In addition to mold rigidity and metallurgical quality of iron melting, the main reasons causing riser feeding failure in nodular iron castings production are: (a) open and cold metal flowing-over risers were adopted; (b) riser location was not proper; (c) riser was too small or/and not enough high; (d) ingates did not freeze up instantly as soon as pouring finished;(e) there’re isolated hot spots in the casting which are not connected with feeding channel of the riser; (f) the feeding channel of castings with small size and thin sections is too narrow for feeding liquid to enter casting; and so on.