Abstract
Austempered ductile irons (ADI) are attractive for thick-walled and highly stressed gear components due to the possibility to design complex structures requiring a combination of high strength and moderate ductility. In this study, ADI was developed and optimized for industrial planetary carriers with shaft diameters ranging from 120 to 460 mm. The material was characterized by correlating fatigue properties to microstructural parameters using samples prepared from cast and heat treated carriers. The optimized castings exhibit a tension-compression fatigue strength enhanced by 25% compared with castings of the same size of nominally the same material grade. A scaling behavior was developed in order to estimate fatigue strength on the basis of the maximum defect size in the tested volume. The maximum defect can be either a graphite nodule or a micropore. By optimizing the microstructure of a thick-walled casting according to the typical loading conditions, a structurally graded component with a uniform degree of utilization can be obtained. This allows efficient castings and heat treatment of thick-walled ADI parts.
Similar content being viewed by others
References
DIN EN 1564 (2011) Founding – Ausferritic spheroidal graphite cast irons
SEW Eurodrive (2016) Catalog: industrial gear units, P.002–P.102 series planetary gearmotors (edn 11/2016)
DIN 50125 (2009) Testing of metallic materials – tensile test pieces
ASTM (2007) ASTM E 466–07, standard practice for conducting force controlled constant amplitude axial fatigue tests of metallic materials
Cullity BD, Stock SR (2001) Elements of X‑ray diffraction. Prentice Hall, New Jersey
Avrami M (1939) Kinetics of phase change I. J Chem Phys 7:1103–1112
Avrami M (1940) Kinetics of phase change II. J Chem Phys 8:212–224
Avrami M (1941) Kinetics of phase change III. J Chem Phys 9:177–184
Haenel B, Haibach E, Seeger T, Wirthgen G, Zenner H (2012) FKM-guideline – analytical strength assessment of components in mechanical engineering, 6th edn. VDMA, Frankfurt a. M.
Tanaka Y, Yang Z, Miyamoto K (1995) Evaluation of fatigue limit of spheroidal graphite cast iron. Mater Trans JIM 36(6):749–756
Yang Z, Sato K, Miyamoto K, Tanaka Y (1995) Effects of graphite nodule size and austempering conditions on tensile properties and fatigue strength of ADI. J Jpn Foundrym Soc 67(3):203–208
Murakami Y (2002) Metal fatigue: effects of small defects and nonmetallic inclusions. Elsevier, Oxford
Sofue M, Okada S, Sasaki T (1978) High quality ductile cast iron with improved fatigue strength. AFS Trans 86:173–182
Shanmugam P, Prasad Rao P, Rajendra Udupa K, Venkataraman N (1994) Effect of microstructure on the fatigue strength of an austempered ductile iron. J Mater Sci 29:4933–4940. doi:10.1007/bf00356546
Lin CK, Wei JY (1997) High cycle fatigue of austempered ductile irons in various-sized Y‑block castings. Mater Trans JIM 38(8):682–691
Einfluss auf das Festigkeitsverhalten von ausferritischem Gusseisen mit Kugelgraphit (ADI) bei statischer, zyklischer und dynamischer Beanspruchung. Forschungsstelle: IFG, Düsseldorf, Abschlussbericht AiF-Forschungsvorhaben IGF 15641BG (2011) Düsseldorf (in German)
Acknowledgements
The authors gratefully acknowledge Dr. Maximilian Schwenk for the cooling curve simulations by FDM and Carlos Ries for painstaking analysis of reams of micrographs (both SEW-EURODRIVE GmbH & Co. KG).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lohmiller, J., Hoffmeister, J., Hermes, J. et al. Development and investigation of austempered ductile iron (ADI) for thick-walled gear components. Forsch Ingenieurwes 81, 253–263 (2017). https://doi.org/10.1007/s10010-017-0238-9
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10010-017-0238-9