Advances in Materials Processing Technologies, 2006

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Authors: A.O. Akii Ibhadode
Abstract: Design equations based on die expansion are derived for selecting punch and counterpunch dimensions in completely closed die forging. The method imposes lower limits on the punch (counterpunch) – container radial clearance and forging height tolerance that may be specified.
Authors: Jose L. Diéguez, L. Corbacho, E. Ares
Abstract: The present paper studies the process of electro discharge machining, estimating the relative importance of main influence factors. The first step is to evaluate the possibilities of a design of experiments based on an orthogonal array, an appropriated method to systems with multiple factors changing in numerous levels After of the realization of the experiences the theory of grey systems is used to know which combination of factors optimize all of the variables. Finally the analysis of the variance is applied to investigate which of the factors significantly affects the global answer of the system.
Authors: A.M. Camacho, E.M. Rubio Alvir, Cristina González Gaya, M.A. Sebastián
Abstract: The Finite Element Method (FEM) has become an indispensable tool in metal forming analysis [1,2]. Contrary to the traditional methods, FEM allows to analyze more realistic situations, either geometric and tensional. On the other hand, the drawing process is one of the most ancient metal forming operations and, nowadays, this process is widely used in industrial field. However, the influence of the main parameters in the mechanics and efficiency of the process has been scarcely studied. Drawing processes have been analysed by FEM, assuming plane strain and axisymmetrical conditions in order to check the possibility of extrapolating results from one case to another. Besides, this numerical method is compared with analytical and experimental methods. Also, FEM is used for studying the influence of several technological parameters on variables such as the drawing force or the die pressure, and for obtaining results of stresses and strains in certain regions of the model.
Authors: Rodrigo Luri, C.J. Luis-Pérez
Abstract: In this work, the strain field attained by using a severe plastic deformation (SPD) process called equal channel angular extrusion (ECAE) is studied by the finite element method (FEM). The three-dimensional model with circular section includes shear friction between the part and the die, the material strain hardening behaviour and a rigid-deformable contact between the billet and the die. In the ECAE process the part is extruded through two channels with similar diameter that intersect at an angle. When the extrusion process has been performed, the processed material remains it cross section, so there is not any geometric limitation to achieve the desired plastic strain. There are different ways of processing the material by using the ECAE process; those ways of processing are called routes. In this work two passages of route C have been simulated. Using route C means that the billet has been rotated 180º between each passage. Deformations imparted to the processed material have been calculated and a comparison with experimental results has been carried out.
Authors: Manuel Estrems, Patricio Franco, Ramon Fernández
Abstract: The main objective of this work is the analysis of hydroforming for the manufacture of joint bellows of AISI 316 steel for different values of diameter. The initial thickness of the metallic tube is of 1 mm and diameters between 500 and 1200 mm are considered. The Finite Element Method is applied to study the tensile stress and thickness reduction at the wave peak of the final part. The numerical results are compared to the recommendations given by the EJMA standard. More critical values of wave thickness and tensile stress are predicted by simulation.
Authors: Jose Antonio Ortiz Marzo, Carlos Rio, Xavier Salueña Berna, Jasmina Casals Terré, Ana I. Capilla
Abstract: This study starts from a firm’s needs to improve manufacturing costs and times in an external turning operation with the material according to the standard AISI 630 (martensitic stainless steel, hardened by precipitation), with a hardness of 355 HB. It has been developed a basic factorial design of experiments with two factors (cutting speed and feed per revolution), with constant depth of cut and two levels, with three central points. This experiment has resulted in the obtaining of the machined meters from a tool life criterion, which has limited basically the tool flank wear, VB = 0,2 mm. The balance between the tool wear, maximum machining length and the minimum machining time has been considered from the analysis of the results.
Authors: Pedro Jose Núñez López, Jorge Simao, José M. Arenas Reina, C. de la Cruz
Abstract: The paper evaluates the feasibility of monitoring cutting forces for in-process prediction of the workpiece surface roughness, using regression based models (RG) and artificial neural network (ANN) techniques. The three orthogonal cutting force components (Fx, Fy, Fz) and the machined length L have been chosen as input variables. In the experimental test, AISI-1045 steel material was turned using a TiN coated carbide tool and employing a range of machining conditions (cutting speed: v=150, 200, 250 m/min; feed rate: f=0.15, 0.20, 0.25 mm/rev; depth-of-cut: d=1, 2, 3 mm). The results provided a wide range of measured cutting force and surface roughness values (Ra and Rq), which were used for adjustment and validation of the prediction models. Two prediction models were developed and subsequently the model accuracy was assessed by comparing the surface roughness predicted by the models with that measured by a 2D profilometer. The results highlighted the reasonably good fit given by both models, with the ANN based model providing best accuracy for surface roughness prediction. The prediction of the output surface roughness in an automated turning process was established and was found to be feasible by the monitoring of cutting forces.
Authors: Aitzol Lamikiz, Jose Antonio Sánchez, Luis Norberto López de Lacalle, D. del Pozo, J.M. Etayo
Abstract: A laser polishing method applied on metallic surfaces is presented in this work. One of the most important applications of this technique is the small-medium injection mould polishing manufactured by rapid manufacturing processes (RM) such as selective laser sintering. The polishing method has been applied to different surfaces including a laser-sintered part. Topography and roughness parameters measurements show that laser polishing can achieve surface improvements up to three times in mean roughness parameter with no macro-geometric deviations.
Authors: Petru Moldovan, Gabriela Popescu, Marilena Cuhutencu
Abstract: The aim of the paper is to present the influence of a new multifunctional material, a master alloy named Al-Sr-Ti-B, in aluminum foundry alloys. The Al-Sr-Ti-B master alloy represents a new combination of two master alloys, already known in aluminum industry, AlTiB and AlSr, used in treatment of aluminum alloys for grain refining and modification. As Strobloy, our master alloy contain fast dissolving SrAl4 particles and also nucleating particles as TiB2 and (Al,Ti)B2 which are important first in modification and second in grain refining of aluminum alloys. The paper presents optic and electron microscopy studies realized on AlSi7Mg alloy treated with this new multifunctional material
Authors: Ulvi Şeker, Adem Kurt
Abstract: In this paper, a mathematical model has been developed for the cutting tool stresses in machining of nickel-based super alloy Inconel 718 used in aircraft and spacecraft industries, nuclear power systems and steam generators etc. necessitating oxidation and corrosion resistance, high temperature and strength. The cutting forces were measured by a series of experimental measurements and stress distributions on the cutting tool were analyzed by means of the finite element method using Ansys software. The mathematical modeling process of the compressive stresses in x, y and z directions was carried out with multiple regression analysis regarding to Ansys stress results depending on the cutting forces and the chip–tool contact area. It is found that model results had good agreement with the Ansys stress results.

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