Search results

The purpose of this paper is to study the microstructure and the high-temperature tribology behavior of a high-speed steel (HSS) roller material with boron as the main alloy element under different heat treatments, aiming to provide some theoretical references for its engineering application.

The samples of high boron HSS were quenched at 900°C, 1,000°C, 1,050°C and 1,150°C. The microstructure, composition and phase composition of this new HSS were analyzed by OM, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometer. The surface hardness and the tribology behavior under high temperature were measured by Rockwell hardness tester and the high-temperature friction and wear tester. The wear morphology was observed by SEM.

The high-temperature friction coefficient and the relative wear rate of the high boron HSS decrease first, then increase with the rise of the quenching temperature. When the quenching temperature is 1,050°C, both the friction coefficient (0.425) and the relative wear rate (79 per cent) are the smallest. Under the high-temperature friction environment, the high boron HSS mainly includes oxidation wear, adhesive wear and abrasive wear. The effect of abrasive wear is weakened gradually with the rise of the quenching temperature, and the high-temperature wear resistance is improved significantly. Compared with the traditional roll materials, the service life of the new high boron HSS is greatly improved. It is an ideal substitute product for the high chromium cast iron roll.

The boron element replaces other precious metals in high boron HSS, which has the advantage of low production cost, and it has a wide application in the field of roll materials. In this paper, the microstructure, the transformation of hard phases and the high-temperature tribology behavior of this new high boron HSS under different heat treatments were studied, aiming to provide some theoretical references for its engineering application.

The purpose of this paper is to determine the optimum level of geometrical parameters such as helix angle, nose radius, rake angle and machining parameters such as cutting speed, feed rate and depth of cut to arrive minimum surface roughness and tool wear during end milling of Al 356/SiC metal matrix composites (MMCs) using high speed steel end mill cutter.

L27 Taguchi orthogonal design with six factors and three levels is employed for conducting experiments. Analysis of variance (ANOVA) is carried out using Minitab16 software to find the influence of each input parameter on output performance measure. Grey-fuzzy logic multi optimisation algorithm is used to find the optimum level of the input parameters for minimum surface roughness and tool wear simultaneously.

It is found that optimal combination of helix angle 40°, nose radius 0.8 mm, rake angle 12°, cutting speed 90 m/min, feed rate 0.04 mm/rev and depth of cut 1.5 mm have generated minimum surface roughness of 0.4063 µm and tool wear of 0.0375 mm. From ANOVA analysis, it is found that cutting speed influence is more on output performance followed by helix angle and rake angle compared with other machining and geometrical parameters.

The influence of tool geometry during end milling of MMC using Grey-fuzzy logic algorithm has not been explored previously.

The purpose of this paper is to find out the optimal level as well as the influence of end mill cutter geometrical and machining parameters while machining metal matrix composite. End milling is carried out on Al 356/SiC metal matrix composites (MMC) using high-speed steel (HSS) end mill cutter. The optimum level of input parameters such as helix angle, nose radius, rake angle, cutting speed, feed rate and depth of cut are calculated for minimum temperature rise.

L27 Taguchi orthogonal design, signal-to-noise (S/N) ratio, are applied for conducting experiments, and to find the optimal level of input parameters for minimum temperature rise, respectively. Analysis of variance (ANOVA) is used to analyze the significance of input parameters on temperature rise.

It is found that the optimal combination of helix angle 400, nose radius 0.8 mm, rake angle 80, cutting speed 30 m/min, feed rate 0.04 mm/rev and depth of cut 0.5 mm have generated minimum temperature rise. From ANOVA analysis, it is found that rake angle influence is more on output performance followed by cutting speed and nose radius compared with other machining and geometrical parameters.

The influence of geometrical parameters such as helix angle, nose radius and rake angle of end mill cutter on temperature rise while machining MMC has not been explored previously.

The purpose of this paper is to study the influence of the cutting conditions (cutting speed, feed rate and cutting depth) on the roughness (Ra) and on the flank wear (Vb) of the steel AISI 4140.

Mixed ceramic (CC650) and polycrystalline cubic boron nitride (PCBN) have been used to carry out straight turning tests under dry conditions.

The results indicate that PCBN is more efficient than mixed ceramic (Al2O3+TiC) used in terms of wear resistance regardless of the aggressiveness of the AISI 4140 at 50 hardness rockwell (HRC). Consequently, it is the most powerful. Surface quality attained with PCBN tool considerably compares with that of grinding. Even when the tool wear VB reached 0.3 mm, the majority of the recorded Ra values did not exceed 1 m at the various speeds tested. The correlation of tool wear Vb and surface roughness Ra established allows obtaining experimental empirical data on the cutting tool wear from measured surface roughness for practical use in industry. The values of constants and the coefficient of determination R² of this mathematical model will be calculated. Mathematical models expressing the relation between the elements of the cutting regime and technological parameters (tool life and roughness) are proposed.

Many works have been already made in the similar manner, but this study of CC650 and PCBN wear is the first. Through this study, we propose a mathematical model expressing the relation between the elements of the cutting regime, tool life and roughness.

The purpose of this paper is twofold. First review the relevant literature in machining using minimum quantity lubrication (MQL), contrast the economical, environmental, and technical attributes of this technology to conventional flood‐cooling techniques. Second highlight areas of relevant future research.

