R. Dasgupta

Factors controlling the abrasive wear response of a zinc-based alloy silicon carbide particle composite

Abstract Attention has been focused in this study on the (two-body/high-stress) abrasion characteristics of a zinc-based alloy reinforced with hard SiC second phase articles (SPPs) under the influence of varying load, sliding distance and abrasive size. The unreinforced matrix alloy processed similarly was also subjected to identical test conditions. It was observed that the wear response of the specimens is influenced markedly by the applied load, sliding distance and the size of the abrasive particles. Different operative wear mechanisms were found to be responsible for the changing behaviour of the samples. Reinforcement with hard SPPs (SiC) in the zinc-based alloy matrix was beneficial when tests were conducted with fine abrasive particles over the entire range of applied loads and sliding distance. On the contrary, however, this trend reversed when coarser abrasive particles were used. Further, the wear rate reduced with sliding distance, while load affected the wear behaviour of the specimens in the opposite manner. These effects, of course, were more prominent under severe conditions of abrasion (i.e. higher load or coarser abrasive). The wear characteristics of the samples have been explained on the basis of factors such as degradation of the abrasive, as well as reinforcing SPP and abrasion-induced work hardening of the subsurface regions. In addition, the predominance of one or more processes such as capping, clogging, shelling and attrition, leading to a deteriorating cutting efficiency of the abrasive and brittle fragmentation of the SPPs, affected the wear response of the specimens markedly under a given set of experimental conditions.

Wear characteristics of a hardfaced steel in slurry

Abstract This study discusses some observations made during the wear testing of hardfaced layers deposited on a low carbon steel. Two kinds of (wear resistant) hardfacing materials were (separately) overlayed on a steel substrate and characterized for their microstructural features and wear behavior. Conditions of wear testing were varied in terms of the content of sand particles in the slurry, the speed of rotation of the specimens and the distance traversed. The substrate material was also subjected to identical tests in order to assess the effects of hardfacing/ overlaying. Hardfacing of the steel substrate resulted in a significant improvement in the wear resistance (inverse of wear rate) over that of the substrate, irrespective of the test conditions. Speed of rotation had a mixed influence on the wear rate wherein the intermediate speed caused maximum wear loss. The distance traversed had a mixed influence on the wear rate of the specimens in the sense that in some cases wear rate decreased with distance while a reverse trend was noted in the remaining situations, whereas under one test condition, the wear rate first decreased with distance, attained a minimum and then again tended to increase. Moreover, the larger sand content in the slurry led to lower wear rates. The wear behaviour of the specimens has been explained on the basis of the predominating material removal mechanisms, such as erosion and abrasion, in different situations. These have been further substantiated through their wear surface and sub-surface characteristics.

Abrasive wear behaviour of zinc-aluminium alloy - 10% Al2O3 composite through factorial design of experiment

AbstractTwo body abrasive wear behaviour of a zinc-aluminium alloy - 10% Al2O3 composite was studied at different loads (1–7 N) and abrasive sizes (20–275 μm) as a function of sliding distance and compared with the matrix alloy. The wear rate of the composite and the matrix alloy has been expressed in terms of the applied load, abrasive size and sliding distance using linear factorial design approach. The study suggests that the wear rate of the alloy and composite follow the following relations:

Low-Stress Abrasive Wear Behaviour of a 0.2% C Steel: Influence of Microstructure and Test Parameters

\begin{gathered} Y_{{\text{alloy}}} = 0.1334 - 0.0336x_1 + 0.0907x_2 + 0.0296x_1 x_2 + 0.0274x_2 x_3 - 0.0106x_3 x_1 \hfill \\ {\text{ }} - 0.0201x_1 x_2 x_3 \hfill \\ Y_{{\text{comp}}} = 0.0726 - 0.028x_1 + 0.062x_2 + 0.03x_3 - 0.024x_1 x_2 + 0.028x_2 x_3 - 0.016x_3 x_1 \hfill \\ {\text{ }} - 0.014x_1 x_2 x_3 \hfill \\ \end{gathered}

Slurry erosive wear characteristics of a hard faced steel: effect of experimental parameters

where, x1, x2 and x3 are the coded values of sliding distance, applied load and abrasive size respectively. It has been demonstrated through the above equations that the wear rate increases with applied load and abrasive size but decreases with sliding distance. The interaction effect of the variables exhibited a mixed behaviour towards the wear of the material. It was also noted that the effect of load is less prominent for the composite than the matrix alloy while the trend reversed as far as the influence of the abrasive size is concerned.

