scholarly journals A Simulation-Based Approach to Predict the Springback Behavior of Ultra-High Strength Spring Strips

2019 ◽  
Vol 949 ◽  
pp. 48-56 ◽  
Author(s):  
Karsten Richter ◽  
Franz Reuther ◽  
Roland Müller
Keyword(s):  
Process Design ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Material Behavior ◽  
High Yield ◽  
Simulation Based ◽  
Bending Process ◽  
The Impact ◽  
Free Bending ◽  
Springback Behavior

One effect of high influence on the dimensional accuracy during bending is springback. It inevitably occurs due to the elastic proportion in the material behavior. The impact is notably high when producing springs made of ultra-high strength spring strips of the steel grade 1.4310 (X10CrNi18-8). The high yield ratio needed to fulfil the functionalities required during application leads to dimensional inaccuracies that have to be compensated during the production process. This paper reports a simulation-based approach to predict the springback behaviour of ultra-high strength spring strips with tensile strengths TS = 1500-1800 MPa. Based on the results of advanced material testing and modelling, the numerical prediction of the springback behavior of an exemplary bending process (free bending) has been investigated in detail. This helps to obtain deeper knowledge and understanding of the springback phenomenon and to achieve suitable strategies for a more efficient industrial tool and process design while processing ultra-high strength spring strips.

Room Temperature Forming of AA7075 Aluminum Alloys: W-Temper Process

2015 ◽  
Vol 651-653 ◽  
pp. 199-204 ◽  
Author(s):  
Eneko Sáenz de Argandoña ◽  
Lander Galdos ◽  
Rafael Ortubay ◽  
Joseba Mendiguren ◽  
Xabier Agirretxe
Keyword(s):  
Aluminum Alloys ◽  
Room Temperature ◽  
Hot Stamping ◽  
Dimensional Accuracy ◽  
Industrial Condition ◽  
High Strength ◽  
Industrial Applications ◽  
Hot Forming ◽  
High Yield ◽  
Industrial Designers

As important light-weight structure material, aluminum alloys have been widely used in automotive and aerospace industries. In the last years, the manufacturing of parts with high strength and good dimensional accuracy has become the main objective in industrial applications. Within the available aluminum alloys, the 7xxx series has attract the interest of the industrial designers due to the high yield strength and ultimate tensile strength they present. However, the formability of these alloys in as-received industrial condition is very poor at room temperature and various studies are being carried out to develop efficient warm and hot forming processes to form them industrially using heated tools. In the present paper, the W-Temper forming is studied as an alternative to the warm and hot forming processes. Heat treatment temperatures and critical times are presented and an industrial B-Pillar is formed to validate the new process. In the last chapter, the final mechanical properties of the part are reported, before and after a virtual e-coat process where the W-Temper forming is compared with a hot stamping process.

An Investigation on Effect of Residual Stress on Springback Behavior of High Strength Steel in U-Bending Process

2011 ◽  
Vol 189-193 ◽  
pp. 2864-2868
Author(s):  
Komgrit Lawanwong
Keyword(s):  
Residual Stress ◽  
Fem Simulation ◽  
Sheet Thickness ◽  
High Strength ◽  
Spring Back ◽  
Workpiece Material ◽  
Bending Process ◽  
Commercial Program ◽  
Deform 2D ◽  
Springback Behavior

Bending process is an important process in the metal sheet forming in many industries. The main problem of the bending process is the spring-back phenomenon after removing the punch. This research aims the investigation on effect of residual stress on springback behavior of sheet metal in U bending process. The corner setting technique and bottoming process were designed for experiments. The corner setting technique and bottoming has reduced the thickness in bending area to 5, 10, 15 and 20 percent of the original sheet thickness. Clearance between punch and die of both processes was equal to same the thickness. The residual stress value and springback phenomenal were investigated by commercial program code DEFORM 2D which was able to analyze the effect stress and force in bending area. Electrolytic zinc coated carbon steel grade JIS; SECC, JIS; 440 and JIS; 590 which having the thickness of 1 mm were employed as the workpiece material for all experiments. The result of three materials in conventional U bending die shows larger spring back than the corner setting technique and bottoming process. Moreover, the corner setting technique reduces spring back value in bending process but requires high bending force. Corner setting technique and bottoming process at 15% and 20% shows that the spring go of all parts. The FEM simulation results explained the effect of residual stress to springback phenomenal. Comparisons between experimental and finite element method results were also performed.