The approach consists of describing the essential elements of MQL as a technology, reviewing the relevant research by focusing on the most frequently used machining processes in this industry, highlighting the findings as they compare to flood cooling, and pointing to directions of required research in this technology.

The application of MQL in machining has shown better results in some processes; including in drilling, a cleaner environment, and a more cost‐effective machining technology. Further research is required however to better understand the underlying cause an effect phenomena in machining using microlubrication technology including environmental and health effects of this technology.

The paper provides a body of knowledge required for all stakeholders to better use or design machining systems using microlubrications.

This paper focuses on the state of the art of MQL and how it contrasts with conventional methods of machining.

ACCURATE measurement of critical features on wing roots for Airbus Industrie A300‐series aircraft is now being carried out in 25 per cent of the time previously required and at much lower capital cost at British Aerospace, Chester, following the installation of a Kern ECDS co‐ordinate measuring machine from E Leitz (Instruments) Ltd.

This paper aims to provide a detailed review of various cutting fluids (CFs).

Friction and wear are inevitable in machine parts in motion. The industrial sector uses various kinds of lubricants, which include engine oils, CFs, hydraulic fluids, greases, etc. to control friction and wear. The main purpose of using CF is to remove heat produced during machining and to reduce cutting forces, tool wear and energy associated with it. Thus, it increases the productivity and quality of the manufacturing process. But more than 80% of the CFs used in the industries now are mineral oil-based. These mineral oils and additives are highly undesirable because of their toxicity, nonbiodegradability, pollution and ecological problems. Hence, these petroleum-based oils in the lubrication system can be substituted with alternatives such as vegetable-based CF. Several studies are being conducted in the field of eco-friendly CFs. Because of the variance in fatty acid profile and availability, the selection of vegetable oils (VOs) is another problem faced nowadays. The present study is focused on bio-based oils and many eco-friendly additives. Various machining processes and comparisons relating to the same have also been made. The aim is to minimize the use of mineral oil and thereby introduce sustainability in production.

In this present study, bio-based oils, additives and various characteristic behavior of them in machining are being discussed. The VOs are found to be a potential base oil for industrial CFs.

This paper describes the importance of sustainable CFs.

The main purpose of this paper is to explore the use of solid lubricant during orthogonal machining of carbon steels. This is a pioneer work in Nigeria. Most works have been on oblique cutting using conventional oil as lubricants.

Different steels (low, medium and high carbon) were machined at different cutting conditions and tool geometries to determine the effects on surface characteristics while applying solid lubricant.

The results showed considerable improvement in the surface finish with the use of solid lubricant. There was also a decrease in surface roughness values as compared to wet machining.

Further works on solid lubricant's effects on cutting force and residual stress could be done.

From the findings of this work, solid lubricant use can be advocated as a better alternative to conventional cutting fluid. It is easily recoverable from the chips after machining.

So far, in Nigeria, solid lubricant has not been exploited as coolant during machining. This paper will be a platform for other researches on solid lubricants as coolant during cutting/machining in Nigeria.

This review paper reveals the literature on ultrasonic, chemical-assisted ultrasonic and rotary ultrasonic machining (USM) of glass material. The purpose of this review paper is to understand and describe the working principle, mechanism of material removal, experimental investigation, applications and influence of input parameters on machining characteristics. The literature reveals that the ultrasonic machines have been generally preferred for the glass and brittle work materials. Some other non-traditional machining processes may thermally damage the work surface. Through these USM, neither thermal effects nor residual stresses have been generated on the machined surface.

Various input parameters have the significant role in machine performance characteristics. For the optimization of output response, several input parameters have been critically investigated by the various researcher.

Some advance types of glasses such as polycarbonate bulletproof glass, acrylic heat-resistant glass and glass-clad polycarbonate bulletproof glass still need some further investigation because these materials have vast applications in automobile, aerospace and space industries.

Review paper will be beneficial for industrial application and the various young researcher. Paper reveals the detail literature review on traditional ultrasonic, chemical assisted ultrasonic and rotary USM of glass and glass composite materials.

This paper aims to study the effect of microcrystalline cellulose (MCC) on the mechanical property and shape memory property of water-borne epoxy (WEP).

In the present study, the MCC/WEP composites were successfully prepared by melt-blending, freeze-drying and hot-pressing. The mechanical property tests were performed using a tensile test instrument (Instron Corp, Norwood, Massachusetts, USA). dynamic mechanical analysis Q800 was performed to analyze the sample’s dynamic mechanics. The thermal–mechanical cycle tests performed on a thermal mechanical analysis (TMA) Q400 in dynamic TMA mode enabled to analysis of the shape memory properties of the MCC/WEP composites.

The results showed that the inclusion of 2 wt.% MCC led to significant improvements in tensile strength and modulus of the composites, with tensile strength increasing by 33.2% and modulus expanding by 65.0%. Although the inclusion of the MCC into WEP enhanced the shape memory property, the MCC/WEP composites still maintained good shape memory fixity and shape memory recovery ratio of more than 95.0%.

This study has a significant reference value for improving the mechanical properties of WEP and other water-borne shape memory polymers.