Flux cored welding wire, also known as powder cored welding wire or tubular welding wire, is divided into two categories: gas protection and non gas protection. The surface of flux cored welding wire is made of materials such as low carbon steel or low alloy steel with good plasticity, just like solid core welding wire. The manufacturing method is to first roll the steel strip into a U-shaped cross-sectional shape, then add welding powder prepared according to the dosage to the U-shaped steel strip, roll it tightly with a rolling mill, and finally draw it to produce different specifications of flux cored welding wire.