Development of High Cr Sintered Stainless Steel with High Heat and Wear Resistance

Against the background of environmental problems, the market for variable nozzle turbochargers, which enable countermeasures for improved fuel economy and exhaust gas regulations, has grown rapidly in recent years. Because the nozzle ring is a main part which is used under a particularly severe temperature environment, even among turbocharger parts, high Cr cast steel is generally used. In response to market needs for further improvement in heat resistance and cost reduction, EW-50 which has heat resistance and wear resistance was developed, as this material is suitable for parts such as nozzle rings. EW-50 has higher wear resistance and oxidation resistance than the conventional high Cr cast steel over the entire temperature range up to 1323K. As EW-50 also makes it possible to reduce costs by near net shape production, its large potential for application to variable nozzle-type turbocharger parts was confirmed.

This report presents examples of material development using EW-50 as a base in order to respond to diverse needs.