Science and Technology of Casting Processes

351 Pages·2016·70.85 MB·English

by  Srinivasan M. (Ed.)

SCIENCE AND
TECHNOLOGY OF
CASTING PROCESSES
Edited by
Malur Srinivasan
SCIENCE AND
TECHNOLOGY OF
CASTING PROCESSES
Edited by Malur Srinivasan
Science and Technology of Casting Processes
http://dx.doi.org/10.5772/3128
Edited by Malur Srinivasan
Contributors
Limei Tian, Zhaoguo Bu, Zhihua Gao, Na Li, Edgardo Roque Benavidez, Sebastian Friedhelm Fischer, Andreas Bührig-
Polaczek, Ioan Ruja, Constantin Marta, Doina Frunzaverde, Monica Rosu, Ram Prasad, Malur Srinivasan, Subramanyam
Seetharamu, Tasaki, Qing Liu, Xiaofeng Zhang, Shinichiro Komatsu, Ramaprasad ( M.S.Ramaprasad) Meenasamudram
Seshadri
Published by InTech
Janeza Trdine 9, 51000 Rijeka, Croatia
Copyright © 2012 InTech
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Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those
of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published
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Publishing Process Manager Iva Lipovic
Technical Editor InTech DTP team
Cover InTech Design team
First published September, 2012
Printed in Croatia
A free online edition of this book is available at www.intechopen.com
Additional hard copies can be obtained from [email protected]
Science and Technology of Casting Processes, Edited by Malur Srinivasan
p. cm.
ISBN 978-953-51-0774-3

