Stretch Forming of Ti-6Al-4V Hybrid Parts at Elevated Temperatures

2021 ◽  
Vol 883 ◽  
pp. 135-142
Author(s):  
Jan Hafenecker ◽  
Richard Rothfelder ◽  
Michael Schmidt ◽  
Marion Merklein
Keyword(s):  
Metal Forming ◽  
Material Flow ◽  
Elevated Temperatures ◽  
Sheet Material ◽  
Stretch Forming ◽  
Forming Process ◽  
Hybrid Parts ◽  
Cost Efficient ◽  
Punch Geometry ◽  
Hemispherical Punch

Hybrid components produced by two or more different process technologies grant the possibility to compensate the drawbacks of the used processes. The combination of additive manufacturing (AM) and forming offers geometrical freedom in extensions of geometrical simple parts in a cost-efficient way. Unlike the combination of bulk metal forming and AM, sheet metal forming and AM is less investigated. Especially for Ti-6Al-4V, which is widely used in AM but has a low formability at room temperature, research is still needed. In this study, the formability of hybrid parts made of Ti‑6Al‑V consisting of sheet material and additively manufactured elements (AME) is investigated for a hemispherical punch geometry. Thus, a designed tool for forming of hybrid parts at elevated temperatures is used. First investigations with a specially designed stretch forming tool demonstrate the distinct influence of the additively manufactured bodies on the stretch forming process of hybrid parts made of Ti‑6Al‑4V. Namely, the achievable drawing depth is reduced for hybrid parts as the functional elements are placed in the area of highest stresses, distorting material flow.

Hydrodynamic Lubrication in Hemispherical Punch Stretch Forming

1986 ◽  
Vol 53 (2) ◽  
pp. 440-449 ◽  
Author(s):  
Kuo-Kuang Chen ◽  
D. C. Sun
Keyword(s):  
Strain Hardening ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Model Problem ◽  
Hydrodynamic Lubrication ◽  
Sheet Material ◽  
Stretch Forming ◽  
Variable Friction ◽  
Hemispherical Punch

The existence and consequence of hydrodynamic lubrication in sheet metal forming is demonstrated using a model problem of hemispherical punch stretch forming. The problem is solved by incorporating a lubrication analysis into an incremental plasticity analysis. The sheet material is assumed to be elastic plastic with strain hardening, and the lubricant is assumed isoviscous. The study identifies two dimensionless parameters controlling the condition of lubrication. The resulting variable friction at the punch-sheet interface is found to affect significantly the distribution of strains in the sheet metal and its formability.

scholarly journals Material flow control in sheet-bulk metal forming processes using blasted tool surfaces

2018 ◽  
Vol 190 ◽  
pp. 13003 ◽  
Author(s):  
Marion Merklein ◽  
Maria Löffler ◽  
Daniel Gröbel ◽  
Johannes Henneberg
Keyword(s):  
Metal Forming ◽  
Material Flow ◽  
Simultaneous Occurrence ◽  
Tribological Behaviour ◽  
Forming Process ◽  
Functional Elements ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Main Challenge ◽  
Functional Components

Highly-integrated and closely-tolerated functional components can be produced by sheet-bulk metal forming which is the application of bulk forming operations on sheet metals. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as stress and strain states which reduce the geometrical accuracy of the functional elements. Thus, one main challenge within sheet-bulk metal forming is the identification of methods to control the material flow and thus to improve the product quality. One suitable approach is to control the material flow by local modifications of the tribological conditions. Within this study requirements regarding the needed adaption of the tribological conditions for a specific sheet-bulk metal forming process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved die filling of the functional elements. Based on these results abrasive blasting as a method to modify the tool surface and thus influencing the tribological behaviour was investigated. For the determination of the tribological mechanism of blasted tool surfaces, the influence of different blasting media as well as blasting pressures on the surface integrity and the friction were determined. The correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.

A Study on Warm Micro Backward Extrusion of SUS 304 Stainless Steel

2011 ◽  
Vol 486 ◽  
pp. 139-142
Author(s):  
Chao Cheng Chang ◽  
Dinh Hiep Nguyen ◽  
Hsin Sheng Hsiao
Keyword(s):  
Stainless Steel ◽  
Metal Forming ◽  
Material Flow ◽  
Elevated Temperatures ◽  
304 Stainless Steel ◽  
Electrical Heater ◽  
Backward Extrusion ◽  
Water Based ◽  
Inner Diameter ◽  
The One

A metal forming system comprising an electrical heater, capable of conducting processes at elevated temperatures, was developed to perform micro backward extrusion processes of SUS 304 stainless steel. Two punches with diameters of 1.6 mm and 1.8 mm were used to extrude the billets inside the die with an inner diameter of 2 mm. All processes were lubricated with water-based graphite and conducted under isothermal conditions at 400 °C. The results show that the developed extrusion system can be used to produce the stainless steel components with a micro cup-shaped profile. Moreover, the variation in the rim height of the cups produced by the 1.8 mm diameter punch is greater than the one by the 1.6 mm diameter punch. The results show that a decrease in the clearance between the punch and die could lead to an increase in the inhomogeneity of material flow in the micro backward extrusion processes.

Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
H. Hetzner ◽  
J. Koch ◽  
S. Tremmel ◽  
S. Wartzack ◽  
M. Merklein
Keyword(s):  
Contact Pressure ◽  
Metal Forming ◽  
Material Flow ◽  
System Analysis ◽  
Sheet Thickness ◽  
Fe Model ◽  
Forming Process ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Functional Features

This paper is focused on a combined deep drawing and extrusion process dedicated to the new process class of sheet bulk metal forming (SBMF). Exemplified by the forming of gearings, combined sheet and bulk forming operations are applied to sheet metal in order to form local functional features through an intended and controlled change of the sheet thickness. For investigations on the form filling and the identification of significant influencing factors on the material flow, a FE simulation model has been built. The FE model is validated by the results of manufacturing experiments using DC04 with a thickness of 2.0 mm as blank material. Due to the fact that the workpiece is in extensive contact to the tool surface and that the pressure reaches locally up to 2500 MPa, the tribological conditions are a determining factor of the process. Thus, their influence is discussed in detail in this paper. In the first instance, different frictional zones having a distinct effect on the resulting material flow are identified and their effect on improved form filling is demonstrated. Subsequently, a more comprehensive methodology is developed to define tribological zones of forming tools. For this, a system analysis of the digital mock-up of the forming process is performed. Besides friction, other relevant aspects of forming tool tribology like contact pressure, sliding velocity, and surface magnification are considered. The gathered information is employed to partition the tools into tribological zones. This is done by systematically intersecting and re-merging zones identified for each of the criterion. The so-called load-scanning test allows the investigation of the friction coefficient in dependence of the contact pressure and possible loading limits of tribological pairings. It provides an appropriate tribological model test to evaluate tribological measures like coatings, surface textures and lubricants with respect to their targeted application in particular zones. The obtained results can be employed in the layout of further forming processes to reach the desired process behavior. This can be, for example, an improved form filling, less abrasive wear and adhesive damage or lower forming forces, respectively tool load for an improved durability of the die.

Multi-Input Multi-Output (MIMO) Modeling and Control for Stamping

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Yongseob Lim ◽  
Ravinder Venugopal ◽  
A. Galip Ulsoy
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
Process Model ◽  
Complex Geometry ◽  
Flow Characteristics ◽  
Forming Process ◽  
Punch Force ◽  
Force System

The binder force in sheet metal forming controls the material flow into the die cavity. Maintaining precise material flow characteristics is crucial for producing a high-quality stamped part. Process control can be used to adjust the binder force based on tracking of a reference punch force trajectory to improve part quality and consistency. The purpose of this paper is to present a systematic approach to the design and implementation of a suitable multi-input multi-output (MIMO) process controller. An appropriate process model structure for the purpose of controller design for the sheet metal forming process is presented and the parameter estimation for this model is accomplished using system identification methods. This paper is based on original experiments performed with a new variable blank holder force (or variable binder force) system that includes 12 hydraulic actuators to control the binder force. Experimental results from a complex-geometry part show that the MIMO process controller designed through simulation is effective.

Effective Forming Processes of Hub Forging from Aluminum Alloy AlCu2SiMn

2013 ◽  
Vol 773-774 ◽  
pp. 115-118
Author(s):  
Andrzej Gontarz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Metal Forming ◽  
Material Flow ◽  
Theoretical Research ◽  
Material Consumption ◽  
Forming Process ◽  
Metal Forming Process ◽  
Large Material

This paper presents results of theoretical and experimental research works on metal forming process of a hub. A typical technology of forging on hammer of this part with flash was discussed. Two new processes of a hub forging were proposed, characterized by large material savings in comparison with typical technology. The first process is based on forming without flash of a forging with axial cavity. The second one is connected with forming of forging from pipe billet. The realization of these processes is possible at the application of a press with three movable working tools. Theoretical research works were done on the basis of simulations by means of finite element method. Simulations were made mainly in order to determine kinematics of material flow in forging processes and precision of shape and dimensions of obtained products. The first of the proposed processes was experimentally verified and a product of good quality was obtained. Material consumption of the analyzed processes and other factors acting on their effectiveness were also compared.

