Influence of Subsurface Structure on the Linear Reciprocating Sliding Wear Behavior of Steels with Different Microstructures

Abstract

The present work investigates the influence of subsurface microstructure on the linear reciprocating sliding wear behavior of a number of steels with ferrite-pearlitic, pearlitic, bainitic, and martensitic microstructures under dry unlubricated condition. The change in the underlying microstructure with depth from worn-out surface of steel sample intimately relates to the associated hardness variation and wear volume. The present paper is not about comparison of wear resistance of steels with different structures; rather it is on mutual influence of wear and substructure for individual microstructure. Inherent toughness of the matrix and ability of microstructural components to get deformed under the reciprocating action of the ball decide the wear resistance of the steels. Bainite has good amount of stability to plastic deformation. Ferrite shows severe banding due to wear action. Work hardening renders pearlite to be wear resistant. Temperature rise and associated tempering of martensite are observed during wear.

Appendix

(a) Calculation of T _b , the bulk surface temperature[51, 52]

$$ \left( {T_{b} - T_{0} } \right)\frac{{k_{1} }}{{l_{1b} }} + \left( {T_{b} - T_{0} } \right)\frac{{k_{2} }}{{l_{2b} }} = \frac{\mu Fv}{{A_{n} }} $$

where A _n is the apparent area of contact given by, $A_{n} = \pi r_{0}^{2}$, as indicated in Figure 11. μ is the coefficient of friction and v is the sliding velocity of ball-on-disk.

After substituting the value of the given parameters, the value of T _b is obtained to be 343 K (70 °C).

(b) Calculation of other parameters involved in Eq. [9]

$$ T^{\prime}_{b} = T_{b} - \frac{{A_{r} }}{{A_{n} }}\left( {T_{b} - T_{0} } \right) $$

$$ F_{s} = \frac{{H_{0} A_{n} }}{{\left( {1 + 12\mu^{2} } \right)^{1/2} }} $$

$$ l_{1f} = l_{2f} = \frac{{\pi^{1/2} r_{j} }}{2} $$

$$ r_{j} = r_{0} \left\{ {\left[ {1 - \frac{F}{{F_{s} }}} \right]\left[ {\frac{{r_{0} }}{{r_{a} }}} \right]^{2} + 1} \right\}^{ - 1/2} $$

The various parameters are defined as r _j is contact junction radius, F _s is seizure load, load at which A _r becomes equal to A _n , l _1f and l _2f is effective heat diffusion distances in ball and flat specimen, respectively, for flash heating, $T^{\prime}_{b}$ is sink temperature for heat flow from an asperity, l _1b is effective linear heat diffusion distance (adjustable in tribometer) for ball, bulk heating, l _2b is effective heat diffusion distances for flat specimen, bulk heating, k ₁ and k ₂ is thermal conductivity of ball and flat specimen