an electroweld fitting or electroweld collar for synthetic resin pipes comprising a body of a thermoplastic and / or weldable synthetic resin , on the inner surface of which a heating coil is arranged . in order to weld an electric current is conducted to the heating coil , whereby the material of the body is strongly heated and becomes plastic . the invention solves the problem of reliably applying the contact pressure in the welding zone while using a reduced amount of material . to achieve this it is proposed that a reinforcement in the form of a winding or a tube be arranged on the outer surface of the body and that the thermal coefficient of expansion of the reinforcement be smaller than that of the body .