Effect of the Small Addition of Ti on the Mechanical Properties of Hot Direct Rolled Steel Sheets

Abstract

The effect of a small addition of titanium on the mechanical properties of hot direct rolled steels was examined in the laboratory simulation. The small addition of titanium increases the strength of hot direct rolled steels, however the strength of conventional reheating hot rolled steels does not change with the small addition of titanium. The ferrite grain refinement of hot direct rolled steels is also observed with the small addition of titanium.
In hot direct rolling process, titanium seems to be mostly solute during the cooling stage from solidification to the start of hot rolling, and to precipitate as fine carbides/nitrides during or after hot rolling. The dependence of the strength and low temperature toughness on the nitrogen content in the titanium bearing hot direct rolled steels suggests that the strength in low nitrogen steels is due to the fine TiC precipitates and TiN precipitates for high nitrogen steels.