Non-standard H-shaped steel manufacturing method and special tool

The invention discloses a non-standard H-shaped steel manufacturing method. The non-standard H-shaped steel manufacturing method comprises the following steps that a standard H-shaped steel web is cut to form two T-shaped steel workpieces; I-shaped groove machining is conducted on webs of the two T-shaped steel workpieces; the two T-shaped steel workpieces are assembled into an H-shaped steel workpiece; the assembled H-shaped steel workpiece is placed on a tool frame of a special tool and fixed to the tool frame through a clamp; a run-on plate is additionally mounted on the tool frame, and the run-on plate is fixed to a web of the assembled H-shaped steel workpiece in a spot mode; front submerged-arc welding is conducted on the web of the H-shaped steel workpiece; the special tool is integrally turned over by 180 degrees, and back submerged-arc welding is conducted on the web of the H-shaped steel workpiece; H-shaped steel formed after welding is slowly cooled; and the clamp is loosened, the H-shaped steel is