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Effect of carburized layer on rolling contact fatigue of 52100 ball bearing steel
354
Fatigue abstracts
influence of dynamic strain aging on the fatigue or cyclic behaviour of these materials. Lee and Hill reported, in their study of the effect of oxygen on the fatigue behaviour of Zircaloy-2 at 623 K, that the stress range increased during cycling until fracture occurred. These authors attributed this effect to the normal fatigue hardening typical of annealed materials. In a previous work, it was reported that Zircaloy-4 samples show cyclic hardening, and it was attributed to an increased rate of dislocation accumulations due to dislocationsolute atoms interactions. The purpose of the present study was to examine the cyclic deformation characteristics of Zircaloy-4 in the temperature range 573-873 K and to show that the abnormal cyclic hardening observed in this material can be considered as a new aspect of dynamic strain aging. Graphs, photomicrographs, 10 ref.
Retained austenite and residual stress distribution in deep cooled carburized mierostructures. Grosch, J. and Schwarz, O. Tekhnologiya Legkikh Splavov (1995 71-76) Conference: 1995 Carburizing and Nitriding With Atmospheres. Cleveland,
Fatigue strength evaluation system for structural members of construction and industrial vehicles. Nakamura, T., Nagashima, K. and Nakashima, M. Hitachi Zosen Technical Rev. (Jan. 1996) 56 (4), 33-39
Bending fatigue behaviour of vacuum carburized AISI 8620 steel. Evanson, K., Krauss, G., Medlin, D. and Patel, M.J. Tekhnologiya Legkikh Splavov (1995) 61--69 Conference: 1995 Carburizing and Nitriding With Atmospheres, Cleveland,
In an attempt to develop high reliability construction and industrial vehicles in the shortest possible time, the authors tried to establish a strength evaluation system which would permit a simple, precise evaluation of durability for the structural members of the above vehicles. Many service loads of the above vehicles were analyzed by a mini-computer, which resulted in a database that included the service frequency distribution, the maximum stress range, and the fatigue damage by using the modified Miner's law. Furthermore, the conventional design curve (E Rmax-D curve) was presented by considering the fatigue properties of the material, with regard to the relation between a fatigue damage and a maximum stress range as a linear regression curve. Graphs, 9 ref.
Overcoming limitations of the conventional strain life fatigue damage model. Vogel, J.H. and Langlais, T.E.
J. Engng Mater. Techn. (Trans. ASME) (1996) 118, 103-108 The strain-based approach to fatigue life prediction usually relies on the conventional strain-life equation which correlates the elastic and plastic strain to the life. The correlation is based on separate log-linear curve fits of the elastic and plastic components nf the strain data vs. the life. It is well known, however, that these linear relationships may be valid only within a specific interval of stress or strain. When material behaviour approaches elastic-perfectly plastic, for instance, it is not uncommon for the test data to deviate from liuearity at both very high and very low strains. For such materials a separate fit of each curve is likely to give material constants significantly inconsistent with the fit of the cyclic stress-strain curve, especially if a good local fit over a restricted interval is obtained. In this work, some of the errors that arise as a result of this inconsistency arc described, and recommended methods are developed for treating these errors. Numerical concerns are also addressed, and sample results are included. Graphs, 20 ref.
Thermomechanical and isothermal fatigue behaviour of bare and coated superalioys. Kadioglu, Y. and Sehitoglu, 11. J. Engng Mater. Techn. (Trans. ASME) (1996) 118, 94-102 Thermomechanical fatigue (TMF) and isothermal fatigue (IF) experiments were performed on bare Mar-M246 and bare and coated Mar-M247 nickel based superalloys at strain ranges from 0.335-1%. The experiments were conducted in air, through a temperature range of 500-1038°C at a constant strain rate of 5.0 x 10 5 s-~. Due to the coarse-grained structure of Mar-M246, TMF lives scattered considerably under low strain range conditions. Electron microscopy studies show that significant surface oxidation and T" depleted zones occur for Mar-M246 under these conditions. In the surface grain, where the change in -/' morphology is most pronounced, 7 ' rafted along axes approx +45 ° from the loading axis. The influence of a protective coating on the IF and TMF lives of Mar-M247 was also examined. Results indicate that the coating does not significantly affect the fatigue lives of Mar-M247. The oxidation behavior of bare and coated Mar-M247 was investigated via x-ray microprobe and Auger spectroscopy. Through these analyses, it is evident that the coating was completely degraded when exposed to the test environment for a long time. In both Mar-M246 and Mar-M247, in-phase thermomechanical fatigue (TMF IP) loading resulted in intergranalar cracking. TMF IP loading promoted multiple cracks at the coating/substrate interface of coated Mar-M247. Finally, Eshelby techniques were used to calculate stress distributions in the vicinity of a surface oxide and second-phase particle at the coating/substrate interface. Graphs, photomicrographs, 55 ref.
