Long and plate castings are easy to deform. After some castings are processed, they will deform after a period of time.
Preventive measures: add reinforcement properly; increase machining allowance properly; adopt reverse deformation process; conduct stress relief annealing to eliminate internal stress of casting; adopt aging treatment.
There are incomplete fusion cracks or pits on the casting, and the boundary edge is smooth. Preventive measures: increase the pouring temperature and pouring speed; improve the pouring system; do not cut off the flow during pouring.
Lack of flesh in castings due to incomplete filling of the cavity with liquid metal. Preventive measures: increase pouring temperature and pouring speed; do not cut off the flow and prevent running fire; spot pouring and feeding in place at the later stage of pouring.
It should be emphasized that, while taking preventive measures for various defects, it is also necessary to strengthen the process discipline inspection and supervise, correct and assess the phenomenon of violating the process operation.