Technical Basis for the Proposed Weld Residual Stress Guidance in API 579-1/ASME FFS-1

Recent progress in the simulation of weld residual stress (WRS), and in its verification and validation (V&V) has provided the opportunity to re-examine existing WRS guidance (Annex E of the Fitness-for-Service (FFS) standard, API 579-1/ASME FFS-1). Comprehensive review of existing guidance and corresponding basis documents, supplemented by validated weld residual stress analysis are utilized to assess the appropriateness of the existing Annex E, and to develop proposals for alternate approaches. The simulation techniques used to support the proposed guidance are described in detail here. The European NeT Program provides an important part of the V&V of all results, and is the focus of this paper. Results using the presented methods show excellent agreement with measurement, therefore providing a sound basis for supplemental analysis to extend available experimental results as necessary. The methods also provide a baseline from which to assess future modeling simplifications for special cases.