Self-protection flux-cored wire for extrusion roller cover surface layer

The invention relates to the technical field of welding materials, in particular to a self-protection flux-cored wire for a squeeze roller cover surface layer, which comprises a flux core and a cold-rolled low-carbon steel strip, and is characterized in that the flux-cored wire comprises the following components: C, Cr, Nb, Mn, Si, V, Ti, BiO, Al, Mg, TiO2, Na2SiF6 and the balance of iron powder; and the carbon content in the cold-rolled low-carbon steel strip is less than 0.03%. Compared with the prior art, the method has the beneficial effects that the welding layer metal has high hardness and high wear resistance, the post-welding hardness can reach HRC65 or above after two layers are overlaid, the weight loss of the wear-resistant layer does not exceed 0.242 g through an LGM-130 dry sand rubber wheel abrasive wear experiment test, the wear-resistant surface is free of furrows, pits or flake spalling, the wear resistance is excellent, and the service life is long. The method is used for online welding repa