Contents
Preface VII
Section 1 Disposable Mold Castings 1
Chapter 1 Sand Mold Press Casting with Metal
Pressure Control System 3
Ryosuke Tasaki, Yoshiyuki Noda, Kunihiro Hashimoto and Kazuhiko
Terashima
Chapter 2 Progress in Investment Castings 25
Ram Prasad
Chapter 3 New Casting Method of Bionic Non-Smooth Surface on
the Complex Casts 73
Tian Limei, Bu Zhaoguo and Gao Zhihua
Chapter 4 Evaluation and Modification of the Block Mould Casting
Process Enabling the Flexible Production of Small Batches
of Complex Castings 87
Sebastian F. Fischer and Andreas Bührig-Polaczek
Section 2 Reusable Mold Castings 115
Chapter 5 Permanent Molding of Cast Irons –
Present Status and Scope 117
M. S. Ramaprasad and Malur N. Srinivasan
Chapter 6 Control Technology of Solidification and Cooling in the Process
of Continuous Casting of Steel 169
Qing Liu, Xiaofeng Zhang, Bin Wang and Bao Wang
VI Contents
Chapter 7 Mould Fluxes in the Steel Continuous Casting Process 205
Elena Brandaleze, Gustavo Di Gresia, Leandro Santini, Alejandro
Martín and Edgardo Benavidez
Section 3 Evaluation of Castings 235
Chapter 8 Segregation of P in Sub-Rapid Solidified Steels 237
Na Li, Shuang Zhang, Jun Qiao, Lulu Zhai, Qian Xu, Junwei Zhang,
Shengli Li, Zhenyu Liu, Xianghua Liu and Guodong Wang
Chapter 9 Accuracy Improving Methods in Estimation of Graphite
Nodularity of Ductile Cast Iron by Measurement
of Ultrasonic Velocity 265
Minoru Hatate, Tohru Nobuki and Shinichiro Komatsu
Chapter 10 Fracture Toughness of Metal Castings 285
M. Srinivasan and S. Seetharamu
Chapter 11 Research on Simulation and Casting of Mechanical Parts Made
of Wear-and-Tear-Resistant Steels 313
Ioan Ruja, Constantin Marta, Doina Frunzăverde and Monica Roşu
Preface
Casting process is the most direct method of producing a product from the chosen material.
Though products in all the three major classes of materials, metals, ceramics and polymers
can be produced by this method, casting of metals is by far the most widely used process.
The basic steps in the casting process are preparation of the material in the liquid state,
transferring the liquid material into a shaping mold, allowing the transformation of liquid
material in the mold into a solid form. The solid object can then be used directly in
applications or subjected to secondary operations like thermal treatment involving solid
state transformations or material removal. In one important case (continuous casting), the
solid is subjected to significant plastic deformation to get the final shape of the object. In
recent times, innovations have been developed to process some metallic materials in a semi-
solid form, giving rise to interesting behavior of the castings.
As with any other process, the factors affecting the casting process are the quality, the cost
and the environmental effects. The choice of a given casting process will have to be made
consistent with acceptable levels of the degree of combination of these factors. Several
alternatives may be available to make a cast product, as for example, a sand casting or a
permanent mold casting, as the latter may have a lesser environmental impact. The decision
may not be a straightforward one, as factors such as molten metal temperature and casting
size may favor the sand casting process. On the other hand, the product quality of a
permanent mold casting may be better than that of a sand casting. It follows therefore that a
careful analysis of the science and technology of each process is extremely important. In
view of the complexity of each, it is advisable to undertake separate studies of each and
later, based on a suitable combination, choose a process that leads best towards the goal of
high quality, low cost and low environmental impact.
The science of metal casting mainly deals with control of fluid mechanics and heat transfer
at the macro-level and the additional control of mass transfer both at the micro-level and
macro-level. All the three factors are interwoven but each is capable of independent analysis
before integration with others. Also, to conform to the designer's requirements, an
engineered casting must possess acceptable level of properties, the mechanical properties
often being most important. Solid mechanics mainly governs the mechanical behavior of
castings. The technology used deals with both cost and environmental aspects, consistent
with the proper application of the scientific factors. Needless to say, the goal of attaining
high quality, low cost and low environmental impact in a casting process is not easy and
requires extensive research and understanding in each area. Obviously, proper evaluation
VIII Preface
procedures must be established to assess the quality, reliability and serviceability of the
castings.
This book is a collection of chapters contributed by experts in their fields. The effect of
environmental impact is recognized in two chapters but in view of the growing global
concerns, it is desirable to have more extensive documentation of this factor and its
interaction with the science and processing of castings.
Prof. Malur Srinivasan
Professor of Mechanical
Lamar University
Texas, USA.
Section 1
Disposable Mold Castings
Chapter 1
Sand Mold Press Casting with Metal Pressure Control
System
Ryosuke Tasaki, Yoshiyuki Noda,
Kunihiro Hashimoto and Kazuhiko Terashima
Additional information is available at the end of the chapter
http://dx.doi.org/10.5772/51082
1. Introduction
A new casting method, called the press casting process, has been developed by our group in
recent years. In this process, the ladle first pours molten metal into the lower (drag) mold.
After pouring, the upper (cope) mold is lowered to press the metal into the cavity. This
process has enabled us to enhance the production yield rate from 70% to over 95%, because
a sprue cup and runner are not required in the casting plan [1]. In the casting process, mol‐
ten metal must be precisely and quickly poured into the lower mold. Weight controls of the
pouring process have been proposed in very interesting recent studies by Noda et al. [2].
However, in the pressing part of the casting process, casting defects can be caused by the
pattern of pressing velocity. For example, the brake drum shown in Fig. 1 was produced
with the press casting method. Since the molten metal was pressed at high speed, the prod‐
uct had a rough surface. This type of surface defect in which molten metal seeps through
sand particles of the greensand mold and then solidifies, is called Metal Penetration. Metal
penetration is most likely caused by the high pressure that molten metal generates, and it
necessitates an additional step of surface finishing at the least. Thus, the product quality
must be stabilized by the suppression of excess pressure in the high-speed press. For short-
cycle-time of production, a high-speed pressing control that considers the fluid pressure in
the mold is needed. Pressure control techniques have been proposed for different casting
methods [3-4]. In the injection molding process, the pressure control problem has been suc‐
cessfully resolved by computer simulation analysis using optimization technique by Hu et
al. [5] and Terashima et al. [6]. Furthermore, a model based on PID gain selection has been
proposed for pressure control in the filling process. Although the pressure in the mold must
be detected in order to control the process adequately using feedback control, it is difficult