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Parameter Optimization Study on Control of Distortion in Bright Bar Used In Rack Application Subjected To Induction Heat Treatment

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材料热处理学报 2004年第5期25卷 579-581页

作者： k. Palaniradja N. Alagumurthi v. Soundararajan Department of Mechanical Engineering Pondicherry Engineering College India Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

The engineering properties of metals and alloys are related to their structures. The change in mechanical properties of the metals and alloys can be achieved by the process of heat treatment. Induction hardening is one such a process involves phase transformation by rapid heating and cooling of the outer surface. Induction hardening improves the outer surface hardness and wear resistant properties keeping the original toughness and ductility in the inner core. However past experiences shows that during heat treatment, parts have undergone dimensional changes due to thermal fluctuations and phase transformations. Dimensional changes can lead to excessive distortion in the component which always presented difficulties to the uses of many varieties of steels which can be hardened by induction hardening. The dimensional changes in components which have been induction hardened have for a long time proved costly and troublesome to manufacturers. These difficulties apply particularly in the automotive industry where the amount of distortion in rack and pinion assembly has been related to their noise level in operation and investigators have suggested a link between distortion and the initiation of fatigue failure. [1] Although the complete elimination of distortion would be an ideal aim, manufacturers are reconciled to the fact that a certain amount of distortion is an inherent part of the hardening process. However, if the amount of distortion is uniform and predictable, an allowance could be made in the initial machining operations. It was with these aims that investigations into the control of distortion in bright bar (EN 18D steel) used in rack application (Power steering assembly) have been carried out by parameter optimization

关键词：感应加热淬火变形 EN18D钢析因法回归模型

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On The Enhancement of Wear Resistance of Hardened Carbon Tool Steel (AISI 1095) With Cryogenic Quenching

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材料热处理学报 2004年第5期25卷 531-535页

作者： v.Soundararajan N.Alagurmurthi k.Palaniradja Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

Many experimental investigations reveal that it is very difficult to have a completely martensitic structure by any hardening process. Some amount of austenite is generally present in the hardened steel. This austenite existing along with martensite is normally referred as the retained austenite. The presence of retained austenite greatly reduces the mechanical properties and such steels do not develop maximum hardness even after cooling at rates higher than the critical cooling rates. Strength can be improved in hardened steels containing retained austenite by a process known as cryogenic quenching. Untransformed austenite is converted into martensite by this treatment. This conversion of retained austenite into martensite results in increased hardness, wear resistance and dimensional stability of steel. Wear can be defined as the progressive loss of materials from the operating surface of a body occurring as a result of relative motion at the surface. Hardness, load, speed, surface roughness, temperature are the major factors which influences wear. Many studies on wear indicate that increasing hardness decreases the wear of a material. With this in mind, to study the surface wear on a surface modified (Cryogenic treated) steel material an attempt has been made in this paper. In this study as a Part -I Hardening was carried out on carbon tool steel (AISI 1095) of different L/D ratio with conventional quenchants like purified water, aqueous solution and Hot mineral oil. As a Part -II hardening was followed by quenching was carried out as said in Part-1 and the hardened specimen were quenched in liquid Nitrogen which is at sub zero condition. The specimens were tested for its microstructure, hardness and wear loss. The results were compared and analyzed. The alloying elements increases the content of retained austenite hence the material used was AISI1095 (Carbon 0.9%, Si 0.2%, MnO.4% and the rest Iron)

关键词： AISI1095钢液态氮低温淬火抗磨损性

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Study on Surface Engineering of Normalized Steels Subjected To Machine Hardening

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材料热处理学报 2004年第05B期25卷 1329-1332页

作者： N.Alagurmurthi k.Palaniradja v.Soundararajan Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

Engineering the surfaces of components to improve the life and performance of parts used in automotive and aerospace engineering is the active area of research. Suitable Thermal/ Mechanical/Thermo mechanical surface engineering treatments will produce extensive rearrangement of atoms in metals and alloys and corresponding marked variations in Physical, Chemical and Mechanical properties. Among the more important of these treatments are heat treatment processes such as hardening by Quenching, Induction hardening and Case Carburizing which rely on phase transformations to produce desired changes in mechanical properties. Other processes where phase transformation occur are casting, welding and machining etc. [1] Phase transformation may be homogeneous or heterogeneous. Homogeneous involves rearrangements in the structure of the material taking place simultaneously in all parts of the solid, while the heterogeneous transformation involves structural changes which are more localized. Alternatively they could be called as Isothermal and Nonisothermal transformation. But irrespective of the classification, these transformations alter the structure of the material giving rise to changes in the mechanical and physical properties of the processed material. It is of interest to review some consequences of surface modification in isothermal (Normalizing) and nonisothermal transformations (Machining) of low carbon steels.

