Self-protection flux-cored wire for bottom layer of extrusion roller

The invention relates to the technical field of welding materials, in particular to a self-protection flux-cored wire for a squeeze roller priming coat, 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, Mn, Si, Ni, K4TiO4, Al and Na2SiF6. Compared with the prior art, the method has the beneficial effects that preheating is not needed before welding, the method can be used at normal temperature, the repairing link is simplified, the production and site requirements are reduced, and the production cost is reduced; (2) the use requirement of surfacing more than three layers is met; (3) welding layer metal and base metal are well fused, the bonding strength is high, and (4) the welding layer metal is an austenite and ferrite double-phase structure and has high crack resistance, the tensile strength is about 550 MPa, the section elongation rate is 24% or above, fatigue cracks and welding cracks on the ro