Advanced FE model validation of cold-forming process using DIC: Air bending of high strength steel

2020 ◽  
Vol 13 (3) ◽  
pp. 409-421 ◽  
Author(s):  
S. Gothivarekar ◽  
S. Coppieters ◽  
A. Van de Velde ◽  
D. Debruyne
Keyword(s):  
Model Validation ◽  
High Strength Steel ◽  
High Strength ◽  
Fe Model ◽  
Forming Process ◽  
Cold Forming ◽  
Air Bending

scholarly journals Springback Compensation in Cold Forming Process for High Strength Steel / Kompensacja sprężynowania w procesie formowania stali na zimno

2015 ◽  
Vol 60 (4) ◽  
pp. 2471-2478 ◽  
Author(s):  
P. Bałon ◽  
A. Świątoniowski
Keyword(s):  
High Strength Steel ◽  
Early Stage ◽  
High Strength ◽  
Forming Process ◽  
Cold Forming ◽  
Software Application ◽  
High Durability ◽  
High Level ◽  
Short Time ◽  
Ahss Steel

Process of metal forming in automotive parts construction becomes more and more demanding due to tightened up tolerance and trials to realize very complex and in many cases unworkable design in mass production. Moreover it is required to cut and limit costs of die production and simultaneously keep high quality. Furthermore, construction elements are more often produced from materials which belong to High Strength Steel or Ultra High Strength Steel. Application of this kind of materials considerably reduces construction mass due to high durability. Nevertheless, it results in appearance of springback effect. Springback value depends mainly on used material as well as part geometry and in extreme cases deviation value from target part might reach in some areas high level. Reduction of implementation time, development of metal components and greater restrictions about designing and producing stamping tools generate extra costs. Designing of dies requires using of appropriate Finite Element Method software to make them more economic and less time-consuming. Therefore analysis of forming process alone is not enough to be taken into account. During the design process it is needed to include the die compensation to reach optimized blank sheet. Prediction of springback effect by tryout method and then correction of deviation is difficult arduous and painstaking. Virtual compensation methods make it possible to receive precise result in a short time. This way gives a huge economic advantage eliminating useless milling and allows to produce of die just in time. Optimization process can relate to individual operation as well as take into consideration intermediate stages in the final result, at the same time increasing the accuracy. Die compensation with software application was experimentally verified by prototype die. Quality requirements regarding products of sheet stamping process are very high due to the technologies of automatic assembly of formed components. Springback, as the main source of drawpieces inaccuracy, is the function of material data, shape of tools and process parameters. Therefore, springback deformation becomes critical problem especially for AHSS steel when the geometry is complex. Hence, it is necessary not only to find springback effect value but also include it during early stage of designing by tooling designers.

Enhancement of the tensile shear strength for joining low-ductility aluminium to high-strength steel by using electrically-assisted mechanical clinching (EAMC)

2021 ◽  
pp. 095440542199565
Author(s):  
Abozar Barimani-Varandi ◽  
Abdolhossein Jalali Aghchai
Keyword(s):  
Shear Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Fe Model ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Electroplastic Effect ◽  
Fracture Displacement ◽  
Electrically Assisted ◽  
Mechanical Clinching

The present work studied the enhancement of the tensile shear strength for joining AA6061-T6 aluminium to galvanized DP590 steel via electrically-assisted mechanical clinching (EAMC) using an integrated 2D FE model. To defeat the difficulties of joining low-ductility aluminium alloy to high-strength steel, the electroplastic effect obtained from the electrically-assisted process was applied to enhance the clinch-ability. For this purpose, the results of experiments performed by the chamfering punches with and without electrically-assisted pre-heating were compared. Joint cross-section, failure load, failure mode, fracture displacement, material flow, and failure mechanism were assessed in order to study the failure behaviour. The results showed that the joints clinched at the EAMC condition failed with the dominant dimpled mechanism observed on the fracture surface of AA6061 side, achieved from the athermal effect of the electroplasticity. Besides, these joints were strengthened 32% with a much more fracture displacement around 20% compared with non-electrically-assisted pre-heating.

High-Strength Steel Hot Forming Mechanics Performance and Characteristic Experimental Study

2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Absorption Capacity ◽  
Hot Forming ◽  
Gas Content ◽  
Strength Increase ◽  
Gradual Change ◽  
Forming Process

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.

