Showing papers by "A. Karimi Taheri published in 2006"
TL;DR: In this article, an upper bound limit for the deformation load in the case of radial forging of rods and tubes was derived based on deformation work, and the model was used to assess the effects of the process parameters.
40 citations
TL;DR: In this article, a slab analysis is developed to predict the rolling pressure distribution and rolling force in the wire flat rolling process, where the variations of width of contact area between the rolls and wire during rolling are considered.
32 citations
TL;DR: In this paper, the effects of various process parameters such as initial temperature, soaking time, rolling speed and cooling conditions are investigated and the optimum rolling program is determined based on the achieved results.
Abstract: In this study, hot rolling behavior of a low alloy steel in the dual-phase region is studied. The effects of various process parameters such as initial temperature, soaking time, rolling speed and the cooling conditions are investigated. Then, mechanical testing and microstructural studies are performed and the effects of process parameters are studied and finally the optimum rolling program is determined based on the achieved results. The results show that rolling speed significantly alters the final microstructures and mechanical properties. Higher rolling speed results higher volume fraction of ferrite phase. In addition, the optimum dual-phase microstructure for this steel can be obtained with; an initial rolling temperature of 900 °C, after 30 min soaking time, a strain rate of 3.8 s-1 and cooled at the rate of 250 °C /s.
23 citations
TL;DR: In this article, the combined Finite and Slab Element Method (FSEM) was used to investigate the creation of macroscopic shear bands, due to material flow tracks in the cross section of a wire after flat rolling.
21 citations
TL;DR: In this paper, a computer simulation on the basis of the Finite Element Method and Monte Carlo Model is developed to simulate the microstructure of the non-uniformly deformed copper workpiece after annealing.
Abstract: A computer simulation on the basis of the Finite Element Method and Monte Carlo Model is developed to simulate the microstructure of the non-uniformly deformed copper workpiece after annealing. Using the computer simulation, the effects of annealing time and temperature on the microstructure inhomogeneity of the workpiece are simulated and investigated quantitatively, by defining an Inhomogeneity Factor, to design an annealing program for reducing the microstructure inhomogeneity. The results show that with increasing the parameters of annealing time and temperature, the inhomogeneity is decreased when one of the parameters is constant. Also, at high annealing temperature, the annealing time changes the inhomogeneity slowly compared with which occurs at low annealing temperature. The simulation results agree well with the experimental values.
6 citations
TL;DR: In this paper, the authors presented an assessment of the ability of combined finite and slab element method (FSEM) for analyzing the wire flat rolling process, where the effective strain field of flat rolled wire is predicted for different reductions in height and frictional conditions.
Abstract: Purpose – The purpose of this paper is to present an assessment of the ability of combined finite and slab element method (FSEM) for analyzing the wire flat rolling processDesign/methodology/approach – Using the FSEM, the effective strain field of flat rolled wire is predicted for different reductions in height and frictional conditions The validity of the method is assessed by performing the Vickers microhardness measurements on the flattened wire cross section Also, the creation of macroscopic shear bands in cross section of the flat rolled wire is investigated and confirmed by microhardness and metallographic examinations Moreover, the lateral spread and width of contact area are predicted by the FSEM for different reductions in height and frictional conditionsFindings – The FSEM and microhardness results show the minimum and the maximum effective strains at the round edge and center of the flattened wire, respectively Also, the results show the bands of maximum effective strain at cross section
3 citations
TL;DR: In this paper, two methods have been used to assess the simulated material microstructures in order to determine the mean grain size and the size of the largest grain in the presence of second phase particles.
Abstract: With the development of computing systems for data processing, the image processing and image analyzing methods have been developed on the basis of pixel assessment These methods can analyze and detect the images by assigning a value for each pixel and using the matrices calculations In the present research, two methods have been used to assess the simulated material microstructures In the first method, the vertices of the microstructure are counted to determine accurately the mean grain size by the Euler's relationship, while in the second method, the image processing and image analyzing methods are utilized to assess the microstructure image To verify the accuracies of the methods their results were compared with the experimental results achieved using the standard Heyn intercept method It was found that in comparison with the common grain size measurement, the image processing method presents a higher accuracy compared with the Eulers's relationship More information about the microstructure properties such as the mean grain size and the size of the largest grain in the presence of second phase particles are evaluated
1 citations