Abstract: The purpose of this paper is to assess the material characteristic by using vibration signal analysis during drilling process. Generally, material with high mechanical properties exhibits low damping capacity and vice versa. The main objective of this paper is to develop a relationship between the signal parameters and the strengths of materials. Aluminum alloy 1100, stainless steel 304, and mild steel were selected as the specimens to be drilled using CNC machine. The vibration signal was captured using a transducer and recorded using a DAQ system. The signal parameters such as maximum amplitude, vibration energy, and the RMS value were extracted using MATLAB software. From the results obtained, the graphs of signal parameters versus strength of each specimen are plotted to show their relationship. It was found that the signal parameters increased exponentially as the strengths of materials increased. Besides that, the vibration signal of the specimens are analysed and compared based on their mechanical characteristics.
Abstract: Large scale Potts model Monte Carlo simulation was carried on 3-dimensional square lattices of 1003 and 2003 sizes using the Metropolis algorithm to study grain growth behavior. Simulations were carried out to investigate both growth kinetics as well as the Zener limit in two-phase polycrystals inhibited in growth by second phase particles of single-voxel size. Initially the matrices were run to 10,000 Monte Carlo steps (MCS) to check the growth kinetics in both single phase and two-phase poly-crystals. Grain growth exponent values obtained as a result have shown to be highest (~ 0.4) for mono-phase materials while the value decreases with addition of second phase particles. Subsequently the matrices were run to stagnation in the presence of second phase particles of volume fractions ranging from 0.001to 0.1. Results obtained have shown a cube root dependence of the limiting grain size over the particle volume fraction thus reinforcing earlier 3D simulation efforts. It was observed that there was not much difference in the values of either growth kinetics or the Zener limit between 1003 and 2003 sized matrices, although the results improved mildly with size.
Abstract: In this paper a study of the corrosion resistance is shown in a physiological medium of multilayer coatings [TiN/TiCN] n with periods bilayers of 1, 50 and 150 deposited on silicon substrates ( 100 ) and stainless steel AISI 316 LVM by the method of RF magnetron reactive sputtering with an RF power ( 13.56 MHz ) and using two targets of Ti and TiC. The electrochemical behavior simulated body environment was evaluated by the technique of using Tafel polarization curves, in Hanks solution as electrolyte. Morphological characterization was performed using scanning electron microscopy (SEM) on silicon substrates (100), also was used to characterize the mechanism of attack on the uncoated steel and coated steels. Was found to be markedly increased corrosion resistance to the deposition of multilayer coatings evidencing the effect of the spatial period ( Λ ) in reducing the degradation of these coatings , the effect was shown for the substrate alloy type stainless steel AISI 316 LVM, confirming the good performance of the variation of the bilayers period.
Abstract: The paper innovatively proposes using atomic force microscopy (AFM) and the concept of specific down force energy (SDFE) to establish a method for fabricating T shape nanochannel grooves on silicon (Si) substrate. Using the single-pass multi-layer cutting method of nanochannel groove using AFM proposed by the paper, a nanochannel looked like T shape is fabricated. For fabricating T shape nanochannel, it is set that cutting is firstly carried out for one pass on each cutting layer at a fixed down force. Then the probe carries out cutting for repeated passes. Using this cutting way by AFM and SDFE theory, the cutting depth and width of each pass can be predicted. The results of simulation and experiment of fabricating method for T shape nanochannel is further compared.
Abstract: In this study, a U-channel bending test with tension were used to evaluate the surface damage resistance of dual-phase (DP) steel against heat treated Mo-Cr cast iron, and a numerical simulation model of the U-channel bending were developed to analyze the interface contact pressure on formed part that is an important influencing factor of surface damage. Investigation results for two bare steel sheets DP780 and DP590 demonstrate that DP780 steel showed more severe surface damage on formed part, and that for the steel DP780 greater interface contact pressure is induced as a result of effect of larger plastic deformation.
Abstract: A gas turbine blade operates under severe conditions including high temperature, high speed rotation, and frequent starts and shutdowns. Under such operating conditions, a blade is exposed to a thermo mechanical fatigue environment. These conditions shorten the life of the turbine parts and reduce the reliability of the gas turbine. Therefore, research on the characteristics of blade material is necessary. In this study, thermo-mechanical fatigue (TMF) tests were conducted for IN738LC, which is base a material for turbine blades. Tests were conducted under both the IP (in-phase) and OP (out of-phase) conditions, and tests results were compared in terms of fatigue life. After obtaining the ε-N curves, additional TMF tests were conducted according to variations in fatigue life. The purpose of the TMF test is to observe the change in mechanical properties of materials damaged during TMF and how these relate to fatigue life. For this purpose, an indentation test was conducted and the relationship between hardness and fatigue life were obtained.
Abstract: As the oil and gas industry grows rapidly worldwide over the years, the production of produced water is also increasing. Million barrels of water are produced each day worldwide. This situation has become a major problem and a to the environment and ecosystem. Produced water contains many constituents such as dispersed oil, metals and chemicals that have a high toxicity and very harmful to the marine life. Therefore, it must be treated prior disposal to the environment or reinjection into the well and formation. There are many methods of treatments such as liquid-liquid hydrocyclone, floatation technology and membrane technology. Membrane technology is quite a new technology for the treatment of produced water in oil and gas industry. This paper is focused on the viability of using composite membranes which are Polysulfone (PSU), Polysulfone-bentonite (PSU-bentonite), PSU-PVP (Polysulfone-Poly vinyl pyrrolidone) and Polysulfone-Poly vinyl pyrrolidone-bentonite (PSU-PVP-bentonite) for the treatment of produced water. The objectives of this study are; 1) to characterize the produced water, 2) to prepare and cast the composite membrane and 3) to investigate the membrane performance in treating the produced water. The performance of the composite membrane were tested by using the produced water as wastewater feed and the best composite membrane is determined by the membrane performance. In the membrane preparation process, a method have been used namely phase inversion method. This research found that technically composite membrane have a good potential to be used in treating produced water from Malaysian oil and gas field. Thus, further technical and economic study on this treatment method is suggested for industrial scale application.
Abstract: Manganese steel (Hadfield) is one of the important alloys in industry due to its special properties. High work hardening ability with appropriate toughness and ductility are the properties that caused this alloy to be used in wear resistance parts and in high strength condition. Heat treatment is the main process through which the desired mechanical properties and microstructures are obtained in Hadfield steel. Iterations of Taguchi designed experiments and analysis were used to determine optimum heat treatment for minimizing grain boundary carbide content in Hadfield steel. Experimental variable chosen for this study included austenitizing temperature and time and rate of quenching. The austenitizing temperature and the cooling rate by changing in quenched solution were seen to have the greatest influence on carbide content in Hadfield steel.
Abstract: Manganese steels have extensively application in industries due to good resistance to wear, high work hardening capability with high toughness and ductility. Heat treatment is the main process to obtain desired mechanical properties and microstructure in this steel. The austenitizing temperature, the austenitizing time and the rate of quenching are the main factors in heat treatment. In this research, Taguchi analysis was used to determine optimal heat treatment for minimizing grain boundary carbide content with optimum hardness. Experimental variable chosen for this study included austenitizing temperature and time and the rate of quenching. In the optimization by Taguchi approach, L9(3)3 array, employing nine experiments, with three levels for each factor, was chosen for DOE. The austeitizing temperature and the cooling rate by changing in quenched solution were seen to have greatest influence on hardness of these steels.