Contact properties of Cu-Mn austempered ductile iron gears. Experimental evaluation using the FZG test rig.

• Type: Article in International Conference Proceedings Book
• Date: 2005

Authors

magalhaes, ll (Author) Other; seabra, jo (Author) FEUP

Conference proceedings International

Title: International Conference on Gears, Pts 1 and 2: EUROPE INVITES THE WORLD

Pages: 1145-1163

International Conference on Gears

Garching, GERMANY, SEP 14-16, 2005

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 0 Citations

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-000-5Y9

Abstract (EN): This work presents results from FZG tests of gears manufactured using a recently developed ductile iron. The main objective of the work was to evaluate the performance of different austempered varieties of this ductile iron in terms of pitting and scuffing resistance, having in mind the production of power-transmission gears. In the early 1990's Santos et al. [1] proposed an innovative chemical composition for a ductile iron using Copper and Manganese as alloy elements, a material that can be successfully austempered allowing the production of Austempered Ductile Irons (ADIs) presenting excellent combinations of mechanical properties, including high-strength varieties that reach ASTM grade 5 (exhibiting tensile strength above 1600 MPa). Several ADIs resulting from different austempering treatments of the referred ductile iron were used to produce type A and type C FZG gears that were tested in the FZG test rig. Observed failure modes include scuffing, pitting and spalling. Gear scuffing tests were performed using an additive-free lubricant, revealing a high scuffing load capacity, since failure never occurred before FZG load stage 11. Gear pitting tests allowed the determination of the contact pressure levels at which different damage mechanisms are preponderant and provided information to correlate the properties of each ADI variety with the imposed contact conditions and the accomplished number of cycles. The evolution of sub-surface fatigue cracking mechanisms was studied and relevant parameters concerning contact resistance were analysed, namely the influence of the matrix structure and graphite nodules on the severity of the pitting and spalling phenomena. Finally, a contact severity parameter including the contact pressure imposed during FZG pitting tests and the tensile strength of materials (p(o)(2)/sigma(r)) is proposed to characterize contact fatigue results.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 19