KEY FEATURES AND APPLICATIONS 309L is a high alloy 23 Cr 12 Ni wire primarily used for surfacing of low alloy steel & dissimilar welding between mild steel/ferritic steels to austenitic stainless steels. The high alloy content and higher ferrite content offers a ductile and crack resistant weldment. The higher silicon content gives better arc stability and weld fluidity. Superior to type 308L. When surfacing on mild steel a corrosion resistance equivalent to ASTM 304 is obtained at the first run.