Control slide having a defined broken circular ring edge

A control slide for use in a slide valve, with the control slide defining a central axis, the control slide comprising:

• at least one first portion which is circular-cylindrical with respect to the central axis,
• at least one second portion assigned to each first portion, each second portion including an end face at an end of the second portion that is nearest to the associated first portion, the end face extending inclined by at least 45° in relation to the central axis,
• wherein a circular ring edge, which extends around the central axis in a circular ring shape having a substantially constant cross-sectional shape, is formed between the first portion and the second portion,
• wherein the control slide is made of steel,
• wherein the at least one first portion is surface-hardened in such a way that the hardness on the surface of the control slide decreases from the first portion via the circular ring edge toward the end face,
• wherein the cross-sectional shape of the circular ring edge includes a straight portion and a curved portion which is free of abrupt bends, the straight portion directly adjoining the associated first portion, the curved portion directly adjoining the straight portion and the end face,
• wherein a diameter of the control slide in the straight portion decreases in a direction from the first portion toward the second portion, and
• wherein the hardness on the surface of the control slide decreases steadily from the end of the straight portion, which faces the first portion, into the first portion.