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.

Drawability of Ti-6Al-4V Sheet at Elevated Temperatures

2010 ◽  
Vol 654-656 ◽  
pp. 902-905 ◽  
Author(s):  
Nho Kwang Park ◽  
Jin Gee Park ◽  
Sang Hyun Seo ◽  
Jeoung Han Kim
Keyword(s):  
Residual Stresses ◽  
Slip System ◽  
Process Parameters ◽  
Elevated Temperatures ◽  
Plastic Anisotropy ◽  
Drawing Ratio ◽  
Limit Drawing Ratio ◽  
Blank Holding Force ◽  
Forming Temperature ◽  
Increasing Temperature

Titanium and its alloys are difficult-to-form materials due to limited slip system and plastic anisotropy. Titanium is also prone to change in color due to oxidation at high temperatures. It is thus advisable to conduct deep drawing of titanium and its alloys at temperatures below 600°C. In this study, the drawability of Ti-6Al-4V sheet is evaluated in respect to the process parameters such as forming temperature, forming speed, and blank holding force at elevated temperatures. It is shown that the limit drawing ratio (LDR) increases with increasing temperature, but varies insignificantly with forming speed. The development of residual stresses in the wall of drawn cups during deformation was evaluated.

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.

Forming Limit Diagram of the AMS 5599 Sheet Metal

2013 ◽  
Vol 58 (4) ◽  
pp. 1213-1217
Author(s):  
W. Fracz ◽  
F. Stachowicz ◽  
T. Trzepieciński ◽  
T. Pieją
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Plastic Anisotropy ◽  
Experimental Studies ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Strain Hardening Exponent ◽  
Uniaxial Tensile Test ◽  
Anisotropy Ratio

Abstract Formability of sheet metal is dependent on the mechanical properties. Some materials form better than others - moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another configuration. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. However experimental studies of formability of various materials have revealed basic differences in behaviour, such as the ”brass-type” and the ”steel-type”, exhibiting respectively, zero and positive dependence of forming limit on the strain ratio. In this study mechanical properties and the Forming Limit Diagram of the AMS 5599 sheet metal were determined using uniaxial tensile test and Marciniak’s flat bottomed punch test respectively. Different methods were used for the FLD calculation - results of these calculations were compared with experimental results

Influence of Process Parameters on Limiting Drawing Ratio of IS513 CR3 Grade Steel Sheet during Warm Deep Drawing

2014 ◽  
Vol 984-985 ◽  
pp. 62-66 ◽  
Author(s):  
T. Mayavan ◽  
Loganathan Karthikeyan
Keyword(s):  
Process Parameters ◽  
Deep Drawing ◽  
Steel Sheet ◽  
Experimental Results ◽  
Drawing Ratio ◽  
Influence Of Process Parameters ◽  
Steel Sheets ◽  
Limiting Drawing Ratio ◽  
Warm Deep Drawing ◽  
Grade Steel

In this work the significance of important parameters such as Blank temperature, Blank hold force on limiting drawing ratio (LDR) of IS513 CR3 steel sheets during warm deep drawing was determined. Influence of these parameters was analyzed at three different forming speeds. Experimental results proved that the blank temperature has a higher influence on LDR compared with other parameters especially at low forming speed.

Optimizing Process and Geometry Parameters in Bulging of Pipelines

2019 ◽  
Author(s):  
Shabbir Memon ◽  
Obaidur Rahman Mohammed ◽  
D. V. Suresh Koppisetty ◽  
Hamid M. Lankarani
Keyword(s):  
Process Parameters ◽  
Negative Impact ◽  
Plastic Anisotropy ◽  
Effective Strain ◽  
Additive Model ◽  
Optimum Process ◽  
Strain Hardening Exponent ◽  
Deformation Pattern ◽  
Relative Contribution ◽  
Bulge Height

Abstract The objective of this work is to determine the optimum process and geometry parameters to attain maximum bulge height without necking / splitting failure. The effect of process parameters on strain path and its correlation with bulge height is also carried out., ANOVA is used to study the relative contribution of geometry properties, process parameters and tube thickness. It is found that the strain hardening exponent has the highest impact on bulging followed by plastic anisotropy and thickness of tube has a relatively lesser contribution to limit strains of tube bulging. The effects of process parameters, at a specific bulge height, are studied on effective strain distribution and thinning distribution, the homogeneity of which is expressed in the terms of real Kurtosis value. It is concluded that optimum process parameters not only gives less thinning and greater bulge height, it also gives more uniform deformation pattern (thinning and effective strain). The validation of optimum process parameters obtained through Taguchi is carried out using additive model and it is found that the observed value is well in agreement with the predicted value. It is also found that friction has a negative impact on bulge height as well as thinning. This is because higher friction resists the flow of material and causes the material to thin more rapidly at the critical area where necking is taking place. It is also found that bulge height is maximum at higher pressure and higher bulge length and thinning is minimum at lower pressure and higher bulge length.

