| Delamination behavior of Nb-microalloyed HSLA steel, produced by different processes, has been studied by tensile and impact tests. The plate production processes are: quenched from hot-rolling (designate as HQ sample), air-cooled from hot-rolling (HA), and subsequently cold rolled HQ and HA samples (HQC, HAC). In tensile test, only HQC sample, and in impact test, HQC and HAC samples have shown delamination. The occurrence of delamination in tensile tested sample is strongly affected by carbide precipitates on grain boundaries. However, the contributing factor of delamination in the impact tested samples are suggested to be pancaking of grains and texture by cold rolling. Carbide precipitate on grain boundaries may also contribute delaminating the impact tested HQC sample. Variation of the amount of delamination by aging treatment has been also studied in correlation with the microstructure. |
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