Numerical Analysis and Parameter Optimization of Wear Characteristics of Titanium Alloy Cross Wedge Rolling Die

Cross wedge rolling has the advantages of high production efficiency, good product quality, high material utilization, environmental protection, and low cost. It is one of the best processing methods for producing shaft blanks. In this paper, a cross wedge rolling die of TC4 titanium alloy is studied. Based on the Archard wear model, a modified model suitable for cross wedge rolling die wear analysis is derived through finite element simulation. Then, the modified Archard wear model is imported into Deform-3D software for finite element analysis. Orthogonal experimental design is used to combine and analyze different process parameters. Finally, the beetle antennae search (BAS)-genetic algorithm (GA)-back propagation neural network (BPNN) algorithm is used to predict the degree of die wear and to optimize the simulation parameters, which can acquire the process parameters that have the least impact on die wear. The results show that the wear distributions of cross wedge rolling tools is uneven. In general, the most serious areas are basically concentrated in the wedge-shaped inclined plane and rectangular edge lines. The reason is that the tangential force and radial force received by the die are relatively large, which leads to increased wear. Moreover, the temperature change is most severe on the wedge-shaped ridge line. When in contact with the workpiece, the temperature rises sharply, which makes the local temperature rise, the mold hardness decrease, and the wear accelerate. Through response surface method (RSM) analysis, it is concluded that the deformation temperature is the main factor affecting wear depth, followed by the forming angle, and that there is an interaction between the two factors. Finally, the feasibility of the BAS-GA-BP algorithm for optimizing the wear behavior of dies is verified, which provides a new process parameter optimization method for the problem of die wear in the cross wedge rolling process.

Influence of Die Threading and Finishing Length in the Thread-Rolling Process Using Flat Dies: A Numerical Analysis

In this paper, a numerical analysis of the cold thread-rolling process using flat dies is presented as a function of the die geometry design. Five die geometries with different threading and finishing ratios were modelled to induce different screw deformation rates. An analytical method was proposed by the authors to design die geometries as a function of screw roll rotation. Screw geometry accuracy, induced stress, and die wear were selected to compare the tested geometries. The results showed that three screw rotations in the threading step were sufficient to guarantee good geometry accuracy. Moreover, the results highlighted that die wear is the most affected parameter among all the tested geometries. Finally, a new solution was proposed by the authors to obtain uniform wear and reduce the die length.

Optimization of Controllable Deformation Zone And Die Wear of Aluminum Crown Forgings For Shock Absorber Assembly

In this research, numerical analysis, response surface method (RSM) and experiments are used to investigate and verify the hot forging process for manufacturing aluminum crown forgings for shock absorber assembly. First, establish the computer aided design (CAD) model of the die and the billet, and simulate it from the finite element method (FEM). Second, a new preforming die was designed with a preformed dressing of controllable deformation zone (CDZ) by the CAD software. Third, numerical simulation was combined with RSM to optimize the processing parameters with the aim of minimizing the die wear while the integrity of forgings should be prioritized preserved. According to RSM, the billet size and preformed dressing of CDZ are important factors affecting the distance between die and workpiece (C). The optimal design factor of the preforming die: billet diameter (D), billet length (L) and flash design (F) are 40 mm, 205 mm and CDZ 1, respectively. Through the results of FEM, this study describes the distribution of microscopic grain flow lines are highly related to forming, stress, strain, and temperature as well as die design such as CDZ in preformed dressing. In order to accurately verify that the parameters analyzed by the RSM, both numerical analysis and physical experiments are carried out and optimal scheme exhibit reasonable consistency.

Determinación de los principales factores geométricos que influyen en el desgaste de las matrices de extrusión directa empleadas en la obtención en frío de perfiles de aleaciones de aluminio

Within most employed processes of forming for series productions are extrusion processes. Die wear is one of the major disadvantages of this technological process, so that efforts are made to predict and mitigate its effect on the tool. In this research it simulates by the Finite Element Method, using the DEFORMTM-2D, the process of cold direct extrusion of aluminum alloys 6061-O in a die material AISI D2. It was analyzed geometric parameters of the die such as: the insidence angle, the extrusion ratio, the input radii, the bearing entrance length on the tool, and the friction coefficient; to determine the influence on the tool wear. The Archard's wear model is used to determine the wear intensity in the critical area of tool. The Plackett-Burman fractional factorial design is used to determine the main factors influencing the die wear standing out: the extrusion ratio, friction coefficient and the incidence angle as the main factors that affect the die wear and to a less extent the bearing entrance length at the entrance of the tool of the material and inputs radii. The principal factors have been related from a linear response surface.