Hot Spline Forming of Ultra-High Strength Steel Gear Drum Using Resistance Heating

2014 ◽  
Vol 622-623 ◽  
pp. 201-206 ◽  
Author(s):  
Kenichiro Mori ◽  
Tomoyoshi Maeno ◽  
Shohei Nakamoto
Keyword(s):  
Deep Drawing ◽  
High Strength Steel ◽  
Side Wall ◽  
High Strength ◽  
Axial Direction ◽  
Resistance Heating ◽  
Sectional Area ◽  
Forming Process ◽  
Cross Sectional ◽  
Ultra High Strength Steel

A hot spline forming process of die-quenched gear drums using resistance heating of a side wall of a cup formed by cold deep drawing and ironing was developed. The side wall having uniform cross-sectional area is resistance-heated by passage of the current in the axial direction, the heated side wall of the drawn cup is ironed and is finally die-quenched. The gear drum was successfully formed and the hardness was between 400 and 500 HV. Not only the formability was improved but also the formed dram was hardly oxidised because of rapid resistance heating.

Quadrilateral Shape Rib Forming by Roll Forming Process

2018 ◽  
Vol 878 ◽  
pp. 296-301
Author(s):  
Dong Won Jung
Keyword(s):  
Automotive Industry ◽  
High Strength Steel ◽  
Numerical Study ◽  
Thickness Distribution ◽  
High Strength ◽  
Metal Sheet ◽  
Product Performance ◽  
Roll Forming ◽  
Forming Process ◽  
Roll Forming Process

The roll forming is one of the simplest manufacturing processes for meeting the continued needs of various industries. The roll forming is increasingly used in the automotive industry to form High Strength Steel (HSS) and Advanced High Strength Steel (AHSS) for making structural components. In order to reduce the thinning of the sheet product, traditionally the roll forming has been suggested instead of the stamping process. The increased product performance, higher quality, and the lowest cost with other advantages have made roll forming processes suitable to form any shapes in the sheets. In this numerical study, a Finite Element Method is applied to estimate the stress, strain and the thickness distribution in the metal sheet with quadrilateral shape, ribs formed by the 11 steps roll forming processes using a validated model. The metal sheet of size 1,000 × 662 × 1.6 mm taken from SGHS steel was used to form the quadrilateral shape ribs on it by the roll forming process. The simulation results of the 11 step roll forming show that the stress distribution was almost uniform and the strain distribution was concentrated on the ribs. The maximum thinning strain was observed in the order of 15.5 % in the middle rib region possibly due to the least degree of freedom of the material.

Establishment and Application of Forming Limit Diagram of Multi-Gauge Laser Tailor-Welded Blanks

2010 ◽  
Vol 97-101 ◽  
pp. 420-425
Author(s):  
Wei Chen ◽  
S. Cheng ◽  
Y. Ding ◽  
Y.Q. Guo ◽  
L. Xue
Keyword(s):  
High Strength Steel ◽  
Research Method ◽  
Forming Limit Diagram ◽  
High Strength ◽  
Failure Criteria ◽  
Limit Strain ◽  
Measuring System ◽  
Forming Limit ◽  
Forming Process ◽  
Tailor Welded Blanks

The method for establishing the forming limit diagram (FLD) of multi-gauge high strength steel laser tailor-welded blanks (LTWB) is introduced based on analyzing the failure mechanism of multi-gauge LTWB. The Nakazima test is performed to generate the limit strain of multi-gauge high strength steel LTWB. By means of the ARGUS strain measuring system, the limit strain is measured and the FLD of LTWB is plotted subsequently. The FLD established by the Nakazima test is introduced into the FEA forming process as the failure criteria. Compared with the predicted result of the FLD of thinner metal, better correlation between the simulation and experimental results is indicated by adopting the FLD of LTWB as the necking criteria, which also reveals the validity and practicability of the FLD research method for multi-gauge high strength steel LTWB.

Multi-Objective Optimization for High Strength Steel Sheet Metal Forming Process Based on Response Surface Methodology

2010 ◽  
Vol 154-155 ◽  
pp. 1223-1227 ◽  
Author(s):  
Zhi Guo An ◽  
Yu Zhang
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steel ◽  
High Strength ◽  
Forming Process ◽  
Multi Objective ◽  
Metal Forming Process

In sheet metal forming process, the input process parameters scatter and considerably result in unreliablity in practical production. Optimization for sheet metal forming process is often considered as a multi-objective problem. An optimizition strategy for high strength steel (HSS) sheet metal forming process was suggested based on response surface methodology (RSM). Latin Hypercube Sampling (LHS) method was introduced to design the rational experimental samples; the objective function was defined based on cracking factor wrinkle factor and severe thinning factor; the accurate response surface for sheet metal forming problem was built by Least Square Method; Multi-objective Genetic Algorithm(MOGA) was adoped in optimization and Pareto solution was selected. The strategy was applied to analyze a HSS auto-part, the result has proved this method suitable for optimization design of HSS sheet metal forming process.

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