Good control of chemistry is essential to produce sound S.G Iron castings to the correct mechanical specification. Its well known that Magnesium treatment requires a certain quantity of residual Magnesium in the Iron along with low S' & O level.

In general, a residual Magnesium range of 0.035-0.055% is required in the Iron considering whether its rapid or slow cooling rate to achieve full nodularity. Apart from Magnesium other supplementary additives are also used in the wire to achieve various metallurgical effects c.g. Ferrosilicon, Calcium Alloys, Cerium Misch Metal, and Carbon etc.

• When the cored wire technology is adopted usually the operation sequence are as follows:
• Checking of chemical composition of base Iron
• Adjustment of base metal chemistry if required
• Transfer base iron into treatment ladle & record actual melt weight
• Inject treatment wire into the ladle for carrying out Spheroidising
• De-slag the treated Iron
• Carry out Primary Inoculation in the ladle immediately after slag off the with inoculation wire
• Pouring of casting either directly from the ladle, transfer to pouring ladle or automatic Pouring Furnace
• Secondary inoculation, depending on the castings to be proceeded by use of inoculation wire.

Magnesium Recovery

The computation of recovery is made from typical analytical results according to the following equation:

The Sulphur content before & after the Magnesium treatment, as well as Magnesium content in the iron must be determined. The Magnesium quantity added is known from Mg content (gm/m) of the respective Magnesium Cored wire & length injected (m).

The Mg recovery is influenced by:

• Iron Quantity
• Sulphur level in the Iron
• Treatment temperature
• Feeding speed
• Sheath thickness
• Alloy Composition
• Magnesium content of the Meltex Cored Wire
• Residual Magnesium required
• Cored Wire Addition

The necessary quantity of Meltex Cored Wire is computed according to the following equation:

Meltex offers several wire compositions different application & are differentiated by the S-content of the base Iron. In addition Meltex offers customized wires based on special foundry requirement. Usually the wire diameters for Magnesium treatment are 9mm & 13 mm.