Limiting Drawing Ratio Research Articles

Improvement of deep drawing formability of Mg-6Al-1Zn magnesium alloy sheets with high strength utilizing aging precipitation

The effects of aging precipitation on microstructure, deep drawing formability and tensile properties, were investigated for Mg-6Al-1Zn (AZ61) alloy sheets. The alloy aged at 175 °C for 96 h with high strength exhibited a significant improvement in deep drawability with an increased limiting drawing ratio (LDR) from 1.5 to 1.9, when slightly increasing deformation temperature from room temperature to 100 °C. This LDR (1.9) was even larger than that (1.75) of the unaged alloy drawn at 100 °C. The improved deep drawability can be attributed to the prevention of cracking at the edge of drawn cup, which is closely related to the restrictions of growth of tensile twins and basal slip due to Mg17Al12 precipitates, resulting in the delayed texture strengthening during deformation. The proposed idea of utilizing aging precipitation provides a new strategy for the development of Mg alloy sheets with superior deep drawing formability and high strength.

Prediction of limit drawing ratio in deep drawing process of Mg alloy AZ31 using Fuzzy Logic

The interest in magnesium alloys has progressively increased in several industrial fields in recent years, and AZ31 has become an object of the study of lightweight development. Due to its low density and high specific strength, magnesium alloys represent a promising alternative to aluminum alloys and high strength steels, especially for applications in the automobile industry, being used in structural components to reduce weight and, consequently, improve performance fuel efficiency. In recent decades, several tests were conducted to evaluate the formability of AZ31 and showed its high dependency on the temperature range. The main objective of the present study is to propose a fuzzy model to predict the limit drawing ratio (LDR) of an AZ31 sheet by varying its thickness, temperature, and speed in wide ranges. In order to validate the proposed model, comparisons were made with 6 studies performed by other authors -an amount of 46 experimental tests-, showing a very good agreement between experimental results and fuzzy results. The model predicts the limit drawing ratio with an accuracy of 92.1%.

Determination of Limit Drawing Ratio of SS 304 Steel using Sheet Hydroforming Process with Female Die

Sheet hydroforming with female die process (SHF-D) is easily applicable without pressure and blank holder force control compared to the sheet hydroforming with punch process. Shallow parts can be produced easily with using SHF-D process which is used a lower cost production method in a wide variety of sectors. Limiting drawing ratio (LDR) is indication of formability of sheet metals is determined by using cylindrical punch die. In this study, for the first time, the LDRs of the SS 304 material with different thicknesses was determined experimentally by using the SHF-D instead of sheet hydroforming with punch unlike in the literature. Finite element analysis of SHF-D process has been realized. The results showed that relatively shallow sheet metal parts can be easily produced without the control of pressure and blank holder by means of SHF-D using obtained LDR. It is important to know the forming limit in the SHF-D, since it can be a more economical production method, especially in the manufacture of shallow and large parts used in the automotive and aerospace industries and obtain more quality products than that from classical deep drawing process. By knowing these ratios, die design and parts manufacturing can be realized less costly. The LDR was experimentally obtained as 1.82 with using the sheet hydroforming with female die for the SS 304. The FEA results are in good agreement with experimental results. So, it is useful to analyze the finite element method before designing the dies that will be used with the SHF-D.

Investigation of deep drawing of square cups using high-strength DP600 and DP800 sheets

This study investigated the deep drawing of square cups using high-strength du-al phase DP600 and DP800 sheets via both experimental and finite element meth-ods. The limiting drawing ratio (LDR) and wall thickness distribution were exam-ined. The initial thickness of the materials used in the study was equal to 1-mm. The experiments were carried out at room temperature using both Teflon film and graphite spray lubricants at the same time. In terms of LDR, both experimental and numerical results corresponded with each other. A ratio of 1.97 LDR was reached for the DP600 steel and 1.92 LDR for the DP800. Given that the thick-ness distribution between the experimental and numerical results, an accord of over 90% was noticed. For the DP600 steel, the lowest experimental thickness value was 0.864 mm and the lowest numerical value was 0.87 mm. For the DP800 steel, the lowest experimental thickness value was measured to be 0.89 mm while the lowest numerical value was found to be 0.88 mm. In the conclusion, the pre-sent paper proves that the experimental results in the deep drawing of square cups can be achieved with very satisfying results by using numerical methods.

