Weld Integrity And Performance

Key articles from over 10 separate ASM publications are brought together as a practical reference on weld integrity crack prevention. This book thoroughly covers the essentials of weld solidification and cracking, weldability and material selection, process control and heat treatment, failure analysis, and fatigue and fracture mechanics weldments. Contents also include an appendix for quick reference of tabular data on weldability of alloys, process selection, recommended interpass and heat treatment temperatures, and qualification codes and standards.

High-performance steels and aluminum alloys pose significant challenges to resistance welding processes. Unfortunately for students in materials science, metallurgy, and manufacturing, most available books provide only a superficial treatment of resistance spot welding. Surveying the topic in a scientific and systematic manner, Resistance Welding: Fundamentals and Applications supplies practical insight into every aspect of the field. This book comprehensively examines every aspect of resistance welding, from metallurgy and fundamental physical processes, such as electrothermal processes and discontinuities, to mechanical testing, process monitoring and control, weld quality and inspection, expulsion, and numerical simulation. The authors consider the influence of mechanical characteristics of welding machines and emphasize statistical design, analysis, and inference in resistance welding research, enabling students to conduct their own investigations. They present state-of-the-art research results from their own studies as well as from other leading experts, and the text's many examples are derived from real experiments. Case studies and nearly 300 figures illustrate the concepts. Resistance Welding: Fundamentals and Applications imparts a fundamental understanding of resistance welding processes and phenomena that empowers students to approach high-performance steels, aluminum alloys, and other new materials with confidence. It is an ideal upper-level undergraduate or graduate text for courses in assembly and joining processes, fundamentals of welding, and manufacturing processes.

The Welding Engineer's Guide to Fracture and Fatigue provides an essential introduction to fracture and fatigue and the assessment of these failure modes, through to the level of knowledge that would be expected of a qualified welding engineer. Part one covers the basic principles of weld fracture and fatigue. It begins with a review of the design of engineered structures, provides descriptions of typical welding defects and how these defects behave in structures undergoing static and cyclical loading, and explains the range of failure modes. Part two then explains how to detect and assess defects using fitness for service assessment procedures. Throughout, the book assumes no prior knowledge and explains concepts from first principles. Covers the basic principles of weld fracture and fatigue. Reviews the design of engineered structures, provides descriptions of typical welding defects and how these defects behave in structures undergoing static and cyclical loading, and explains the range of failure modes. Explains how to detect and assess defects using fitness for service assessment procedures.

The objective of the three-year ADIMEW project, which started in November 2000, was to contribute to the development and verification of analysis methods that describe the behaviour of cracked dissimilar metal welds (DMW). The complexity of the problem results from the prevailing mixed-mode loading conditions, the variation in material constitutive equations across the weld zone, and the presence of large residual stress fields. Under these circumstances, classic fracture mechanics concepts are difficult to apply. The project had the following technological and scientific aims:- Quantify the accuracy and conservatism of structural integrity procedures used by the nuclear industry in Europe to predict the behaviour and assess the safety of circumferential defects at the surface of dissimilar metal welds, - Perform a unique verification of the load-carrying capacity of an industrially representative cracked DMW under operating conditions in a large-scale structural test. To do this, a special assembly was prepared, with circumferential cracks introduced into the surface of a dissimilar metal weld between low-alloy steel and austenitic steel pipes with a diameter of 450 mm, - Rapidly disseminate the results for the benefit of operators, regulators and research organisations in Europe, in collaboration with the Network for Evaluating Structural Components (NESC). In order to reach these objectives, a large-scale nuclear DMW was tested and the different analytical methods available checked against the experimental results. Complementary innovative actions have been done on mixed-mode rupture, comparison of notch and crack toughness values. The ADIMEW project had an organisation similar to the one of the BIMET project with complementary objectives: larger diameter and higher temperature. The ADIMEW project followed on from the successful Fourth Framework Programme (FP4) BIMET project which had complementary objectives but considered smaller-diameter weld mock-ups tested at ambient rather than service temperature. The main focus of ADIMEW project was the performance of a single benchmark 4-point bend-pipe test, conducted on a nominal 16" piping assembly at 300 °C and containing a ferritic to stainless steel (A508-308/309SS-316SS) DMW. A notch-like defect was inserted at the ferritic steel/buttering layer interface, to simulate plant experience of damage at the worst-case location for a crack in such components. A second DMW mock-up was also manufactured for the experimental determination of welding residual stresses and for the generation of material property data for input to the analysis procedures. A range of analysis methodologies, including conventional flaw assessment methods, J approaches and local-approach methods have been applied to predict the critical load for initiation of the defect, the extent of crack growth, and the path followed by the crack through the weld up to the maximum load. Consideration has also been given to factors such as welding residual stresses, mixed-mode loading and constraint effects. The ADIMEW test was successfully executed in July 2003. The complete results of investigations of the test pieces were available in October 2003 and the post-test analysis was completed by December 2003.

This valuable guide to quality welding covers techniques used for Indy and NASCAR race cars, experimental aircraft, and other applications requiring high-quality welds, including 4130 steel, stainless and aluminum. Learn how to select equipment, set up your welding shop, pre-weld jigging and fitting, and how to choose the right process and fill metal for each project. Includes chapters on the latest technology in filler metals and welding rod.