Low cycle fatigue property of pressure vessel steel 16MnR under earthquake load. Gong, S.H., Sheng, G.M., Li, }I., Wei, S.L., Sun, H.Z., Nan, T.Y. and Liu, 14I.}'. Iron Steel (China) (1995) 30 (10), 48-52 The fatigue property of usual pressure vessel steel 16MnR is researched by the high strain low cycle fatigue test simulating the case of heavy earthquake and by use of Elcentro spectrum. Graphs, photomicrographs, 12 ref.
Effect of carburized layer on rolling contact fatigue of 52100 ball bearing steel. Kotkowski, K., Cegielski, H. and Przylecki, Z. Tekhnologiya Legkikh Splavov (1995) 77-82 Conference: 1995 Carburizing and Hitriding With Atmospheres, Cleveland, Ohio, USA (6-8 Dec. 1995) Results of investigations of rolling contact fatigue life of 52,100 ball bearing steel for two groups of specimens, carburized and non-carburized, are presented in the paper. Carburized layer improves the contact fatigue life ten times, when < l0 lives are compared, or improves the fatigue strength by approx. 18%, when load capacities are compared. Graphs, 18 ref.
Ohio, USA (6-8 Dec. 1995) Microstructures with a high hardness and a low amount of retained austenite resulting in a high stability as to dimensional changes can be established by deep cooling even with high carbon and alloying contents. High residual tensile stresses in the austenite at the surface may initiate cracks in all applications with maximum tensile stresses at the surface of the component and must be considered in all approaches to fatigue behaviour of carburized steels by the suggested idea of a local fatigue strength. Photomicrographs, graphs, 26 ref.
Ohio, USA (6-8 Dec. 1995) The bending fatigue performance of aircraft quality AISI 8620 steel was evaluated after vacuum carburizing. Case depths of 0.45 mm (0.018 in.) and 1.30mm (0.051 in.) were produced by carburizing in propane atmospheres, and both sets of specimens were subjected to a cold stabilizing treatment at - 7 3 ° C before tempering. Bending fatigue was evaluated with Brugger type cantilever beam specimens under tension-tension loading with a stress ratio of 0.1. Bending fatigue specimens were characterized by light metallography to determine microstructure and prior austenitic grain size, x-ray analysis for residual stress and retained austenite measurements, and scanning electron microscopy to evaluate fatigue crack initiation, propagation and overload. The case microstrueture of the specimens with the deeper case contained 10-20/xm diameter carbides at the prior austenitic grain boundaries and had a fatigue endurance limit of 1230MPa (180 ksi). The shallow case specimens had case microstmctures with 1-2 p.m diameter spherodized carbides decorating the austenitic grain boundaries and had an endurance limit of 1370 MPa (200 ksi). The high endurance limits resulting from both carburiziug processes are attributed to the lack of surface intergranular oxidation and to high residual compressive surface stresses, in excess of 900 MPa (130 ksi), which are attributed primarily to the cold stabilization treatment. Graphs, photomicrographs, 22 ref.
