Residual Stress Relaxation and Fatigue Strength of AISI 4140 under Torsional Loading after Conventional Shot Peening, Stress

Author:  Menig, Schulze, Vohringer
Source:  Conf Proc: ICSP-8 Sept. 16-20, 2002 Garmisch-Partenkirchen, Germany
Doc ID:  2002040
Year of Publication:  2002
Abstract:  
Authors Rainer Menig, Volker Schulze and Otmar Vohringer Institut fur Werkstoffkunde I, Universitat Karlsruhe (TH), Karlsruhe, Germany Abstract Cylindrical rods of 450 C quenched and tempered AISI 4140 were conventionally shot peened, stress peened and warm peened while rotating in the peening device. Warm peening at Tpeen=310 C was conducted using a modified air blast shot peening machine with an electric air flow heater system. To perform stress peening using a torsional pre-stress, a device was conceived which allowed rotating pre-stressed samples without having material of the pre-loading gadget between the shot and the samples. Thus, same peening conditions for all peening procedures were ensured. The residual stress distributions present after the different peening procedures were evaluated and compared with results obtained after peening of flat material of the same steel. The differently peened samples were subjected to torsional pulsating stresses (R=0) at different loadings to investigate their residual stress relaxation behavior. Additionally, the pulsating torsional strengths for the differently peened samples were determined.