Investigation of consecutive two-stage hydrodynamic deep drawing of aluminum cylindrical cups

In the deep drawing process, achieving a higher drawing ratio has always been considered by researchers. In this study, a new concept of hydrodynamic deep drawing with two consecutive stages without additional operations such as annealing is proposed to increase the limit drawing ratio of the cups. The effective parameters were investigated numerically and experimentally in the forming of Al1200 cylindrical cups. At first, the desired value of punch diameter ratio was determined based on finite element simulation results and was utilized to increase the cup formability. Next, the effects of pressure paths on the cup thickness, separation, and rupture were studied in each forming stage. The cup formability was investigated based on a new proposed framework to obtain the maximum possible limiting drawing ratio, and the desired conditions were determined. Finally, a cup was formed with a high drawing ratio of 3.4 which was a good achievement in comparison with the literature.

Comparative study of formability characteristics in deep drawing of DP 590 steel using analytical models

ABSTRACT The aim of the present work is to perfectly utilise the resources with minimal wastage of material by the implementation of theoretical models for prediction of different responses of deep drawing viz., limiting drawing ratio (LDR), and maximum drawing load (MDL). Initially, some trial and error experimental and finite element (FE) simulations are performed to find the coefficient of friction (COF) values under lubricated (L) and non-lubricated (NL) conditions which is difficult to find from experiments. The various processing conditions like temperature, blank holding pressure (BHP), blank diameter and lubrication are used as input. The coupled effect of temperature and lubrication helped in increasing the formability of the material and also reduced the maximum load required to draw the cup. The experimental limiting drawing ratio (LDR) was observed to be 1.933 under 400°C lubricated condition which is 3.53% more than other processing conditions. Further, several models namely: Leu, Whiteley, Hosford, Atkinson, Siebel, Siebel-Beissiwagner, Lange and Groover have been applied for the prediction of LDR and MDL among which Leu’s and Siebel’s analytical relation has displayed the least error of 2.452% and 7.977% respectively.

Effect of Interface on the Deep Drawability of Ti/Al Multilayered Composites

Ti/Al multilayered composites (LMCs) with different layers were prepared by hot-pressing and hot-rolling. The effects of interface on the deep drawability of LMCs were explored. The results indicate that LMCs with more layers have a higher limit-drawing ratio (LDR) and exhibit an excellent deep drawability. The texture strength of the Ti layer gradually weakens with the increase of layers, which leads to the smaller yield ratio (σs/σb), the plastic strain ratio (r), and the larger strain hardening index (n), thus the deep drawability of LMCs with more layers is enhanced effectively. The Ti/Al interfaces in three, five, and seven layers of LMCs exhibit straight, small wave-like interlocking, and dense serrated structures at the corner of the cylindrical parts, respectively. The component metals become thinner with the increase of layers, and the increased interfacial pressure promotes the formation of an increasingly firm overlapped interfacial structure. The load transfer via the interfaces makes the stress distribution between layers more uniform with the increase of layers, which helps to coordinate deformation. Deflection and tearing occur when the cracks propagate to the interface due to the complex stress state, which hinders and delays the crack penetration, thereby improving the deep drawability of LMCs with more layers.

Effect of temperature on the deep drawing forming performance of Ti/Al laminates: experimental investigation and finite element analysis

In this study, Ti/Al laminates are deep-drawn at elevated temperatures to investigate the effect of temperature on forming performance using numerical and experimental methods. Equipment for warm deep drawing process in a vacuum atmosphere is developed. The corresponding deep drawing finite element model (FE model) is established and validated by thickness distribution along the drawn cups’ radial direction. Based on the developed FE model, the thickness strain in different temperature is compared. Following this, the process window is established to determine the optimum temperature. The ratio curve of plastic deformation to sliding (D/S curve) during warm deep drawing is established to characterize the sustainable formability of Ti/Al laminates. The results indicated that the maximum limit drawing ratio in 200°C is consistent with the minimum thickness reduction. The safe forming area narrows with the increase of the drawing ratio. The D/S curve is short and presented fluctuations in the middle-temperature section of 150–250°C, as revealed well sustainable formability. Furthermore, the thickness of constituent layers for Ti/Al laminates is measured from micromorphology diagrams and compared. It is observed that the thickness strain of outside layers has more possibility to decline in bottom radius and is higher in flange radius than inner layers.

