2004 Volume 45 Issue 2 Pages 479-487
Direct near net shape casting is an attractive process for the production of sheet metal because of its economical profit and the production of a new microstructure due to the fast solidification rate. To explore further advantages of direct near net shape casting, the differences in the mechanical properties between the as-cast and annealed strips of a steel with comparatively high contents of the impurities (Cu, P and S) were investigated in this paper with an emphasis on the microstructural effects. This process not only produced fine microstructures but also resulted in nano-scale copper sulfides. The as-cast strip has higher yield and tensile strengths and maintains high work hardening ability at higher stress levels than that of the annealed strip. Both the as-cast and annealed strips have a superior balance of strength and work hardening ability compared to the strips without the impurities. The nano-scale copper sulfide particles in the as-cast strip contributed most to the increase in the yield strength. The as-cast strip also could not produce the good work hardening ability without the nano-size particles. Further improvements in strength and work hardening ability can be attained by controlling the particles' size and the volume fraction in the strip.
