Sharif Digital Repository

In this research, the hot and warm rolling of stainless steel 304 was studied. First the rolling process was simulated using Finite Element Method software ABAQUS and the distribution of temperature and strain in the process under discontinuous conditions were predicted. Next, hot and warm rolling of stainless steel 304 under different conditions was carried out. Specimens were cut and subject to mechanical testing, metallography and electron microscopic studies. Data obtained from these experiments and the predicted trends from ABAQUS were compared, therefore studying the effect of different parameters on the microstructure and mechanical properties of the rolled specimen. Results indicate... 

MP210 alloy is a member of multiphase family alloys, a class of wrought nickel-cobalt base alloys extensively used in high-quality applications including aerospace fasteners, gas turbine engines and petrochemical industry. Very limited information can be found in the literature about the microstructure and phase transformations of this alloy. The aim of this work is characterizing the aging response of the material and identifying the major strengthening phases precipitated in different range of temperatures and also studying the static recrystallization behavior of this alloy. The effect of age-hardening heat-treatment on the microstructure of MP210 superalloy was investigated using... 

In this work we intend toeconomically recovery of residual from terephthalic acid production unit in the Tondgooyan petrochemical company. Major component of this residual is catalysts, benzoic acid and amount of terephthalic acid product. Catalysts contains of cobalt, manganese and bromide which recycled by water extraction. Effective variable on extraction process is dilution ratio of water to residue, extraction temperature and time. Optimum condition of catalystsrecovery consist of dilution ratio of water to residue 6:1, extraction temperature and time is 45 C° and 40 minrespectively. Recovery yield of cobalt, manganese and bromide in this optimum condition is 91.21, 91.89 and 92.53... 

Boric acid (H3BO3) is a weak monobasic acid that exist as a white powder in the standard conditions. In industry, it is used in manufacturing of fiberglas filaments, precious metals soldering and production of flat panel LCD displays. In all of these applications, normal grade boric acid is used, but nuclear industry demands an ultrapure boric acid (UPA) for controlling of the reactivity and power levels in pressurized water reactors. Annual consumption of UPA in Bushehr Power Plant (BPP) is around 60 metric tons. Currently, this amount is imported from Russia, but atomic energy organization of Iran plans to displace it by the acid made inside the country. Domestic production of UPA in... 

Severe plastic deformation (SPD) can refine microstructure of steel and increase its strain energy. Ultra-rapid annealing (URA) influences on the temperature and kinetics of recrystallization and transformation, and causes to improve the mechanical properties of steel. In this research, low-carbon steel with the average grain size of 80 μm was subjected to SPD using 2 passes of constrained groove pressing (CGP) method and its grains size is reduced to 30 μm. Ultra-rapid annealing with the reference heating rate of 200 oC/s was performed on SPDed steel up to subcritical and intercritical temperature ranges. Other heating rates of 75 oC/s to 1800 oC/s were performed for further examinations.... 

In this study, non-isothermal annealing of multi-directionally forged (MDF) aluminum alloy 2024 has been investigated. Two initial heat treatments have been considered, the solution treated (without S′/S (Al2CuMg)) and the over-aged (with S′/S (Al2CuMg)) conditions. DSC curves have shown that GPB zones/Cu-Mg co-clusters have been dynamically formed during MDF. This dynamic formation of these meta-stable phases has been modeled and in the presented model volume fraction of meta-stable phases has been calculated and its effect on the dislocation density has been considered. Although, hardness of solution treated sample has been increased by two-fold after MDF, hardness of over-aged sample has... 

Equal Channel Angular Pressing (ECAP) is one of the most applicable severe plastic deformation procedures (SPD) which results in improvement of strength and ductility through grain refinement. WE43 magnesium alloy belongs to a group of alloys for medical industry because of its good biocompatibility. In this study, equal channel angular pressing was performed at different temperatures, strain rates and number of passes on strip-shape samples to achieve proper mechanical properties. Tensile properties, hardness and microstructural evolutions were evaluated and the results were analyzed according to the EDS test. Results shows that at 380 ℃ and 440 ℃ grain refinement was accomplished by...