scope:

In this report an extensive study was conducted on A516 grade 70 steel to investigate the effect of shallow cracks in weldment HAZs. Charpy V-notch (CVN) and crack-tip opening displacement (CTOD) tests were utilized to characterize the fracture toughness behavior of the heat-affected zone (HAZ) of A516-70 SMAW weldments. The test results are explained on the basis of microstructural features in the HAZ and fractographic examination. Optical light microscopy (OLM) and scanning electron microscopy (SEM) were used for these evaluations. A computer-assisted imaging system was also utilized and it proved to be a powerful tool for fracture surface analysis. It was possible to predict toughness of actual weldment HAZ specimens by determining the area fractions corresponding to ductile tearing and cleavage. In this report an experimental fracture toughness study was performed on A516 grade 70 steel to compare crack tip opening displacement (CTOD) values of laboratory specimens with simulated and actual weld microstructures. The effect of crack depth to specimen width, a/W, ratio on CTOD toughness was studied for a/W ratios of 0.2 and 0.5. Experimental testing also included Charpy V-Notch (CVN) impact tests at equivalent CTOD temperatures and tension tests of each of the simulated microstructures with 39.4 Kj/cm (100 Kj/in) heat input. Actual weldments were tested to investigate whether the simulated microstructures give similar toughness results as the actual HAZ regions. Publication of this document - WRC Bulletin No. 403 - Report No. 1 was sponsored by the Committee on Failure Modes of Components of the Pressure Vessel Research Council (PVRC) and Report No. 2 was sponsored by the Subcommittee on Transportation Structures of the American Iron and Steel Institute and the PVRC Committee on Failure Modes of Components