Papers by Keyword: Slab Method

Abstract: Ring rolling (RR) is a widely used process for producing seamless rings, but its complex thermo-mechanical behavior often requires costly experiments or FEM simulations. This study presents a novel analytical method for predicting torque and energy in RR that explicitly accounts for the fishtail effect, a lateral deformation of the ring cross-section. The approach combines a slab-based mechanistic model with a regression linking fishtail deformation to the kinematic ratio between mandrel feed and ring rotation. Validation was performed via FEM simulations on an industrial AISI 1045 steel case, covering thirty conditions with varying feed rates and rotational speeds. Results show that conventional models ignoring fishtail can overestimate errors by over 60% for torque and 50% for energy, whereas the proposed method reduces errors below 15% in most cases. These findings highlight the importance of including fishtail effects, offering a fast, reliable, and efficient tool for early-stage RR process design and optimization.

Abstract: Today environmental aspects are of great importance in the sustainability of the planet, in this aspect anti-corrosive treatments facilitate the durability of metal structures. Among the most widely used anticorrosive metals is Zinc and its alloys. In the deep galvanizing process of large steel structures, tanks containing Zinc in a molten state at a temperature of 460 °C are necessary. Then, to protect elements that are too large or that need to be treated "in situ", metallization is used, which consists of projecting molten zinc wire on the metal surface that has previously been subjected to a process sandblasting (mechanical abrasion). The two main methods of metalizing are electric arc and flame. In the present work an industrial wiredrawing draft has been studied, determining the drawing force and the power required in each stage. For this purpose, linear strain hardening model vs non-linear strain hardening model that takes strain rate hardening into account has been proposed for its implementation in the analytical model of the process and finite element model (FEM) has been developed too. The use of Hall Petch equation has been allowed to get a prediction of the evolution of the grain size during the wiredrawing sequence.

Abstract: This study is to set a goal to create a model solving the temperature distribution and its evolution for the process of dieless drawing metal wire parts by using slab method and postulating that the wire end suffers a proportional deformation. The results from using a SUS304 stainless wire in 5 mm diameter dielessly drawn show that the highest temperature locates on the symmetry plane at the process beginning, so that the necking takes place there and an end will be formed securely. As a result, the method proposed by this study is feasible. In addition, for a given final shape of the metal wire end, there are many possibilities to get different temperature distribution and its evolution by setting different temperature boundary condition. The higher the boundary temperature set, the higher the temperature distribution, but the lower the drawing force needed.

Abstract: The friction caused power losses and bulging deformation are always inevitable. The rotating compression forming can reduce the compression force and bulging deformation in metal forming. Furthermore, the bounded double-layer metal material is able to have advantage in proper material cost saving and meeting the required strength for customer. Accordingly, this present study proposes the analysis based on Slab Method (SM) and Finite Element Method (FEM) under constant shear friction to predict the compression force and the rotating moment in the rotating compression forming. Moreover the bulging deformation profiles, the effective stress, the effective strain, the velocity field, the compression force, the rotating moment, and the twist angle can be obtained from FEM simulations. It is also shown that the predicted results have the same trend to verify the acceptance of analysis models.

Abstract: This study establishes an analysis model based on the slab method assuming constant shear friction. The rotating compression forming of the double-layers bounded clad ring is derived by considering von Mises’ yield criterion with the shear stress. Effects of the frictional factor, shear yield stress ratio, rotating angular speed of the ring, frictional factor ratio, clad ring height ratio etc on compression characteristics are investigated effectively. Moreover, the compression pressure, radial stress for each layer, radial stress of the whole layer, and compression force are also predicted effectively. Finally, the FEM simulation is carried out to compare with the slab method to realize the variations of both models.

Abstract: According to the structure of the crank arm, the conformal mapping method was adopted to transform the elliptical section map of it to the round. Then by the slab method an analytical model for final upsetting force of the crank arm was established, which is a derivation based on assumptions of axisymmetric plastic forming status. Finally, a simulation was implemented in case of the second crank of crankshaft 6G32. Accordance to it the accuracy of the analytical model was examined. Further more the causes of the data deviation from the model and the simulation were analyzed in this thesis.

Abstract: The scope of this work is to study a forging process at room temperature and at macroscopic level. The mechanism of deformation is influenced by the friction and the reduction ratio, but the influence of the geometry of the billet (aspect ratio) needs also to be taken into account. The objective will be to compare the results obtained during a simulation with the code based on Finite Element Method (DEFORM 2D/3D), with those obtained by analytical methods in order to validate the numerical model. Taking into account that deformation is not uniform and the free surface suffers a phenomenon known as barrel-shaped, that is not covered by analytical methods, the data obtained will compared with those obtained with the FEM code ABAQUS. The aim of this comparison between analytical and numerical methods using two commercial codes instead one, is a proposed way to validate a Finite Element simulation when experimental data are not available or do not exist yet.

Abstract: Based on analyzing the stress-strain characters of material in nosing deformation zone, and considering two influencing factors, i.e. material thickness variation and material work-hardening, according to ignoring and considering the influence of additional bending stress at the entrance of die, and the different forms of work-hardening of metal materials, a new set of mathematical models of deformation force calculated for tube nosing with conical die are set up by utilizing slab method that belongs to one of the theoretic methods solving the problems of metal plastic forming. Furthermore, the scope of the application of every mathematical model of deformation force calculated for tube nosing with conical die is classified from conical die semi-angle and work-hardening of metal material point of view in theory.

Abstract: In asymmetric roll bonding, two metal sheets with dissimilar properties are subject to a rolling step to create a bimetal strip. The paper reviews earlier work in this field which generally uses the upper-bound or finite element methods. The use of the slab method appears simpler than the former, but allows identifying critical aspects of process and model which were not addressed before. To obtain a complete set of equations, the bonding problem must be analysed not only from the cinematic viewpoint, but also from a mechanical one. After defining mechanical equilibrium, one additional cinematic equation is needed to solve the problem, which is obtained by minimising the plastic work in the zone where both sheets deform plastically but are not yet bonded. The new model has the advantage over earlier approaches in that it not only predicts the final thickness of both sheets but also permits to determine whether the bonding is possible under given process conditions. Keywords: Roll Bonding, Cladding, Modelling, Adhesion, Slab method.

Abstract: In this paper, based on the modified slab method theory, an analytical solution for ring rolling process is presented. The non-uniformity of the normal and shear stresses across the section of the deforming material are considered. The friction factor multiplied by the shear yield strength is used to present friction between the main roll and the ring. Complete expressions for the ring rolling pressure, force and torque are obtained and the position of neutral point is predicted. The influence of the process parameters such as friction factor, main roll rotational speed, feed speed, and others was investigated. Analytical results obtained from the present formulation were compared to previous experimental works and good agreement and improvements were observed.