Why Transport Care Matters
Alloy cored wires - steel strips filled with compacted alloy powder such as calcium silicon, calcium aluminum or calcium iron - are used for precise ladle metallurgy additions in steelmaking and foundry work. The wire's performance depends on the integrity of the strip shell and the uniformity of the powder core. Damage during transport - moisture ingress, crushing, kinking or corrosion - can break the strip, contaminate the core or alter the filling rate, which in turn disrupts the feed rate and alloy recovery at the point of use. Transport precautions protect both the physical wire and the chemical consistency the process depends on.
Typical Cored Wire Specifications
The precautions below apply generally to the common cored wire family. The table lists typical specifications for the three main alloy types:
| Type | Main Components (%) | Wire Diameter (mm) | Strip Thickness (mm) | Strip Weight (g/m) | Core Powder Weight (g/m) | Uniformity (%) |
|---|---|---|---|---|---|---|
| Silica calcium wire | Si55Ca30 | 13 | 0.35 | 145 | 230 | 2.5-5 |
| Aluminum calcium wire | Ca26-30 Al3-24 | 13 | 0.35 | 145 | 210 | 2.5-5 |
| Calcium iron wire | Ca28-35 | 13 | 0.35 | 145 | 240 | 2.5-5 |
Coil weight is typically 600 kg ± 100 kg, with custom weights available on request. Quality requirements include a firm covering with no seams or broken lines, uniform core composition and a high filling rate.
Packaging Requirements
Standard export packing for cored wire is steel strapping, waterproof plastic film and an iron cover, which protects the coils from crushing, moisture and handling damage. Coils are arranged in either horizontal or vertical orientation, with two packaging styles: internal tap (pay-off from the inside) and external tap (pay-off from the outside). Ensure the selected pay-off style is compatible with the receiving end's feeding equipment, and mark it clearly on the packing documents. During transport, additional protective tubing, sheathing or wrapping should be used where coils may contact other cargo.
Moisture Protection
Cored wires are sensitive to moisture. Calcium-bearing cores react with water, and even absorbed humidity can degrade powder flow and promote corrosion of the strip. Avoid direct exposure to rain or high-humidity environments throughout loading, transit and storage. Use moisture-proof bags, desiccants or moisture-proofing agents inside the packing, keep containers sealed and dry, and reject any coil whose wrapping shows water damage before unloading.
Mechanical Protection
Although cored wire has a degree of flexibility, excessive bending or twisting can cause internal damage or breakage of the strip and core. During transport, avoid tight curves and angles, do not stack heavy cargo on top of coils, and keep the wire away from sharp objects, sharp edges or other items that could cut or indent the strip. Secure coils safely in the vehicle with ropes, buckles or packing material to reduce vibration and swinging, and use isolation pads or separation material where coils might rub against each other or the container wall.
Temperature and Receiving Inspection
Some cored wire types are sensitive to high temperatures, so avoid prolonged exposure to heat, contact with hot surfaces or storage in hot areas during transport and interim storage. On arrival, inspect the packing for water damage, crushing and broken strapping before accepting; check coil weight against the shipping documents and verify the type marking and pay-off orientation. If a certificate of analysis is required by contract, confirm it accompanies the shipment and matches the lot markings.
FAQ
Q1: Why must cored wire be kept dry during transport?
Calcium-bearing cores react with moisture, which degrades powder flow, promotes strip corrosion and can cause violent reactions when the wire is fed into molten steel. Dryness protects both the product and the process.
Q2: Can cored wire coils be stacked during shipping?
Stacking is possible only if the coils are protected from crushing, normally with proper dunnage and load distribution. Heavy stacking on unprotected coils can deform the strip and damage the core.
Q3: What is the difference between internal and external tap packaging?
Internal tap pays off from the inside of the coil and external tap from the outside. The right choice depends on the feeding machine design at the receiving plant; the wrong orientation makes installation difficult.
Q4: How is cored wire quality verified on receipt?
Check packing integrity, coil weight, markings and pay-off style, and confirm the certificate of analysis for core composition and uniformity if specified in the contract.
Q5: What is the typical coil weight of cored wire?
Standard coil weight is 600 kg ± 100 kg, with custom weights produced to user requirements. Confirm the exact weight range at order placement.