Influence of experimental parameters on the erosive-corrosive wear of Al-SiC particle composite

Abstract Erosive–corrosive wear behaviour of Al–hard particle composite has been studied in synthetic mine water plus sand slurry at varying speeds (900 and 600 rpm) and at different angles of inclination (0°, 45° and 90°) of the specimen surface with respect to the slurry movement. It has been noted that the wear rate is significantly higher at normal incidence angle and at higher speed as compared to that occurred at lower speed and shallower incidence angle. These may be due to higher degree of normal impact energy offered by the erodant on the specimen surface in such experimental condition. The mechanism of material removal from the specimen surface was examined to be associated with number of subsequent and repetitive stages. It is observed that interface between alloy and hard particle plays an important role in the process of material removal under synergistic effect of corrosion and erosion. At higher speed and normal impact angle, the particles also get fractured, fragmented and finally pulled out from the specimen surface which in turn causes significantly higher wear rate.

Wear response of a Zn-base alloy in the presence of SiC particle reinforcement: A comparative study with a copper-base alloy

A low (0.2%) carbon steel has been subjected to heat treatment to form varying quantities of ferrite plus martensite in its microstructure. This was achieved by holding the samples in the two-phase (ferrite plus austenite) region at three different temperatures (750, 780, and 810 °C) for a specific duration followed by quenching in ice water. In another exercise, the steel was also subjected to annealing treatment by austenitizing at 890 °C followed by furnace cooling for comparison purposes. The samples were subjected to low-stress (three-body) abrasion tests using an ASTM rubber wheel abrasion test apparatus at different wheel speeds (150, 273 and 400 rpm corresponding to linear speeds of 1.79, 3.26 and 4.78 m/s respectively) for different sliding distances at a fixed load of 49 N. Crushed silica sand particles of size ranging from 212 to 300 μm were used as the abrasive medium. The wear rate of samples decreased progressively with sliding distance until a (nearly) steady-state condition was attained. This was considered to be due to abrasion-induced work hardening of subsurface regions as well as the greater tendency of protrusion of the harder martensite/pearlite phase at longer sliding distances, thereby providing greater resistance to wear. Decreasing wear rate with increasing treatment temperature 750–810 °C could be attributed to the greater volume fraction of the hard martensite phase in the samples containing ferrite plus martensite. The lower wear rate observed in the case of the samples containing ferrite plus martensite over the annealed ones comprising ferrite and pearlite was attributed to the higher bulk hardness of the former. Increasing linear speed from 1.79 to 3.26 m/s led to an increase in wear rate. This could be attributed to greater tendency of the abrasive particles to create deeper scratches and scouping (digging). A reduction in wear rate with a further increase in the linear speed from 3.26 to 4.78 m/s could be due to a change in the mechanism of wear from predominantly sliding to rolling of the abrasive particles in view of the increased plastic deformability characteristics of the specimens due to higher frictional heating. The present investigation clearly suggests that it is possible to attain a desired combination of bulk hardness and microstructure (consisting of ferrite plus martensite) leading to optimum abrasion resistance in low-carbon steels. The quantity of the two phases in turn could be varied by suitably controlling the heat-treatment temperature.

The Effects of Primary Silicon Particles on the Sliding Wear Behavior of Aluminum-silicon Alloys

This study examines the abrasive wear behavior of two iron-base hardfacing materials with different combinations of carbon and chromium after deposition on a steel substrate. Effects of applied load and sliding distance on the wear behavior of the specimens were studied. Operating material removal mechanisms also were analyzed through the scanning electron microscopy (SEM) examination of typical wear surfaces, subsurface regions, and debris particles.The results suggest a significant improvement in the wear resistance of the hardfaced layers over that of the substrate. Further, the specimens overlaid with the material with low carbon and high chromium contents attained better wear resistance than the one consisting of more carbon but less chromium. The former specimens also attained superior hardness.Smoother abrasion grooves on the wear surfaces and finer debris formation during the abrasion of the hardfaced samples were consistent with wear resistance superior to that of the substrate.