WELDING METALLURGY AND WELDABILITY OF NICKEL-BASE ALLOYS

Transcription

1 WELDING METALLURGY AND WELDABILITY OF NICKEL-BASE ALLOYS John N. DuPont John C. Lippold Samuel D. Kiser A JOHN WILEY & SONS, INC., PUBLICATION

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3 WELDING METALLURGY AND WELDABILITY OF NICKEL-BASE ALLOYS

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5 WELDING METALLURGY AND WELDABILITY OF NICKEL-BASE ALLOYS John N. DuPont John C. Lippold Samuel D. Kiser A JOHN WILEY & SONS, INC., PUBLICATION

6 Copyright 2009 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) , fax (978) , or on the web at Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) , fax (201) , or online at Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) , outside the United States at (317) or fax (317) Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at Library of Congress Cataloging-in-Publication Data: DuPont, John N. Welding metallurgy and weldability of nickel-base alloys / John N. DuPont, John C. Lippold, and Samuel D. Kiser. p. cm. ISBN (cloth) 1. Nickel Welding. 2. Nickel Metallurgy. 3. Nickel alloys Welding. 4. Nickel alloys Metallurgy. I. DuPont, John N., 1964 II. Kiser, Samuel D III. Title. TS227.L dc Printed in the United States of America

7 This book is dedicated to Alden and Pauline DuPont, who inspired me when I was young, and Ryan and Caitlin, who have been inspiring me ever since. John N. DuPont Lehigh University, 2009 This book is dedicated to my wife, Mary Catherine Juhas, who has supported me throughout my career and remains a constant source of strength, inspiration, and good humor. John C. Lippold The Ohio State University, 2009 This book is dedicated to Jackie Kiser, my friend, my spiritual partner, and my co - worker in all that I set out to do. Samuel D. Kiser Special Metals Welding Products Company, 2009

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9 CONTENTS Preface xiii 1. Introduction Ni-base Alloy Classification Commercially Pure Nickel Alloys Solid-Solution Strengthened Alloys Precipitation-Strengthened Alloys Other Specialty Alloys History of Nickel and Ni-base Alloys Corrosion Resistance Nickel Alloy Production 12 References Alloying Additions, Phase Diagrams, and Phase Stability Introduction General Influence of Alloying Additions Phase Diagrams for Solid-Solution Alloys The Ni-Cu System The Ni-Cr System Ni-Mo System The Ni-Fe-Cr System Ni-Cr-Mo System Phase Diagrams for Precipitation Hardened Alloys γ Formers Phase Diagrams for Precipitation-Hardened Alloys γ Formers Calculated Phase Stability Diagrams PHACOMP Phase Stability Calculations 40 References Solid-Solution Strengthened Ni-base Alloys Standard Alloys and Consumables Physical Metallurgy and Mechanical Properties 51 vii

10 viii CONTENTS 3.3 Welding Metallurgy Microstructural Evolution in the Fusion Zone Interfaces in Single Phase Austenitic Weld Metal Solidification Subgrain Boundaries (SSGBs) Solidification Grain Boundaries (SGBs) Migrated Grain Boundaries (MGBs) Elemental Segregation during Solidification Phase Transformation Sequence Heat Affected Zone Postweld Heat Treatment Stress Relief Heat Treatments Homogenization of Weld Metal Microstructure Mechanical Properties of Weldments Hydrogen Effects Postweld Heat Treatment Weldability Fusion Zone Solidification Cracking HAZ Liquation Cracking Avoiding Solidification and Liquation Cracking Ductility-Dip Cracking Description of Ductility-Dip Cracking Proposed Mechanisms for Ductility-Dip Cracking Ductility-Dip Cracking in Ni-base Weld Metals Avoiding Ductility-Dip Cracking Corrosion Resistance Case Studies Pitting Corrosion in MONEL Welds 149 References Precipitation-Strengthened Ni-base Alloys Standard Alloys and Consumables Physical Metallurgy and Mechanical Properties Welding Metallurgy Microstructural Evolution in the Fusion Zone Elemental Segregation during Solidification Phase Transformations γ Formation 175

11 CONTENTS ix Phase Transformations Carbide Formation Phase Transformations γ Formation Effect of Nb and C Fusion Zone Microstructure Predictions using New PHACOMP Heat-Affected Zone Postweld Heat Treatment Mechanical Properties of Weldments Weldability Solidification Cracking Effect of Minor Element Additions B and Zr Effect of Nb Additions Cast Pin Tear Test Results Summary of Solidification Cracking HAZ Liquation Cracking Composition Effects Effect of Grain Size Effect of Heat Treatment Effect of Thermal Stress/Strain Summary of HAZ Liquation Cracking Strain-Age Cracking Mechanism for Strain-Age Cracking Effect of Residual, Thermal and Aging Stresses, and Joint Restraint Composition Effects Grain Size Preweld Condition of the Base Metal Effect of Welding Procedure Effect of Postweld Heat Treatment Summary of Strain-Age Cracking 248 References Oxide Dispersion Strengthened Alloys and Nickel Aluminides Oxide Dispersion Strengthened Alloys Physical and Mechanical Metallurgy Welding Metallurgy Summary of the Weldability of ODS Alloys Nickel Aluminide Alloys Physical and Mechanical Metallurgy Weldability of the Ni-Aluminides Elevated Temperature Cracking Hot Ductility Behavior Brazing 276

