This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Gears for Demanding Applications. A Comparison Between Cast Iron, Wrought Steels and P/M Steels
Technical Paper
2000-01-0405
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Event:
SAE 2000 World Congress
Language:
English
Abstract
The most important standards covering gear design are reviewed. Some small differences, mainly formal, are analyzed. The calculation procedures require the introduction of different parameters, which are determined by material, working conditions, stress level and type, geometrical features, surface finish and lubrication requirements. As a basic comparison, the material-dependent parameters are reviewed, for fully dense steels, cast iron, P/M steels. The most important properties, to be considered for a reliable and sound design of mechanical parts, are presented, with their typical ranges. For sintered - and heat-treated - steels the influences exerted on significant properties by porosity, uneven diffusion of alloying additions and production sequence, are discussed. A comparison with the most traditional ferrous materials systematically shows the advantages of a controlled lack of homogeneity, in cases of fatigue resistance requirements, provided that sintering bonds are properly developed and carbon content and distribution is achieved. Strength improvements linked to density increases are the ground for development of new processing methods, such as overall or selected densification; This is especially valuable when a controlled gradient of local properties is a desired result. Different porosity and microstructure patterns are presented and their corresponding influences on strength and performance features are analyzed. The effects of local changes in elastic parameters are examined for torque-transmitting teeth. The requirements of various gear applications enable us to classify some specific material choices and corresponding processing sequences, aimed at reaching the optimum balance between suitability for manufacturing, functional reliability and cost. The forming possibilities inherent of P/M processing when applied properly to gear processing allow for the overcoming of some geometric constraints that are required when machining steels. Some examples of improved design are presented. Finally, the prospects of future enhancements of P/M processing and materials for demanding gear applications are outlined.
Recommended Content
Authors
Topic
Citation
Bonetti, G., Navazio, A., and Zingale, P., "Gears for Demanding Applications. A Comparison Between Cast Iron, Wrought Steels and P/M Steels," SAE Technical Paper 2000-01-0405, 2000, https://doi.org/10.4271/2000-01-0405.Also In
References
- BRIAN JAMES W. “Ferrous Powder Metallurgy Steels for Gear Applications” MPIF seminar. New Advances in Gear Technology Arlington Heights, II. April 21-22 1998
- SANDEROW HOWARD I. “Powder Metallurgy Gears. Failure Modes and Analysis Techniques” P/M International Conference, MPIF/APMI Vancouver, Canada June 1990
- SAE-15 “Gear Design. Manufacturing and Inspection Manual” Society of automotive Engineers, Inc. Warrendale, PA 1990
- ANSI/AGMA “American National Standard. Specifications for Powder Metallurgy Gears” Agma standard 6008-A98 American Gear Manufacturers Association Alexandria, Virginia 1998
- JONES P. K. BUCKLEY-GOLDER K. DAVID H. LAWCOCK R. SARAFINCHAN D. SHIVANATH R. YAO L. “Fatigue Properties of advanced High Density Powder Metall Alloy Steels for High Performance Powertrain Applications” 1998 Powder Metallurgy World Congress & Exibition, MPIF/APMI Granada, Spain October 18-22 1998
- JONES P. K. LAWCOCK R. SHIVANATH R. “Metallurgical strategies for high endurance powder metal components for advanced powertrain applications” ISATA 29 th Int. Symposium on Automotive Technology and Automation Florence, Italy 1996
- LAWCOCK R. BUCKLEY-GOLDER K. SARAFIN-CHAN D. “Testing of High Endurance PM Steels for Automotive Transmission Gearing Components” SAE Special Publication, P/M Applications (SP-1447) Warrendale, PA March 1999 15 22
- “Calculation of load capacity of spur and helical gears”
- ANSI/AGMA 2001-C95 “Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth”
- British Standard Institution 1986 “Method for calculation of contact and root bending stress limitations for metallic involute gears”
- Deutsches Institut für Normung e.V.
- ANSI/AGMA 908-B89 “Geometry Factors for Determining the Pitting Resistance and Bending Strength of Spur, Helical and Herringbone Gear Teeth”
- MPIF 43 standard “Determination of Hardness of Powder Metallurgy Products” 1991
- ASTM Standard A536-84 “Standard Specifications for Ductile Iron Castings” 1993
- ASM Specialty Handbook “Cast Irons” Davis and Associated 1996
- BOCCHINI G. F. “The influence of porosity on the characteristics of sintered materials” Reviews on Powder Metallurgy and Physical Ceramics 2 4 1985
- BOCCHINI G. F. SILVA G “Wrought Steels, Cast Irons, P/M Steels: Property Comparison for Design Purposes” 1998 Int. Conference on Powder Metallurgy and Particulate Materials, MPIF/APMI Las Vegas, Nevada May 31 June 4 1998
- LINDQVIST B. “Influence of microstructure and porosity on fatigue properties of sintered steels” Metal Powder Report Elsevier 44 443 448 1989
- BOCCHINI G. F. “Warm compaction of metal powders: why it works, why it requires a sophisticated design approach” Powder Metallurgy 42 2 Inst. of Materials London, UK 1999
- L'ESPERANCE G. HARTON S. DE REGE A. NIGARURA S. “Evaluation of the Hardenability, Microstructure and Properties of Various Sinter Hardening Alloys” Advances in Powder Metallurgy & Particulate Materials, MPIF/APMI Princetown, NJ 3 25 1995
- DUCHESNE E. L'ESPERANCE G. DE REGE A. “Sinter hardening: Predictability, Powder Design and Process Optimization” P/M International Conference, MPIF/APMI Vancouver, Canada June 1999
- DAVALA B. GRAHAM A. H. CAUSTON R. J. “Application of High Performance Materials and Processes - Alloy Systems” 1998 Int. Conference on Powder Metallurgy and Particulate Materials, MPIF/APMI Las Vegas, Nevada May 31 June 4 1998
- D'AMAS H. LLANES L. PENAFIEL J. BAS J. ANGLADA M. “Tempering effects on the tensile response and fatigue life behavior of a sinter hardened steel” Material Science and Engineering Elsevier 1999