135° clock rolling, which denotes that the rolling direction clockwise rotates 135° after per pass, was utilized to develop a desired cold-rolled texture distribution through the thickness of Ta plate. Meanwhile, the influence of starting... more
135° clock rolling, which denotes that the rolling direction clockwise rotates 135° after per pass, was utilized to develop a desired cold-rolled texture distribution through the thickness of Ta plate. Meanwhile, the influence of starting texture and microstructure was also investigated in detail. Texture from surface to center of the initial androlledTaplateswascharacterizedbyX-raydiffraction(XRD).Inordertoexplorethecorrelationbetweenini- tial microstructure and the evolution of rolling texture, through-thickness microstructure of the initial Ta plate was observed by optical microscope (OM). Results showed that 135° clock rolling was effective to mitigate the through-thickness texture gradients often existing in cold-rolled tantalum plate. It was found, furthermore, that texture and microstructure prior to rolling play a particular role in the formation of rolling texture
In the shape rolling process, the reduction of the number of passes is a challenging topic for the steel industry. This can be achieved by enhancing the design approach or by developing new rolling passes that allow the production of high... more
In the shape rolling process, the reduction of the number of passes is a challenging topic for the steel industry. This can be achieved by enhancing the design approach or by developing new rolling passes that allow the production of high cross-section reductions such as with the slit roll pass.
However, in order to design a robust roll pass, the lateral spread of the workpiece must be predicted correctly to prevent incomplete, or even worse, excessive roll groove fulfilling (which may cause roll damage).
In the present investigation, the possibility of using a finite element model to predict the lateral spread in a slit roll pass is investigated. The results of the finite element model are then used to adapt and calibrate two analytical models that were developed originally for strip rolling and shape rolling with concave grooves.
This paper intends to describe nonlinear effects occurring in rolling mills dynamics. That is necessarily for vibrations damping and reliable diagnostics of rolling mills equipment under non-stationary working conditions. Three types of... more
This paper intends to describe nonlinear effects occurring in rolling mills dynamics. That is necessarily for vibrations damping and reliable diagnostics of rolling mills equipment under non-stationary working conditions. Three types of nonlinear effects are investigated taking place in drivelines and stands of different design, namely, transient torsional vibrations in hot rolling mills, chatter vibrations in tandem cold rolling mills and parametrical vibrations in high-speed wire and rod rolling mills. The procedure is proposed for natural frequencies identification when short transient torque signals restrict application of the Fourier transform. Some considerations given on using nonlinear effects for wear diagnostics and vibrations control based on natural frequencies and modes analysis of multi-body systems.
The campaign increase of the rolls in mills reduces remarkably reduce the production costs The premature wear out of the rolls generates a reduction of the campaign leading to replacement and reconditioning. Therefore, it is extremely... more
The campaign increase of the rolls in mills reduces remarkably reduce the production costs The premature wear out of the rolls generates a reduction of the campaign leading to replacement and reconditioning. Therefore, it is extremely important to increase the campaign. This roll change need can be reduced enhancing mechanical and tribological properties on the surface by the deposition of chromium thin layers. This study evaluated the campaign of tool steel rolling mill rolls with chrome plating comparing to the results of uncoated cylinders.
The aim of the present research work is to study the influence of hard chrome covered skin pass cold rolling rolls using 2D/3D surface topography, i.e. roughness characterization. The common stochastic structure Shot Blast Texturing (SBT)... more
The aim of the present research work is to study the influence of hard chrome covered skin pass cold rolling rolls using 2D/3D surface topography, i.e. roughness characterization. The common stochastic structure Shot Blast Texturing (SBT) does not meet all requirements related to the production line regards to the finished product. The Hard Chrome layer, applied on these SBT rolls, can improve the sheet surface quality and is of fundamental interest mainly for those steel mills that do not have another alternative to new surface structures such as those that may be provided by the EDT, LT, EBT, etc. methods. The function of the generated surfaces, obtained by these different methods is going to influence the tribological properties during the subsequent forming processes. On the other hand, they can increase the product final cost or require large investments to obtain such surfaces. The results here presented are in accordance with other recently published research work, showing that there is a relationship between these parameters, and that further detailed studies are needed.
Usiminas as a company that has the expertise in manufacturing flat steel products in aim to hold and increase the leadership in the production and market of these products has invested huge amount of money in modernization of the hot... more
Usiminas as a company that has the expertise in manufacturing flat steel products in aim to hold and increase the leadership in the production and market of these products has invested huge amount of money in modernization of the hot rolled products manufacturing. The Hot Mill installed in 2012 at Cubatão Plant is one of the most modern in the world. Aggregating added value on the products profitilium the New Continuos Pickling completes the line of products offering increasing the range in dimensions and qualities. The Mix of hot rolled products now attends to thinner gauges as wider widths, beyond steel grades not offered before. This work aims to demonstrate the main steps of this project and the benefits and results achieved with the installation of new production line, this being the state of the art production of pickled, endowed with a high technological level that ensures obtaining products with high added value, meeting the most stringent quality standards.
