Alloy powders such as silicon-calcium powder, calcium-iron powder, carbon powder, titanium powder, aluminum-silicon powder and rare earth powder are wrapped with cold-rolled steel strips to make alloy cored wires. The alloy cored wires are fed into molten steel by wire feeding method for secondary refining. This technology has long been applied in economically developed countries such as France, the United States, Japan and Germany. Since the 1990s, this technology has also been widely used in China’s iron and steel industry. Subsequently, the demand for alloy cored wires has been increasing, and the production of cored wires is forming a large industry in China.