Valve cone, a valve and a valve manufacturing process

A valve cone comprising a cylindrical body extending along a longitudinal axis and having a cylindrical surface and at least one, axially extending recess which, inside a contour line, extends between a first end position at a first end of the cylindrical body and a second end position between the first end of the body and the opposite second end of the body, the recess having a radial depth and a width, the recess having a cross-section, in a plane perpendicular to the longitudinal axis, the area of which gradually decreases from a maximum value close to said first end towards the second end position, and the body in said cross-section perpendicular to the longitudinal axis having a boundary line which is continuously concave towards the recess, characterized in that the portion of the recess which extend from the second end position has a width greater than its depth and, the recess has a longitudinal section, in a plane along the longitudinal axis, in which the boundary line of the body towards the recess has an essentially continuous convex bend.