The effect of scratches on the fatigue life and fatigue crack growth of aluminium 2024-T3 clad. Nader, N~A. Dissertation Abstr. Int. 54 (9) An experimental study of the effect of scratches on the fatigue life and fatigue crack growth of AI 2024-T3 clad material has been conducted. The results show that Al 2024-T3 clad material is a scratch sensitive material with a drop in life as much as 95% for material with scratch depth of 100 p.m. Also, it has been found that cracks propagate faster in scratched samples than unscratched and at a lower stress intensity factor. In addition, a model that predicts the fatigue crack propagation of scratched samples has been developed. Furthermore, scanning electron microscope fractographes show that scratches generated microcracks which are responsible for decreasing the fatigue life of the material. Fretting of 8090 and 7075 aluminium alloys under interrupted fatigue
loading conditions in air and vacuum environments. Elliott, C.B. Ill Dissertation Abstr. Int. 54 (8) This dissertation documents an investigation of the fatigue characteristics of 8090 and 7075 aluminium alloys under fretting conditions in air and vacuum environments. The underlying purpose of the programme is to provide insights into the effects of corrosion, specifically oxidation in air, on the fretting fatigue process. Significant conclusions of this research are that: (1) General statements of the relative effects of wear and corrosion on the fretting fatigue process are meaningless unless tied to a specific material. (2) The base line for fretting fatigue investigations to study the effects of wear and corrosion should be tests conducted in a vacuum or, possibly, an inert environment. ( 3 ) F o r specimens tested in air, cracks can join other cracks or return to the surface, forming pits or troughs and debris, or propagate into the material. (4) Crack nucleation and early propagation are influenced by local conditions in the area of relatively great damage where the crack is formed. The final chapter of the dissertation discusses how these conclusions relate to current efforts of the fretting fatigue community to standardize its testing methods. Mechanical fatigue of copper-based shape memory alloy after different
heat treatment. Lu, L., Lai, M.O. and Lim, A.S. Scripta Mater. (1 Jan. 1996) 34 (1), 157-162 The influence of heat treatment and deformation ratio on the shape memory effect of a Cu-17.5Zn-5A1 alloy was examined. It was found that the degradation life decreased with an increase in betatizing temperature from 750 to 900°C. Specimens heat treated by step quenching showed longer degradation life than those directly quenched into ice water. This advantage disappeared when high betatizing temperatures were used. Several types of defects were observed in the forms of microvoids, microcracks, fracture of inclusions and oxidation of surface layer. Heat treatment produced a layer of material with lower Zn and AI contents. The layer constituted a discontinuity of martensitic transformation between the layer and the material at the core which led consequently to the formation of cracks between the layer and the core. All of the defects contributed to the permanent deformation of the specimens. Photomicrographs, graphs, 18 ref.
Fatigue abstracts
influence of dynamic strain aging on the fatigue or cyclic behaviour of these materials. Lee and Hill reported, in their study of the effect of oxygen on the fatigue behaviour of Zircaloy-2 at 623 K, that the stress range increased during cycling until fracture occurred. These authors attributed this effect to the normal fatigue hardening typical of annealed materials. In a previous work, it was reported that Zircaloy-4 samples show cyclic hardening, and it was attributed to an increased rate of dislocation accumulations due to dislocationsolute atoms interactions. The purpose of the present study was to examine the cyclic deformation characteristics of Zircaloy-4 in the temperature range 573-873 K and to show that the abnormal cyclic hardening observed in this material can be considered as a new aspect of dynamic strain aging. Graphs, photomicrographs, 10 ref.
Retained austenite and residual stress distribution in deep cooled carburized mierostructures. Grosch, J. and Schwarz, O. Tekhnologiya Legkikh Splavov (1995 71-76) Conference: 1995 Carburizing and Nitriding With Atmospheres. Cleveland,
Fatigue strength evaluation system for structural members of construction and industrial vehicles. Nakamura, T., Nagashima, K. and Nakashima, M. Hitachi Zosen Technical Rev. (Jan. 1996) 56 (4), 33-39
Bending fatigue behaviour of vacuum carburized AISI 8620 steel. Evanson, K., Krauss, G., Medlin, D. and Patel, M.J. Tekhnologiya Legkikh Splavov (1995) 61--69 Conference: 1995 Carburizing and Nitriding With Atmospheres, Cleveland,
In an attempt to develop high reliability construction and industrial vehicles in the shortest possible time, the authors tried to establish a strength evaluation system which would permit a simple, precise evaluation of durability for the structural members of the above vehicles. Many service loads of the above vehicles were analyzed by a mini-computer, which resulted in a database that included the service frequency distribution, the maximum stress range, and the fatigue damage by using the modified Miner's law. Furthermore, the conventional design curve (E Rmax-D curve) was presented by considering the fatigue properties of the material, with regard to the relation between a fatigue damage and a maximum stress range as a linear regression curve. Graphs, 9 ref.