Comparison of Material Behavior and Economic Effects of Cold and High Temperature Forming Technologies Applied to High-Strength Steels

2005 ◽  
Vol 6-8 ◽  
pp. 101-108 ◽  
Author(s):  
Reimund Neugebauer ◽  
Angela Göschel ◽  
Andreas Sterzing ◽  
Petr Kurka ◽  
Michael Seifert
Keyword(s):  
Elevated Temperatures ◽  
High Strength Steels ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Economic Effects ◽  
Material Behavior ◽  
Spring Back ◽  
Forming Process ◽  
Cold Forming ◽  
Forming Tools

The focus of forming high-strength steel at elevated temperature is to improve its forming properties like elongation and to reduce the power requirements during the forming process in opposite to cold forming. Because of the undefined and large spring-back effects parts made by cold forming are not able to achieve the demanded dimensional accuracy, which is necessary for laser welding operations in car body assembly. The reduction of the spring-back behavior is another advantage of the temperature controlled forming technology. On the other side the forming at elevated temperatures requires increased costs for forming tools and tempering equipment. For a fundamental evaluation of this technology, expenditures for the complete process chain have to be considered.

On the Identification of a Loading Scheme in Large Radius Air Bending

2015 ◽  
Vol 639 ◽  
pp. 155-162 ◽  
Author(s):  
Vitalii Vorkov ◽  
Richard Aerens ◽  
Dirk Vandepitte ◽  
Joost R. Duflou
Keyword(s):  
High Strength ◽  
Material Behavior ◽  
Large Radius ◽  
Element Analysis ◽  
Camera System ◽  
Bending Angle ◽  
Air Bending ◽  
Contact Points ◽  
Bending Process ◽  
Loading Diagram

Large radius air bending has a different loading diagram than conventional bending, which affects the material behavior during the bending process. In order to establish a correct loading diagram, the position of the contact points between the plate and the punch is determinant. The position of the contact points is depending on the evolution of the bending process and the influence of the material is unknown. In this work, the determination of the position of the contact points in large radius air bending has been studied by means of both an experimental campaign and finite element analysis. Experiments were performed on a press-brake with a capacity of 50 metric tons. High-strength steel Weldox 1300 and aluminum alloy AlMg3, and punches of radii 30, 35 and 40 mm have been used. During the bending process, the punch movement has been monitored and the bending angle has been measured by means of images recorded by a camera system. Based on the obtained results, the relation between the bending angle and the position of the contact points is discussed.

Investigation of Springback Prediction for an Aluminum 7000 Sheet Subjected to Press Forming

2019 ◽  
Vol 889 ◽  
pp. 203-210
Author(s):  
Quoc Tuan Pham ◽  
Jung Han Song ◽  
Joong Cheul Park ◽  
Young Suk Kim
Keyword(s):  
High Strength ◽  
Material Behavior ◽  
Material Anisotropy ◽  
Aerospace Applications ◽  
Excellent Corrosion Resistance ◽  
Press Forming ◽  
Bending Process ◽  
Automotive Part ◽  
Springback Prediction ◽  
Abaqus Software

Aluminum 7000 series have been widely used in the aircraft and aerospace applications owing to its advantages of lightweight, high strength, and excellent corrosion resistance. Recently, the sheets have been applied in the automotive engineering in order to reduce the weight of commercial cars. For this demand, press forming is a common forming method used to produce a designed automotive part. However, springback is one of the main reasons to limit applications of the aluminum 7000 series. This study develops several material models that consider important material behavior including Young's modulus, Bauchinger's effect, and material anisotropy on springback prediction for the tested material. These models have been implemented in ABAQUS software to analysis a bending process and estimate springback amount. As a result, the effects of each material behavior on springback were clarified. Based on simulation results, it is found that correctly capturing the Bauchinger's effect is the major key to the success of springback prediction for such kind of material.

