Two-layer reducers are made of composite steel. The inner layer is uniformly through-hardened over its entire length. The wear layer has a hardness of 63 HRC. Reducers have weld-end geometries according to customer specifications. The male-female geometry of the weld-end surfaces centers the pipe and seals it tightly. O-rings are used as sealing elements. Particularly suitable for GRP “High performance plastics” due to the tight tolerances and after additional treatments of internal surfaces.