Overcoming limitations of the conventional strain life fatigue damage model. Vogel, J.H. and Langlais, T.E.
J. Engng Mater. Techn. (Trans. ASME) (1996) 118, 103-108 The strain-based approach to fatigue life prediction usually relies on the conventional strain-life equation which correlates the elastic and plastic strain to the life. The correlation is based on separate log-linear curve fits of the elastic and plastic components nf the strain data vs. the life. It is well known, however, that these linear relationships may be valid only within a specific interval of stress or strain. When material behaviour approaches elastic-perfectly plastic, for instance, it is not uncommon for the test data to deviate from liuearity at both very high and very low strains. For such materials a separate fit of each curve is likely to give material constants significantly inconsistent with the fit of the cyclic stress-strain curve, especially if a good local fit over a restricted interval is obtained. In this work, some of the errors that arise as a result of this inconsistency arc described, and recommended methods are developed for treating these errors. Numerical concerns are also addressed, and sample results are included. Graphs, 20 ref.
Thermomechanical and isothermal fatigue behaviour of bare and coated superalioys. Kadioglu, Y. and Sehitoglu, 11. J. Engng Mater. Techn. (Trans. ASME) (1996) 118, 94-102 Thermomechanical fatigue (TMF) and isothermal fatigue (IF) experiments were performed on bare Mar-M246 and bare and coated Mar-M247 nickel based superalloys at strain ranges from 0.335-1%. The experiments were conducted in air, through a temperature range of 500-1038°C at a constant strain rate of 5.0 x 10 5 s-~. Due to the coarse-grained structure of Mar-M246, TMF lives scattered considerably under low strain range conditions. Electron microscopy studies show that significant surface oxidation and T" depleted zones occur for Mar-M246 under these conditions. In the surface grain, where the change in -/' morphology is most pronounced, 7 ' rafted along axes approx +45 ° from the loading axis. The influence of a protective coating on the IF and TMF lives of Mar-M247 was also examined. Results indicate that the coating does not significantly affect the fatigue lives of Mar-M247. The oxidation behavior of bare and coated Mar-M247 was investigated via x-ray microprobe and Auger spectroscopy. Through these analyses, it is evident that the coating was completely degraded when exposed to the test environment for a long time. In both Mar-M246 and Mar-M247, in-phase thermomechanical fatigue (TMF IP) loading resulted in intergranalar cracking. TMF IP loading promoted multiple cracks at the coating/substrate interface of coated Mar-M247. Finally, Eshelby techniques were used to calculate stress distributions in the vicinity of a surface oxide and second-phase particle at the coating/substrate interface. Graphs, photomicrographs, 55 ref.
Low cycle fatigue property of pressure vessel steel 16MnR under earthquake load. Gong, S.H., Sheng, G.M., Li, }I., Wei, S.L., Sun, H.Z., Nan, T.Y. and Liu, 14I.}'. Iron Steel (China) (1995) 30 (10), 48-52 The fatigue property of usual pressure vessel steel 16MnR is researched by the high strain low cycle fatigue test simulating the case of heavy earthquake and by use of Elcentro spectrum. Graphs, photomicrographs, 12 ref.
Effect of carburized layer on rolling contact fatigue of 52100 ball bearing steel. Kotkowski, K., Cegielski, H. and Przylecki, Z. Tekhnologiya Legkikh Splavov (1995) 77-82 Conference: 1995 Carburizing and Hitriding With Atmospheres, Cleveland, Ohio, USA (6-8 Dec. 1995) Results of investigations of rolling contact fatigue life of 52,100 ball bearing steel for two groups of specimens, carburized and non-carburized, are presented in the paper. Carburized layer improves the contact fatigue life ten times, when < l0 lives are compared, or improves the fatigue strength by approx. 18%, when load capacities are compared. Graphs, 18 ref.
Ohio, USA (6-8 Dec. 1995) Microstructures with a high hardness and a low amount of retained austenite resulting in a high stability as to dimensional changes can be established by deep cooling even with high carbon and alloying contents. High residual tensile stresses in the austenite at the surface may initiate cracks in all applications with maximum tensile stresses at the surface of the component and must be considered in all approaches to fatigue behaviour of carburized steels by the suggested idea of a local fatigue strength. Photomicrographs, graphs, 26 ref.
