Welding backing block and welding blacking

The utility model provides a welding backing block. The welding backing block is a ceramic backing block which has a top surface and a bottom surface that are parallel. A head-end inclined surface and a tail-end inclined surface are parallel. Furthermore a 45 DEG included angle is provided between the head-end inclined surface of the backing block and a top surface, and a 45 DEG included angle is provided between the tail-end inclined surface of the backing block and a bottom surface. In connection, the welding backing blocks can be successively connected to a strip-shaped welding backing, and can be connected to a welding backing used for an angle iron butt joint through changing the connection mode thereby obtaining convenient use and saved cost. The utility model also provides a welding backing. The welding back comprises a plurality of weldng backing blocks which are connected with one another to a strip-shaped object. The bottom surfaces are fixedly connected through a fixing strip. The welding backing b