A turbocharger, with a turbine and compressor housing connected to a bearing housing. An inflow housing of the turbine and bearing housing are connected via a fastening device mounted to a flange of the inflow housing with a first section and partially overlaps a flange of the bearing housing with a second section. Between the inflow housing and the bearing housing, flanges of a nozzle ring and of a sealing cover are clamped. Adjoining surfaces contacting one another in a region of a first, second, and/or a third contact clamping region are hardened.