High Purity Ferro Silicon Nitride Lump 10-50 mm for HSLA and Stainless Steel
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High Purity Ferro Silicon Nitride Lump: Product Overview
Ferro silicon nitride, written FeSiN in mill specifications, is a nitrogen bearing master alloy used to introduce nitrogen into steel, cast iron and refractory systems. The high purity lump supplied in the 10 to 50 millimetre size range is made for melts in which material consistency and low residual levels are decisive, including high end steel grades, precision castings and specialised alloy systems.
Because nitrogen is added as a solid alloy rather than as a gas, the treatment fits normal charging practice. The material can be weighed, charged to the ladle or the furnace in a controlled quantity and allowed to dissolve, so the nitrogen addition is reproducible from heat to heat instead of depending on gas flow control at the ladle.
Chemistry and Nitrogen Content
Nitrogen content in the supplied lump typically falls between eight and fifteen per cent and can be adjusted inside that window to match the requirement of the steel grade being produced. The high purity formulation keeps sulfur, phosphorus and heavy metals low so that the nitrogen benefit is not offset by residual elements that would reduce toughness or raise the risk of cracking during hot working.
| Parameter | Supplied range | Comment |
|---|---|---|
| Nitrogen content | 8 to 15 per cent | adjustable to the ordered technical requirement |
| Lump size | 10 to 50 millimetres | screened for ladle and furnace charging |
| Sulfur and phosphorus | held to low levels | keeps residuals inside the limits of the steel grade |
| Heavy metals | minimised | supports clean melting practice and cleaner end product |
Silicon and iron make up the balance of the alloy, and the composition is set so that the nitrogen carrier dissolves readily in the bath. Material is released against lot chemical analysis, and that assay is the basis on which the addition is calculated.
Why the Lump Form Matters in Melting Practice
The 10 to 50 millimetre lump gives predictable dissolution behaviour. Fine powder oxidises at the bath surface and much of it is carried into the slag or the dust extraction system, so nitrogen recovery becomes erratic. Oversized pieces dissolve too slowly and release nitrogen late in the heat. The screened lump dissolves steadily once the bath has reached temperature, which allows nitrogen recovery to be estimated with confidence and written into the addition calculation.
Lump handling is also simpler than powder handling. The material can be charged with the same equipment used for other ferroalloys, it needs no briquetting or injection equipment, and the size band is narrow enough to avoid bridging in the feeding system while remaining easy to weigh accurately.
Applications: HSLA Steel, Stainless Steel and Cast Iron
In high strength low alloy steel, nitrogen combines with nitride forming elements to refine the grain and raise strength, so nitrogen bearing practice supports the property targets of the grade without a large increase in alloy cost. Nitrogen also improves fatigue life, which matters in components that see cyclic loading in service.
In stainless steel manufacture, nitrogen acts as an interstitial strengthener and as an austenite stabiliser, so it raises strength and supports the austenitic structure at the same time. The addition also improves resistance to pitting corrosion in chloride bearing environments, which is why nitrogen alloyed stainless grades are chosen for aggressive service in the chemical and marine industries.
In high performance cast iron, nitrogen refines the graphite structure and raises strength, and a consistent lump size keeps the addition stable across a large operation where many heats are treated in sequence. Refractory and ceramic systems also take the material as a combined nitrogen and silicon source.
Quality Control and Custom Composition
Each lot is released against third party testing so the nitrogen figure on the certificate matches the material actually delivered, and the low residual levels claimed for the high purity grade are demonstrated by the same analysis. Composition can be tailored within the manufacturing window when a steel grade calls for a particular nitrogen level or a tighter residual limit, and the size band can be adjusted for the charging equipment in use.
Storage matters as much as analysis. The lumps are packed to stay dry because absorbed moisture introduces hydrogen at the ladle, and the material should stay under cover until it is charged.
FAQ: Ferro Silicon Nitride Lump 10-50 mm
Q: What nitrogen content can the FeSiN lump deliver?
Nitrogen content typically ranges from eight to fifteen per cent and can be adjusted within that window to match the technical requirement of the steel grade being treated.
Q: Why is the alloy supplied as 10 to 50 millimetre lump?
The size band balances dissolution rate against losses. Powder is lost to slag and dust extraction, while oversized pieces dissolve too slowly and release nitrogen late in the heat.
Q: Which steel grades benefit most from a nitrogen addition?
High strength low alloy steel, austenitic and duplex stainless steel and high performance cast iron, where nitrogen raises strength, supports the austenitic structure and improves resistance to pitting corrosion.
Q: How does nitrogen affect the properties of stainless steel?
As an interstitial element it raises strength and acts as an austenite stabiliser, and it improves resistance to pitting and crevice corrosion in chloride bearing service.
Q: How is the material qualified before dispatch?
Every lot carries a chemical analysis from third party testing that reports the nitrogen level and the residual elements, so the assay used for the addition calculation is traceable to the delivered batch.
Q: Can composition and lump size be customised?
Yes. Nitrogen level, residual limits and the screened size band can all be set within the manufacturing window of the process, which allows the alloy to be matched to a specific melting route.
