0
Research Papers: Friction & Wear

Computation of Sliding Friction and Ratcheting Strain of Sintered and Hardened Steels Under Contact Fatigue Conditions

[+] Author and Article Information
N. Govindarajan1

No. 3, Flat-B, Raj Enclave, Balaji Colony, IV Cross Street, Velachery, Chennai 42, Tamil Nadu, Indianggovind@yahoo.com

R. Gnanamoorthy

Department of Mechanical Engineering, IIT Madras, Chennai 600036, Indiagmoorthy@iitm.ac.in

1

Corresponding author.

J. Tribol 130(4), 041602 (Aug 06, 2008) (10 pages) doi:10.1115/1.2959107 History: Received December 25, 2007; Revised May 11, 2008; Published August 06, 2008

Fatigue properties of powder metallurgy parts are affected mainly by the porosity fraction. Even though it has inferior mechanical and physical properties over the conventional materials, the application of powder metallurgy products in automotive fields is seen in recent trends. The rolling-sliding contact fatigue behavior of sintered and hardened steels has been investigated by performing experiments that represent practical sliding friction coefficient component prevailing in the medium- and heavy-duty bearings and gears. Introduction of sliding friction coefficient changes the typical failure pattern and wear rate of sintered and hardened steels. The sliding friction has been computed from available models and compared with the experimental data. The ratcheting strain has also been predicted for sintered and hardened steels for various contact pressures and sliding friction coefficients. The maximum value of this strain is responsible for surface crack initiation. The wear particle analysis is carried out for the sintered and hardened steels under rolling-sliding contact fatigue conditions. The ferrogram slides for pore free steel under the rolling-sliding contact fatigue conditions are also prepared to study the effect of porosity in wear mechanism. The characteristics of wear morphology and the size, shape, and concentration of worn particles for sintered and hardened steels are also analyzed for various rolling-sliding contact fatigue conditions.

Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Variation of friction coefficients at different slide-roll ratios for constant load and velocity

Grahic Jump Location
Figure 2

Relationship between sliding friction coefficients and slide-roll ratio

Grahic Jump Location
Figure 3

Predicted and experimental sliding friction coefficients for contact pressure of 1000MPa

Grahic Jump Location
Figure 4

Comparison of rolling and transition friction coefficients with various contact pressures and 0.1% slide-roll (SR) ratio

Grahic Jump Location
Figure 5

Effect of friction coefficients and contact pressures on fatigue life (along with the lower and upper bounds) of sintered and hardened steels

Grahic Jump Location
Figure 6

Effect of the endurance limit on sliding friction coefficient

Grahic Jump Location
Figure 7

Number of pits on the surface of roller under contact fatigue conditions (for various contact pressures with 0.01 sliding friction coefficient)

Grahic Jump Location
Figure 8

Ratcheting stress-strain trajectory diagram with yield locus for PM and pore free steels. (This is drawn without considering the stress concentration effect at pore edges in PM steels; sometimes, this yield locus curve of PM steel may exceed the pore free steel of the same composition depending on the material processing methods such as stress raiser seen at pore edges.)

Grahic Jump Location
Figure 9

Shear stress contour plot of sintered steel for 1000MPa contact pressure under the contact zone for various friction coefficients

Grahic Jump Location
Figure 10

Location of equivalent von Mises stress with sliding friction coefficients (for constant pressure)

Grahic Jump Location
Figure 11

Forward flow displacement for various contact parameters

Grahic Jump Location
Figure 12

Ratcheting strain measurements for various contact parameters with the number of cycles

Grahic Jump Location
Figure 13

Ratcheting strain rate with respect to the number of cycles for various contact parameters

Grahic Jump Location
Figure 14

Ratcheting strain rate with friction coefficients for various contact pressures and numbers of cycles (along with limiting friction coefficients)

Grahic Jump Location
Figure 15

Microscopic views of the ferrogram slide at the initial stage of test condition for 1400MPa and 0.1% slide-roll ratio (at various positions of the ferrogram slide) (a) entry position of ferrogram (b) middle position of ferrogram (c) exit position of ferrogram

Grahic Jump Location
Figure 17

Microscopic views of the ferrogram slide at the initial stage of test condition for 1400MPa and 1.4% slide-roll ratio (at various positions of the ferrogram slide) (a) entry position of ferrogram (b) middle position of ferrogram (c) exit position of ferrogram

Grahic Jump Location
Figure 18

Microscopic views of the ferrogram slide at the failure stage of test condition for 1400MPa and 1.4% slide-roll ratio (at various positions of the ferrogram slide) (a) entry position of ferrogram (b) middle position of ferrogram (c) exit position of ferrogram

Grahic Jump Location
Figure 16

Microscopic views of the ferrogram slide at the failure stage of test condition for 400MPa and 0.1% slide-roll ratio (at various positions of the ferrogram slide) (a) entry position of ferrogram (b) middle position of ferrogram (c) exit position of ferrogram

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In