Abstract: The Inconel713 C Ni-based cast supper-alloy,a high-tech material in space/aircraft/automobile/ship-building industries,was refined by removing O/N impurities in vacuum induction furnace.The influence of the refining conditions,including the timing/content of carbon addition,melting-rate,reduction temperature/time,on the O/N-contents was investigated.The results show that the refining conditions had a major impact.To be specific,as the melting time increased,the O-content changed in a decrease-increase mode,accompanied by a linear decrease of N-content.The Inconel713 C alloy with the O/N contents below 10×10^-6 was produced under the optimized conditions in 3-step:first,the raw materials mixed with 0.14%(wt) of carbon powder were pre-reduced and completely melted for 80 min in vacuum induction furnace,next,0.03% of carbon powder was added into the molten alloy,and finally,the molten C-added Inconel713 C alloy was reduced at 1450℃ for 25 min.