Svensson - 2000;1993;

CONTROL of
MICROSTRUCTURES and
PROPERTIES in
STEEL ARC WELDS

Materials Science and Technology

Series Editor
Brian Ralph
Brunei University
Uxbridge, U.K.

Control of Microstructures and Properties in Steel Arc Welds

Lars-Erik Svensson, The Esab Group, Gothenburg, Sweden

The Extraction and Refining of Metals

Colin Bodsworth, Brunei University, Uxbridge, U.K.

Quantitative Description of the Microstructure of Materials

K. J. Kurzydlowski, Warsaw University of Technology, Warsaw, Poland

Grain Boundary Properties and the Evolution of Microstructure and Texture

G. Gottstein, Institute of Metallurgy and Metal Science, RWTH Aachen, Germany

L. S. Shvindlennan, Institute of Solid State Physics, Russian Academy of Sciences, Moscow, Russia

Lars-Erik Svensson

The Esab Group
Esab AB, Gothenburg, Sweden

Library of Congress Cataloging-in-Publication Data

Svensson, Lars-Erik.

Control of microstructures and properties in steel arc welds / Lars-Erik Svensson.

p. cm. (Materials science and technology)

Includes bibliographical references and index.

ISBN 0-8493-8221-1

1. SteelWelding. 2. Gas and metal arc welding. 3. MicrostructureMathematical models. 4. SteelMechanical properties. 1. Title. II. Series: Materials science and technology (Boca Raton, Fla.)

TS227.2.S96 1994

612.5212dc20

94-1203
CIP

This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use.

Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher.

CRC Press, Inc.'s consent does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from CRC Press for such copying.

Direct all inquiries to CRC Press, Inc., 2000 Corporate Blvd., N.W., Boca Raton, Florida 33431.

1994 by CRC Press, Inc.

No claim to original U.S. Government works
International Standard Book Number 0-8493-8221-1
Library of Congress Card Number 94-1203
Printed in the United States of America 1 2 3 4 5 6 7 8 9 0
Printed on acid-free paper

Welding is a fascinating subject, involving knowledge from many disciplines such as physics, chemistry, metallurgy, electronics, and mechanical engineering. However, welding is still in many respects regarded as a craftsmanship, with the welder having a large influence on the final properties of the welded joint. Thus, the possibility of predicting and controlling the properties of a welded joint is limited.

The intention of this book is to show that the properties of a weld in steel can be predicted and controlled through control of the microstructures that appear. There has been a rapid development in this field during the 1980s, mainly through the development of models for the microstructure of steels subjected to welding. These models are quantitative to a certain degree, with calculations carried out on mainframe computers or PCs. However, it must be realized that these models are still far from mature and certainly much more development is needed to say that we can completely control the microstructure and properties of a welded joint.

The book begins with a chapter on the welding processes and the defects that are commonly associated with welds, i.e., what is commonly described as the weldability of steels. The chemistry and processing of the base material is described in the relation between the properties and the microstructure of the welded joint is described. The book ends with a chapter in which some specific cases of welding of steels are discussed.

The book is intended to be used by undergraduate and graduate students specializing in welding. It is also aimed at practicing welding engineers, who may find that it improves their understanding of the factors that control the properties of welds, a subject which I believe occupies much of their time today.

Lars-Erik Svensson

Gothenburg

February 1993

During the writing of the book I have had a lot of help from many people. First of all, I would like to express my deep gratitude to Dr. Harry Bhadeshia, University of Cambridge, U.K. We have been cooperating on the subjects dealt with in this book since 1982, developing the model for calculating the micro-structure and properties of weld metals. Without his cooperation, this book would never had been written. During the course of writing, Harry also read numerous drafts of the text and made a lot of sensible comments, improving the quality of the content substantially.

I have also received a lot of very helpful comments from several other people. In particular, I would like to thank Dr. Peter Hart of TWI, Cambridge, U.K.; Dr. Anders Samuelson and Mr. Jan Steninger of Swedish Steel AB in Oxelsund, Sweden (who also kindly provided ); Dr. Tad Siwecki of the Institute of Metals Research in Stockholm, Sweden; Dr. Graham Thewlis of British Steel in Rotherham, U.K.; Drs. Ron Smith and Stan Ferree of Alloy Rods Inc., Hanover, PA; Dr. David Widgery of Esab Group (U.K.), Waltham Cross, U.K.; Messr. Nils Thalberg and Johan Elvander and Dr. Lennart Wittung of Esab Group, Gothenburg, Sweden; and Mr. Klas Weman, Esab Arc Equipment in Lax Sweden.

I am very grateful to my employer, Esab AB, for their permission to write the book and use so many illustrations and examples from the work carried out in the Esab laboratories. In particular, I would like to mention Dr. Anders Backman, Vice President, Consumables, and Mr. Bertil Pekkari, Technical Director, for their interest and encouragement.

Many illustrations have been produced by the staff in the Esab Group Central Laboratory in Gothenburg. Also, the many hours of discussions during investigations have been an invaluable source of knowledge and inspiration. My sincere thanks are devoted to my colleagues Mr. Bengt Utterberg, Ms. Berit Gretoft, Ms. Susan Pak, Ms. Ann-Charlotte Gustavsson, and Dr. Leif Karlsson.