Fracture analysis of laser beam welded superalloys Inconel 718 and 625 using the FITNET procedure

This paper presents results of the analysis for residual strength prediction of two laser beam welded superalloys (Inconel 625 and 718) using the fitness-for-service (FFS) procedure FITNET. The analysis is based on Option 3 of the Fracture Module of the procedure arising from the European Community funded project FITNET (www.eurofitnet.org). Analysis option 3 requires full stress–strain curves of the materials as input data. Since the strength mismatch ratio (M) between the weld and the base metals for both alloys was less than 10%, a homogeneous solution route has been used for welded tension loaded specimens containing through thickness central cracks. The FITNET predictions of the attained maximum load levels of the specimens were verified with the generated experimental results. The analysis methodology, as well as comparison between predictions and experimental results are provided. Accurate yet conservative estimation of the maximum load carrying capacities have been achieved depending on the input data; as the input data becomes more detailed, the degree of conservatism decreases.