Silicon Magnesium Nodulizer for Cast Iron Production Graphite Spheroidization and Foundry Applications

A nodulizer is judged by one result: graphite that grows as spheres instead of flakes. Silicon magnesium nodulizer achieves this because magnesium has a stronger affinity for sulphur and oxygen than for iron, clearing the melt before it can influence graphite. The silicon carrier makes the addition practical — it lowers the melting range and lets the magnesium enter the iron gradually. Foundries that treat cast iron daily treat the nodulizer as a process input rather than a commodity: the same grade, the same fraction, and the same certificate format, heat after heat.

Grade names look alike and behave differently. The published list runs from FeSiMg5Re2 through FeSiMg6Re1 and FeSiMg7Re1 to FeSiMg7Re3, FeSiMg8Re3, FeSiMg8Re5, FeSiMg8Re7 and FeSiMg10Re7. Magnesium climbs across that list from 4.0–6.0% to 9.0–11.0%, and rare earth climbs from 0.5–1.5% to 6.0–8.0%. Two lots with the same name can still differ inside the window, so the receiving check is the certificate plus a fracture inspection, not the label.
Physical condition separates good lots from tired ones. Fresh material has a clean grey break, sharp edges and little dust. Material that has absorbed moisture shows a dull surface, white patches and crumbling corners, and it will lose magnesium before it reaches the bath. Bags should stay closed until the heat is ready, and the store should be dry and free of floor damp.
Recovery is set by the station rather than by the label. A covered tundish typically returns 40–60% of the magnesium, sandwich practice 25–45%, and cored-wire injection 50–75%, with the remainder leaving as vapour and slag. A supplier who can name the recovery band for your method is easier to hold to a dosing figure.

The table is a map of the family, not a substitute for the grade you ordered. A 5% nodulizer and a 10% nodulizer both satisfy the silicon column and both sit under the aluminium ceiling, yet they are not interchangeable in a ladle. Match the magnesium band to the heat, then check the certificate against the band.

The obvious user is the ductile iron foundry, but the same alloy appears in several places along the casting route.

• Ladle treatment for general jobbing work, where the alloy is plunged under a bell or dropped into a pocket.
• In-mould and in-stream treatment, where a measured granule dose reacts as the metal fills the mould.
• Pipe and fitting production, where long runs demand a stable residual heat after heat.
• Heavy section casting, where magnesium has to survive a slow freeze.
• Ductile iron ingot moulds and mill housings, where section thickness is measured in hundreds of millimetres.

Each route changes the fraction more than the chemistry. A plunger station wants coarse lump; an in-mould pocket wants a fine, dry granule that flows through a dispenser.

• Grade and magnesium band written as a range on the purchase order.
• Fraction in millimetres, with the acceptance rule for oversize and fines.
• Rare earth level, particularly where the charge carries tramp elements.
• Certificate per lot, with the sampling method named.
• Packing that matches the handling equipment — 25 kg bags or 1000 kg jumbo bags.
• Delivery clock understood as 7–14 days from advance payment.

Add one more check that costs nothing: ask for the previous three lot certificates before the first shipment. A supplier whose windows drift from lot to lot will show it there.