Loss of constraint during fracture toughness testing of duplex stainless steels
2013 (English)In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 99, 239-250 p.Article in journal (Refereed) Published
Delamination of the fracture surfaces, so called splits, is an important phenomenon that occurs at sub-zero temperature for hot-rolled duplex stainless steels during impact and fracture toughness testing. To evaluate how the splits influence the fracture toughness, sub-zero temperature fracture toughness testing of 50, 30 and 10 mm thick plates of hot rolled 2205 duplex stainless steel was performed. The results show that the splits cause loss of constraint along the crack front. This can be observed as local difference in crack growth in the specimen. The initiation fracture toughness is not influenced by the specimen thickness. Furthermore, due to the delamination the material exhibits a stable fracture process despite the presence of cleavage fracture. This is interfering with the master curve method so for evaluating the fracture toughness at sub-zero temperatures an assessment of the fracture resistance curve is instead suggested. For assessing the brittle crack behaviour at sub-zero temperatures it is proposed to use the split initiation as a "failure" criteria. The splits are also the cause of the pop-in behaviour observed for the duplex stainless steels. The susceptibility for pop-in is influenced by the microstructure.
Place, publisher, year, edition, pages
2013. Vol. 99, 239-250 p.
Duplex stainless steel, Fracture toughness, Delamination, Splits, Pop-in, Normalization, Master curve
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-122353DOI: 10.1016/j.engfracmech.2013.01.002ISI: 000317325100019ScopusID: 2-s2.0-84875241165OAI: oai:DiVA.org:kth-122353DiVA: diva2:622545
QC 201305222013-05-222013-05-202013-11-08Bibliographically approved