关键词：正火钢研磨硬化比能能量区别速率

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An Efficient Iterative Procedure for Solution of Plasma Loaded Helical Waveguide Problems

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Chinese Physics Letters 2005年第12期22卷 3123-3125页

作者： v. Babovic M. kovacevic k. kanjevac Department of Physics Faculty of Science University of Kragujevac Serbia and Montenegro

The behaviour of axially-symmetric waves travelling on plasma filled screened helical coil is comprehensively studied by Anicin [J. Phys. D： Appl. Phys. 33 （2000） 1276], where all analytical expressions are derived in the full-wave theory, but the diagrams are computed in the quasistatic approximation. We use an iterative procedure to overcome this limitation. The iterative procedure is rapid and we have proven that often the first-order approximant is sufficient to improve defects which are known as immanent to the quasistatic approximation. The fixed point method appears as the natural choice for numerical treatment of formulae which could arise in a broad class of physical problems usually recognized as guided surface plasma waves.

关键词： Iterative methods

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Analysis on Phase Transformation (ATP) Using Computational Thermal Principles (CTP)

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材料热处理学报 2004年第05B期25卷 716-719页

Computer analysis based on computational thermal principles to predict the transformation kinetics in steels at varying temperatures is of great practical importance in different areas of heat treatment. As a result, using the theory of transient state heat conduction with convective boundary conditions, an efficient program named "ATP" (Analysis on Phase Transformation) has been developed to determine the temperature distribution under different quenching conditions for different geometries such as plate, cylinder and sphere. In addition to these the microstructures and the corresponding hardness developed during quenching are predicted using Time Temperature Transformation (TTT) diagram incorporated in the analysis. To approve our work, dilation curves, Heisler charts and time-temperature history curve have been generated. This paper deals with basic objective of the program (ATP) determination of temperature, microstructure and hardness distribution and also includes an online prediction of austenite-pearlite and austenite-martensite transformation in steels along with the corresponding retained fractions. The quenching of a cylinder in gases, liquids and liquid metals is analyzed to show the non-liner effect of cylinder diameter on the temperature and microstructures. Further in the program we have considered a typical 1080 steel cylinders quenched in water for predicting and comparing the program results with experimental values and can be extended even to other grades of steels. The numerical results of program are found to be in good agreement with the experimental data obtained. Finally the quenching process analysis described in the study appears to be a promising tool for the design of heat-treatment process parameters for steels.

关键词：热处理相位变换 ATP 温度分布冷却曲线 CTP

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CP violation in ∧b → ∧l^＋l^- Decay in the Four-Generation Standard Model

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Chinese Physics Letters 2010年第4期27卷 63-66页

作者： v. Bashiry N. Shirkhanghah k. Zeynali Engineering Faculty Cyprus International University Via Mersin 10 Turkey Islamic Azad University Khalkhal Branch Valiasr St. Khalkhal Iran Department of Sciences Ardabil University of Medical Sciences Daneshgah St. Ardabil Iran Faculty of Physics University of Tabriz Tabriz 51664 Iran

We present the first study of CP asymmetry in ∧b → ∧l^＋l^- decay when a new weak phase comes through the extension of three-generation standard model to the four-generation standard model. Taking ｜vt′s^＊vt′b｜ = 0.01, 0.02, 0.03 with phase {60° - 120°}, which is consistent with the b → sl^＋l^- rate and the Bs mixing parameter △mBs, we find out that CP asymmetry is quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, in particular, to search for the fourth generation quarks （t′, b′） via their indirect manifestations in loop diagrams.

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Identifying the optimal HvOF spray parameters to attain minimum porosity and maximum hardness in iron based amorphous metallic coatings

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Defence Technology（防务技术） 2017年第2期13卷 101-110页

作者： S.vignesh k.Shanmugam v.Balasubramanian k.Sridhar Centre for Materials Joining and Research (CEMAJOR) Department of Manufacturing Engineering Annamalai University Annamalai Nagar 608 002 Tamil Nadu India Protective Technologies Department Naval Materials Research Laboratory (NMRL) Ambernath Thane (Dist) Maharashtra India

Flow based Erosion e corrosion problems are very common in fluid handling equipments such as propellers, impellers, pumps in warships, submarine. Though there are many coating materials available to combat erosionecorrosion damage in the above components, iron based amorphous coatings are considered to be more effective to combat erosionecorrosion problems. High velocity oxy-fuel(HvOF)spray process is considered to be a better process to coat the iron based amorphous powders. In this investigation, iron based amorphous metallic coating was developed on 316 stainless steel substrate using HvOF spray technique. Empirical relationships were developed to predict the porosity and micro hardness of iron based amorphous coating incorporating HvOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance. Response surface methodology(RSM) was used to identify the optimal HvOF spray parameters to attain coating with minimum porosity and maximum hardness.

