttiinngg TTeecchhnniiqquuee Ananda Mani Paudel Western Michigan University Follow this and additional works at: https://scholarworks.wmich.edu/dissertations Part of the Industrial Engineering Commons RReeccoommmmeennddeedd CCiittaattiioonn Paudel, Ananda Mani, "Optimizing Green Sand Properties of Fluidized Sand from Aeration and Developing New Green Sand Testing Technique" (2010). Dissertations. 618. https://scholarworks.wmich.edu/dissertations/618 This Dissertation-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Dissertations by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. OPTIMIZING GREEN SAND PROPERTIES OF FLUIDIZED SAND FROM AERATION AND DEVELOPING NEW GREEN SAND TESTING TECHNIQUE by Ananda Mani Paudel A Dissertation Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements for the Degree of Doctor of Philosophy Department of Industrial and Manufacturing Engineering Advisor: Sam Ramrattan, Ph.D. Western Michigan University Kalamazoo, Michigan May 2010 UMI Number: 3410416 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMT UMI 3410416 Copyright 2010 by ProQuest LLC. All rights reserved. This edition of the work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 OPTIMIZING GREEN SAND PROPERTIES OF FLUIDIZED SAND FROM AERATION AND DEVELOPING NEW GREEN SAND TESTING TECHNIQUE Ananda Mani Paudel, Ph.D. Western Michigan University, 2010 Aeration sand filling is a new molding technique in foundry. Using this technique, sand with smooth flow can be filled in any orientation and shape using low-pressure air. This is not possible by conventional gravity and high-pressure blow filling techniques. Aeration was introduced as an energy-efficient and environmentally- friendly sand molding technique. In addition, aeration has its niche on quality of molds it could produce. Friability, one of the crucial green properties for the quality mold was significantly low in aeration in comparison to the gravity and high-pressure blow filling. The fluidization action in aeration acted upon the sand clay interfaces and created the interactions with them, and induced better surface abrasive property. In other words, aeration lowered the friability in the green sand allowing a lower compactibility levels in green sand molding, which was not possible with the conventional molding techniques. The range of 30-35% was suggested as the optimal working range of compactibility for aeration molding technique for selected sand and clay composition. Advance cone jolt and thermal erosion tester were developed and used to examine the green sand properties of the foundry sand. Advance cone jolt was sensitive to the clay composition and contamination in green sand, whereas thermal erosion tester demonstrated its relevance in evaluating mold surface behavior at an elevated temperature. Thermal erosion test displayed less sand erosion in the molds built in the aeration. Green sand in aeration was benefited by the favorable clay orientation. Homogeneous and isotropic distribution of clay platelets occurred during fluidization, which produced a better clay coating on the sand grains and increased the grain to grain bonding. Scanning electron microscope displayed a uniform clay coating and universal micro-tribometer showed greater bonding strength in the surface of the molds produced in aeration. Casting trial along with the relevant standard AFS tests for green sand properties were carried out, and analyzed using design of experiments and statistical tools. Copyright by Ananda Mani Paudel 2010 ACKNOWLEDGEMENTS I would like to express my gratitude to my dissertation advisor, Professor Sam Ramrattan for his patience, guidance and counsel throughout this research. This research also benefited from the numerous communiques and advice from Professor Pnina Ari- Gur. I am thankful to Professor Steven Butt, Professor Leonardo Lamberson and Professor Tarun Gupta for reviewing my work and providing valuable suggestions. My special thanks to Dr. Hiroyasu Makino from Sintokogio, Japan for his support and technical assistance. I would like to thank Dr. Mitchel Keil, Mr. Deepak Ravindra and Ms. Debbie Aliya for their help during the course of experiments and sharing technical expertise. I am equally thankful to Mr. Glen Hall, Mr. Peter Thannhauser and Mr. Abraham Poot, for their technical support, and Mr. Kamaleshwaran Nagarajan, and Mr. Rajiv Bharadwaj for their help in conducting the experiments. Finally, I am grateful to my mom for her inspiration, and my wife, Puspa, daughter, Bhawana, and son, Aaron, for their sacrifices and continual support during these years of my study. Ananda Mani Paudel u TABLE OF CONTENTS ACKNOWLEDGEMENTS ii LIST OF TABLES ix LIST OF FIGURES xi CHAPTER I. INTRODUCTION 1 H. LITERATURE REVIEW 6 Sand Molding Techniques 6 Gravity Filling 7 High-pressure Blow 8 Aeration Filling 9 Fluidizing Bed 12 Fluidizing Mechanism 12 Viscosity of Fluidized Sand 14 Molding Materials 15 Sand 15 Silica Sand 16 Olivine 18 Chromite 18 Ceramic Media 19 in Table of Contents-Continued CHAPTER Clay 19 Electrostatic Force 21 Surface Tension 22 Frictional Force 22 Water 23 Relationship between Clay and Moisture 24 Critical Bentonite Content 24 Water/ Effective Clay Ratio 25 Green Sand Properties and AFS Sand Test 26 Compactibility 26 Moisture Content 28 Bulk Density 28 Permeability 28 Green Compressive Strength 30 Splitting Strength 31 Mold Hardness 31 Percent Friability 31 Sand Toughness 33 Flowability 34 Volatility 34 iv Table of Contents-Continued CHAPTER Sand Control Program 35 Sand/Metal Ratio 37 Chemical Properties 37 Alternative Sand System 38 Friability in Green Sand 39 Casting Defects Due to Moisture 42 Water Explosion 43 Scabbing 43 Friability Related Casting Defects 46 Comments on AFS Standard Tests 46 Cone Jolt Toughness Test 47 Erosion Test 48 AFS Standard Testing Procedure 49 Preparation of Green Sand 49 Design of Experiments 51 Sand-Clay Interactions 51 X-ray Diffraction 51 Scanning Electron Microscope (SEM) 53 Universal Micro-tribometer 54 m. OBJECTIVE 56 IV. METHODOLOGY 60 v