Report Number 2: Comparison of the CTOD fracture toughness of simulated and weldment HAZ regions in A516 steel with deep and shallow cracks
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. This study was undertaken as a joint project with the University of Tennessee. Specimens with simulated microstructures from the coarse, fine or intercritical zones were produced in a Gleeble thermal simulator with thermal cycles that represented a 39.4 Kj/cm and 11.0 Kj/cm heat input. Because the thermally simulated specimens were limited to 12.5 x 12.5 mm (0.5 x 0.5 inch) cross-section, the CTOD tests at the University of Kansas were performed on these same size three-point bend specimens. 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. Good correlation was found between the CVN and CTOD test results on the upper shelf, both for the simulated HAZ and actual weldment HAZ specimens. Also, the results of this study support the conclusions of previous work which showed that increased elastic-plastic fracture toughness is associated with a reduction in the a/W ratio of CTOD test specimens.
- OSTI ID:
- 109998
- Journal Information:
- Bulletin - Welding Research Council, Journal Name: Bulletin - Welding Research Council Journal Issue: 403; ISSN 0043-2326; ISSN WRCBA2
- Country of Publication:
- United States
- Language:
- English
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