The application of cored wire technology in casting is mainly implemented through ladle metallurgy, with the following objectives:
Steel refining to produce clean steel with low oxygen and sulfur contents;
Calcium treatment to modify the characteristics of inclusions;
Alloying element addition to precisely adjust the chemical composition of molten steel.
(1) Enhanced Final Deoxidation
The wire feeding method is adopted to intensify the final deoxidation process of molten steel. After steel tapping, aluminum wire is fed into the ladle to replace other aluminum addition measures. This converts dissolved oxygen in the steel into alumina, stabilizes the residual aluminum content in the steel at a certain level, and greatly reduces the dosage of aluminum. Under normal conditions, the aluminum consumption is 0.20–0.40 kg per ton of steel, with a recovery rate of 90%–100%.
(2) Calcium Treatment
Its core task is to add calcium to the steel via cored wire technology (mostly in the form of CaSi alloy), so that alumina and aluminosilicates formed during aluminum deoxidation in the steel are transformed into liquid calcium aluminate at the pouring temperature. This reduces the quantity, modifies the shape and reduces the size of inclusions, ultimately purifying the molten steel and improving steel properties such as isotropy, toughness, machinability and hydrogen-induced cracking (HIC) resistance. Depending on the steel grade, 0.15–0.5 kg of calcium is generally fed into each ton of molten steel.
(3) Alloy Composition Adjustment
When other alloying elements are fed into molten steel via cored wire — especially for elements that are difficult to add conventionally or have unstable addition effects — the elements can be delivered directly into the deep molten steel without contact with air and slag, under relatively high pressure, and with a large contact area and long contact time with the molten steel. Therefore, this approach features high addition efficiency and stable results, enables precise control of element dosage, and allows fine composition tuning within a range close to the analytical error. It can meet strict technical application requirements, and well define and control the heat treatment parameters in subsequent manufacturing processes.
Steel refining to produce clean steel with low oxygen and sulfur contents;
Calcium treatment to modify the characteristics of inclusions;
Alloying element addition to precisely adjust the chemical composition of molten steel.
(1) Enhanced Final Deoxidation
The wire feeding method is adopted to intensify the final deoxidation process of molten steel. After steel tapping, aluminum wire is fed into the ladle to replace other aluminum addition measures. This converts dissolved oxygen in the steel into alumina, stabilizes the residual aluminum content in the steel at a certain level, and greatly reduces the dosage of aluminum. Under normal conditions, the aluminum consumption is 0.20–0.40 kg per ton of steel, with a recovery rate of 90%–100%.
(2) Calcium Treatment
Its core task is to add calcium to the steel via cored wire technology (mostly in the form of CaSi alloy), so that alumina and aluminosilicates formed during aluminum deoxidation in the steel are transformed into liquid calcium aluminate at the pouring temperature. This reduces the quantity, modifies the shape and reduces the size of inclusions, ultimately purifying the molten steel and improving steel properties such as isotropy, toughness, machinability and hydrogen-induced cracking (HIC) resistance. Depending on the steel grade, 0.15–0.5 kg of calcium is generally fed into each ton of molten steel.
(3) Alloy Composition Adjustment
When other alloying elements are fed into molten steel via cored wire — especially for elements that are difficult to add conventionally or have unstable addition effects — the elements can be delivered directly into the deep molten steel without contact with air and slag, under relatively high pressure, and with a large contact area and long contact time with the molten steel. Therefore, this approach features high addition efficiency and stable results, enables precise control of element dosage, and allows fine composition tuning within a range close to the analytical error. It can meet strict technical application requirements, and well define and control the heat treatment parameters in subsequent manufacturing processes.