Advanced Materials and Processes Research Institute
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Abrasion-induced microstructural changes during low stress abrasion of a plain carbon (0.5% C) steel
No full textA plain carbon (0.5% C) steel was subjected to various heat treatment cycles to produce a variety of microstructures. Low stress abrasion tests were conducted using an ASTM standard rubber wheel abrasion test apparatus. Crushed silica sand particles were used as the abrasive medium. The wear loss decreased progressively with the number of test intervals until a steady state was reached. The steady state abrasion resistance was found to increase linearly with bulk hardness up to about 350 HV beyond which there was a marginal increase.\ud
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Abrasion-induced changes were studied via metallographic examinations of transverse sections and hardness vs. depth (below the abraded surface) profiles. Abraded surfaces and wear debris were examined in a scanning electron microscope equipped with a wavelength-dispersive X-ray spectroscope. The hardened steel showed a large number of continuous and parallel grooves, while the annealed specimen revealed a considerable amount of micropitting in addition to the grooves. Wear debris from the annealed specimen was mainly of the flake type, while long micromachining chips of the “card-deck” type were observed in the case of the hardened steel. The results of this study revealed that the material removal mechanisms during abrasion of steels are controlled by the properties of a layer beneath the abraded surface. The properties of this layer are in turn governed by the bulk microstructure
Microstructural Modifications and Improvement in Properties of a Hypoeutectic Al-Si alloy Dispersed with Graphite Particles
No full textAnnual Progress Report for the year 1991
No full textAnnual Progress Report of Regional Research Laboratory, Bhopal for the year 199
An Empirical Model for Batch Coal Flotation
No full textResults obtained from batch flotation experiments on seven coal samples, having widely varying size and size-wise ash distributions have been used to develop a simple empirical model for predicting the performance through first order kinetic behaviour. The kinetic equation describing the variation of recoveries of non-ash and ash materials with flotation time is given as\ud
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R = R∞\ud
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The first order rate constant (kN ) and the equilibrium recovery (Rn∞ for the recovery of non-ash material are related to the weight percents of non-ash materials present in the coarse fraction above 75 μ m (CNA) and in fines fraction below 75 μ (FNA) in the feed, collector dosage (C) and frother dosage ( F) by the equation:\ud
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kN = A (CNA)1.069 (FNA) − 0.083 (C) 0.083(F) 0.045\ud
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RN∞ = B (CNA)0.407 (FNA)-− 0.0061 (C) 0.172 (F) 0.126\ud
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Similar relationships have been noted for rate constants and equilibrium recovery (kA and RA∞ respectively) of ash material also\ud
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Four characteristic constants have been identified which would describe the feed coal characteristics for any coal. One experiment has to be carried out on a given coal sample at known levels of reagent dosages to estimate these constants and using these constants, the yields and ash content of the concentrates obtained at any other conditions can be estimated with the help of equations developed. The model developed has been found to predict the flotation performance very satisfactoril
Triblological behaviour of red mud filled polyester composites.
No full textAbrasive wear behaviour of different composition redmud polyester composites was studied by using SUGA abrasion tester. Wear loss was more in case of 5Phr composite as compared to 15 Phr redmud polyester composites. Effect of particle size on wear loss was also observed and explained on the basis of the microstructures of the worn surfaces
Pretreatment of glassy carbon electrode leading to surface modification in ferro/ferricyanide and potassium chloride medium
No full textThe Significance of Matrix Microstructure on the Solid Lubrication Characteristics of Graphite in Aluminium Alloys
No full textAl alloy 2014- graphite particle composite was synthesized using a solidification processing technique. Wear tests of as-caste end of heat-treated alloys and composites were conducted under dry conditions on a pin-on-disc wear test apparatus. Scanning electron microscopy examination of sliding surfaces did not show the formation of a graphite film. It appeared from the present investigation that graphite particles either were engulfed in the coarse wear debris or might have been pulled off the sliding surfaces because of a poor inter-facial bond between aluminium and graphite. However, in (Al-Si alloy)-graphite composites in the heat-treated condition, the formation of a graphite film was detected. The present study suggests that the matrix micro-structure plays a significant role in the solid lubrication characteristics of graphite in aluminium alloys