Experimental Study on Galling Behavior of Advanced High Strength Steel in Sheet Metal Forming

2012 ◽  
Vol 502 ◽  
pp. 36-40
Author(s):  
Ying Ke Hou ◽  
Shu Hui Li ◽  
Yi Xi Zhao ◽  
Zhong Qi Yu
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Sheet Material ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Process ◽  
Advanced High Strength Steels ◽  
Sheet Materials ◽  
Materials Used

Galling is a known failure mechanism in many sheet metal forming processes. It limits the lifetime of tools and the quality of the products is affected. In this study, U-channel stamping experiments are performed to investigate the galling behavior of the advanced high strength steels in sheet metal forming . The sheet materials used in the tests are DP590 and DP780. In addition to the DP steels, the mild steel B170P1 is tested as a reference material in this study. Experimental results indicate that galling problem becomes severe in the forming process and the galling tendency can be divided into three different stages. The results also show that sheet material and tool hardness have crucial effects on galling performance in the forming of advanced high strength steels. In this study, DP780 results in the most heaviest galling among the three types of sheet materials. Galling performance are improved with increased hardness of the forming tool.

Effective Forming Processes of Hub Forging from Aluminum Alloy AlCu2SiMn

2013 ◽  
Vol 572 ◽  
pp. 265-268
Author(s):  
Andrzej Gontarz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Metal Forming ◽  
Material Flow ◽  
Theoretical Research ◽  
Material Consumption ◽  
Forming Process ◽  
Metal Forming Process ◽  
Large Material

This paper presents results of theoretical and experimental research works on metal forming process of a hub. A typical technology of forging on hammer of this part with flash was discussed. Two new processes of a hub forging were proposed, characterized by large material savings in comparison with typical technology. The first process is based on forming without flash of a forging with axial cavity. The second one is connected with forming of forging from pipe billet. The realization of these processes is possible at the application of a press with three movable working tools. Theoretical research works were done on the basis of simulations by means of finite element method. Simulations were made mainly in order to determine kinematics of material flow in forging processes and precision of shape and dimensions of obtained products. The first of the proposed processes was experimentally verified and a product of good quality was obtained. Material consumption of the analyzed processes and other factors acting on their effectiveness were also compared.

Research on Different Loading Methods of the Multi-Roller-Pressing Flexible Stretch Forming

2014 ◽  
Vol 898 ◽  
pp. 257-260
Author(s):  
Wei Chuan Zhang ◽  
Yong Feng Li ◽  
Ming Zhe Li
Keyword(s):  
Vibration Amplitude ◽  
Sheet Material ◽  
Stretch Forming ◽  
Forming Force ◽  
Forming Process ◽  
Explicit Finite Element ◽  
Force Loading ◽  
Loading Method ◽  
Loading Methods ◽  
Distribution Of Stress

Based on the multi-roller-pressing flexible stretch forming (MRPFSF) process, force loading and displacement loading were researched. The process of spherical parts of 08AL sheet material were simulated by means of an explicit finite element method. The variations of the forming force in stretch-forming process and the distribution of stress after springback were analyzed comparatively for both loading methods. The results show that the change of the forming force in the force loading method has fluctuation. With the depressing of rollers, the vibration amplitude is smaller. At the end of forming, the forming forces of both loading methods are gradually consistent. The stress distribution of spherical parts formed by the two loading method is accordant.

Evaluation of Drawability of Titanium Welded Sheets / Ocena Tłocznosci Spawanych Blach Tytanowych

2013 ◽  
Vol 58 (1) ◽  
pp. 139-143 ◽  
Author(s):  
P. Lacki ◽  
J. Adamus ◽  
W. Wieckowski ◽  
J. Winowiecka
Keyword(s):  
Metal Forming ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
The Finite Element Method ◽  
Forming Process ◽  
Blank Holder ◽  
Design And Optimization ◽  
Commercially Pure ◽  
Titanium Grade ◽  
Hemispherical Punch

In the paper experimental and numerical results of sheet-metal forming of titanium welded blanks are presented. Commercially pure titanium Grade 2 (Gr 2) and Ti6Al4V titanium alloy (Gr 5) are tested. Forming the spherical cups from the welded Gr 2 || Gr 5 blanks, and uniform Gr 2 and Gr 5 blanks is analysed. Numerical simulations were performed using the PamStamp 2G v2012 program based on the finite element method (FEM). Additionally, drawability tests using the tool consisting of die, hemispherical punch and blank-holder were carried out. Thickness changes and plastic strain distributions in the deformed material are analysed. The obtained results show some difficulties occurring during forming of the welded blanks made of titanium sheets at the same thicknesses but at different grades. It provide important information about the process course and might be useful in design and optimization of the sheet-titanium forming process.

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