Hi all,

In piping materials we had added Niupto 9% to 70%(Incolly) in carbon steel and in SS as it is helpful to improve mechanical properties. Same as Si % is also useful to improve such properties but why Si% is restricted to Max 0.75%

You are in the wrong forum for this question, although I'm sure someone will give you an answer. Eng Tips Forum has a Metallurgy section that would be more appropriate.