Roll Casting of Al-Mg-Si Alloy

The aluminum alloy Al–5%Mg–2%Si, the chemical content of which is close to that of the Magsimal-59 aluminum alloy commonly for die casting, was successfully cast into strips using a vertical high-speed twin-roll caster at a speed of 30 m/min. This means that Al–5%Mg–2%Si is suitable for the high-speed twin roll-casting. The as-cast Al–5%Mg–2%Si strip was then successfully cold-rolled to a thickness of 0.7 mm. Tension and cup tests were conducted on the cold-rolled annealed strips. The tensile stress was 205 MPa and the elongation was 20% for a thickness of 1 mm. The limiting drawing ratio was 2.0 at a 0.7 mm thickness. The present results demonstrates that Al–5%Mg–2%Si can be used for die casting and sheet forming. This means that use of this alloy for both sheet forming and die casting could eliminate the need for the separation of wrought aluminum alloys from cast aluminum prior to processing at recycling plants.

Investigation on sheet flexible-die drawing process

The characteristics of sheet flexible-die drawing process were discussed, compared with traditional sheet drawing process, sheet flexible-die drawing process can improve the limit drawing ratio, reduce the forming force, balance the thickness distribution and enhance the formability of the sheet. In this paper, the forming principle, research status and the forming characteristics of hydroforming, viscous pressure and solid granules sheet drawing process were demonstrated. In addition, the improvement of forming quality and efficiency under the aid of ultrasonic vibration, electricity, magnetic field and the mixture of them were also reviewed.

Витягування циліндричних деталей із не суцільного матеріалу

A new method for drawing cylindrical parts from a flat metal mesh netting with square openings has been proposed, developed and investigated. According to this method, drawing is carried out from a square workpiece, whose sides are parallel to the diagonals of the netting mesh. A new method of drawing parts with flange clamping of a sheet workpiece has been proposed and experimentally tested, which differs in that the workpiece is pre-perforated; perforation of the workpiece is performed only in the flange area, whose inner diameter is equal to the average diameter dc of the cylindrical part obtained; perforation of the workpiece is performed so that the sum  of all jumpers by the width ai on each concentric circle of the location of the perforation holes is equal to the circumference at the average diameter dc of the cylindrical part obtained, i.e. formula is valid. The use of the proposed method, in comparison with the known one, creates such conditions for drawing, under which the limiting drawing ratio becomes significantly lower (< 0,46), which makes it possible to conduct a deeper drawing of parts in one press run. The scientific novelty of this research is as follows. Usually, when manufacturing parts such as caps or box shapes, stamping is used in several runs to avoid the phenomenon of tearing- off of the bottoОдержаноm. However, the use of stamping in several runs leads to a complication of the process equipment and an increase in the cost of the product, which is justified only for cases of obtaining a high-quality product and provided that the integrity of the part is intact at a considerable depth. When trying to draw parts of considerable depth, objective difficulties arise associated with breaking-off of the bottom, which are due to exceeding by the tensile stresses in the critical section of the workpiece (between the bottom and lateral surfaces) of the ultimate tensile strength в of the latter. As part of the research described in this article, a way to overcome those difficulties has been proposed. It is based on the fact that when implementing the stamping process at lower values of the drawing ratio than the critical one, a metal mesh netting or perforated workpiece is used, and tearing-off of the bottom is therefore no longer observed. This method made it possible to obtain an integral shape of the part while using a significant depth of drawing due to the prior perforation of the workpiece, which significantly reduces the cost of the product. That means that the obtained scientific result in the form of a proposed kinetic description of the stamping process compared to the known one creates such drawing conditions, under which the unevenness of the height of the cylindrical portion of the part is significantly reduced, which in turn reduces by 35-40% the cost of stamping cylindrical parts from a flat metal mesh netting with square openings. This result is interesting from a theoretical point of view. As far as the practical point of view is concerned, a mechanism of transition of plastic bending of netting meshes into cold volumetric expanding of its constituent wires has been revealed, which makes it possible to determine the conditions for using the process of manufacturing parts from metal mesh netting or perforated workpieces. Consequently, an applied aspect of using the scientific result obtained is the possibility of improving the typical technological process of stamping, where the stamping force will be significantly reduced and hence the stress in the critical section, which will make it possible to reduce significantly the limiting drawing ratio and increase the depth of stamping. This constitutes prerequisites for the transfer of the obtained technological solutions of the process of drawing from a metal mesh netting or a perforated workpiece.

