Effect of acicular ferrite formation on grain refinement in the coarse-grained region of heat-affected zone

Journal Article · Thu Jul 15 04:00:00 EDT 2010 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2010.04.004· OSTI ID:22066262

Wan, X L; Wei, R ^[1]

---

1. Institute of Advanced Steels and Welding Technology, Hubei Provincial Key Laboratory for Systems Science on Metallurgical Processing, Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China)

The microstructure of acicular ferrite and its formation for the grain refinement of coarse-grained region of heat-affected zone of high strength low-alloy bainite steels were studied using three-dimensional reconstruction technique. Crystallographic grain size was analyzed by means of electron backscatter diffraction. It was revealed that the microstructure in the coarse-grained region of the heat-affected zone consisted of predominantly bainite packets and a small proportion of acicular ferrite. Acicular ferrite was of lath or plate-like rather than needle or rod-like morphology. Tempering of the coarse-grained region of heat-affected zone showed that the acicular ferrite was more stable than the bainite, indicating that the acicular ferrite was formed prior to bainite. The acicular ferrite laths or plates divided the prior austenite grains into smaller and separate regions, and confining the bainite transformed at lower temperatures in the smaller regions and hence leading to the grain refinement in the coarse-grained region of the heat-affected zone.

• OSTI ID: 22066262
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 7 Vol. 61; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
AUSTENITE
BAINITE
CRYSTAL STRUCTURE
ELECTRON DIFFRACTION
FERRITE
GRAIN REFINEMENT
GRAIN SIZE
HEAT AFFECTED ZONE
LOW ALLOY STEELS
MORPHOLOGY
PLATES
TEMPERING