Design guidelines for PM parts subject to dry rolling–sliding wear

Cristofolini, I.; Pilla, Melania; Straffelini, Giovanni; Molinari, A.

doi:10.1179/1743290112y.0000000032

Cited by 3 publications

(3 citation statements)

References 25 publications

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“…In two previous works, the anisotropy of dimensional variations of different iron alloys was investigated by dilatometry, and the evidence of a significant shrinkage in alpha field below the Curie point was obtained. 2,3 Shrinkage kinetics in the 600–700°C temperature range was discussed with reference to the shrinkage model based on volume and grain boundary diffusion proposed by German, 1 and the diffusion coefficients calculated from experimental curves result much higher than those reported in literature for an equilibrium density of structural defects in the iron lattice. The hypothesis that diffusivity is strongly increased by dislocation introduced in the particle contact regions by prior cold compaction was then proposed to justify not only the enhanced shrinkage kinetics but even its anisotropy.…”

Section: Introductionmentioning

confidence: 97%

Shrinkage kinetics during early stage sintering of cold isostatically compacted iron powder

et al. 2013

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Dilatometry experiments have been carried out to investigate the shrinkage kinetics on cold isostatic pressed iron specimens in the 550-730uC temperature range, showing that dimensional contraction is much higher than that predictable on the basis of the shrinkage kinetics models, which neglect the effect of the prior cold compaction. The greater shrinkage is due to an enhanced diffusivity which may be attributed to the large density of structural defects accumulated in the powder particles during compaction (structural activity). A time depending effective lattice diffusion coefficient was determined, with an Arrhenius type dependence on temperature.

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Section: Introductionmentioning

confidence: 97%

Shrinkage kinetics during early stage sintering of cold isostatically compacted iron powder

et al. 2013

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“…Sonsino [4] found that the fatigue properties of PM components are inferior to those of wrought or cast parts. Cristofolin [5] focused on the effect of material variables (i.e., porosity and micro-hardness) and geometric parameters (i.e., contact length) on wear resistance in dry rolling-sliding contact. He built a knowledge base usable in the design step to take account of the effects of material variables (porosity and microhardness) and geometric parameters on wear resistance.…”

Section: Introductionmentioning

confidence: 99%

A pin-on-disc study of the tribology characteristics of sintered versus standard steel gear materials

Sosa

Olofsson

2015

Wear

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a b s t r a c tThough powder metallurgy (PM) allows manufacturing of complex components, including gears, we lack knowledge of the tribological performance of PM versus standard steel gear materials. Using a pin-ondisc machine, we simulate the sliding part of gear tooth contact in boundary and mixed lubricated regions, comparing the tribological characteristics of two sintered gear materials with those of a standard gear material. The comparison considered damage mechanisms, wear, and friction between these materials in different configurations (i.e., standard versus standard, sintered versus sintered, and sintered versus standard). The results indicate that, for pairings of the same gear materials, i.e., RS-RS (16MnCr5), AQ-AQ (Distaloy AQ þ 0.2% C), and Mo-Mo (Astaloy 85Mo þ0.2% C), RS has a lower friction coefficient. For PM and RS combinations, both PM pins have lower friction coefficients with RS disc material than do RS pins with PM disc materials. For the wear coefficient, at low and high speeds, RS pins always display better wear resistance than do AQ or Mo pins because of their high hardness and compacted microstructure. For RS-PM combinations, Mo pins display higher wear resistance than do AQ pins because their larger and more numerous pores enable good lubrication. Pins in the Mo-RS combination displayed the highest wear resistance, mainly because the pores in Mo discs hold lubricant, lubricating the contact surface and preventing adhesive wear. For the RS pin in the Mo-RS combination and the AQ pin in RS-AQ, the damage mechanism is slight adhesive wear and scuffing. For pins in the PM-PM, RS-PM, AQ-RS, and RS-RS combinations, the damage mechanism is a heavier scuffing-type adhesive wear.

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“…The sintered density was measured by the water displacement method. The load bearing surface (Mr 2 ) was determined from the Abott–Firestone curves [8] recorded on the lateral surface of the rings. It resulted 0.79 and 0.83 for the low and high density specimens, respectively.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Influence of the microstructure on the subsurface and surface damage during lubricated rolling–sliding wear of sintered and sinterhardened 1.5%Mo–2%Cu–0.6%C steel: theoretical analysis and experimental investigation

Mekonone

Pahl²,

Molinari

2018

Powder Metallurgy

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The influence of the microstructure on density on the resistance to subsurface and surface damage, during lubricated rolling-sliding wear of a 1.5%Mo-2%Cu-0.65%C sintered and sinterhardened steel, was investigated. The nucleation of subsurface contact fatigue cracks and the occurrence of surface plastic deformation due to surface stresses were studied through a theoretical analysis and confirmed through wear tests. The expected positive effect of density and sinterhardening was confirmed. Moreover, the resistance of the steel to the two damage mechanisms investigated depends on the microstructural heterogeneity. The theoretical model for subsurface and for surface damage may be used to predict the resistance of the material but, depending on the distribution of the microstructural constituents, either a local or a mean approach in defining the properties of the metallic matrix has to be used.

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Design guidelines for PM parts subject to dry rolling–sliding wear

Cited by 3 publications

References 25 publications

Shrinkage kinetics during early stage sintering of cold isostatically compacted iron powder

Shrinkage kinetics during early stage sintering of cold isostatically compacted iron powder

A pin-on-disc study of the tribology characteristics of sintered versus standard steel gear materials

Influence of the microstructure on the subsurface and surface damage during lubricated rolling–sliding wear of sintered and sinterhardened 1.5%Mo–2%Cu–0.6%C steel: theoretical analysis and experimental investigation

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