Analysis of the Potential of Incremental Stress Superposition on Air Bending

2014 ◽  
Vol 622-623 ◽  
pp. 1173-1180 ◽  
Author(s):  
Andres Weinrich ◽  
Chrstioph Becker ◽  
Frauke Maevus ◽  
Sami Chatti ◽  
A. Erman Tekkaya
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Forming Limits ◽  
Air Bending ◽  
Bending Process ◽  
New Process ◽  
Sheet Metal Bending ◽  
Stress Superposition ◽  
Positive Effect ◽  
Springback Behavior

Springback and limited forming limits of modern high strength steels are a big challenge in manufacturing engineering. Both aspects are crucial in sheet metal bending processes. Different modifications of the air bending process have already been developed in order to reduce springback and also to increase the forming limits of materials. A new method (the incremental stress superposition on air bending) has been developed. Studies of this new process alternative show a positive effect on the springback behavior. In order to investigate the potential of this process a comparison with other already established bending processes have been carried out. A possible process control to extend the forming limits has also been investigated.

Effect of Stretching on Springback in Rotary Stretch Bending of Aluminium Alloy Profiles

2021 ◽  
Vol 883 ◽  
pp. 175-180
Author(s):  
Jun Ma ◽  
Torgeir Welo ◽  
Jørgen Blindheim ◽  
Taekwang Ha
Keyword(s):  
Process Capability ◽  
Dimensional Accuracy ◽  
The Novel ◽  
Designed Experiments ◽  
Stretch Bending ◽  
Wide Range ◽  
Bending Process ◽  
Formed Part ◽  
Springback Behavior ◽  
Strong Ability

Stretch bending is widely used for manufacturing profile-type parts. However, one of the challenges faced by the bending-type forming processes is springback, which significantly reduces the dimensional accuracy of formed part, process flexibility and overall equipment effectiveness. In this study, we focus on the springback behavior in a newly developed flexible rotary stretch bending process for profiles. Using the Al-Mg-Si alloy rectangular hollow extrusions, the effect of stretching on springback, as well as process capability, is evaluated by a series of carefully designed experiments conducted for a wide range of stretching strains. Increasing the stretching strain from about 2% to 4%, the springback chord height can be reduced by about 32% and the process capability can be improved significantly, showing the strong ability of the novel flexible stretch bending strategy for controlling springback and dimensional accuracy.

Effect of Heating Parameters on the Part’s Properties in Hot Stamping Process

2012 ◽  
Vol 557-559 ◽  
pp. 2417-2422
Author(s):  
Rui Ge ◽  
An Long ◽  
Yin Chen
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Hardness Measurement ◽  
Material Behavior ◽  
Hot Forming ◽  
Accuracy Test ◽  
Stamping Process ◽  
Proper Design

In the automotive industry, the hot forming of high strength steels offers the possibility to obtain significant reduction of weight without affecting the structural performances of final products. Compared with conventional sheet metal forming, the proper design of hot stamping process chain requires the deep knowledge of both interface phenomena and material behavior at high temperatures in order to obtain the desired properties of final products in terms of microstructure and strength characteristics. The work presented in this paper aims at accurately evaluate the effect of heating parameters on the properties of final sheet components produced in hot forming operations. Different from that in the lab, all the samples and parts used for the experimental test were produced in the production line, which can objectively show the manufacturing properties and microstructure character of products in mass. Microstructure evaluation, hardness measurement and dimensional accuracy test after hot stamping were performed and considered. The best heating parameters for the researched hot stamping B-Pillar’s production were obtained through the above research.

Increasing the Dimensional Accuracy of U-Bend Product of High Strength Steel Sheets by Pressure Pad

2019 ◽  
Vol 962 ◽  
pp. 159-166
Author(s):  
Pongsakorn Leetrakul ◽  
Komgrit Lawanwong
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
Kinematic Hardening ◽  
Bending Moment ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Steel Sheets ◽  
New Process ◽  
Springback Reduction ◽  
Springback Behavior

To reduce springback in U-shape of high strength steel sheet, the present paper proposes a new process parameter in U-bending technique. This paper aims to present the effect of clearance between die and pressure pad on springback behavior. The process in this work consists of four steps: (1) clamping of a sheet between a punch and a pressure pad, (2) bending with constant clamping force, (3) pushing-up at bottom of the part by using the pressure pad, and (4) final release tool. From the experimental results, decreasing of bending moment by bottom pushing-up resulted in the springback reduction. An appropriate of the clearance between die and pressure pad combined with bottom pushing-up force can be reduced springback. Our results suggested that the Y-U model, an advanced kinematic hardening, is essential for accurate numerical simulation of springback behavior.

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