Preform Design of Powder Metallurgy Turbine Disks Using Equi-Potential Line Method

2006 ◽  
Vol 128 (3) ◽  
pp. 677-682 ◽  
Author(s):  
Yuhong Liu ◽  
Fuguo Li ◽  
Shuxin Wang ◽  
S. Jack Hu
Keyword(s):  
Electrostatic Field ◽  
Hot Forging ◽  
Similarity Criteria ◽  
Preform Design ◽  
Forming Process ◽  
Energy Principle ◽  
Practical Applications ◽  
Material Forming ◽  
Billet Shape ◽  
Preform Shape

In a material hot forging process, rational preform design not only ensures that metal flows properly in die cavity and that final products have excellent quality, but also reduces tooling cost. In the present work, it is proved in theory that the differential equation of electric potential (∇2ϕ=0) in the electrostatic field is similar to the differential equations of velocity potential function (∇2φ=0) and velocity stream function (∇2ψ=0) in velocity field during the material forming process, with all three represented in the form of the Laplace equation. Moreover, the material flow in the plastic stage and the energy in electrostatic field all meet the least-energy principle. Therefore, according to the similarity criteria, an equi-potential line (EPL) method is proposed for the design of the preform shape in material hot forging. Different voltages are applied to the billet shape and the final product shape to generate a proper electrostatic field. One optimal equi-potential line is selected among the innumerable equi-potential lines as the basic shape of the preform shape and is processed into the preform shape following a three-step procedure. The preform design by the EPL method is compared with that by the traditional industrial method. The results show that the proposed method for preform design is feasible and reliable for practical applications.

Preform Design in Metal Forming

1989 ◽  
Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan
Keyword(s):  
Metal Forming ◽  
Simulation Technique ◽  
Production Costs ◽  
Process Conditions ◽  
Preform Design ◽  
Forward Simulation ◽  
Forming Process ◽  
Closed Die Forging ◽  
Preform Shape

Preform design in metal forming refers to the design of an initial shape of the workpiece that, when it has undergone an associated forming process, forms the required product shape with desired property successfully without formation of defects and without excessive waste of materials. A carefully selected preform can contribute significantly to the reduction of the production costs. Preform design problems are encountered in various metal-forming processes, such as closed-die forging, shell nosing, rolling, and sheet-metal forming. Design of an optimal preform shape requires simultaneous determination of optimal process conditions. However, we are here concerned with the determination of the best preform shape under a given set of process conditions. In this chapter, a new method of “backward tracing” is introduced as an alternative approach to the solution of preform design, and the applications of this method to some specific processes are discussed. Similarly to the forward simulation technique, the backward tracing method uses the finite-element method. The forward simulation technique has been discussed in the previous chapters. Backward tracing refers to the prediction of the part configuration at any stage in a deformation process, when the final part geometry and process conditions are given. The concept is illustrated in Fig. 15.1. At time t = t0, the geometrical configuration x0 of a deforming body is represented by a point Q. The point Q is arrived at from the point P, whose configuration is given as x0–1 at t = t0–1, through the displacement field during a time-step Δt, namely, x0 = x0–1 + u0–1 Δt, where u0–1 is the velocity field at t = t0–1. Therefore, the problem is to determine u0–1, based on the information (x0) at point Q. The solution scheme is as follows: taking a loading solution u0 (forward) at Q, a first estimate of P can be made according to P(1) = x0 – u0 Δt.

Estimation of Residual Stress in Cold Rolled Iron-Disks Using Magnetic and Ultrasonic Methods and Neutron Diffraction Technique

1994 ◽  
Vol 376 ◽  
Author(s):  
V.L. Aksenov ◽  
A.M. Balagurov ◽  
G.D Bokuchava ◽  
J. Schreiber ◽  
Yu.V. Taran Frank
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Sheet Metal ◽  
Diffraction Method ◽  
Calibration Procedure ◽  
Rolled Sheet ◽  
Forming Process ◽  
Practical Applications ◽  
Ultrasonic Methods ◽  
Cold Rolled

ABSTRACTVariation of internal stress states in cold rolled sheet metal can essentially influence the result of forming processes. Therefore it is important to control the forming process by a practicable in line testing method. For this purpose magnetic and ultrasonic nondestructive methods are available. However, it is necessary to calibrate these techniques. This paper describes a first step of such a calibration procedure making use of the neutron diffraction method. On the basis of the diffraction results an assessment of the magnetic and ultrasonic methods for the estimation of residual stress in the cold rolled iron-disks was made. Reasonable measuring concepts for practical applications to forming processes with cold rolled sheet metal are discussed.

