Ceramic arc striking plate for welding of base materials with different widths

A ceramic arc striking plate for welding of base materials with different widths comprises a bottom face contacted with a column base material; a non-use welding face which is disposed on the side perpendicular to the bottom face and contacted with an end face of a beam base material which has been chamfered; and a sunk welding use face which is opposite to the non-use welding face, wherein the welding use face and the non-use welding face are connected by a step surface which is disposed at the angle corresponding to the groove angle of the beam base material. The welding use face is disposed at the position for face rotation from the face parallel to the non-use welding face towards inside of the arc striking plate at a stipulated angle with the intersecting line of the welding use face and the step face as the center shaft. In this way, the expanded size of the welding use face to the bottom face is bigger than the size of an initial layer part S1 relatively to a surface part S2, and the ratio of S2 to S1