Ohio, USA (6-8 Dec. 1995) The bending fatigue performance of aircraft quality AISI 8620 steel was evaluated after vacuum carburizing. Case depths of 0.45 mm (0.018 in.) and 1.30mm (0.051 in.) were produced by carburizing in propane atmospheres, and both sets of specimens were subjected to a cold stabilizing treatment at - 7 3 ° C before tempering. Bending fatigue was evaluated with Brugger type cantilever beam specimens under tension-tension loading with a stress ratio of 0.1. Bending fatigue specimens were characterized by light metallography to determine microstructure and prior austenitic grain size, x-ray analysis for residual stress and retained austenite measurements, and scanning electron microscopy to evaluate fatigue crack initiation, propagation and overload. The case microstrueture of the specimens with the deeper case contained 10-20/xm diameter carbides at the prior austenitic grain boundaries and had a fatigue endurance limit of 1230MPa (180 ksi). The shallow case specimens had case microstmctures with 1-2 p.m diameter spherodized carbides decorating the austenitic grain boundaries and had an endurance limit of 1370 MPa (200 ksi). The high endurance limits resulting from both carburiziug processes are attributed to the lack of surface intergranular oxidation and to high residual compressive surface stresses, in excess of 900 MPa (130 ksi), which are attributed primarily to the cold stabilization treatment. Graphs, photomicrographs, 22 ref.
The effect of scratches on the fatigue life and fatigue crack growth of aluminium 2024-T3 clad. Nader, N~A. Dissertation Abstr. Int. 54 (9) An experimental study of the effect of scratches on the fatigue life and fatigue crack growth of AI 2024-T3 clad material has been conducted. The results show that Al 2024-T3 clad material is a scratch sensitive material with a drop in life as much as 95% for material with scratch depth of 100 p.m. Also, it has been found that cracks propagate faster in scratched samples than unscratched and at a lower stress intensity factor. In addition, a model that predicts the fatigue crack propagation of scratched samples has been developed. Furthermore, scanning electron microscope fractographes show that scratches generated microcracks which are responsible for decreasing the fatigue life of the material. Fretting of 8090 and 7075 aluminium alloys under interrupted fatigue
loading conditions in air and vacuum environments. Elliott, C.B. Ill Dissertation Abstr. Int. 54 (8) This dissertation documents an investigation of the fatigue characteristics of 8090 and 7075 aluminium alloys under fretting conditions in air and vacuum environments. The underlying purpose of the programme is to provide insights into the effects of corrosion, specifically oxidation in air, on the fretting fatigue process. Significant conclusions of this research are that: (1) General statements of the relative effects of wear and corrosion on the fretting fatigue process are meaningless unless tied to a specific material. (2) The base line for fretting fatigue investigations to study the effects of wear and corrosion should be tests conducted in a vacuum or, possibly, an inert environment. ( 3 ) F o r specimens tested in air, cracks can join other cracks or return to the surface, forming pits or troughs and debris, or propagate into the material. (4) Crack nucleation and early propagation are influenced by local conditions in the area of relatively great damage where the crack is formed. The final chapter of the dissertation discusses how these conclusions relate to current efforts of the fretting fatigue community to standardize its testing methods. Mechanical fatigue of copper-based shape memory alloy after different
heat treatment. Lu, L., Lai, M.O. and Lim, A.S. Scripta Mater. (1 Jan. 1996) 34 (1), 157-162 The influence of heat treatment and deformation ratio on the shape memory effect of a Cu-17.5Zn-5A1 alloy was examined. It was found that the degradation life decreased with an increase in betatizing temperature from 750 to 900°C. Specimens heat treated by step quenching showed longer degradation life than those directly quenched into ice water. This advantage disappeared when high betatizing temperatures were used. Several types of defects were observed in the forms of microvoids, microcracks, fracture of inclusions and oxidation of surface layer. Heat treatment produced a layer of material with lower Zn and AI contents. The layer constituted a discontinuity of martensitic transformation between the layer and the material at the core which led consequently to the formation of cracks between the layer and the core. All of the defects contributed to the permanent deformation of the specimens. Photomicrographs, graphs, 18 ref.