How to adjust the amount of inoculant?

In the cast iron industry, a certain amount of inoculant is added to the molten iron before casting, in order to change the solidification process of molten iron and improve the as-cast structure. So as to improve the casting performance, casting more perfect effect. So many workers will ask, how much should be added? How to adjust the amount of inoculant added? Henan Stellar Metallurgy Company invited Mr. Wu, the foundry technical director with whom it has cooperated for many years, to pass on his experience summary:

(1) the amount of inoculant added to ductile iron is generally more than that of gray iron.

  (2) If the molten iron after inoculation treatment is poured for a long time, the amount added should be increased because of inoculation decline.

  (3) Thin-walled castings are prone to white mouth, and the amount of inoculant should be increased accordingly.

  (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 cavity; If the block is too small, it is easy to oxidize and cause slag, and it is also easy to develop gestation recession.

  (6) The inoculant used in the fluid-inoculation method is small in bulk, generally 0.2-0.8mm, and the amount of inoculant added is 0.05% ~0.2%; The lumpiness of the inoculation method is generally required to be ≤0.25mm and the amount of addition ≤0.1%.

The other inoculation methods are generally added 1-3mm or 3-8mm in size, and the amount of addition is 0.1%~0.8%.

These are the experience of Master Wu, who has been guiding the production line for many years. Wu said: different manufacturers, different furnace types, different inoculant products may have slightly different dosage, need to be adjusted according to different production requirements.

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