Ni reduction in metal

1) How to reduces Nitrogen gas in molten metal in induction furnace.please tell..

2) This means you donot superheat much and donot lose temp in pouring and conveying liquid metal 3) Though appears to be like curiosity....Is this a general enquiry or a specific?

4) Normally nitrogen gas is developed in metal when poured into a heavy cored casting 5) Or through your carburizer 6) What sort of defect is being faced