Title

EFFECTS OF SPLIT-OUT ON J-R CURVES OF HOT-ROLLED STEELS

Authorship

Ipiña, Juan E. Perez; Korin, Ivan

DOI

10.5151/2594-5327-20917

Downloads

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Abstract

The Split-out phenomenon is a sudden instability which takes place near the crack tip, and is generated by a rapid growth and arrest of a crack at the divider orientation. This phenomenon is related to stress triaxiality in the front of the crack tip when the structure is under plane strain conditions, plus the existence of weak interfaces oriented normal to the thickness direction. The weak interfaces can be generated as a result of some metallurgical process such as hot-rolling lamination in materials with a high level of impurities, as well as steels where the structure results in a strong banding of ferrite and pearlite. When a cracked structure is loaded, the high z stresses related to the plain strain state can lead to a split-out brought about by delamination of the weak interfaces. During a fracture toughness test, this is noticed as a drop in the load-displacement record, which is similar to that produced by the well known pop-in instability in welded joints. As the split-out has been less studied than the pop-in, and due to the similarities between both load-displacement records, it is very common to consider both instabilities under the same failure acceptance criterion although their etiologies are completely different. In this work the effect of split-out on the J-R curve behavior is studied and a methodology to avail them is proposed.

 

Keywords

Split-out; Hot rolled steel; Fracture toughness.