sites for pit initiation. The pits are joined shortly after initiation producing much larger, shallower [12 
and “lacy” edging damages, (Fig. 4b). Yet, the water quenched GTA melt shows no subsequent [13 
pit growth (Figs. 4c and 4d) and the pits are round, smooth and quite deep. [14 
[15 
16 
4. CONCLUSION | 
[17 
The following conclusions may be drawn from the experimental results. [18 
(1) Rapid solidification of austenitic-ferritic DSS with a Cr.q/Nieq ratio of 1.84 and at cooling rate [19 
of the order of 10° °C/s results in an two phase structure and a change of dendritic to cellular [20 
substructure. The volume fraction of austenite is reduced for 18.4 vol. %, the structure [21 
morphology changes to lathy-ferrite or intercellular austenite and the microstructure becomes [22 
finer for an order of magnitude. Furthermore, the secondary phases content is lower, while the [23 
non-metallic inclusions are smaller and possibly of different composition. 
(2) The described changes in microstructure lead to the increase in pitting corrosion resistance. 
(3) As the cooling rate increases the rate of anodic dissolution in 0.5 M NaCl decreases and 
the pitting potential becomes more positive. 
(4) The superior resistance of rapidly solidified and immediately water quenched alloy is 
proposed to be due to solid state transformation discussed above. 
(5) The cooling rate also influences the distribution of pits and their morphology. The pit size 
decrease but the regularity of their shape and the number of pits increases with the cooling rate. 
5. REFERENCES 
[11 S. Atamert, J. E. King, Z. Metallkde., 82 (1991)3, 230-239. 
[2] T. Ogawa, T. Koseki, Weld. J., 68 (1989)5, 181-s - 191-s. 
[3] K. Tamaki, K. Yasuda, M. Kimura, Corrosion, 45 (1989)9, 764-770. 
[4] M. J. Cieslak, W. F. Savage, Weld. J., 59 (1980)5, 136-s - 146-s. 
[5] D. E. Nelson, W. A. Baeslack lil, J. C. Lippold, Weld. J. 66 (1987)8, 241-s - 250-s. 
[6] B. F. Dixon, Weld. J. 68 (1989)5, 171-s - 181-s 
[71 G. El Nayal, J. Beech, Mat. Sci. and Tech. 2 (1986)6, 603-610. 
[8] J. A. Brooks, A. W. Thompson, Int. Mater. Rev., 36 (1991)1, 16-44. 
[9] J. A. Brooks, M. I. Baskes, F. A. Grenlich, Metall. Trans. A, 22A (1991)4, 915-926. 
[10] S. A. David, J. M. Vitek, T. L. Hebble, Weld. J., 66 (1987)10, 289-s - 300-s. 
[11] J. W. Elmer, S. M. Allen, T. W. Eagar, Metall. Trans. A, 20A (1989)10, 2117-2131. 
306  Prakt. Met. Sonderbd. 26 (1995)