Silicon Calcium Cored Wire Export Prices from China (Ca30Si60, Ca28Si55)

February 10, 2023 Silicon Calcium Cored Wire Export Quotations

Silicon calcium cored wire offers from China for February 10, 2023 were assessed on an FOB Tianjin basis in US dollars per tonne. Two core compositions were quoted, both in a nominal 13 millimetre diameter.

Product	Index	Price (USD/ton)	Port	Remarks
Silicon calcium cored wire	Ca30Si60, 13 mm	1650-1750	Tianjin port	FOB, USD/ton
Silicon calcium cored wire	Ca28Si55, 13 mm	1500-1600	Tianjin port	FOB, USD/ton

The table reproduces the published offer range for the two specifications. The higher-calcium Ca30Si60 grade sits about 150 USD/ton above the Ca28Si55 grade at the low end of the published ranges, which is consistent with the greater quantity of calcium-silicon alloy carried in each metre of wire.

Decoding the Ca30Si60 and Ca28Si55 Indexes

In a calcium-silicon cored wire, the index describes the active alloy powder sealed inside the steel sheath. Ca30Si60 means a nominal 30 percent calcium and 60 percent silicon in the core alloy, with the balance substantially iron and minor elements. Ca28Si55 means a nominal 28 percent calcium and 55 percent silicon. The wire therefore delivers not pure calcium but a calcium-silicon master alloy, which is far less reactive than metallic calcium and much easier to handle and feed.

Silicon in the alloy lowers the activity of calcium and raises the density of the core material, which improves feeding behaviour and calcium recovery in the ladle. A higher calcium content does not automatically mean a better purchase: the useful metric for a steel shop is the quantity of calcium successfully dissolved in the steel per tonne of wire consumed, and that depends on wire design as much as on the index.

How Cored Wire Performs in Calcium Treatment

Cored wire is injected into the ladle through a wire feeder at a controlled speed. The steel sheath melts in the steel bath and releases the calcium-silicon powder at depth, so that the calcium dissolves in the liquid steel rather than vaporising at the surface; calcium vaporises far below steelmaking temperature, which is why deep injection and a controlled feed rate matter so much.

The dissolved calcium performs two duties:

It reacts with sulphur in the steel to form stable calcium sulphide, converting elongated manganese sulphide inclusions into globular ones and improving transverse ductility and through-thickness properties.

It modifies solid alumina inclusions into liquid calcium aluminate, which stays fluid and prevents nozzle clogging and alumina build-up during continuous casting of aluminium-killed steel.

Both reactions are strongly dependent on the calcium-to-sulphur ratio and on the oxygen content of the steel at the time of treatment. Under-treated heats retain alumina clusters; over-treated heats waste calcium and can produce coarse calcium aluminate inclusions. That is why the wire specification, the feed rate and the treatment sequence are normally agreed together rather than chosen independently.

Why the 13 Millimetre Diameter Matters

Wire diameter governs the stiffness of the wire, the speed at which it can be fed, the sheath-to-core mass ratio and the depth at which the powder is released. A 13 millimetre wire is a widely traded size: it is stiff enough to penetrate the slag layer and reach the steel bath without buckling, yet flexible enough to run through standard feeding equipment and to be coiled for transport.

For a given diameter the buyer should confirm the strip thickness of the sheath, the core mass per metre of wire, and the consistency of the fill. A uniformly filled wire feeds predictably and delivers a repeatable calcium input per metre. Poorly filled or damp wire causes erratic feeding, spitting at the ladle and variable recovery, all of which raise the effective cost per treatment even if the unit price looks attractive.

Purchasing Points and FOB Tianjin Delivery

Tianjin port is the reference loading point for the offers above. It is the principal gateway for wire producers located in Henan, Hebei and Shandong, with dense rail and road connections and frequent sailings to Asia, the Middle East, Europe and the Americas.

On FOB terms the seller handles inland transport, export clearance and loading, while the buyer arranges ocean freight and insurance. When comparing offers, purchasers should align:

Core index and the analytical basis used to certify calcium and silicon content.

Steel sheath material, strip thickness and the core mass per metre of wire.

Coil weight, coil inner diameter and packing, including moisture-proof wrapping on pallets.

Butt-joint quality and the permitted number of joints per coil, since weak joints break in the feeder.

Shipment window and the sailing schedule from Tianjin to the destination port.

Payment terms and inspection arrangements before loading.

Documentation for an export consignment normally comprises the commercial invoice, packing list, certificate of analysis, certificate of origin and the bill of lading. Specifying the acceptance limits for the core index and for moisture at the time of the order avoids later disagreement over what constitutes conforming material.

Storage and handling on arrival. Calcium-silicon cored wire is sensitive to moisture. Coils should be stored under cover, off the ground and away from standing water, and opened only immediately before use. Damp core material loses calcium to hydrolysis, the powder cakes and the wire no longer feeds smoothly. Buyers in humid climates often specify additional wrapping and desiccant before dispatch.

Coils should be handled with slings or a suitable pallet arrangement rather than dropped, because the sheath is thin and easily crushed; a deformed coil pinches the wire and causes feeding stoppages at the ladle stand. Rotation of stock on a first-in, first-out basis also keeps older coils out of the treatment sequence.

Frequently Asked Questions

Q: What does the Ca30Si60 index mean?
It describes the core alloy: a nominal 30 percent calcium and 60 percent silicon, with the balance largely iron and minor elements, sealed inside a steel sheath.

Q: What were the February 10, 2023 export prices?
Ca30Si60 in 13 mm diameter was quoted at 1650-1750 USD/ton and Ca28Si55 in 13 mm at 1500-1600 USD/ton, both FOB Tianjin port.

Q: Why is Ca30Si60 more expensive than Ca28Si55?
It carries more calcium and more silicon per tonne of core material, so more alloy is required to fill each metre of wire and the material cost per tonne is higher.

Q: What is calcium treatment used for?
It shapes sulphide and oxide inclusions in steel, improving transverse ductility and preventing alumina nozzle clogging during continuous casting of aluminium-killed grades.

Q: Does a larger wire diameter give better calcium recovery?
Not by itself. Recovery depends on how deep the powder is released, on the feed rate and on the steel oxygen and sulphur levels at treatment, not on diameter alone.

Q: How should cored wire be stored?
Under cover, off the ground, away from water, with packaging opened only just before use, because absorbed moisture degrades the core alloy and disrupts feeding.