Fracture Assessment of a Repair-Welded BI-Material Steel by Defect Assessment Procedure SINTAP

Abstract

In many industries, bi-material components in the form of clad plates are used due to their superior environmental and mechanical properties. During the service life of these bi-material components, cracks or crack-like detects may develop in the cladding or at the interface (underclad discontinuities) having different orientations with respect to the interface, and may penetrate into the substrate. Welding of those damaged parts after completely removing the imperfection by gouging or grinding is a well-established industrial practice. Defect assessment of the integrity of such a repaired and complex structure should be conducted and obviously it would be a difficult task. This study aims to apply the recently developed European Structural Integrity Assessment Procedure (SINTAP), to a through thickness centre cracked clad steel wide plate, containing shallow and deep repair welds, to validate the SINTAP procedure for this type of bi-material structure and also to establish a procedure for the assessment of such a complex repaired structure. Based on the used input data, various assessment levels (including mis-match option) using the crack driving force (CDF) route are worked for predicting the failure loads. The degree of conservatism has been reduced by using higher analysis levels of the SINTAP. The SINTAP procedure has been verified and a methodology to conduct SINTAP-based assessments is presented.