Development of Drop-weight Tearing Test and Its Application in Evaluation of Material Resistance to Ductile Fracture

The technical development of drop-weight tearing test (DWTT),complying with the standards of GB/T 8363 and API RP 5L3 etc.was reviewed,together with the introduction of its application in evaluation of the dynamic fracture toughness,especially the material resistance to ductile fracture for high strength and high toughness materials like high-grade pipeline steels,pressure vessel steels and ship steels with excellent crack arrest performance.In summary,The first generation DWTT machine with high impact energy is capable of breaking the specimen to rate the percentage of shear area (pSA) on the fracture surface.The second generation machine is able to measure the DWTT energy absorbed by the DWTT speciemen,as an alternative to the conventional Charpy impact,when dealing with the large-scale or real-size samples.The third generation machine is equipped with the instrumented impact functionality for further analysis on the dynamic fracture toughness of materials,on the basis of elastic-plastic fracture mechanics,especially providing a way to estimate the critical crack tip openning angle (ψCTOA,c) for pipeline steels.