Abstract: A fastening element is disclosed for screwing onto a threaded pin. The fastening element includes a rotation-symmetrical hole of an inner diameter formed by a recess, which is larger than a thread base diameter and smaller than a thread outer diameter of the threaded pin. At least one chip receiving groove in a longitudinal direction of the recess is formed in the recess of the break-through. The fastening element has a lower hardness than the threaded pin.

Abstract: A pipe connection is provided for connecting pipes of a motor vehicle, particularly exhaust pipes for an exhaust system or intake pipes for the intake tract of a combustion engine, with two pipes to be connected to each other. It is provided that at least one of the pipes has a thread which can be brought into engagement with a mating thread of a connecting element of the pipe connection to be connected to the other pipe. An exhaust system is provided for a motor vehicle and an air intake system is provided for a motor vehicle and a motor vehicle.