Small square billet dummy bar head connecting assembly and assembling method thereof

An embodiment of the invention provides a small square billet dummy bar head connecting assembly and an assembling method thereof, and relates to the technical field of square billet forming. The dummy bar head connecting assembly comprises a connecting piece, a flow blocking steel sheet and a cold steel fixing box, wherein the connecting piece is used for being arranged in a crystallizer and connected with a dummy bar head on a dummy bar, and the flow blocking steel sheet and the cold steel fixing box are sequentially arranged on the connecting piece in a sleeving mode from bottom to top; a first cold steel assembly is arranged on the inner side wall of the cold steel fixing box, a second cold steel assembly is arranged in the cold steel fixing box, and a third cold steel assembly is arranged at the bottom part of the cold steel fixing box; and when molten steel is poured into the cold steel fixing box, the first cold steel assembly and the third cold steel assembly are used for firstly forming an initial bl