Welding Deformation and Residual Stress Prevention

Generally, welding produces welding deformation and residual stress in the products, which influences the quality and performance of the products. Although many engineers and researchers have made great effort how to control these incidents, they have still remained unresolved. Welding Deformation and Residual Stress Prevention provides a unique computational approach to the prediction of the effects of deformation and residual stress on materials. The goal is to provide engineers and designers with the ability to create their own computational system for predicting and possibly avoiding the problem altogether.

• The basic theories including "theory of elastic-plastic analysis" and  "inherent strain theory" , and analysis procedures are described using a simple three-bar model.
• Online simulation software to perform basic analysis on welding mechanics
• Examples of strategic methods and procedures are illustrated to have solved various welding-related problems encountered in the process of construction.
• Appendices present data bases for welding residual stresses, temperature dependent material properties, etc.

• Welding Engineers
• Civil Engineers: Construction Engineers, Structural Engineers, Pipeline Engineers, Pipeline Designers
• Mechanical Engineers: Machine Designers, Manufacturing Engineers, Product Designers

Preface

List of Symbols

Chapter 1. Introduction to Welding Mechanics

1.1 Basic Concepts of Welding and Welding Mechanics

1.2 Process of the Production of Residual Stress and Inherent Strain

1.3 Reproduction of Residual Stress by Inherent Strain and Inverse Analysis for Inherent Strain

1.4 Numerical Examples of Residual Stress, Inherent Strain, and Inherent Displacement

References

Chapter 2. Introduction to Measurement and Prediction of Residual Stresses with the Help of Inherent Strains

2.1 Inherent Strains and Resulting Stresses

2.2 Measured Strains in Experiments and Inherent Strains

2.3 Effective and Noneffective Inherent Strains

2.4 Determination of Effective Inherent Strains from Measured Residual Stresses

2.5 Most Probable Value of Effective Inherent Strain and Accuracy of the Measurement of Residual Stress

2.6 Derivation of Elastic Response Matrix

2.7 Measuring Methods and Procedures of Residual Stresses in Two- and Three-Dimensional Models

2.8 Prediction of Welding Residual Stresses

References

Chapter 3. Mechanical Simulation of Welding

3.1 Heat Flow and Temperature During Welding

3.2 Basic Concepts of Mechanical Problems in Welding

References

Chapter 4. The Finite Element Method

4.1 Finite Element Method as A Powerful Tool for A Variety of Problems

4.2 Types of Problems and the Corresponding Basic Equations

4.3 Basic Concepts of the Variational Principle

4.4 How to Solve a Problem with More Than One Element

4.5 Incremental Method for Nonlinear Problems

4.6 Simple Examples of Analyzing Thermal Elastic-Plastic-Creep Behavior

4.7 Basic Theoretical Solutions to Validate Results Obtained by the FEM

4.8 Flow of Analysis for Welding Deformation and Residual Stress

4.9 Checklist for Rational Simulation

4.10 Troubleshooting for Problems Experienced in Computation

References

Chapter 5. Q&A for FEM Programs

5.1 Q&A for Program Introduction

5.2 Q&A for Welding Heat Conduction Program heat2d.exe

5.3 Q&A for Thermal Elastic-Plastic Creep Program tepc2d.exe

5.4 Q&A for the Inherent Strain–Based Program inhs2d.exe

5.5 Q&A for Postprocessing Program awsd.exe

5.6 Q&A for Sample Data

References

Chapter 6. Simulation Procedures for Welding Heat Conduction, Welding Deformation, and Residual Stresses Using the FEM Programs Provided on the Companion Website

6.1 Simulation Steps Using the Welding Heat Conduction FEM Program

6.2 Simulation Steps Using the Thermal Elastic-Plastic Creep FEM Program

6.3 Simulation Steps Using the Inherent Strain FEM Program

6.4 Numerical Experiment for Residual Stress Measurement Using the Inherent Strain FEM Program

6.5 Computation Steps for the Prediction of Residual Stresses by the Inherent Strain Method

References

Chapter 7. Strategic Simulation Analyses for Manufacturing Problems Related to Welding

7.1 Cold Cracking at the First Pass of a Butt-Welded Joint Under Mechanical Restraint

7.2 Cold Cracking of Slit Weld

7.3 Analysis of Welding Residual Stress of Fillet Welds for Prevention of Fatigue Cracks

7.4 Multipass-Welded Corner Joints and Weld Cracking

7.5 Analysis of Transient and Residual Stresses of Multipass Welding of Thick Plates in Relation to Cold Cracks, Under-Bead Cracks, etc.

7.6 Improvement of Residual Stresses of a Circumferential Joint of a Pipe by Heat-Sink Welding

7.7 Prediction of Deformation Produced by Line Heating

7.8 Simulation of Resistance Spot Welding Process

7.9 Prediction of Welding Distortion Produced in Large Plate Structures

References

APPENDIX A. Residual Stress Distributions in Typical Welded Joints

List of Residual Stress Distributions in Typical Welded Joints

A.1 Residual Stresses in Base Metals

A.2 Residual Stresses in Welded Joints of Plates; In 2-Dimensional

A.3 Multipass Butt Welds of Thick Plates; 3-Dimensional

A.4 Electron Beam Welding, Thick Plate

A.5 First Bead of Butt Joint; Rcc (Rigidly Restrained Cracking) Test Specimen

A.6 Multipass-Welded Corner Joint

A.7 Fillet Welds: 3-Dimensional

A.8 Repair Weld of Thick Plate

A.9 Circumferential Welded Joint of Pipes

Contents of Programs and Data on the Companion Website

Index

About the Authors