An electromagnet and method for producing the electromagnet. The electromagnet is intended to maintain pretensioning force of fastening by a force acting on a yoke over intended operating time under changing operating temperatures. The yoke encloses an armature that is provided with a flange, which conducts magnetic flux from a housing to the armature, the housing being connected on the one hand to a flange of the yoke and on the other hand to a core flange in a material-bonding manner by welding. The electromagnet can be used for actuation of valves, couplings or other electromechanical adjusting elements.