How to Use Ca-Si Cored Wire
I. Prerequisites and Preparation
Equipment Preparation: Ensure the wire feeder operates stably. Calibrate the angle and length of the guide tube to guarantee smooth feeding of the cored wire without jamming. Inspect the ladle for tightness and heat resistance to prevent molten steel leakage or heat loss.
Cored Wire Inspection: Verify that the specifications (wire diameter, length) and chemical composition of the calcium-silicon cored wire meet the smelting process requirements. Check the wire surface to avoid damage, corrosion of the outer steel strip or leakage of core powder. Replace
immediately if quality issues are detected.
Molten Steel Pretreatment: Complete preliminary dephosphorization and temperature raising before tapping. Control the molten steel temperature within 1500-1600℃ (adjust according to steel grade) and keep the slag thickness on the molten steel surface below 50mm to minimize slag interference with the cored wire reaction.
II. Core Operation Steps
Loading and Calibration: Secure the cored wire spool on the feeder's support frame. Thread the wire through the guide tube. Adjust the feeding speed to the predetermined process setting (typically 2-6 m/s, adjusted based on wire diameter and ladle capacity), ensuring a uniform and stable speed.
Feeding Quantity Control: Calculate the total wire quantity based on molten steel weight, target composition (calcium and silicon content), and the expected recovery rate. Formula reference: Wire Quantity (kg) = Molten Steel Weight (t) × Target Si/Ca Increase (%) ÷ Si/Ca Content in Wire (%) ÷ Recovery Rate (%). Example: For 100t of steel requiring a 0.03% calcium increase, with wire Ca content of 28% and a recovery rate of 40%, the wire quantity = 100 × 0.03% ÷ 28% ÷ 40% ≈ 26.8kg.
Reaction Observation: Monitor the molten steel surface during feeding. Uniform bubble emission (CO and SO₂ gases from deoxidation and desulfurization reactions) indicates normal reaction. In case of violent splashing or no bubbles, promptly adjust the feeding speed or stop operation to check for issues with molten steel temperature or cored wire quality.
III. Process Control and Precautions
Speed and Depth Control: Excessively fast feeding speed may cause molten steel splashing, while excessively slow speed can lead to surface oxidation of the cored wire. Adjust dynamically according to wire diameter (recommended speed: 2-3m/s for 9mm diameter, 4-6m/s for 16mm diameter). Ensure complete immersion of the cored wire in molten steel to avoid contact with slag.
Temperature and Time Control: Low molten steel temperature results in incomplete melting of the cored wire and reduced reaction efficiency; high temperature intensifies volatilization of alloying elements and lowers recovery rate. After feeding, allow the molten steel to stand for 10-15 minutes (holding time) to ensure sufficient reaction and complete floating or modification of inclusions.
Safe Operation: Operators must wear high-temperature protective equipment (protective clothing, face shields, gloves), stay away from the ladle mouth and guide tube outlet to prevent scalding from splashing molten steel. Prohibit personnel from approaching the wire feeding path during operation to avoid mechanical hazards.
Multi-Batch Feeding: For large-scale addition of alloying elements, divide into 2-3 batches with 5-minute intervals between batches. Avoid violent reactions caused by excessive single-batch feeding to improve the stability of element recovery rate.
1.After the holding period following wire feeding, take samples to test the steel's calcium and silicon content and inclusion morphology. If the target composition is not met, perform supplementary wire feeding based on the test results (recalculate the quantity using the formula above).
2.Observe whether the tundish nozzle remains unobstructed during continuous casting. If clogging persists, adjust the wire feeding quantity or pretreatment process to optimize inclusion modification.
3.Record key parameters from the operation (wire quantity, speed, steel temperature, recovery rate) to build a process database, providing a basis for future production optimization.