Grey-relational analysis for fluid assisted blank holding system in deep drawing process for Al alloy 1050 by using a numerical simulation

The objectives of this work is to develop a fluid assisted blank (FAB) holding system for deep drawing process and to study the effect of process parameters on thickness distribution, wrinkling and strain rate for Al 1050 through experiments. Deep drawing method have been investigated on Al alloy 1050 material, which is one of the lightest material for manufacturing parts. Limiting drawing ratio (LDR) has been improved compared to the conventional constant force mechanical blank holding system. Experiments were carried out by considering input parameters as punch force and blank holding force. The responses were measured using a modern photogrammetric measurement system named ARGUS. Multi-objective optimisation technique, grey relational analysis has been used to find out optimum process parameters for the present conditions. The experimental results reveal that the quality of the resultant cup has been enhanced in terms of thickness distribution, strain rate and surface finish. The effectiveness of the FAB process has also been verified through simulation tools such as LS-DYNA and FEA. These results were compared with the experimental results.

Investigation of deep drawing of lightweight bimetallic Al1050/SS304 sandwich composite cup

The effect of geometrical and process parameters on the deep drawing behavior of Aluminium (Al1050)/Steel (SS304) bimetallic axis-symmetric sandwich composite cup is analyzed by using numerical and experimental approaches. The parameters are selected focusing on the elimination of defects like thinning, thickening, tearing, and wrinkling. The explicit deep drawing analysis of the cylindrical cup is carried out by using the finite element software package. The obtained numerical results are utilized for the optimization and identification of significantly influencing parameters using Taguchi and ANOVA techniques and further validated by performing an experimental test. The effectiveness in the utilization of the Al1050/SS304 sandwich composite sheet for deep drawing of cups is proved by comparing it with the deep drawing of the SS304 sheet. The results suggest that the sandwich composite cup under investigation can be drawn successfully with the higher limiting drawing ratio and low thickness variation. The obtained maximum limiting drawing ratio (2.08) showed that the higher formability of the Al1050/SS304 sandwich composite sheet is possible by a sandwich of the SS304 sheet with an Al1050 sheet.

Forming limit of sheet metal in cylindrical deep drawing with a conical die

It is well-known that the use of a conical die in cylindrical deep drawing can enhance the formability compared with conventional process. The most commonly observed failure mode in the process is fracture near the punch corner or wrinkling in the flange region. In order to obtain the limiting drawing ratio (LDR), a cylindrical deep drawing including only the conical die and flat punch is discussed based on numerical simulation in the paper. A finite element model for the deep drawing with a conical die is developed, and the accuracy of the model is verified by experiments results. The investigation shows that in the cylindrical deep drawing with a conical die, the types of failure above, which can obtain for thinner sheet materials, are obviously related to the sheet thickness and the conical angle, and the optimum conical angle is also found.

Deep drawing behavior of IN625 alloy under the influence of different process parameters

The Ni-Cr based IN625 alloy has been extensively used in critical applications of aerospace and nuclear industries. Various components have been manufactured using sheet metal forming processes. In the present work, the deep drawability of material has been examined under the influence of different process parameters such as temperature, punch speed, lubrication, and blank holding pressure using the processing window. The deep drawability has been analyzed in three different zones, namely, safe, wrinkling, and fracture. The limit drawing ratio increased by 7.12 % on increasing the temperature from 300K to 673K. The thickness distribution across the deep-drawn component plays a crucial role in examining the quality and life of it. Therefore, in this context, a detailed analysis of different process parameters over the drawn cup’s thickness distribution has been done. The minimum thickness was obtained near the punch corner or the cup junction region of the deep drawn cup. The uniformity in the thickness distribution and drawing height also increased with the forming temperature and decrease in punch speed. Additionally, two different yield criteria, namely, Hill 1948 and Barlat 1989, have been analyzed and further used for the numerical analysis using the user material subroutines in Abaqus software. The results predicted using Barlat 1989 yield criterion more closely followed the experimental results as the average absolute error obtained is well within the 5% of the acceptable limit.

