Avesta 309L-SI description: AVESTA 309L-Si is a high-alloy 23 Cr 13 Ni wire primarily intended for surfacing of lowalloy steels and dissimilar welding between mild steel and stainless steels, offering a ductile and crack resistant weldment. The chemical composition, when surfacing, is equivalent to that of ASTM 304 from the first run. One or two layers of 309L are usually combined with a final layer of 308L, 316L or 347.