CA-101S×UC-309/309L is a bonded type flux that contains appropriate quantity of alloy elements. UC-309 is suitable for welding dissimilar metals such as mild steel because of a large quantity of alloy elements. It provides better crack resistibility due to properly controlled ferrite content in austenitic structure.

Welding of 22%Cr-12%Ni stainless steel and dissimilar joints such as stainless steel to mild steel or low alloy steel. 19%Cr-9%Ni type hardsurfacing of mild steel or low alloy steel. Welding of 18%Cr-8%Ni stainless clad steel.