WRC 602 ✓ Most Recent

This WRC Bulletin presents an independent verification of the Weld Residual Stress (WRS) solutions developed in WRC Bulletin 581, Development of New Residual Stress Profiles for API 579-1/ASME FFS-1, authored by P. Dong, S. Song, Z. Jin, D.A. Osage, and D. Spring. This verification utilizes advanced welding Finite Element (FE) simulation tools, including ESI Group’s Sysweld and the Qustom App’s QustomWeld plug-in for ABAQUS, to validate the analytic and numerical modeling procedures outlined in WRC Bulletin 581. The study focuses on three key geometries: circumferential welds in cylinders, longitudinal welds in cylinders, and tee joints.

The purpose of this work is to confirm that the WRS solutions and modeling approaches in WRC Bulletin 581 are suitable for Fitness-For-Service (𝐹𝐹𝑆) applications, particularly for assessments involving crack-like flaws as described in API 579 Part 9. Comparisons between the updated WRS solutions in WRC Bulletin 581 and those previously provided in API 579 Annex 9D are also included.

Weld residual stress plays a critical role in 𝐹𝐹𝑆 evaluations, especially for high-strength materials where it can represent the largest stress contribution. Small variations in predicted residual stress can significantly influence 𝐹𝐹𝑆 Assessment outcomes, underscoring the need for accurate yet appropriately conservative stress solutions. Excessive conservatism can lead to over-predicted stress profiles, potentially biasing the assessment process. The findings presented in this bulletin aim to support the development of reliable WRS profiles, balancing accuracy, and conservatism to address the inherent uncertainties in material properties, geometry, and service conditions.