European Journal of Mechanical Engineering Research (EJMER)

EA Journals


Investigation on the Interrelationship between the Chemical Composition, Heat Treatment Parameters and the Phase Transformation Process, Microstructure Evolution and the Mechanical Properties of Austempered Steel (Published)

The interrelationship between chemical composition, heat treatment parameters, and phase transformation, microstructural evolution and the mechanical properties of austempered steel was studied. Two samples of steel with different percentage composition of carbon of 0.56 and 0.76 were used for the study. They were austentized at the respective temperatures of 8000C, 8400C, 9000C and 9600C for 30 minutes. They were thereafter quenched using bitumen-palm kernel oil, and subjected to austempering isothermal heat treatment at 4200Cfor different time durations of 5, 15, 30, 45 and 60 minutes. The samples were tested for tensile strength, elongation, hardness and impact strength. They were also subjected to microstructural characterization to determine the phases in the microstructures and their effects on the properties of the developed materials. Results obtained revealed that the dominant phases in the microstructure were bainite, matensite and traces of retained austenite. It was found that decreasing austenitizing temperature yields finer grain structures with increase in tensile strength and elongation with decrease in hardness and relatively little effect on the impact strength. At any given austenitizing temperature, shorter austempering holding time yielded optimum properties in tensile strength and elongation while higher hardness values were associated with shorter holding time. These results proved that the process conditions have strong correlation with both the microstructures and the mechanical properties. It was concluded that the most promising microstructures with respect to excellent strength-ductility property are those obtained at the ausenitizing temperature range of 800 -8400C for the austempering time range of 5 – 30 minutes. These materials have potential for load bearing application while those austenitized within the range of 900 – 9600C using austempering time range of 5 – 15 minutes are candidate material for wear resistant application.

Keywords: Austempering, Austenitize, Composition, Heat treatment, Microstructure, Properties

Secondary Products of Petrochemistry in Production of Bitumen Emulsions (Published)

Today, the most important tasks of petroleum processing and petrochemistry are provision of a deep processing of heavy oil raw materials and rational use of wastes and secondary products. One of the directions on effective use of heavy tonnage and at the same time deficit binding material as a bitumen is a wide introduction of bitumen emulsions in water into the road and civil construction practice. In addition to the advantages of bitumen, as an organic binding material, the bitumen emulsions have a number of positive properties, for example more less viscosity in the temperature interval from 0 to 1000С and higher cohesion degree with a rock material surface. One of the most important quality indicators of the bitumen emulsions is their decomposition rate, in accordance with which the emulsions are classified as quick-, mid- and slow-breaking, EBC 1, 2, 3 relatively. In recent years, the most important direction of petroleum processing and petrochemistry is investigation of intensification ways of oil raw material processing and rational use of target and secondary products with optimization of their qualitative features. In solution of these problems, the tasks on development, justification of principles and processing methods, focused on obtaining of products with specified properties are highlighted. In this context, secondary products of a one-staged isoprene synthesis, which do not find rational use to the moment, are of interest. Based on the one-staged isoprene synthesis chemical composition analysis, we can suppose that its use in production of bitumen emulsions will favor to obtaining of the product with specified properties. In this connection, investigations, focused on the use of one-staged isoprene synthesis as a modifier of the bitumen emulsions, are of present interest. The paper presents experimental data on estimation of the secondary products different content effect on the bitumen emulsions’ rheological properties.

Keywords: Bitumen Emulsion, Modifier, Properties, Secondary Products

Scroll to Top

Don't miss any Call For Paper update from EA Journals

Fill up the form below and get notified everytime we call for new submissions for our journals.