关键词： High velocity oxy fuel spray Iron based amorphous metallic coating Micro-hardness Porosity

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Analysis of EMD Algorithm for Identification and Extraction of An Acoustic Signal in Underwater Channel Against Wind Driven Ambient Noise

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China Ocean Engineering 2014年第5期28卷 645-657页

作者： S.Sakthivel MURUGAN v.NATARAJAN k.MAHESWARAN ECE Department SSN College of Engineering Instrumentation Department MIT Campus Anna University Infosys Chennai India

Sonar generated acoustic signals transmitted in underwater channel for distant communications are affected by numerous factors like ambient noise, making them nonlinear and non-stationary in nature. In recent years, the application of Empirical Mode Decomposition(EMD) technique to analyze nonlinear and non-stationary signals has gained much attention. It is an empirical approach to decompose a signal into a set of oscillatory modes known as intrinsic mode functions(IMFs). In general, Hilbert transform is used in EMD for the identification of oscillatory signals. In this paper a new EMD algorithm is proposed using FFT to identify and extract the acoustic signals available in the underwater channel that are corrupted due to various ambient noises over a range of 100 Hz to 10 kHz in a shallow water region. Data for analysis are collected at a depth of 5 m and 10 m offshore Chennai at the Bay of Bengal. The algorithm is validated for different sets of known and unknown reference signals. It is observed that the proposed EMD algorithm identifies and extracts the reference signals against various ambient noises. Significant SNR improvement is also achieved for underwater acoustic signals.

关键词： EMD IMF SNR ambient noises underwater acoustic signals FFT

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Evaluation of Process Capability in Gas Carburizing Process to Achieve Quality through Limit Design Concept

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材料热处理学报 2004年第5期25卷 395-397页

作者： k. Palaniradja N. Alagumurthi v. Soundararajan Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

Steel is the most important metallic material used in industry. This is because of the versatility of its engineering properties under different conditions. In one condition it can be very mild, soft and suitable for any forming operation. In another condition the same steel can be very hard and strong. This versatility is made possible by the different heat treatments that the steel can be subject to. One such treatment is Gas carburizing. This is the most widely used process for surface hardening of low carbon steels. In this method the surface composition of the steel changes by diffusion of carbon and or nitrogen and result in hard outer surface with good wear resistance properties. A striking feature of Gas Carburizing process is that in this process the original toughness and ductility remains unaffected even after heat treatment. 3% nickel chromium case hardened low carbon steels are widely used for critical automotive and machine applications such as rack and pinion, gears, camshaft, valve rocker shafts and axles which requires high fatigue resistance. Fatigue behaviour of case carburized parts depends to a great extent on the correct combination of Hardness Penetration Depth (HPD) and the magnitude of hardness at the surface and beneath the surface with low size and shape distortion. In order to reduce the manufacturing costs in terms of material consumption and elimination of the number of processing steps, the effect of Gas carburizing parameters on the fatigue behaviour should already be considered in the parameter design stage. Therefore it is of importance to optimize the gas carburizing process variables to attain quality products with respect to hardness and case depth. In the present paper, the evaluation of process capability was carried out through a Limit Design Concept called orthogonal array design of experiment. To optimize the process variables the influence of several parameters (Holding time, Carbon potential, Furnace temperature and Quench

关键词：气体渗碳最优化碳势存放时间消火时间炉温

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Fabrication,characterization and optimization of high conductivity and high quality nanocrystalline molybdenum thin films

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Journal of Materials Science & Technology 2019年第11期35卷 2734-2741页

作者： Anil k.Battu Nanthakishore Makeswaran C.v.Ramana Center for Advanced Materials Research(CMR) University of Texas at El PasoEl PasoTX 79968USA Environmental Molecular Sciences Laboratory(EMSL) Pacific Northwest National Laboratory(PNNL)RichlandWA 99352USA

The present study investigated the influence of substrate temperature(Ts)and working pressure(P(Ar))on tailoring the properties of nanocrystalline(nc)molybdenum(Mo)films fabricated by radio-frequency magnetron *** structural,morphological,electrical and optical properties of nc-Mo films were evaluated in *** Mo films exhibited(110)orientation with average crystallite size varying from 9 to 22(±1)nm on increasing *** with structural data,the electrical resistivity decreased from 55μΩcm to 10μΩcm,which is the lowest among all the Mo *** Mo films deposited under variable P(Ar).the(110)peak intensity decrement coupled with peak broadening on increasing P(Ar).Lower deposition pressure yielded densely packed thin films with superior structural properties along with low resistivity of 15μΩ*** conditions to produce high quality Mo films with excellent structural,morphological,electrical and optical characteristics for utilization in solar cells as back contact layers were identified.

关键词： Molybdenum Thin films Microstructure Electrical characteristics Optical properties Solar cells

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