Test results showed that for smelting of recycled casting superalloy M17(0. 16C

8.79Cr

5.79Al

4.93Ti

3.29Mo

15.20Co

0.78V

0.015B

0.073Zr

0.002S

0.001P

0.00110

0.0010N)by a 25 kg vacuum in- duction funace

with increasing repeated smelting number of times

the Si content in alloy increased slightly

while the change of main elements in alloy and deleterious element S

P and H was not appreciable

and the O and N content tended to increase; and the morphology of primary carbides in alloy changed from Chinese script-type in fresh alloy to blocky type in recycled alloy

the inheritance of primary carbides interrupted the back feeding shrinkage passage during alloy solidifica- tion to increase the tendency of porosity formation and significantly decrease the plasticity of alloy at clevated temperature.