A Simplified Approach to Estimate Limiting Drawing Ratio and Maximum Drawing Load in Cup Drawing

2004 ◽  
Vol 126 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Daw-Kwei Leu ◽  
Jen-Yu Wu
Keyword(s):  
Friction Coefficient ◽  
Strain Hardening ◽  
Sheet Metal ◽  
Elementary Theory ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Normal Anisotropy ◽  
Limiting Drawing Ratio ◽  
Special Cases ◽  
Cup Drawing

A new and practically applicable equation, including the normal anisotropy R, the strain hardening exponent n, the friction coefficient μ, and the bending factor t0/rd for estimating the limiting drawing ratio LDR (a measure of drawability of sheet metal) in cup drawing of a cylindrical cup with a flat-nosed punch is derived by an elementary theory of plasticity in an explicit form. Whiteley’s and Leu’s equations for estimating the LDR, and Hill’s upper limit value of LDR, all are the special cases of the derived equation. The estimation of LDR agrees well with the experiment. It is shown that the most important parameters for LDR are the normal anisotropy R and friction coefficient μ, however the strain hardening exponent n has little effect on the LDR. On the other hand, a new and simple equation, incorporating the derived LDR and the critical drawing load Pc, for estimating the maximum drawing load Pd at a certain drawing ratio is derived. It also agrees well with the experiment. It is thereby possible to better understand and control the drawing limit of sheet metal in industry necessity.

The Maximum Drawing Ratio in Hydroforming Processes

1990 ◽  
Vol 112 (1) ◽  
pp. 47-56 ◽  
Author(s):  
S. Yossifon ◽  
J. Tirosh
Keyword(s):  
Failure Modes ◽  
Fluid Pressure ◽  
Radius Of Curvature ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Limit Drawing Ratio ◽  
Normal Anisotropy ◽  
Geometrical Properties ◽  
Buckling Instability ◽  
Hydroforming Process

The concept of Maximum Drawing Ratio (MDR), supplementary to the well-known Limit Drawing Ratio (LDR), is defined, examined, and illustrated by experiments. In essence the MDR is reached when the two basic failure modes, namely: rupture (due to tensile instability) and wrinkling (due to buckling instability) are delayed till they occur simultaneously. Thus the process is beneficially utilized for higher drawing ratio by postponing earlier interception of either one of the above failures alone. The ability to suppress (up to a certain extent) the appearance of these failure modes depends heavily on the fluid-pressure path which controls the hydroforming process. The effect of the material properties, like the strain hardening exponent, the normal anisotropy of the blank, etc., as well as the geometrical properties (i.e., the thickness of the blank, the radius of curvature at the lip, etc.) on the MDR, are considered here in some detail. The nature of the solutions by which MDR is reached is discussed.

scholarly journals Anisotropy Study of Inconel 718 alloy at Sub-Zero temperatures

2020 ◽  
Vol 184 ◽  
pp. 01004
Author(s):  
L Jayahari ◽  
K Nagachary ◽  
Chandra Ch Sharath ◽  
SM Hussaini
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Inconel 718 ◽  
Anisotropy Parameter ◽  
Tensile Tests ◽  
Strain Hardening Exponent ◽  
Inconel 718 Alloy ◽  
Normal Anisotropy ◽  
Axial Tensile ◽  
Forming Characteristics

There is an increase in demand for new alloys in aerospace, power generation and nuclear industries. Nickel Based super alloys are known for having distinctive properties which are best suitable for these industries. In this study Nickel based super alloy Inconel 718, is used. Over the many years of intense research and development, these alloys have seen considerable evolution in their properties and efficiency. Behaviour of materials and its forming characteristics can be precisely analysed by determining anisotropic behaviour and mechanical properties. In the present study, tried to analyse the mechanical properties of Inconel 718 like yield strength (Ys), ultimate tensile strength (UTS), strain hardening exponent (n) and strain hardening coefficient (k). Uni-axial tensile tests were conducted on specimens with various parameters such as orientations, temperature and Strain rate. Anisotropy of Inconel 718 alloy was measured based on measurable parameters. The normal anisotropy parameter (f) and planer anisotropy (Δr) were measured and observed that the anisotropy parametres are incresed with the decrease in temperature.

An Analytical Method for Prediction of Limiting Drawing Ratio For Redrawing Stages of Axisymmetric Deep Drawn Components

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Ali Fazli ◽  
Behrooz Arezoo
Keyword(s):  
Process Parameters ◽  
Analytical Method ◽  
Plastic Anisotropy ◽  
Numerical Results ◽  
Analytical Determination ◽  
Strain Hardening Exponent ◽  
Anisotropy Ratio ◽  
Drawing Ratio ◽  
Intermediate Annealing ◽  
Limiting Drawing Ratio

In this paper, an analytical method for estimating the limiting drawing ratio (LDR) of the redrawing stages in deep drawing process of axisymmetric components is represented. In this method, the effects of parameters of blankholder arc, die arc, and punch arc region are taken into account for the analytical determination of LDR. The presented method can predict the limiting drawing ratio for redrawing with/without intermediate annealing processes. The results are compared to numerical results and experimental results reported in the literature and also industrial results reported in handbooks. It is shown that the presented method is in good agreement with the experimental and numerical results. Using the presented method, the effect of some process parameters on the LDR is investigated. It is shown that process parameters such as, coefficient of friction, strain hardening exponent, normal plastic anisotropy ratio, ratio of die arc radius to blank thickness and ratio of blank thickness to diameter has significant effect on the LDR. The effect of intermediate annealing process is also examined.

On Multistage Deep Drawing of Axisymmetric Components

2003 ◽  
Vol 125 (2) ◽  
pp. 352-362 ◽  
Author(s):  
Prakash Sonis ◽  
N. Venkata Reddy ◽  
G. K. Lal
Keyword(s):  
Strain Hardening ◽  
Deep Drawing ◽  
Present Model ◽  
Process Analysis ◽  
Drawing Ratio ◽  
Analysis Model ◽  
Normal Anisotropy ◽  
Minimum Number ◽  
Number Of Passes ◽  
Good Agreement

A process analysis model to determine the limiting drawing ratio for the first draw as well as for redraws is presented considering the effects of normal anisotropy, co-efficient of friction, strain hardening and die arc radius. Predictions of the model presented are in good agreement with the available experimental results. The model can be used by the process planners to determine the minimum number of passes required to achieve the final component geometry. Using the present model, feasible operation sequences which have the minimum number of stages through which the desired cup specification can be achieved is presented for two different cup geometries.

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