The development of an optimum manufacturing and material selection process for the fabrication of labyrinth seal strips

A systematic material selection process using the digital logic model was developed. Material performance requirements were analyzed and alternative solutions were evaluated among various austenitic, ferritic and martensitic stainless steels. The analysis of metallurgical and mechanical properties of failed seal strips was carried out and the main failure parameters were determined and used for the selection of the optimum material. Also mechanical and chemical properties, including creep strength, formability, scaling and corrosion resistance, as well as availability and cost, were used as the key parameters in the material selection and manufacturing stages. The analysis led to the AISI 321 austenitic stainless steel as the most appropriate material. Various manufacturing processes were analyzed and finally a combination of roll forming and three-roll bending was selected as the optimum fabrication method. Rollers and guides were designed, fabricated and used in this investigation. The results indicated that the selected manufacturing procedure is adequate and leads to the expected tolerances required for these materials. Labyrinth seal strips were fabricated from the selected material using the above fabrication method and were approved in industrial scale.