Extending the use of nitriding processes to reduce distortion and fuel consumption

摘要

In order to meet requirements for lower fuel consumption, low friction powertrain-components are needed. Nitriding and nitrocarburizing are thermochemical heat treatment processes that enhance the surface properties, e.g. high resistance to adhesive and abrasive wear as well as low friction and high corrosion resistance, of steel components. Beside this, another benefit is low distortion of the heat treated components due to the low process temperature, which is below the austenitizing temperature.To take a better use of the benefits provided by nitriding processes, and to facilitate replacement of case carburizing which is more commonly used today, a better knowledge and understanding of the properties that are possible to achieve by the different nitriding processes, in combination to selection of steel grade, is needed. A major challenge for many components is how to obtain required strength properties, e.g high-strength fatigue properties, as can be achieved by case carburizing.In this work the influences on compound layer, diffusion zone and residual stresses have been evaluated for different steel grades after nitriding and nitrocarburizing.