GRAIN SIZE CONTROL ON COMPONENTS MADE DIRECTLY FROM CONCAST BILLET
The aim of this project was to investigate grain refining additions which can be used in continuously cast steel and which are effective under conditions of reheating at 1100-1300 C and hot working. The experimental programme confirmed that under conditions simulating continuous casting of billets with sections of 140mm and below, the addition of 0.01-0.02% Ti to a 0.35% C 1% Cr steel led to effective grain refinement at 1100-1300 C. It was confirmed that the optimum titanium addition was in the range 0.01-0.02% and that a normal aluminium addition (>0.010%) is necessary to obtain effective grain refinement. There was little effect of ingot test position or experimental ingot size on the effectiveness of grain size control. The thermomechanical treatments associated with forging and rolling operations led to coarsening of the TiN particle size, but the addition still remained effective. It was demonstrated that use of a titanium addition led to an improvement in the impact toughness of steels hardened from high temperatures, consistent with the refinement in austenite grain size obtained. High strain rate tensile tests showed that there were no major harmful effects on the hot ductility of titanium additions in the range 0.01-0.035%. No advantage was found from additions of vanadium, niobium or zirconium to a titanium-treated steel.
Bibliographic Reference: EUR 12201 EN (1989) 124 PP., MF, ECU 8 THE OFFICE FOR OFFICIAL PUBLICATIONS OF THE EUROPEAN COMMUNITIES, L-2985 LUXEMBOURG
Record Number: 1989128034900 / Last updated on: 1992-08-10
Original language: EN