Flexible heating mat for preforming or consolidating composite parts

A flexible multilayer heating device, of the flexible heating mat type, for implementing preforming or consolidation of fibrous preforms of composite parts, the device comprising:

• at least one first support layer,
• at least one first heating lead arranged on the at least one first support layer and defining a heat-treatment surface adapted to a surface of the composite part to be preformed or consolidated,
• a first network of wires electrically connected to the at least one first heating lead,
• at least one second heating lead arranged on the at least one first support layer and defining at least one thermal-blocking belt at least one periphery of the heat-treatment surface,
• a second network of wires electrically connected to the at least one second heating lead, and
• two reinforcement layers between which, the at least one first support layer implementing the heat-treatment surface and the at least one thermal-blocking belt, the first network of wires and the second network of wires are sandwiched, an assembly system being implemented between the two reinforcement layers so as to form an envelope the edges of which allow the first network of wires and the second network of wires to emerge.