Advanced Materials Research Vols. 875-877

Abstract: The work deals with joining of graphite with stainless steel type AISI 321 by use of active solder type Sn3Ti. Structure of active solder type Sn3Ti is composed of a tin matrix in which the Ti6Sn5 phase is uniformly precipitated and the Ti3Sn phase is non-uniformly distributed. Wettability of Sn3Ti solder was determined in 10-4 Pa vacuum, at temperatures 860, 900 and 950 °C. Wetting angle of Sn3Ti solder on graphite is reduced with increasing soldering temperature and also with prolonged dwell time at soldering temperature. Temperature exerts greater effect on reduction of wetting angle. The lowest wetting angle on graphite 23° was observed at temperature 950 °C/20 min. The lowest wetting angle, observed on steel type AISI 321, attained value 18° at temperature 860 °C/20 min. Based on the results of wettability tests, the joints of graphite with stainless steel type AISI 321 were fabricated. The reactions after soldering resulted in formation of a continuous reaction layer with 5 μm average thickness on graphite/Sn3Ti solder boundary.

Abstract: In this paper, fuzzy AHP to select the appropriate environment-friendly chemical mechanical polishing additives, and the rational design of the polish formulation. Practical application shows that the polish has a good anti-wear, the wear properties and anti-rust properties, stable performance ，and meets the needs of the chemical mechanical polishing, the rate of biodegradation more than 80%.

Abstract: A molding process of aluminum foams by using a rotating mold is proposed in order to improve the mold filling and forming process for light-weight parts of vehicles. Aluminum powder mixed with a foaming agent is extruded into the mold through the die heated to a temperature higher than the melting point, and the mold is filled with the aluminum foam. When the diameter of a cylindrical mold is large, the influence of gravity is significant and the mold is not filled successfully. In the proposed molding, the aluminum foam is extruded into the rotating mold of large diameter and the volumetric ratio of foam to mold cavity is improved. However, the effect of the mold rotation on the mold filling is limited due to friction.

Abstract: Quality of deposition during friction surfacing depends on a number of parameters. With instrumentation many of these parameters can be observed in real time. Monitoring of these parameters allows one to incorporate necessary corrections, whenever, that parameters goes out of the safe domain. Present investigation aims at the potential of monitoring some of these parameters online and the quality of the deposition. It is observed that spindle speed and torque are not effective parameters whereas monitoring material consumption or height of the consumable friction tool is very much useful in monitoring the quality of the deposition

Abstract: Increased use of alternative fuels in cement kilns is a trend in the world. However, replacing fossil fuels like coal with different alternative fuels will give various impacts on the overall kiln process due to the fuel characteristics. Hence, it is important to know to what extent the fossil fuels can be replaced by different alternative fuels without severely changing process conditions, product quality or emissions. In the present study, a mass and energy balance for the combustion of different alternative fuels in a cement rotary kiln was developed. First, the impact of different fuel characteristics on kiln gas temperature, kiln gas flow rate and air requirement were observed by using coal (reference case), meat and bone meal (MBM), two different wood types, refuse derived fuel and a mixture of saw dust and solid hazardous waste as the primary fuel. It was found that the key process parameters depend largely on the chemical characteristics of the fuel. It appears that MBM shows quite different results from other alternative fuels investigated. Next, simulation of combustion of a mixture of coal and MBM in the main burner was carried out in three steps. The first step was combustion of replacing part of coal energy with MBM, and a reduction in kiln exhaust gas temperature compared to the coal reference case was found. In the second step, the fuel feed rate was increased in order to raise the kiln gas temperature to that of the reference case. In the third step, the fuel feed rate and the clinker production rate were changed in order to have not only the same kiln gas temperature but also to obtain the same volumetric flow rate of total exhaust gas from the precalciner as in the reference case. Around 7% of reduction in clinker production rate could be observed when replacing 48% of the coal energy input. Results from a full-scale test using the same mixture of coal and MBM verified the simulation results.

Abstract: Electroless Ni-P alloy was deposited on commercial pure aluminium with different nickel source–reducing species ratios. Deposition time was fixed as two hours. The deposits were characterised for changes in morphology and crystallinity. It was observed that increase in nickel source to reducing species ratio produced a deposit with reduced mean nodule size. Also, nodule size distribution was narrow. Deposits with increased ratio showed higher levels of crystallinity

Abstract: . In this work the physical effects of electromagnetic stirring (EMS) during welding on the microstructure of some commercial 6xxx and 7xxx series of aluminum alloys are investigated. Experiments are carried out with standard GTA equipment in combination with a current carrying coil providing an axial magnetic field. In order to achieve the maximum grain refining effect, a range of optimal stirring parameters is established. It is then demonstrated that the optimal parameters are in the frequency range of 2 to 15 Hz and the corresponding magnetic field intensities of 10 to 25 mT. These parameters are then applied to reduce susceptibility of these alloys to hot cracking. This paper concludes that by application of EMS to GTA welding of aluminum alloys it is possible to refine the grain structure and reduce the hot cracking susceptibility of these alloys, especially those employed in the aerospace and automotive industries.

Abstract: The aims of this research are to improve the preventive maintenance plan and to prepare the autonomous maintenance plan of an automatic labeling system for a carbonated soft drink industry as a case study. The labeling system of the case study has experienced the wastes in maintenance. According to the maintenance problem analysis, the main causes are lack of or inadequate preventive maintenance program, inadequate work order monitoring system, and inadequate staff skills (problem-solving skills of maintenance) to perform work. Therefore, in order to reduce the number and length of machine breakdowns and the seriousness of breakdowns, the preventive maintenance program is used instead of breakdown and routine maintenance by which maintenance skills are required, and in order to improve how machines are operated and handled by improving the skills, and the autonomous maintenance manual is set up to prepare for autonomous maintenance. After the improved preventive maintenance plan has been developed and then implemented, it was found that machine downtime reduced by 1.35% and machine availability increased by 1.74%.

Abstract: In this paper, silane coupling agent and organic modified bentonite were used in tea saponin intumescent flame-retardant coatings to improve the flowability, storage stability and film properties. The effects of silane coupling agent and organic modified bentonite on the flowability, storage stability and film properties were discussed, and flame resistance and pyrolysis performance of the flame-retardant coatings also were investigated. The results show that silane coupling agent can greatly improve the rheological properties, storage stability and film properties of the flame-retardant coating at the amount of 1.5%. Flame-retardant coatings have good dispersion properties and thixotropy, When bentonite modified with cetyltrimethylammonium chloride (CTAC-Bentonite) was introduced to the coatings. Fire resistance test and TG-DTG analysis showed that silane coupling agent/organic bentonite can promote the charring of the coatings and increase the amount of char, which protecting the internal substrates, reducing the thermal degradation rate. What's more, the flame retardancy of the materials was improved significantly owing to the increasing of the amount of residual carbon and the enhancing of thermal stability at a high temperature.

Abstract: ARMOX steels are armored steels used for protect devices and facilities against blasts and explosions. Due to this purpose the ARMOX 500 steel has excellent mechanical properties as are high hardness, tensile strength and good toughness. These properties result from specific production process finished with rolling ant then quenching and tempering. The producer of ARMOX steels recommend their secondary processing (cutting, welding, shaping) at temperatures lower than 200°C due to over tempering and degradation of mechanical properties in heat affected areas. The paper describes the mechanism and reason of this degradation including the simulation of cooling process with ARMOX 500 steel.