Optimization of the preform shape in the three-stage forming process of the shielded slot plate in fuel cell manufacturing

2013 ◽  
Author(s):  
Dong-Yol Yang ◽  
Chang-Whan Lee ◽  
Dong-Woo Kang ◽  
In-Gab Chang ◽  
Tae- Won Lee
Keyword(s):  
Fuel Cell ◽  
Forming Process ◽  
Cell Manufacturing ◽  
Preform Shape

Numerical and Experimental Investigation on the Hybrid Superplastic Forming of the Conical Mg Alloy Component

2018 ◽  
Vol 385 ◽  
pp. 391-396
Author(s):  
Mei Ling Guo ◽  
Ming Jen Tan ◽  
Xu Song ◽  
Beng Wah Chua
Keyword(s):  
Electron Backscatter Diffraction ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Test Results ◽  
Forming Process ◽  
Hyperbolic Sine ◽  
Coarse Grains ◽  
Hot Drawing ◽  
Material Forming ◽  
Backscatter Diffraction

Hybrid superplastic forming (SPF) is a novel sheet metal forming technique that combines hot drawing with gas forming process. Compared with the conventional SPF process, the thickness distribution of AZ31B part formed by this hybrid SPF method has been significantly improved. Additionally, the microstructure evolution of AZ31 was examined by electron backscatter diffraction (EBSD). Many subgrains with low misorientation angle were observed in the coarse grains during SPF. Based on the tensile test results, parameters of hyperbolic sine creep law model was determined at 400 oC. The hybrid SPF behavior of non-superplastic grade AZ31B was predicted by ABAQUS using this material forming model. The FEM results of thickness distribution, thinning characteristics and forming height were compared with the experimental results and have shown reasonable agreement with each other.

Finite Element Simulation of the Yoke Spline under Hot Forging Process

2020 ◽  
Vol 982 ◽  
pp. 106-111
Author(s):  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Hot Forging ◽  
Fem Simulation ◽  
Die Design ◽  
Forming Process ◽  
Element Simulation ◽  
Metal Forming Process ◽  
Automotive Part ◽  
Forging Die ◽  
Hot Forging Process

Nowadays, finite element method (FEM) has been widely used to forecast metal forming process, to analysis problems of workpiece, to decrease production cost, and to save time of die design. This work studied the use of FEM as a tool to design a hot forging die for producing an automotive part named Yoke Spline. The part was made from carbon steel grade S45CVL0. There are three processes to produce Yoke Spline, including the buster, rougher, and finisher processes. The objective of the study was to increase efficiency of production by 5%. To achieve this objective, it was necessary to design a new die in the buster process by using FEM to analyze the die size and shape. The new die must produce the workpieces without any defects. The defects regularly found in the forging workpieces are the dimension out of specification, the under filling, and the crack. The sizes of the buster upper die cover are the width and depth. The die width of 44.5, 46.5 and 49.5 millimeters and the die depth of 25, 28 and 31 millimeters were used in the hot forging simulation. From FEM simulation results, it was found that the die width of 46.5 millimeters and the die depth of 28 millimeters were the best to form workpieces without any defects. In summary, the simulation and experimental results were compatible.

A Data Mining Approach for Generation of Control Signatures

2002 ◽  
Vol 124 (4) ◽  
pp. 923-926 ◽  
Author(s):  
Andrew Kusiak
Keyword(s):  
Data Mining ◽  
Metal Forming ◽  
Rough Set Theory ◽  
Decision Rules ◽  
Forming Process ◽  
Data Mining Algorithms ◽  
Data Mining Approach ◽  
Metal Forming Process ◽  
Material Forming ◽  
Mining Algorithms

Data mining offers methodologies and tools for data analysis, discovery of new knowledge, and autonomous process control. This paper introduces basic data mining algorithms. An approach based on rough set theory is used to derive associations among control parameters and the product quality in the form of decision rules. The model presented in the paper produces control signatures leading to good quality products of a metal forming process. The computational results reported in the paper indicate that data mining opens a new avenue for decision-making in material forming industry.

