Roller combined extrusion method and roller

The invention relates to a roller combined extrusion method and a roller, and relates to the technical field of roller plastic formation.The roller combined extrusion method comprises the steps that a core base body is prepared through a forging method or a casting method, the core base body comprises first connecting parts and a second connecting part, and the second connecting part is arranged between the two first connecting parts; the section of the joint of the first connecting part and the second connecting part is a first inclined surface; forming a surfacing layer outside the second connecting part by using an electroslag heaped melting method to obtain a first extrusion blank; the first extrusion blank is pretreated, and a second extrusion blank is obtained; and performing extrusion forming on the second extrusion blank, and processing to obtain the target roller. The content of carbon and chromium in a surfacing layer material is higher than that in a core base body material, metal compactness and s