The invention relates to a method and a device for producing a high-pressure-tight connection between a pole core and a valve sleeve of a solenoid valve and to an associated valve cartridge for a solenoid valve. According to the invention, the pole core is placed in a two-part compression mold, which comprises a middle die and an outer die, in such a way that a joining gap is produced between an inner bore of the outer die and the placed-in pole core. Subsequently, the pole core is placed against the valve sleeve and the valve sleeve is inserted into the joining gap. Then, the middle die and the outer die are pressed simultaneously with the pole core such that the valve sleeve passes into the joining gap. When a pressed diameter of the pole core is reached, the valve sleeve expands and is shaped in the joining gap between a first shaping edge and a second shaping edge and is joined onto the pole core. The diameter of the inner bore tapers between the first shaping edge and the second shaping edge. Application of further force by the outer die allows the pole core to be pressed deeper into the valve sleeve, in order to carry out a desired stroke setting for the movement of an armature by performing the further shaping of the valve sleeve.