Grains with γ-fiber texture (〈111〉 direction // normal direction (ND)) and θ-fiber texture (〈100〉 direction // ND) show different subdivision behaviors during unidirectional rolling, which leads to orientation-dependent stored energy.... more
Grains with γ-fiber texture (〈111〉 direction // normal direction (ND)) and θ-fiber texture (〈100〉 direction // ND) show different subdivision behaviors during unidirectional rolling, which leads to orientation-dependent stored energy. This orientation dependence in tantalum can be largely alleviated by a novel approach named 135° clock rolling, which is attributed to two reasons. One is that the clock rolling can weaken the micro-shear bands and destroy the parallel dislocation boundaries in γ-fiber grains, thus reducing their stored energies; and the other is that the clock rolling changes the stability of θ-fiber orientations and introduces plenty of " veins " into θ-fiber grains, thereby increasing corresponding stored energies. Therefore, 135° clock rolling narrows the stored energy difference between these two types of grains, which is beneficial for homogenizing the annealing microstructure of tantalum.
Tensile tests are commonly used to provide information on the tensile properties of materials. However, limited tests have been done on the orientation angles of material for the same properties. Thus, the present paper discusses the... more
Tensile tests are commonly used to provide information on the tensile properties of materials. However, limited tests have been done on the orientation angles of material for the same properties. Thus, the present paper discusses the effect of three different angles to the tensile properties of aluminium alloy AA5083 dog-bone specimens based on the original rolling direction. For this purpose, the angles chosen and tested were 0°, 45° and 90°. It is found that, as the orientation angle increases, the ultimate tensile strength also increases. In contrast, the Young’s Modulus decreases as the angle increases. It is also observed that the material is much more ductile when the work hardening increases. Thus, the rolling directions give a significant effect on the tensile properties of AA5083 specimens tested
Tensile tests are commonly used to provide information on the tensile properties of materials. However, limited tests have been done on the orientation angles of material for the same properties. Thus, the present paper discusses the... more
Tensile tests are commonly used to provide information on the tensile properties of materials. However, limited tests have been done on the orientation angles of material for the same properties. Thus, the present paper discusses the effect of three different angles to the tensile properties of aluminium alloy AA5083 dog-bone specimens based on the original rolling direction. For this purpose, the angles chosen and tested were 0°, 45° and 90°. It is found that, as the orientation angle increases, the ultimate tensile strength also increases. In contrast, the Young’s Modulus decreases as the angle increases. It is also observed that the material is much more ductile when the work hardening increases. Thus, the rolling directions give a significant effect on the tensile properties of AA5083 specimens tested.
Tensile tests are commonly used to provide information on the tensile properties of materials. However, limited tests have been done on the orientation angles of material for the same properties. Thus, the present paper discusses the... more
Tensile tests are commonly used to provide information on the tensile properties of materials. However, limited tests have been done on the orientation angles of material for the same properties. Thus, the present paper discusses the effect of three different angles to the tensile properties of aluminium alloy AA5083 dog-bone specimens based on the original rolling direction. For this purpose, the angles chosen and tested were 0°, 45° and 90°. It is found that, as the orientation angle increases, the ultimate tensile strength also increases. In contrast, the Young’s Modulus decreases as the angle increases. It is also observed that the material is much more ductile when the work hardening increases. Thus, the rolling directions give a significant effect on the tensile properties of AA5083 specimens tested
In this article, the influences of ultrasonic vibrations and post-annealing on the formability of multilayered Al5052/MgAZ31B composite were evaluated experimentally. Accordingly, a multilayered Al/Mg composite was produced and then... more
In this article, the influences of ultrasonic vibrations and post-annealing on the formability of multilayered Al5052/MgAZ31B composite were evaluated experimentally. Accordingly, a multilayered Al/Mg composite was produced and then annealed to explore the role of post-annealing on the microstructure and mechanical properties. Additionally, the effect of ultrasonic vibrations on the formability of the annealed Al5052/MgAZ31B composite was examined using the biaxial stretch-forming test. It is concluded that the cold rolling process can significantly enhance tensile strength and microhardness due to increased dislocations' density and applied strain. Moreover, the formability analysis revealed the potential role of post-annealing and high-frequency vibrations in improving the forming limits. Ultrasonic vibrations can also reduce the amount of brittle intermetallic compounds, facilitating dislocation's movement.
