| Title |
Analysis of Toughness and Transition Temperature of High-Toughness Pipeline Steels 2. DWTT Properties and Inverse Fracture Phenomenon |
| Authors |
황병철(Byoung Chul Hwang); 신상용(Sang Yong Shin); 이성학(Sung Hak Lee); 김낙준(Nack J. Kim); 안성수(Seong Soo Ahn) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
API X70 pipeline steel; Drop-weight tear test; Charpy V-notch; CVN; impact test; Inverse fracture |
| Abstract |
In the present study, effects of microstructure on drop-weight tear test (DWTT) properties and inverse fracture occurring in the hammer-impacted region of high-toughness API X70 pipeline steels were investigated. Six kinds of steel specimens were fabricated by varying hot-rolling conditions. The DWTT was conducted on the rolled steel specimens, and the results were discussed in comparison with the Charily V-notch (CVN) impact test data. The DVVTT results indicated that all the specimens showed excellent DWTT properties as the percent shear area well exceeded 85%, irrespective of microstructures, although the inverse fracture occurred at test temperatures below -20℃. The specimens rolled in the single phase region had the lower 85% shear appearance transition temperature (SATT) than the specimens rolled in the two phase region, which was similar to the CVN test results. This 85% SATT had a good correlation with the energy transition temperature (ETT) obtained from CVN test. |