Numerical and Experimental Studies on Extrusion of Fan-Shaped Shell of Magnesium Alloy

2012 ◽  
Vol 626 ◽  
pp. 381-385
Author(s):  
Bao Hong Zhang ◽  
Yao Jin Wu ◽  
Zhi Min Zhang
Keyword(s):  
Numerical Simulation ◽  
Magnesium Alloy ◽  
Experimental Studies ◽  
Extrusion Process ◽  
Base Thickness ◽  
Forming Process ◽  
Backward Extrusion ◽  
Minimal Base ◽  
Billet Shape

This paper presents a case study of optimizing the forming process for a fan-shaped shell component. Numerical simulation was used to study the backward extrusion process of a fan-shaped shell. The underfill defect produced at the opening of the extruded shell due to the billet shape was solved and the minimal base thickness required to avoid the presence of the underfill defect at the bottom corner of the component was defined through the numerical simulation. The extrusion drawing and forming process of the fan-shaped shell were designed on the basis of the results of the numerical simulation. Forming experiments had been performed on the fan-shaped shell at 380 °C and cracking was found on the outside wall in the center of the extruded shell. Choked groove on the inner wall of the die and reducing the lubrication had been used to avoid the presence of cracking. The fan-shaped shell of AZ31 magnesium alloy has been successfully formed by the three-stage forming process of hot upsetting, hot backward extrusion and cold sizing.

Numerical Simulation of the Auto Claw-Pole Thixoforming Process

2011 ◽  
Vol 66-68 ◽  
pp. 1605-1610
Author(s):  
Van Luu Dao ◽  
Sheng Dun Zhao ◽  
Wen Jie Lin
Keyword(s):  
Complex Geometry ◽  
Hot Forging ◽  
Strong Impact ◽  
Forming Process ◽  
Billet Temperature ◽  
Punch Speed ◽  
Initial Billet ◽  
Near Net Shape ◽  
Net Shape Forming ◽  
Die Temperature

Thixoforming is an effective near-net-shape forming process to produce components with complex geometry and in fewer forming steps. In this study, thixoforming was used to replace the conventional hot forging to form the auto claw-pole. The finite element code Forge2008Ó was used to simulate the auto claw-pole thixoforming process. The results show that initial billet temperature, punch speed, die temperature and friction have strong impact on the forming process. Finally, the reasonable process parameters for the auto claw-pole thixoforming were obtained: initial billet temperature 1430~1440°C, punch speed 100~200mm/s and die temperature 300~400°C.

scholarly journals MICRO-SCALE STUDY OF RESIDUAL STRESSES IN CR2O3 COATINGS SPRAYED BY APS

2020 ◽  
Vol 27 ◽  
pp. 42-47
Author(s):  
Franck Decroos ◽  
Cécile Langlade ◽  
Eric Bourillot ◽  
Geoffrey Darut ◽  
Manuel Francois
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Atmospheric Plasma ◽  
Forming Process ◽  
Characterization Methods ◽  
Residual Stress State ◽  
Microwave Microscopy ◽  
Early Failures ◽  
Material Forming

Whichever the application field, every material forming process generates residual stresses on the surface. While they are likely to enhance the aimed properties of the final mechanical part, these stresses may also drastically reduce them and result in early failures. Therefore, understanding the residual stress state remains a major challenge when coating complex parts, especially as most characterization methods at the microscopic scale involve specific sample preparation procedures which may affect the residual stresses field. This work investigates the residual stress state that exists in chromium oxide coatings deposited via Atmospheric Plasma Spray (APS), using two pioneering techniques featuring high spatial resolution: Scanning Microwave Microscopy and Raman Micro-Spectroscopy. The first technique combines the measurement of microwave electromagnetic capacities of a Vector Network Analyzer with the subnanometric resolution of an Atomic Force Microscope: it thus enables performing depth investigations at very accurately defined positions of the probe on the surface. The second technique relies on the principle of photons inelastic scattering and involves a laser beam aiming at the material sample: it allows a fine characterization of the microstructure as well as defects and stresses detection via molecular vibratory signatures. The investigation scale is limited here to a few cubic micrometers. Due to the highly localized scales of our investigations, which also depend on the device, the objective of our procedure required that the comparison should be made not on individual points but on definite mapped areas, every spot being analyzed and post-treated one after another, with optimum measuring parameters. Results have been correlated with XRD measurements to cross-check the average amount of stress observed over a wider area.

Sign in / Sign up

Export Citation Format

Share Document