Seal ring for axially sealing two parts (102, 104) arranged so as to be able to move axially with respect to one another, wherein the seal ring has the following features: two sealing lips, which are arranged circumferentially on an axial first end side of the seal ring, wherein the sealing lips are designed such that they can be spread apart from one another by a first fluid pressure of a first fluid volume to bear in a sealing manner against mutually opposing sealing faces of a first of the parts; and a sealing projection, which is arranged circumferentially on a second end side of the seal ring, oriented axially away from the first end side, wherein the sealing projection is designed in order, when in a state bearing against a sealing face of a second of the parts, to seal the first fluid volume in a region arranged radially inward with respect to the sealing projection against a second fluid volume at a second fluid pressure in a region arranged radially outward with respect to the sealing projection, wherein the two opposing sealing faces of the first part are oriented slanted or normal with respect to the sealing face of the second part, wherein the sealing projection is formed by two partial portions of the second end side of the sealing ring which are sloping with respect to the sealing projection, wherein the seal ring is formed from an elastic material with a first surface roughness in a first surface portion, which comprises the end portions of the sealing lips having the sealing projection and sealing edges, and a second surface roughness in a second surface portion outside of the first surface portion, the first surface roughness being less than the second surface roughness. two sealing lips, which are arranged circumferentially on an axial first end side of the seal ring, wherein the sealing lips are designed such that they can be spread apart from one another by a first fluid pressure of a first fluid volume to bear in a sealing manner against mutually opposing sealing faces of a first of the parts; and a sealing projection, which is arranged circumferentially on a second end side of the seal ring, oriented axially away from the first end side, wherein the sealing projection is designed in order, when in a state bearing against a sealing face of a second of the parts, to seal the first fluid volume in a region arranged radially inward with respect to the sealing projection against a second fluid volume at a second fluid pressure in a region arranged radially outward with respect to the sealing projection, wherein the two opposing sealing faces of the first part are oriented slanted or normal with respect to the sealing face of the second part, wherein the sealing projection is formed by two partial portions of the second end side of the sealing ring which are sloping with respect to the sealing projection, wherein the seal ring is formed from an elastic material with a first surface roughness in a first surface portion, which comprises the end portions of the sealing lips having the sealing projection and sealing edges, and a second surface roughness in a second surface portion outside of the first surface portion, the first surface roughness being less than the second surface roughness.