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.

Forming Limit Extension of High-Strength Steels in Bending Processes

2014 ◽  
Vol 611-612 ◽  
pp. 1110-1115 ◽  
Author(s):  
Mohamed El Budamusi ◽  
Andres Weinrich ◽  
Chrstioph Becker ◽  
Sami Chatti ◽  
A. Erman Tekkaya
Keyword(s):  
Hydrostatic Pressure ◽  
Metal Forming ◽  
Fem Simulation ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Forming Limits ◽  
Air Bending ◽  
Forming Technology ◽  
Bending Process

Bending is a commonly used forming technology in metal forming. The occurring springback and low forming limits of high-strength steels especially during air bending are the main disadvantages. In this paper, the conventional air bending process is applied with a hydrostatic pressure in the bending zone. This was done using an elastomer tool. The advantage of this method is that the flexibility of air bending is maintained by reducing the springback while the forming limits are extended. Furthermore, different geometries for the elastomer tool were investigated by means of a FEM simulation. The investigation leads to a reduction of the process forces by minimizing the springback and to an extension of the forming limits.

Comparison of Offset and Wiping Z-Die Designs for Precision Z-Bent Part Fabrication

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Sutasn Thipprakmas ◽  
Pakkawat Komolruji ◽  
Wiriyakorn Phanitwong
Keyword(s):  
Fem Simulation ◽  
The Finite Element Method ◽  
Spring Back ◽  
Bend Radius ◽  
Dimensional Precision ◽  
Bending Process ◽  
Simulation Results ◽  
Bend Angles ◽  
Selection Of ◽  
Good Agreement

In recent years, the requirements for high dimensional precision on Z-bent shaped parts have become increasingly stringent. To attain these requirements, the suitable selection of the Z-die bending type has to be considered much more strictly. In this research, two types of Z-bending processes, offset Z-die bending and wiping Z-die bending, were investigated using the finite element method (FEM) to identify the spring-back characteristics and dimensions of Z-bent shaped parts. In the case of offset Z-die bending, the spring-back characteristics on both bend angles were similar. In contrast, in the case of wiping Z-bending, the spring-back characteristics on both bend angles were different. In addition, the dimensions of the Z-bent shaped parts were investigated. It was found, in the case of wiping Z-bending, that web thinning was generated and the outer bend radius was out of tolerance. To validate the FEM simulation results, experiments were carried out. The FEM simulation results showed good agreement with the experimental results in terms of the bend angles and the overall geometry of the Z-bent shaped parts. To achieve precise Z-bent shaped parts, the suitable selection of Z-die bending type in the Z-die bending process is very important.

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.

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.

Selection of Bending Parameters for Minimal Spring-Back Using an ANFIS Model and Simulated Annealing Algorithm

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
H. Baseri ◽  
B. Rahmani ◽  
M. Bakhshi-Jooybari
Keyword(s):  
Simulated Annealing ◽  
Simulated Annealing Algorithm ◽  
Fuzzy Inference ◽  
Sheet Thickness ◽  
Spring Back ◽  
Anfis Model ◽  
Inference System ◽  
Bending Process ◽  
Annealing Algorithm ◽  
Tip Radius

In this research, a simulated annealing algorithm was used to minimize the spring-back in V-die bending process. First, an adaptive neuro-fuzzy inference system (ANFIS) model was developed using the data generated based on experimental observations. The output parameter of the ANFIS model is spring-back and the input parameters are sheet thickness, sheet orientation, and punch tip radius. The performance of the ANFIS model in training and testing sets is compared with those observations. The results indicated that the ANFIS model can be applied successfully for prediction of spring-back. Then, the ANFIS model was used as a function in simulated annealing algorithm to minimize the spring-back. The results showed that the proposed model has an acceptable performance to optimize the bending process.

The study of spring-back in wipe-bending processes for perforated components

2011 ◽  
Vol 225 (11) ◽  
pp. 2007-2014 ◽  
Author(s):  
M A Farsi ◽  
B Arezoo ◽  
V Alizadeh ◽  
S Mirzaee
Keyword(s):  
Finite Element ◽  
Carbon Steel ◽  
Sheet Metal ◽  
Low Carbon Steel ◽  
High Strength ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Spring Back ◽  
Bending Process ◽  
Component Material

Bending is one of the processes frequently used during manufacturing of sheet-metal components. Spring-back in bending operations is an important issue when producing precision parts. This issue becomes even more important when the component has any kind of hole on the bending surface. Such components are the focus of study in this paper. Many parameters affect spring-back in the bending process; in the present work, perforated components with an oblong cut are selected, and the influence of cut size, die radius, clearance, and component material on the value of the spring-back in a wipe-bending process are studied. Four different hole sizes, three die radii and clearance, and two different steel materials (high-strength low-alloy steel and low-carbon steel) are used in experiments and finite-element simulations. Results show these parameters have effect on the amount of spring-back in the wipe-bending process.

