Preface

It is a great privilege to be working in the field of materials science and engineering, which I feel is one of the most expanding fields in engineering. Materials are used in all applications around us and this includes (but is not limited to) buildings, offices, cars, aircrafts, ships, rockets, etc. In other words, this field is important to all humans and that is why I personally consider it one of the most interesting fields. I have worked over the years in all aspects of materials engineering starting from the development, alloying, casting, mechanical testing and characterization fields, which have given me a wide expertise in materials engineering. I always wanted to put my efforts into action by gathering research from all over the globe to contribute to the field and support other researchers who thrive to develop materials for the various applications. As a fruitful effort, this book is presented to the research community, in particular those working on the casting of metallic alloys, as a guide and reference. The book discusses the aspects of physical casting, modelling, concerns, and mitigation plans to resolve common issues. I am very grateful and thankful to all authors for their valuable efforts in making this project successful and publishable. The work with IntechOpen is outstanding and I will work with them on other projects once I am given the chance in future. Thank you for reading this book and I hope you have enjoyed its content.

**Dr. Zak Abdallah**

Steel and Metals Institute (SaMI), Swansea University, Swansea, Wales, United Kingdom

**Dr. Nada Aldoumani** Swansea University, Swansea, Wales, United Kingdom

**1**

**Chapter 1**

**Abstract**

**1. Introduction**

**2. Fundamental issues**

mechanisms were unseen and unsuspected.

*John Campbell*

Perspective Chapter: A Personal

Casting processes are reviewed from the point of view of the type of defects they produce and their consequential properties of the castings they produce, particularly resistance to fracture, and therefore, their reliability in service. The ingot casting of steels is criticized for unnecessary degradation of the steel. The fundamental problems of continuous casting of aluminum alloys and steels are seen to be lying in inattention to the details of the processes. Vacuum casting, particularly vacuum arc remelting, as currently executed, is seen to be fundamentally unreliable for any safety critical purposes, particularly its history of

Overview of Casting Processes

helicopter tragedies resulting from its use in helicopter drive trains.

**Keywords:** metal casting, entrainment, oxide film, bifilm, defect, fracture

I have written about casting processes extensively, some would say, overextensively, but useful new concepts enshrining the new insights into this important subject are being only slowly realized and understood. Their awful importance to the reliability of engineering is yet to be fully adopted. It is useful therefore to offer a short summary in this appropriate volume. A personal reading list is appended.

processes on the quality of the resulting castings. However, of course, the quality of the metal prior to casting is of critical importance; a liquid metal, especially if a secondary metal (such as recycled metal, as is common in the aluminum industry) can be literally crammed with defects, so that despite the excellence of the casting process and the heat treatment process, the resulting casting predictably fails all mechanical property requirements and is scrapped. We shall have time to give only a

brief mention of this important problem. Our subject is the casting process.

Castings have had a poor reputation as a result of their poor and variable properties. For many years this was thought to be somehow associated with the turbulence of the pouring process, but the details were not understood, and efforts to control turbulence, despite all claims to the contrary, were failures. No-one was aware of the degree of failure to control turbulence during mold filling because, of course, molds made or sand or steel were opaque: the awful internal damaging

Space unfortunately forbids any lengthy discussion of the influence of the melting
