Papers by Keyword: Thin Strip

Abstract: The casting of a 600 mm-wide 5182 aluminum alloy strip was attempted using a single-roll caster equipped with a scraper. This caster could cast a strip at speeds ranging from 10 to 40 m/min. These casting speeds are much higher than that of a conventional twin-roll caster. The scraper load suitable for scribing the wide strip was investigated. The strip could be scribed at full width by the scraper. The mechanical properties of the strip were investigated using a tension test and a cup test. The tensile stress was 320 MPa and the elongation was 30%. When deep drawing was conducted, no striped pattern, which occurs via segregation, appeared when both surfaces were facing outside.

Abstract: Cold rolled thin strip has received a great deal of attention through technological and theoretical progress in the rolling process, as well as from researchers who have focused on some essential parameters of strip such as its shape and profile. This paper describes the development of a 3-D finite element model of the shape of thin strip during cold rolling to simulate the cold rolling of WCS (work roll crossing and shifting) in asymmetric rolling. This finite element model considers the asymmetrical rolling parameters such as variations in the diameters of the rolls and the crossing angle as the work roll shifts on the strip during cold rolling. The shape and profile of the strip are discussed in the asymmetrical and symmetrical rolling conditions, while the total rolling force and distribution of stress are discussed in the case where the roll cross angle and axial shifting roll changes. The results can then be used to control the shape and profile of thin strip during rolling.

Abstract: To help optimize cold rolling operations, mixed lubrication models have been developed and embedded in roll bite models. The resulting models combine micro-fluidics in a porous medium (the lubricant flow between the contacting rough surfaces), microplasticity (roughness flattening / scratching), macro-plasticity (strip reduction) and roll thermo-elasticity. They are therefore really complex and need a lot of physical data. Based on previous developments, a new, simpler version of our lubrication model has been coupled with a new roll bite model recently presented: slab method for the strip elastic-plastic deformation (Prandtl-Reuss equations), a complete influence functions set for the roll deformation with circumferential displacements, and an efficient, adaptive relaxation technique when iterating between roll and strip models. The lubrication model is elaborated on Wilson and Sheu’s mixed lubrication model. The paper describes the implementation and compares its results with our previous, more complex version; a reasonable agreement is found. Several test cases of increasing difficulty show the robustness of the model and of its implementation. As a conclusion, a brief perspective is provided on how this new type of roll bite model could be used in industry.

Abstract: Strip profile control during rolling is required to assure the dimensional quality of rolled thin strip is acceptable for customers. Throughout rolling, the strip profile is controlled by using the advanced shape control rolling mill, such as the combination of work roll crossing and shifting during asymmetrical rolling, the one of the valuable methods to control the strip profile quality in rolling process. In this paper, the influences of cold rolling parameters such as the crossing angle and axial shifting value of work rolls on the strip profile are analysed. The strip shape control is discussed under both symmetrical and asymmetrical rolling conditions. The obtained results are appropriate to control the rolled thin strip profile in practice.

Abstract: Controlling cold strip profile is a difficult and significant problem has been found in industry during thin strip rolling. At present choosing the new type of strip rolling mill is the one of main methods to control the strip shape quality in cold rolling. The influences of rolling process parameters such as the work roll cross angle and work roll shifting on the strip shape and profile of thin strip are recognised throughout this study. The results show that the roll crossing and shifting is efficient way to control the strip shape. The increase of the work roll crossing angle would lead to improve the strip profile significantly by decreasing the exit strip crown and edge drop. The strip profile would be enhanced if the axial roll shifting was increased. Moreover, the total rolling force was analysed in detail by changing the roll cross angle and axial shifting roll.

Abstract: Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during the metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.

Abstract: Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.

Abstract: In this paper, finite element models of the strip shape during cold rolling of thin strip in both symmetrical and asymmetrical rolling cases have been successfully developed, and the effects of rolling parameters on strip shape such as the thickness distribution along the strip width have been obtained. The strip edge drop and shape are discussed under both symmetrical and asymmetrical rolling conditions. Simulation results show that the asymmetrical rolling can reduce the strip edge drop dramatically, which is useful in improving the strip shape and reducing the energy cost during cold rolling of thin strip. The developed finite element model has been verified with the experimental value. The obtained results are applicable to control the rolled thin strip shape in practice.

Abstract: The torsional deformation properties of a TiNi shape-memory alloy thin strip were investigated. The results are summarized as follows. (1) The martensitic transformation starts at the edge of the thin strip. (2) The fatigue life in pulsating torsion is longer than that in alternating torsion. (3) A simple rotary driving element can be developed by using SMA-thin strip torsion.

Abstract: Cracks in metal product significantly decrease quality and productivity of the rolled thin strip. In this paper the stress intensity factor (SIF) solution of edge crack defect of thin strip during cold rolling was investigated, and a globe analysis was applied to the problem of free edge of thin strip. The effective stress intensity factor range is important because it represents the major physical cause of crack growth. The present study provides insights of the mechanics of edge crack growth that has been frequently observed during thin strip rolling. The efficiency and reliability of the SIF analytical modelling has been demonstrated. The proposed method for predicting edge crack is useful for producing defect-free products in rolling, and provides insights of the mechanism of edge crack growth.