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.

Effect of Cu Content on the Formability and Portevin-Le Chatelier Effect of Al-Mg Alloys

2015 ◽  
Vol 817 ◽  
pp. 150-157
Author(s):  
Peng Cheng Ma ◽  
Di Zhang ◽  
Lin Zhong Zhuang ◽  
Ji Shan Zhang
Keyword(s):  
Plastic Strain ◽  
Stress Drop ◽  
Strain Ratio ◽  
Mg Alloys ◽  
Dynamic Strain ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Plastic Strain Ratio ◽  
Cu Content ◽  
Al Mg Alloys

Al-Mg alloys developed for auto body sheets with different Cu contents were fabricated in the laboratory scale. The effects of Cu content on the microstructures, formability and Portevin–Le Chatelier(PLC) effect of the alloys were investigated by polarizied optical microscopy and room temperature tensile testing. It has been found that with increasing Cu content, there was little change of the strain hardening exponent, but the plastic strain ratio and limiting drawing ratio increased firstly and then decreased. A quantitative statistical analysis of the characteristics of the PLC effect was made, including the stress drop and the reloading time, which follow a common linear relationship with plastic strain, and the increase rate of stress drop and reloading time was bigger with more Cu content. A detailed discussion of the corresponding mechanism of Cu and Cu-containing precipitates on the dynamic strain aging(DSA) was made.

Enhanced Formability of AZ31 Magnesium Alloy Sheet Processed by Equal Channel Angular Rolling and Annealing Treatment

2007 ◽  
Vol 26-28 ◽  
pp. 91-94
Author(s):  
Zhen Hua Chen ◽  
Yong Qi Cheng ◽  
Wei Jun Xia ◽  
Hong Ge Yan ◽  
Ding Chen
Keyword(s):  
Magnesium Alloy ◽  
Rolling Direction ◽  
Annealing Treatment ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Magnesium Alloy Sheet ◽  
Optical Microstructure ◽  
Az31 Magnesium Alloy Sheet

In order to improve the formability of AZ31 magnesium alloy sheet at room temperature, a new process, so-called equal channel angular rolling (ECAR) and followed by annealing treatment was applied to process the sheet. The optical microstructure of the as-received sheet was similar with that of the ECARed one after annealing treatment, the Erichsen value and limiting drawing ratio of the ECARed sheet was about 6.26mm and 1.6, respectively, which was much larger than that of 4.18mm and 1.2 for the as-received sheet. These can be attributed to the low yield ratio and high strain hardening exponent due to the modified texture induced by the shear deformation during ECAR process, which is favor of the activations of basal slipping and twinning at ambient temperature, especially deforming at the rolling direction.

scholarly journals Multi Draw Radius Die Design for Increases in Limiting Drawing Ratio

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 870 ◽  
Author(s):  
Wiriyakorn Phanitwong ◽  
Sutasn Thipprakmas
Keyword(s):  
Deep Drawing ◽  
Material Flow ◽  
Rolling Direction ◽  
Die Design ◽  
Drawing Ratio ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Limiting Drawing Ratio ◽  
Proper Design ◽  
Main Barrier

As a major sheet metal process for fabricating cup or box shapes, the deep drawing process is commonly applied in various industrial fields, such as those involving the manufacture of household utensils, medical equipment, electronics, and automobile parts. The limiting drawing ratio (LDR) is the main barrier to increasing the formability and production rate as well as to decrease production cost and time. In the present research, the multi draw radius (MDR) die was proposed to increase LDR. The finite element method (FEM) was used as a tool to illustrate the principle of MDR based on material flow. The results revealed that MDR die could reduce the non-axisymmetric material flow on flange and the asymmetry of the flange during the deep drawing process. Based on this material flow characteristic, the cup wall stretching and fracture could be delayed. Furthermore, the cup wall thicknesses of the deep drawn parts obtained by MDR die application were more uniform in each direction along the plane, at 45°, and at 90° to the rolling direction than those obtained by conventional die application. In the present research, a proper design for the MDR was suggested to achieve functionality of the MDR die as related to each direction along the plane, at 45°, and at 90° to the rolling direction. The larger draw radius positioned for at 45° to the rolling direction and the smaller draw radius positioned for along the plane and at 90° to the rolling direction were recommended. Therefore, by using proper MDR die application, the drawing ratio could be increased to be 2.75, an increase in LDR of approximately 22.22%.

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