PREDICTION OF THE DELTA-TRANSITION TO GAMMA-TRANSITION IN AUSTENITIC STAINLESS-STEELS DURING LASER TREATMENT

Laser remelting experiments have been performed with austenitic stainl ess steels to evaluate the effects of composition (Cr/Ni-equivalent be tween 1.52 and 1.61) and solidification velocity (V-s=1 to 30 mm/s) on the phase selection between primary delta-ferrite and primary gamma-a ustenite. Experimental results were compared with previous work. The C r/Ni-equivalent is useful to predict the transition from delta to gamm a by comparison with microstructural transitions in the Fe-Cr-Ni terna ry system. The delta to gamma transitions can be modeled by the dendri te growth theory for multicomponent systems. The calculated results sh ow the potential of this approach for the analysis of microstructure f ormation.