12 x CONTENTS Summary of the Weldability of Nickel Aluminide Alloys 276 References Repair Welding of Ni-base Alloys Solid-Solution Strengthened Alloys Precipitation-Strengthened Alloys Alloy Effect of δ-phase Formation Rejuvenation Heat Treatments Summary of Repair Weldability of Alloy Waspaloy Single Crystal Superalloys Control of Single Crystal Weld Repairs Solidification Cracking Optimizing Processing Parameters 317 References Dissimilar Welding Application of Dissimilar Welds Influence of Process Parameters on Fusion Zone Composition Carbon, Low Alloy and Stainless Steels Determining Weld Metal Constitution Fusion Boundary Transition Region Weldability Solidification Cracking Clad Disbonding Creep Failure in the HAZ of Carbon Steel or Low Alloy Steel Postweld Heat Treatment Cracking Postweld Heat Treatment Cracking in Stainless Steels Welded with Ni-base Filler Metals Super Austenitic Stainless Steels Dissimilar Welds in Ni-base Alloys Effect on Corrosion Resistance %Ni Steels Physical Metallurgy of 9%Ni Steels Hot Cracking of Ni-base Deposits Super Duplex Stainless Steels Case Studies 364

13 CONTENTS xi Postweld Heat Treatment Cracking of Thick Section Welds in Alloy 800H Made with ENiCrFe-2 Filler Metal Alloy 925 Welded with ERNiCrMo-15 (INCO-WELD 725NDUR) for Manufacturing Vacuum Insulated Oil Patch Tubing Corrosion-Fatigue of Alloy 625 Weld Overlays Overlay of Safe-End Welds using High-Cr, Ni-base Filler Metals 373 References Weldability Testing Introduction Weldability Testing Approaches Types of Weldability Test Techniques The Varestraint Test Technique for Quantifying Weld Solidification Cracking Technique for Quantifying HAZ Liquation Cracking Modified Cast Pin Tear Test The Sigmajig Test The Hot Ductility Test The Strain-to-Fracture Test Other Weldability Tests 401 References 402 Appendix A Composition of Wrought and Cast Nickel-Base Alloys 403 Appendix B Composition of Nickel and Nickel Alloy Consumables 409 Appendix C Corrosion Acceptance Testing Methods 415 Appendix D Etching Techniques for Ni-base Alloys and Welds 419 Author Index 423 Subject Index 431

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15 PREFACE The motivation for this textbook arose from our desire to develop a reference for engineers, scientists and students that would represent an up - to - date perspective on the welding metallurgy aspects and weldability issues associated with Ni - base alloys. Although this subject has been treated in handbooks and other reference texts associated with welding/joining and engineering materials, this represents the first stand - alone textbook dedicated to the topics of welding metallurgy and weldability of nickel and nickel alloys. This book focuses on the metallurgical behavior of Ni - base alloys with particular emphasis on weldability issues. It does not specifically address welding process or procedure issues, nor does it provide guidance as to process/ procedure selection. The book begins with a chapter introducing the history of nickel and nickel alloy development. The second chapter discusses the role of alloying elements and presents phase diagrams that describe phase stability in these alloys, including the use of thermodynamic computational techniques to develop phase diagrams for complex systems. Two chapters are then dedicated to the two largest groups of Ni - base alloys, the solid - solution strengthened alloys and the precipitation - strengthened alloys (or superalloys ). Another chapter describes the weldability issues associated with specialty alloys nickel aluminides and oxide dispersion strengthened alloys. Finally, there are chapters that address the topics of repair welding, dissimilar welding, and weldability testing. Some of these chapters contain case studies that will allow the reader to see how the concepts described can be applied in real world situations. In the preparation of this textbook, the authors have brought together a collective 80 years of experience with Ni - base alloys. For many years, Professors DuPont and Lippold have conducted research and taught courses on these topics at Lehigh University and Ohio State University, respectively. Mr. Kiser has been involved with Ni - base consumable development and applications at Special Metals Welding Products Company (formerly INCO) for over 40 years. This combined effort has resulted in a textbook that has both technical breadth and depth, providing a resource for university students, and practicing engineers and scientists. Special thanks go to Dr. S. Suresh Babu (Ohio State University), Dr. Steve Matthews (Haynes International), Dr. Charles Robino (Sandia National Laboratories), and Mr. J. Patrick Hunt, Mr. Brian A. Baker and Dr. Rengang Zhang (all from Special Metals Corp.), who carefully reviewed individual xiii