目前球铁生产中经常遇到的—个疵病就是黑点,由于黑点而报废的铸件不在少数,一般感觉到在浇注系统内设置普通的撇渣措施甚至采用拔塞外浇口也很难消除,因此有的工厂就企图以增大加工余量来解决,或者改变浇注位置使黑点位于铸件内不重要的部位.即使如此,黑点层的深度仍不是稳定不变的,有时仍要超出加工 At present, the ductile iron often encountered in production - a flaw is the black spots, due to black spots and scrapped the casting of a few, the general feeling in the pouring system to set the ordinary skimming measures or even using the plug out of the gate is also very difficult to eliminate , So some factories try to increase the allowance to solve the problem or change the pouring position so that the black spot is located in the casting where the casting is not important.However, the depth of the black spot layer is still not stable, and sometimes still exceed Processing