Surface residual stresses after cooling with and without martensitic transformation of AISI 4140 steel

The paper presents the results of experimental residual stress measurements after quenching of AISI 4140 heat-treatable steel in a 15% polymer water solution. The influence of thermal and transformational residual stresses was revealed by cooling from the temperature of 600°C and by quenching from the austenitisation temperature TA = 860°C. Temperature-time curves were recorded during quenching and residual stresses were measured after the completion of cooling. Transformational stresses were also measured for different specimen masses. The data were obtained as a part of broader theoretical and experimental research work on quenching conditions and resulting stresses in practical applications. The aim of this research is to provide expert data for modelling purposes and practical guidelines in order to achieve compressive surface stresses after quenching.