Enhancement of upper shelf energy through delamination fracture in 0.05 pct P doped high-strength steel

Meysam Jafari, Yuuji Kimura, Kaneaki Tsuzaki

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29 Citations (Scopus)


An ultrafine elongated grain (UFEG) structure with strong (110)//rolling direction (RD) fiber deformation texture was produced by warm-caliber rolling at 773 K (500 °C) and final tempering at 823 K (550 °C), namely tempforming in the 1200 MPa-class, medium-carbon, lowalloy steel with phosphorus (P) content of 0.053 wt pct. Charpy impact tests and tensile tests were performed at a temperature range of 77 K (-196 °C) to 623 K (350 °C) on the tempformed (TF) samples along with a conventional quenched and tempered (QT) samples. The QT structure showed a low upper shelf energy of 70 J and a high ductile-to-brittle transition temperature (DBTT) of 373 K (100 °C) as a result of P segregation and intergranular fracture. A remarkable increase in the upper shelf energy to 150 J from 70 J and a low DBTT of approximately 103 K (-170 °C) were obtained in the UFEG structure. P segregation embrittlement disappeared completely in the UFEG structure, and ductile fracture on the planes normal to RD along with delamination fracture on the planes along RD were observed at a temperature range of 123 K (-150 °C) to 423 K (150 °C). The enhanced delamination occurred because of the microstructural anisotropy of the UFEG structure, a strong (110)//RD fiber deformation texture, and interfaces (i.e. ferrite grain boundaries and cementite particles-ferrite matrix interfaces) weakened by P segregation as feasible crack propagation paths. We studied the delamination (crack-arrester-type) fracture in 0.053 pct P doped high-strength steel along with upper shelf energy and DBTT obtained from the UFEG structure.

Original languageEnglish
Pages (from-to)2453-2465
Number of pages13
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Issue number7
Publication statusPublished - Jul 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys


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