Showing 5 results for Wear Rate
Behzad Jabbaripour, , , ,
Volume 12, Issue 5 (1-2013)
Abstract
γ–TiAl intermetallic has outstanding properties such as high resistance against fatigue, oxidation, corrosion, creep, dynamic vibration and high working temperature. These intermetallics are applied in aerospace and automotive industry, turbojet engines and blade manufacturing. In this paper, powder mixed electrical discharge machining (PMEDM) of γ–TiAl intermetallic by means of different kinds of powders including Al, SiC, Gr, Cr and Fe is investigated to compare the output characteristics of the process such as surface roughness, tool wear rate, material removal rate and surface topography with each other. This is an experimental investigation, by means of die sinking EDM machine and a special tank for machining. The results indicate that, aluminum powder as the most appropriate kind of powder in the optimum particle concentration of 2 g/l, improves the surface roughness about 32% comparing with conventional EDM, decreases the tool wear rate about 19%, but decreases the material removal rate about 7.5% and also the Al powder leads to improving the machined surface topography and decreasing the surface defects and micro cracks.
Moslem Mohammadi Soleymani, Majid Fooladi Mahani, Masoud Rezaeizadeh, Mehdi Bahiraie,
Volume 15, Issue 4 (6-2015)
Abstract
Milling is one of the most important operational stages in processing the minerals. Lifters are usually used with mill liners to extend their life and to enhance the grinding and crushing efficiency. Lifters worn and consequently their dimensions change during the course of operation. These changes in dimensions have a significant influence on the overall economic performance of the mills. Therefore, it is useful to know the relationship between the mill operation and the lifter profile, and the influence of lifter wear on the change in lifter profile. The wear is influenced by a range of parameters such as: media charge level, slurry filling, slurry concentration, and mill speed. In this work, the influences of these operating parameters were investigated using a pilot mill (1000 * 500 mm). To this end, a Copper ore was used to prepare slurry at 40%, 50%, 60%, 70%, and 100% solids concentration by mass. The tests covered a range of slurry filling (U) from 0.5 to 3 with solid charge between 15% and 35% of mill volume and 3 different speeds 65%, 75% and 85% of critical speed. It is found that the mill charge and the mill speed significantly affect the wear rate. For wet condition, increase in the slurry concentration and slurry filling leads to a remarkable decrease in the amount of the wear. By increase in the feed filling (in dry condition) the wear increases too. Wear rate in wet conditions is 2-4 times of dry condition.
Mohammadreza Shabgard, Ahad Gholipoor,
Volume 17, Issue 12 (2-2018)
Abstract
Electric discharge machining is one of the most widely used non-traditional machining techniques which use thermal energy for machining in small dimensions, machining complex shapes and machining hard materials with high strength such as ceramics and heat-treated steels. In this study the ultrasonic vibrations and magnetic field assisted EDM process as a new hybrid process was introduced and used for machining of AISI H13 too steel, to solve the EDM process limitations such as low material removal rate. In this investigation, several experiments were designed and performed based on full factorial method by selecting pulse current and pulse duration as most effective parameters of EDM process in order to study the effects of applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of EDM process, simultaneously, on material removal rate and tool wear rate. According the results, applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of EDM process, simultaneously, despite the increases of tool wear rate, increases the material removal rate as compared with EDM (60%), ultrasonic vibrations assisted EDM (40%) and magnetic field assisted EDM processes (55%) in all pulse durations and pulse currents except in pulse current of 32 A. In pulse current of 32 A, because of the interference of the influences of applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance, the material removal rate and tool wear ratio are decreased.
S. Dinarvand, B. Jabbaripour,
Volume 20, Issue 7 (6-2020)
Abstract
Modern intermetallic compound of gamma titanium aluminide (γ-TiAl) due to its low density, high elastic modulus, high resistance to oxidation, corrosion, and ignition has recently been considered in the aerospace and automotive industries. Traditional machining of this alloy is so difficult. In the current study, electrical discharge machining of γ-TiAl samples is investigated using different tool electrodes of graphite, copper, and aluminum. The results show that when using aluminum electrodes, tool wear rate is averagely 3.2 times more than copper and 5.8 times more than graphite tools. In addition, when using graphite electrodes, the average material removal rate is 4.2 times more than copper and 7.7 times more than aluminum. Machining by aluminum tool leads to formation of Al2O3 and TiO2 oxide compounds on the work surface but in machining by graphite electrode, TiC and Ti8C5 carbide phases are created on the work surface. In machining by graphite due to formation of hard carbide compounds in the recast layer, the microhardness is higher than the machined sample by the aluminum tool, where oxide compounds exist on the surface and the hardness of recast layer in the machined sample by copper electrode is less than the other two electrodes, because of existing phases such as copper oxide with less hardness. The highest electrochemical corrosion resistance belongs to the machined specimen using graphite tool and the lowest corrosion resistance is related to the machined sample by aluminum electrode. Reducing oxide and aluminum compounds and increasing carbide phases enhance the corrosion resistance of γ-TiAl machined samples.
Gouhar Ranjbari,
Volume 23, Issue 10 (10-2023)
Abstract
In this paper, tool and workpiece wear ratio and surface roughness in the removal process of Ti-6Al-4V by spark are modeled using fuzzy algorithm. In the machining process using a spark, a copper electrode is used as a tool and equal channel angular pressing (ECAP) process is applied to the tool. In this combined modelling the number of ECAP passes, current, spark presence time and spark absence time are used as input parameters. The evaluation and validation results of fuzzy modeling, using experimental data, show that the fuzzy algorithm is capable of modeling and establishing relationships between response variables based on input parameters with high accuracy. Therefore, by using this method, one can easily predict the response variables and avoid the need of conducting experiments that require spending a lot of time and cost.
