Primeros resultados de la excavación del castillo medieval de Dos Hermanas (Montemayor, Córdoba)

First results of the excavation of the medieval castle of Dos Hermanas (Montemayor, Cordoba)In the south of the kingdom of Córdoba, there is the castle so-called Dos Hermanas, located in the municipality of the current town of Montemayor. It has been considered that the construction of the castle of this stately town was the result of the first moments of decline of the fortress of Dos Hermanas, located on the bank of the Carchena stream. Currently, a first excavation campaign has been carried out that brings us closer to the anthropic occupation of the site. At the same time, the archival research gives new information to the history of the site, exceeding the date of 1340, when Don Martín Alonso de Córdoba partially destroyed the Arab fortress of Dos Hermanas to build the castle of Montemayor. The first data extracted from the field work support the written sources, providing us with new data that allow us to make a more complete and novel interpretation. The survival of part of the facilities of the Dos Hermanas castle with an occupation from Roman times to the sixteenth century that shows the total non-depopulation of the place in the fourteenth century, as previously thought. A high degree of conservation of the structures found inside the wall enclosure appears a southern bay with stables with nine mangers. To the west, there is a vain and an angled staircase that allowed access from the parade ground until the round pass over the main door, which is also preserved. The objective of this proposal will be to present these first results of the archaeological intervention centered on the southern wall of the castle. These research works are accompanied by a consolidation project of the main structures, all financed by the Provincial Delegation of Cordoba and Montemayor Town Hall, whose continuity is developed in 2019 and 2020.

Fe-Simulation of Hot Continuous Rolling of 40Cr Alloy Steel Round Bar and Roll Pass Design

40Cr alloy steel is widely used in the mechanical manufacturing industry and the quality of its rolled round bar has a great consequence on the quality and useful time of the final mechanical parts. By analyzing the characteristics of thermal plasticity of 40Cr steel, the Hensel-Spittel flow stress model of 40Cr steel was established in this study. For the possible continuous rolling schedule of Φ80mm 40Cr steel from 200mm×200mm billet, the advanced technology of viscoplastic FEM by LARSTRAN/SHAPE was used to create 3-D thermo-mechanical coupled simulation models for 8-pass hot continuous rolling processes. From the rolling process simulation the stress, strain, temperature distribution and rolling force variation were obtained. The simulation results included the comparison of plastic deformation of round pass with curved side wall and round pass with straight-side wall as well as the cause of rolling defect (e.g. crack). Based on the numerical analysis the reliable roll pass sequence wa constructed, which was verified by actual tests.

Rolling Process of AZ31 Alloy Bar Using Three Roller Mill

Structure and pass system of Y-type mill which have three-roller is analyzed. A hot rolling method to produce magnesium alloy bars through flat triangle-arc triangle-round pass system is put forward. Using Deform-3D software, the rolling process of AZ31 alloy bar is simulated to determine the parameters of the rolling process and die. The experiment verifies that the hot rolling process is feasible. The organizational structure is analyzed with metallographic microscope, and the results show that dynamic recrystallization is occurred, the grain size is obviously refined, and the mechanical property of the material is improved in hot rolling process.

Study on Hot Rolling Process of Mg-Gd-Y-Nd-Zr Alloy Bar

A hot rolling method to produce Mg-Gd-Y-Nd-Zr alloy bars through oval-vertical elliptical-round pass system is put forward. The mechanical model of Mg-Gd-Y-Nd-Zr alloy has been established. Using Deform-3D software, the rolling process of Mg-Gd-Y-Nd-Zr alloy bar is simulated at rolling temperature 450°C, rolling speed 0.4m/s. And equivalent stress distribution and load variation has been obtained. It provides a theoretical basis for the hot rolling bars of magnesium alloy. The experiment verifies that the hot rolling process is feasible. The organizational structure is analyzed with metallographic microscope, and the results show that dynamic recrystallization is occurred, the grain size is obviously refined, and the mechanical property of the material is improved in hot rolling process.

3D FEM Modelling and Experimental Verification of the Rolls Wear during the Bar Rolling Process

Numerical modelling of the round bar rolling process, while considering the wear of the passes depending on their shape, was carried out within the present work. For the theoretical study of the rolling process, the Forge2008® was employed, which is finite element method-relying software that enables the thermomechanical simulation of rolling processes in a triaxial strain state. The wear model implemented in the Forge2008® permits no quantitative evaluation, but only comparative analysis of the wear of rolls. In order to use the results of simulation employing the simplified Archard model for the quantitative evaluation of roll wear, it is necessary to define the wear factor and hardness of the tool as a function of temperature. The paper present a methodology for the determination of the quantitative wear of rolls based on the results of computer simulations performed using the Forge2008® software for a selected round pass during rolling of round bars.

A Research on the Forward Slip Coefficient in Alloyed Bar Rolling by the Round-Oval-Round Pass Sequence

For predicting the forward slip coefficient and veocity of outgoing workpiece exactly during alloyed bar rolling by Round-Oval-Round pass sequence, the influence of the spred of the outgoing workpiece and its contact boundary condition was considered and the calculating formula for the effective height of outgoing workpiece and the mean roll radius was proposed individually. Moreover, the new parameters were substituted into the Shinokura and Takai Formula to modify it. Then a modified forward slip coefficient firmula was proposed. The validity of the theoretical model has been examined by the bar rolling experiment and the numerical simulation using three-dimensional rigid-plastic FEM. Compared with the Shinokura and Takai dormula, the predict accuracy of the modified formula was improved apparently. So, it can be applied in alloyed bar rolling to predict the the forward slip coefficient and veocity of outgoing workpiece exactly.