Advanced Integration of Multi-Scale Mechanics and Welding Process Simulation in Weld Integrity Assessment

Abstract

We also acknowledge the helpful input and feedback from the following during this program • US Department of Energy-Dr. Mahesh Jha, Project Monitor, for his insight and timely input during the course of this effort, • PRCI Staff-Mr. Ken Lorang, and Mr. David Young for their project management assistance and support during this program, and • PRCI Members-Mr. David Horsley of British Petroleum (formerly of TransCanada Pipelines), and Dr. Joseph Zhou of TCPL, for their technical input and guidance with regard to the impact of this work on the pipeline industry.

Multiscale characterisation of weldments

“…9. 51 The detailed hardness map can also be used to define the size of the HAZ. As noted earlier, the actual 'size' of the HAZ may vary in a given weldment, depending upon what criterion is used to distinguish the HAZ from the BM.…”

“…Finer probes may also be useful when the microstructure is not homogeneous but rather consists of two phases (or more) such as the mixed ferritezaustenite microstructures prevalent in most stainless steel welds. The finer resolution of hardness measurements 9 a optical macrostructure of seam weld in pipeline steel and b corresponding hardness distribution in primary and reheated weld metal regions as well as softening in heat affected zone 51 10 Variation in nanohardness of ferrite and austenite phases as function of aging time in 308 stainless steel weld 53 Vitek can be achieved with the use of nanoindentation devices. These instruments have been developed over the last two to three decades, and they have a working resolution of y1 mm.…”

“…optical macrostructure of seam weld in pipeline steel and b corresponding hardness distribution in primary and reheated weld metal regions as well as softening in heat affected zone51 10 Variation in nanohardness of ferrite and austenite phases as function of aging time in 308 stainless steel weld53 Vitek and BabuMultiscale characterisation of weldments Science and Technology of Welding and Joining 2011 VOL 16 NO 1…”

Characterization of slip lines in single edge notched tension specimens

“…The importance of ECA is illustrated in reference [1], which mentions a pipeline project for which around 2% overall project savings could be achieved from the application of ECA. Having a model that takes into account weld heterogeneity could improve the accuracy of ECAs and thus save the industry a considerable budget, improve safety and reliability.…”

“…Reliability is related to the limit states that are considered. Assessing the uncertainty on each ECA parameter rather than using bounding theorems reduces conservatism, accumulation of uncertainty effects and hence promotes overall safety [1]. In light of obtaining such heterogeneity models, the theory of slip lines is used by Soete Laboratory as a starting point.…”