When to add ductile iron inoculant? What is the method of joining?
The spheroidizing treatment is the base of ductile iron production, and the inoculation treatment is the key of ductile iron production. The inoculation effect determines the diameter, number and roundness of the graphite ball. In order to ensure the inoculation effect, the inoculation treatment adopts multi-stage inoculation treatment. The closer the inoculation treatment is to casting, the better the inoculation effect is. It takes a certain amount of time from gestation to pouring, and the longer the time, the more severe the gestation decline.
In the cast iron industry, a certain amount of inoculant is added to the molten iron before casting, so as to change the solidification process of the molten iron and improve the structure of the casting state, so as to improve the performance of the casting and achieve better results. When is the ductile iron inoculant added? How do you join it?
(1) the inoculant of nodular cast iron is generally more than that of gray cast iron.
(2) Thin-walled castings are prone to white mouth, and the amount of inoculant should be increased accordingly.
(3) If the molten iron after inoculation treatment is poured for a long time, the addition amount should be increased due to inoculation decline.
(4) when there is more slag in molten iron, the inoculant will be wrapped and difficult to melt as soon as it contacts with slag, so the amount added will increase accordingly.
(5) Excessive addition of inoculant will lead to excessive slag, lower temperature of molten iron and shrinkage cavity produced by eutectic group.
If the inoculant block is too large, it will not be able to inoculate the molten iron evenly, and the unmelted inoculant will be poured into the mold cavity.
If the inoculant block is too small, it is easy to oxidize and cause slag, and it is also easy to have inoculation decline.
