On the Processing of Martensitic Steels in Continuous Galvanizing Lines: Part 1 |
| |
Authors: | Taejin Song Jaihyun Kwak B C De Cooman |
| |
Affiliation: | (1) Materials Design Laboratory, Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang, 790-784, South Korea;(2) Technical Research Laboratory, POSCO, Gwangyang, 545-090, South Korea; |
| |
Abstract: | Whereas low-carbon (<0.2 mass pct) martensitic grades can be produced easily in continuous annealing processing lines equipped
with the required cooling capacity, the thermal cycles in continuous galvanizing lines make it difficult to produce hot-dip
Zn or Zn-alloy coated high-strength martensitic grades. This is because of the tempering processes occurring during dipping
of the strip in the liquid Zn bath and, in the case of galvannealed sheet steel, the short thermal treatment required to achieve
the alloying between the Zn and the steel. These short additional thermal treatments last less than 30 seconds but severely
degrade the mechanical properties. Using a combination of internal friction, X-ray diffraction, and transmission electron
microscopy, it is shown that the ultrafine-grained lath microstructure allows for a rapid dislocation recovery and carbide
formation during the galvanizing processes. In addition, the effective dislocation pinning occurring during the galvannealing
process results in strain localization and the suppression of strain hardening. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|