Plate for heating devices of machines for the machining of profiled elements made of plastic material

1) Plate (1) for heating devices of machines for the machining of profiled elements made of plastic material, said plate (1) comprising a substantially plate-shaped main body (2) provided with a coupling surface (3) which can be coupled to a resistance assembly (21) of a heating device (20) and provided with a working surface (4), opposite said coupling surface (3), intended to contact an area to be welded of a profiled element (P) made of plastic material and provided with a series of grooves (5) and with a coating of at least one non-stick material, wherein it comprises at least one ferromagnetic portion (6) associated with said coupling surface (3), made of at least one ferromagnetic material and adapted to magnetically couple to a corresponding magnetic portion (22) of said resistance assembly (21).