Fatigue Behaviour of Three Variants of the Roller Bearing Steel Sae 52100

Abstract

Stress-controlled, low-cycle, push-pull fatigue tests were performed on three variants of the bearing steel SAE 52100 with slightly different compositions and heat treatments. The experiments demonstrated differences in the cyclic plastic behaviour of differently hardened steels (bainitically-hardened and martensitically-hardened, respectively), whereas the two martensitic variants, which differ in composition, behaved very similarly. Bainitically-hardened SAE 52100 steel exhibited initial hardening followed by cyclic softening above a stress amplitude level of 1200 MPa. In contrast, the rnartensiticallyhardened variants showed a pronounced cyclic hardening. The deformation behaviour of the martensitically-hardened bearing steel in a monotonic tensile test and during the first cycles can be well understood on the basis of the transformation of retained austenite. This process leads to an onset of plastic deformation at lower stresses compared to the bainitically-hardened bearing steel. As a result of the subsequent cyclic hardening of the rnartensitic variants, the CSS curves are almost identical for the differently hardened conditions under investigation. Additional tests under pulsating compression documented that a high negative mean stress enhances the cyclic plasticity. NOMENCLATUREE, = Young's modulus at zero stress N = number of cycles N, = number of cycles till failure R, = tensile strength R f 1 2 = 0.2% yield strength As,, = plastic strain range E, = total strain E,, = elastic strain sp, = plastic strain u = stress

Fatigue in martensitic 100Cr6: Relationship between rolling contact fatigue microstructural transitions and repetitive push testing

“…Hence, both methods has been employed in this study; the actual strain range after a number of cycles would reach the value lower than 5.5×10 −4 predicted via the averaging method and near to 3.5×10 −4 obtained by the displacement method. Despite the different acquisition methods of previous studies [3][4][5], all data showed ∆γ C in the order of 10 −4 , supporting the results obtained in this study. Only the value used by Bhargava et al [6] and Hahn et al [12] for their calculations is significantly higher (Fig.…”

“…In other words, conventional bearing testing methods cannot determine the experienced strain for the stress cycles due to the spatial and temporal variation in the stress state. As a result, structural fatigue tests have been carried out to obtain the strain range in cyclic torsion [3] and push-pull tests [4]. However, not enough data were obtained for stress-controlled tests, and the stress-strain responses used for calculations vary.…”

Influence of silicon content on the precipitation of secondary carbides and fatigue properties of a 5%Cr tempered martensitic steel

“…Concerning the cyclic loading, martensitic or bainitic steels have typical fatigue behaviour: an overall significant softening till rupture [9][10][11][12][13][14][15][16][17][18][19][20] as shown in Fig. 2.…”

Thermal Stability of Retained Austenite in High-carbon Steels during Cryogenic and Tempering Treatments

“…However, the role of RA, which is of essential importance in high-carbon steels, has been a controversial subject in controlling both wear and fatigue behavior, 4) the reported data and results seem scattered and lack of systematic research. 3,12,13) The underlying mechanism of cryogenic treatment on RA is far from being well understood, more efforts and examinations should be devoted to assess the thermal stability of RA. It is noteworthy that the presence of metastable phases in the multiphase structures will in turn provide the new possibilities to optimization of industrial processing routes to achieve the extraordinary high-quality of the steels and products.…”