FREMGANGSMAADE TIL FREMSTILLING AF PANSREDE TALLERKENVENTILER

摘要

A hard facing (7) is arranged on the valve material in the external valve area (4). The purpose of the invention is to reduce tensile stresses in the hard facing (3) and a susceptibility to cracking caused by these. To this end, the material of the valve disc base (5) in one partial area (6) without a circumferential edge area (7) is heated three dimensionally in the form of a block in excess of its high temperature yield point and then subjected to rapid cooling. The heating is advantageously performed by an induction coil. The edge area (7) is of a dimension which permits deformation of this during the shrinkage process of the partial area (6). In the process the valve outside diameter (8) is reduced.