Abstract: Friction hardfacing of 2A12 aluminum consume rod on Q235 low carbon steel substrate was achieved. The result show that the preheat of substrate can improve the interface quality, the sound weld with good formation and without defects can be obtained. The surfacing layer is refined under the thermal-mechanical reaction, the grains of the substrate metal near the interface have been distorted along the consume rod rotation direction. The Fe and Al element diffused, and its diffusion range increases when the substrate is preheated. The hardness of the surfacing layer is lower than that of the base material, and it is lower when the substrate is preheated. For the hardness distribution of the consume rod, that in base material is higher than that of friction rolling zone and heat-affected zone, and the friction rolling zone is harder than heat-affected zone.