What Is Silicon-Calcium?
Silicon-Calcium (Si-Ca) is a composite ferroalloy produced by carbothermically reducing quartz, lime, and coke in an electric arc furnace. It consists primarily of silicon (typically ≥55%) and calcium (typically ≥28%), with strictly controlled levels of impurities such as carbon, aluminum, phosphorus, and sulfur. The alloy appears as a silver-gray metallic material and is supplied in various granular sizes to suit different furnace conditions.
Why Is It Used in Steelmaking?
Silicon-Calcium serves two essential functions in ladle metallurgy:
Strong Deoxidation – Calcium has a high affinity for oxygen, effectively reducing dissolved oxygen levels in molten steel and preventing pinhole and blowhole defects in the final product.
Inclusion Modification – Perhaps its most valued role: Si-Ca transforms brittle, angular alumina (Al₂O₃) inclusions into low-melting-point calcium aluminates. These spherical inclusions readily float out of the melt, significantly improving steel cleanliness.
Why Is It Used in Steelmaking?
Using Silicon-Calcium in secondary refining delivers measurable advantages to production operations:
Reduced Nozzle Clogging – Modified inclusions are less prone to adhering to submerged entry nozzles during continuous casting, minimizing production interruptions.
Improved Steel Fluidity – Cleaner molten metal flows more consistently, enabling stable casting speeds and better surface quality of billets and slabs.
Enhanced Mechanical Properties – Sulfide shape control (rounding elongated MnS inclusions) boosts the ductility, toughness, and fatigue resistance of finished steel products.
Higher Yield Rates – Reduced rejection rates and less internal scrap translate directly to improved profitability per ton of steel.
Application Scope
Silicon-Calcium is indispensable in the production of high-value steel grades, including:
| Application | Steel Type |
|---|---|
| Oil & Gas Pipeline | API X-series, high-strength low-alloy (HSLA) steels |
| Automotive Exposed Panels | Deep-drawing IF steels, galvanized sheets |
| Wire Rod & Fasteners | Tire cord, cold-heading quality steels |
| Heavy Machinery | Forging steels, wear-resistant grades |
| Specialty Bar Products | Bearing steels, gear steels |
The alloy is typically added during ladle refining (LF or VD processes) at a rate of 0.5–2.0 kg per ton of steel, depending on initial oxygen content and final grade requirements.
Product Specifications
Our Silicon-Calcium alloy is manufactured under strict quality control protocols, ensuring batch-to-batch consistency. Standard specifications are as follows:
| Parameter | Typical Value |
|---|---|
| Calcium (Ca) | ≥ 28.0% |
| Silicon (Si) | ≥ 55.0% |
| Carbon (C) | ≤ 0.8% |
| Aluminum (Al) | ≤ 1.5% |
| Phosphorus (P) | ≤ 0.04% |
| Sulfur (S) | ≤ 0.05% |
Custom compositions are available upon request to match specific customer process requirements.
Available Sizes & Packaging
To accommodate different addition methods and furnace configurations, we offer:
Granularity Options: 0–3mm (core wire), 10–50mm, 10–100mm, or customized to your specification.
Packaging:
Standard Packaging: 1 MT big bag (ton bag) with inner waterproof plastic liner.
Small Packaging: 25 kg small bags (available upon request).
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