THE POSSIBILITIES OF THE RETAINED AUSTENITE REDUCTION ON TOOL STEELS | Author : Laszlo TOTH | Abstract | Full Text | Abstract :The retained austenite induces a great deal of internal stress in the steel, often manifesting itself as cracks. Retained austenite also have a negative effect on dimensional stability of the steel components. In tool steels retained austenite is considered to be highly detrimental and is the cause of many application failures. Tool steels must be able to attain high hardness, high compressive strength, good toughness to be suitable for forming of advanced high-strength steels. The high alloying elements content tool steels result is low martensite start and martensite finish temperatures. As a result, the transformation of austenite to martensite does not go to completion when quenching to room temperature. In this work the effects of tempering and cryogenic treatment were investigated for reducing the amount of residual austenite in case of a cold work tool steel and a hot work tool steel. The results showed that in the case of tool steels, during high hardening and three times tempering at high temperatures, the amount of residual austenite was significantly reduced and as a result of cryogenic treatment completely disappeared. |
| INVESTIGATION ON THE SURFACE QUALITY OF BÖHLER S290 POWDER METALLURGICAL TOOL STEEL AFTER WEDM MACHINING | Author : Laszlo TOTH | Abstract | Full Text | Abstract :Nowadays, there is a growing demand for fast, accurate and precise tool manufacturing. At the same time, the requirements for the quality of tool steel materials have also increased. Increasingly, tools are being made from high alloyed, highest purity, segregation free, homogenous and high hardness materials. These materials are difficult to machine with conventional technology. For this problem a solution could be the electrical discharge machining technology (EDM). During the EDM process an electrical discharge occurs between an anode and a cathode in a dielectric medium [1]. The EDM process is characterized by high heat, that cause structural changes on the surface of the machined materials. In EDM process the surface of the machined material is eroded by melting and evaporation due to large quantity of heat [2]. This paper presents a study of the wire EDM machining surface of S290 PM HSS materials with different parameters performed by multiple cutting. The aim of this investigation was to find the optimal parameters and trim cuts number for the efficient production of the tools from S290 HSS PM materials with the required surface quality |
| EDUCATION THROUGH INNOVATION IN THE FIELD OF METALLIC MATERIALS SCIENCE | Author : Adrian IOANA, Daniela TUFEANU, Dragos Florin MARCU, Bogdan FLOREA, Daniela Alice LUTA, Bianca Cezarina ENE, Daniela Ionela JUGANARU, Roxana Marina SOLEA | Abstract | Full Text | Abstract :The importance of the innovation process lies in its main functions, those of generating and leading to the conception and development of new processes and products, based on creativity. Hence the need of education for innovation. In this article we present, for a start, the main stages of an innovation process. Then, elements of innovation management, innovation strategies, innovation activities. We also present aspects regarding the financing of the innovation process and of the technology transfer. As results of the efficient application of these theoretical elements specific to an innovation process, we present the main elements of a patent (Invention Patent no. 107025/1993) of one of the authors. This patent, entitled "Burner" has gone through all stages, from conception to implementation in industry. This implementation took place in the former Special Steels Plant ok Targoviste (COST), in Electric Steel Mill no. 1 (OE1), with a good technological and economic efficiency. |
| GUAR GUM HYDROGEL MICROBIAL FUEL CELL USING B.MEGATERIUM | Author : Sumin KIM | Abstract | Full Text | Abstract :The main factors of a microbial fuel cell (MFC) are the anode and the microorganisms around it that produce electrons. This research focuses on increasing the efficiency of a MFC in plantMFC (PMFC) or aquarium-like conditions by inoculating microorganisms that help produce electrons to the soil. Guar gum was used as a base structure as it can culture microorganisms and create a hydrogel by cross-linking with borax.[1,2] Bacillus megaterium was added to the hydrogel as it can survive under the basic conditions of borax while producing electrons.[3] Glucose was added as well to help culture the bacteria. Then, the change of voltage was observed along with the growth of B.megaterium. A compound consisting of 0.5% glucose, 1% Guar gum, 10% Borax, and B.megaterium culture medium was created with a volume ratio of 1:25:1:1 in each order. This compound will be named GGB-B. GGB-B was able to keep its shape as a hydrogel along with a voltage increase of 250mV compared to control due to the stable growth of B.megaterium. 100g of GGB-B was placed inside a beaker and was covered with aquarium soil. Two goldfishes (Carassius auratus) were added. Voltage, pH, and the health of goldfishes were observed for 9 days. The result was approximately a 150mV increase in voltage compared to control (tap water). pH decrease was about 1.3, showing a pH of 6.12. There was no change in the goldfishes, and the GGB-B under the aquarium soil fused with the soil as it disintegrated. Therefore, when electron-producing microorganisms such as B.megaterium are added to guar gum, the microorganisms would slowly spread over the soil, thereby increasing the efficiency of MFC. This could also apply to PMFC and aquarium-like conditions as well. |
| RESEARCH OF PHYSICO CHEMICAL PARAMETERS BEFORE AND AFTER THE USE OF THERMAL WATER IN THE PEJA BATH | Author : Florent DOBROSHI, Faton MALOKU, Krenar DOBROSHI | Abstract | Full Text | Abstract :With the development and growth of the population, the demand for quality and safe water increases. The desire for a healthy body, at the same time to cure various health problems and to enjoy the natural beauty pushed one for the sources of thermal water springs, mostly natural and rich in innumerable healing properties for each disease. The purpose of this study is to investigate the physicochemical parameters of thermal water in Banja e Pejes, where sampling sites are located at inlet water sources, during use and at some exit points after thermal water has been used by the hospital for the treatment of several different diseases. A total of 12 samples were taken in this paper. dated: 23.12 2020, where samples are in three time frames 4 samples are taken at 8:00 am, the other 4 samples were taken at 11:00 am, and the last 4 samples were taken at 16:00 pm. The assays were performed with the most advanced methods at the University of Mitrovica Laboratory, we used spectrophotometric method, comparative method and in very rare cases standard classical method of analysis. In this case we have determined: temperature, dissolved oxygen, pH, electrical fluidity, odor, taste, turbidity, nitrates and nitrite. The purpose of this research is to analyze thermal waters before and after use by the Banja e Pejes and their discharge into the environment where it can have consequences for both flora and fauna may also have an impact on the waters used for drinking where the day by day is further reduced. |
| INTRODUCTION OF RESIDUAL CHLORINE SENSOR USING CONSTANT VOLTAGE METHOD AND ITS MEASUREMENT PRINCIPLES | Author : Juhyeong KIL | Abstract | Full Text | Abstract :In the past, we could never imagine buying drinkable water. Who would buy to drink water? But now, bottled water are sold just about anywhere in the world, but there are still many countries with water supply shortages. When drinking water is contaminated with microorganisms, it can be exposed to various diseases such as hepatitis, cholera, diarrhea, and typhoid fever. We are not only interested in drinking water, but also the water used in bathrooms, gardens, and laundry of each household. We mention “water quality” because all of these kinds of water are enough to give us a direct stimulus such as odors and greens. When we use tap water in each household, the most direct irritation is the “smell”. In this case, we know that chlorine comes to mind first, and that chlorine is very useful in disinfection. Then, why are we sensitive to toxic odors in drinking water or swimming pools? The answer is simple. The effect of disinfecting with chlorine is only exerted in clear water, and we need to focus on the analysis of residual chlorine that is important for instrumental analysis. Therefore, what is introduced in this study is a “residual chlorine sensor” of a new constant voltage method that can be more accurate in measuring the amount of residual chlorine in water which is the most important factor when it comes to effectively disinfecting our drinking water. |
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