Comparative Efficiency of Artificial Neural Network to Predict Spring-Back Value in U-Bending Process of High Strength Steel

2015 ◽  
Vol 749 ◽  
pp. 319-326
Author(s):  
Arkhom Songkroh ◽  
Bhadpiroon Sresomroeng
Keyword(s):  
Neural Network ◽  
High Strength Steel ◽  
Pearson Correlation ◽  
High Strength ◽  
Final Analysis ◽  
Raw Material ◽  
Work Piece ◽  
Spring Back ◽  
Punch Force ◽  
Bending Process

High strength steel (HSS) was used as raw material in the automotive industry, which required lightweight and high strength, such as chassis and etc. However, the strength and hardness of the steel are relatively high, leading to the low permeability and large spring-back occurring after forming operation. As a result, the work piece is not shaped desire. This research proposes neural network for predicts the spring back values, in U-bending process, that the materials were differences in mechanical properties, such as SPFH590 (JIS) and SPEC980Y (JIS). In the experiment, the input factors for predictable data consists as the punch radius (RP), die radius (Rd), clearance (Cl) and counter punch force (Fc). After that, the input data were analyzed relation with spring-back values by the Pearson Correlation of One-tailed. Next, It was selected by Leave-one-out and k-fold Cross validation (K-fold and LOOCV), to improve efficiency of the prediction process. Moreover, the result was a measurable performance with Root Mean Square Error (RMSE) technique, equal to 0.788 and 2.10 respectively. In the final analysis, the neural network is effective to predict the Spring-back values of SPFH590 (JIS) rather than SPEC 980Y (JIS) in U-bending process.

scholarly journals Conductive Heating during Press Hardening by Hot Metal Gas Forming for Curved Complex Part Geometries

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1104 ◽  
Author(s):  
Mirko Bach ◽  
Lars Degenkolb ◽  
Franz Reuther ◽  
Verena Psyk ◽  
Rico Demuth ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Fem Simulation ◽  
Sheet Thickness ◽  
High Strength ◽  
Measurement Technology ◽  
Hot Metal ◽  
Conductive Heating ◽  
Press Hardening ◽  
Hot Metal Gas Forming ◽  
Reduction Of Co2

Climate targets set by the EU, including the reduction of CO2, are leading to the increased use of lightweight materials for mass production such as press hardening steels. Besides sheet metal forming for high-strength components, tubular or profile forming (Hot Metal Gas Forming—HMGF) allows for designs that are more complex in combination with a lower weight. This paper particularly examines the application of conductive heating of the component for the combined press hardening process. The previous Finite-Element-Method (FEM)-supported design of an industry-oriented, curved component geometry allows the development of forming tools and process peripherals with a high degree of reliability. This work comprises a description regarding the functionality of the tools and the heating strategy for the curved component as well as the measurement technology used to investigate the heat distribution in the component during the conduction process. Subsequently, forming tests are carried out, material characterization is performed by hardness measurements in relevant areas of the component, and the FEM simulation is validated by comparing the resulting sheet thickness distribution to the experimental one.

scholarly journals Experimental, Statistical, and Analytical Evaluation of The Springback Behavior of Martensitic 1400 Sheet in V-Bending

2020 ◽  
Author(s):  
Nuri ŞEN ◽  
Ömer SEÇGİN
Keyword(s):  
Automotive Industry ◽  
High Strength ◽  
Fe Model ◽  
Light Weight ◽  
Analytical Evaluation ◽  
Bending Process ◽  
Punch Radius ◽  
Different Temperatures ◽  
Operation Parameters ◽  
Springback Behavior

Abstract Ultra-high-strength Martensitic 1400 steel is preferred in the automotive industry because of its high strength as well as its light weight. In this study, Martensitic 1400 steel was subjected to the V-bending process. As a result of 48 different tests, the amount of springback resulting from the V-bending process was determined. A finite element (FE) model was then created based on these experimental data. After it was determined that the experimental results concurred with the FE model, without performing new experiments, further analyses were carried out at different temperatures. Using the results of a total of 96 FE analyses, variance analysis was performed and the effects of the operation parameters on springback were determined. As a result of the study, it was concluded that the most effective parameter on springback in the V-bending process was the die angle and that holding time had no significant effect. It was observed that the springback increased in parallel with the punch radius and die angle and that increases in temperature reduced the springback.

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