Dramatically enhanced stamping formability of Mg–3Al–1Zn alloy by weakening (0001) basal texture

The stamping formability of Mg–3Al–1Zn (AZ31) alloy was greatly enhanced through weakening (0001) basal texture by repeated unidirectional bending (RUB). After RUB and subsequent annealing, the max (0001) texture intensity of AZ31 Mg alloy was weakened from 10.7 to 6.3 and thus the Schmid factor for basal <a> slip system increased from 0.25 to 0.29. The RUB prepared AZ31 Mg alloy in annealed condition possessed better stamping formability than the original sheet at 373 K, e.g., larger Erichsen value (7.5 mm vs. 5.5 mm), higher and wider forming limit diagram (FLD), larger limiting drawing ratio (LDR) (1.7 vs. 1.4). The weakened (0001) basal texture resulted in a lower Lankford value (r-value) and a higher strain hardening exponent (n-value), thus enhancing the stamping formability of AZ31 Mg alloy. For the deep-drawing cup of the RUB fabricated AZ31 Mg alloy, a weakened (0001) texture and a high Schmid factor of basal <a> slip system were still remained in the internal area, the central area and the external area of the corner in comparison to the deep-drawing cup of the original AZ31 Mg alloy.

Roll Casting and Die Casting of Si-Added Al-Mg Alloy

Si ranging from 0.2 mass% to 2.0 mass% was added to Al-5%Mg alloy (5182) and strip was cast by a vertical type high-speed twin-roll caster at a speed of 80 m/min. The as-cast strip was cold-rolled down to 1 mm thickness and annealed. The mechanical properties were investigated using cup tests and tension tests. The limiting draw ratio (LDR) of the 5182 alloy was 2.0 and the LDR became smaller as the Si content increased. When the Si content was 2.0 mass%, the LDR was 1.8, which shows that Si-added 5182 can be used for sheet forming, if the Si content is less than 2.0 mass%. The tensile strength and elongation were almost constant when the Si content was less than 1 mass%, but decreased at 2.0 mass% Si. However, the elongation was greater than 20% at 2.0 mass% Si. For die casting, 2.0 mass% Si was determined as the appropriate content from the results of the tension tests. When the Si content is in the range from 1.0 mass% to 2.0 mass%, then the Si added Al-5%Mg has the ability to be used for both die casting and sheet forming.

Numerical optimization of warm hydromechanical deep drawing process parameters and its experimental verification

Abstract Warm Hydromechanical Deep Drawing (WHDD) is considered as an effective sheet metal forming process to overcome low formability problems of lightweight materials, such as aluminum and magnesium alloys, at room temperature. WHDD process combines the advantages of Hydromechanical Deep Drawing (HDD) and Warm Deep Drawing (WDD) processes. In this study, interactive and combined effects of Pressure (P) and Blank Holder Force (BHF) variation on the formability of the AA 5754 aluminum alloy sheets in the WHDD process were investigated experimentally and numerically. Different from available studies, the optimal fluid pressure (P) and blank holder force (BHF) profiles, which were determined numerically using adaptive FEA integrated with fuzzy logic control algorithm (aFEA-FLCA), were validated experimentally for the first time in literature. Consequently, limiting drawing ratios (LDR) of AA5754 material were recorded as 2.5, 2.625, and 3.125 for HDD, WDD, and WHDD processes, respectively. Thus, it was demonstrated that the formability of lightweight materials, such as AA5754, could be increased significantly using the WHDD process through the proposed optimization method. This method was also implemented into the WHDD of an industrial part with complex geometry, successfully forming sharp features with minimal thinning at reduced levels of force, pressure, and time. Consequently, it is reasonably to state that the method developed in this study can be adopted for the manufacturing of any other part using the WHDD process.

Multi Draw Radius Die Design for Increases in Limiting Drawing Ratio

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%.

Experimental Investigation of Blank Temperature and Blank Holding Pressure on the Punch Force and Limiting Drawing Ratio- A Review

Experimental Investigation of Blank Temperature and Blank Holding Pressure on the Punch Force and Limiting Drawing Ratio- A Review