scholarly journals An Infrared Local-Heat-Assisted Cold Stamping Process for Martensitic Steel and Application to an Auto Part

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1543
Author(s):  
Ki-Young Kim ◽  
Eun-Ho Lee ◽  
Soo-Hyun Park ◽  
Youn-Hee Kang ◽  
Jong-Youn Park ◽  
...  
Keyword(s):  
Present Method ◽  
High Strength ◽  
Local Heat ◽  
Industrial Applications ◽  
Bending Test ◽  
Forming Process ◽  
Stamping Process ◽  
Infrared Rays ◽  
Hot Press Forming ◽  
Cold Stamping

The automotive industry has tried to employ ultra-high-strength steel (UHSS), which has a higher strength with a thinner thickness. However, because of its low formability, there is a limit to the use of UHSS in industrial applications. Even though the hot-press-forming method can resolve the formability problem, elevated-temperature conditions lead to side effects—heat transfer and productivity issues. This work presents the concept of an infrared local-heat-assisted cold stamping process. Before the forming process, local areas, where the formability problem occurs, are locally heated by the gathering of infrared rays and cooled to room temperature before delivery. Since the heat treatment is completed by the material supplier, the stamping companies can conduct cold stamping without new investments or the productivity issue. In this work, a heat-assisted cold V-bending test was conducted with a martensitic (MS) 1.5 GPa steel, the CR1470M steel provided by POSCO. The heating effects on the microstructure, hardness, and local ductility were also observed. Finally, a commercial door impact beam was successfully manufactured with the present method. In this application, only a targeted small area was heated. The results show that the present method can improve the formability and springback problems of MS steel in the stamping process.

SPRINGBACK EFFECT OF AUTOMOTIVE LOWER ARM COMPONENT PREPARED VIA BURRING PROCESSING

2015 ◽  
Vol 75 (8) ◽  
Author(s):  
Muhamad Sani Buang ◽  
Shahrul Azam Abdullah ◽  
Juri Saedon ◽  
Hashim Abdullah
Keyword(s):  
Sheet Metal ◽  
High Strength ◽  
Forming Process ◽  
Shape Accuracy ◽  
Automotive Components ◽  
Stamping Process ◽  
Tool Profile ◽  
Stretch Flanging ◽  
Metal Forming Process ◽  
Made In

Complex components of the sheet metal forming process need to be designed with high precision and accuracy in order to prevent defects and misalignment of the end products. One of the sheet metal cool stamping process for these complex automotive components is burring which is the forming of a flange around a hole made in a piece of sheet metal. Springback is a common defect during the burring process. The aims of this paper are to investigate the springback effect and improve shape accuracy of hole burring by inner burring process of lower arm part for automotive lower arm part. The springback defects at hole burring usually happened on the inner burring process. Experimental stretch flanging for cold stamping process of inner burring process was used to investigate the reasons of springback effect around the burred hole for a lower arm part of high strength steel (HSS) sheets SPFH590. From the two designs of burring punch dies, the result shows the values of springback effect for clearance -0.15 which have a big gap at hole burring A arm and B arm diameters, are larger than clearance -0.34 which have small gap for inner burring process of lower arm part. The experimental analysis shows that springback is proportionally related to the punch-die clearance parameter of the tool profile where the springback increase as the clearance increases. 

Effect of Variable Geometry on Springback of High Strength Steel Materials

2015 ◽  
Vol 1134 ◽  
pp. 154-159
Author(s):  
Muhamad Sani Buang ◽  
Shahrul Azam Abdullah ◽  
Juri Saedon ◽  
Yupiter H.P. Manurung ◽  
Mohd Shahir Mohd Hairuni ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
High Strength Steel ◽  
High Strength ◽  
Bending Test ◽  
Geometrical Parameters ◽  
Forming Process ◽  
Element Simulation ◽  
Punch Radius ◽  
Prevention Method

Springback is the phenomenon in which the material strip unbends itself after forming process. It is caused by the geometrical, mechanical properties or other process parameters. This paper focused on finite element simulation investigation on effects of geometrical parameters on the springback amount of the High Strength Steel (HSS). Two geometrical parameters, punch radius (Rp) and die opening (Wo) were selected and their effect on springback studied. Finite element simulation of U-bending test was performed using Simufact.formingTM with material database (MatILDa) and the level of the springback was measured. The result of the simulation shows that different values of punch radius (Rp) and die opening (Wo) are significant to the springback effect. 3 variable values of (Rp) and (Wo) selected in this studied are (2mm, 4mm, 6mm) and (30mm, 36mm, 48mm) respectively. The findings of the simulation could be used to accurately and reliably predict springback behavior of the tested material. The value of the springback increases, as the value of the die opening (Wo) increases. Meanwhile, the increasing value of the punch radius (Rp) will lead to decreasing springback value. From this finding, a proper prevention method can be taken to eliminate springback, achieve improvement in the forming process as well as reduce processing time and cost.

Effects of thread rolling processing parameters on mechanical properties and microstructures of high-strength bolts

2020 ◽  
Vol 62 (10) ◽  
pp. 1017-1024
Author(s):  
Serkan Aktas ◽  
Yasin Kisioglu
Keyword(s):  
Mechanical Properties ◽  
Low Carbon Steel ◽  
High Strength ◽  
Rolling Process ◽  
Processing Parameters ◽  
Industrial Applications ◽  
Low Carbon ◽  
Forming Process ◽  
Cold Forming ◽  
Thread Rolling

Abstract Bolt production with a grade of 10.9 class quality made from AISI4140 material with a low thread rolling index is usually implemented in accordance with the thread rolling method (cold forming) in industrial applications. In this method, the effects of die revolutions and multiple passes are unknown in the thread forming process as the devices are usually operated with respect to geometrical dimensions but not the mechanical properties and microstructures of the material. In the literature there are few studies on microstructures of low-carbon steel having a higher thread rolling index in bolt production. This study experimentally examined the effects of the processing parameters on the mechanical properties and microstructures. Parameters such as forming speed and single or multi-pass influences were considered in the production of M12 × 1.75 and M20 × 2.5 fasteners widely used in industrial applications. The experiments identified the behavior of the mechanical properties, microstructures and micro-hardness of the AISI4140 material at two forming speeds (rpm) and three passes in the thread rolling process. Thus, significantly sensible outcomes as a function of processing parameters were obtained considering the thread strength viewpoints.

Effect of Dies Temperature on Mechanical Properties of Hot Stamping Square-Cup Part for Ultra High Strength Steel

2010 ◽  
Vol 129-131 ◽  
pp. 390-394
Author(s):  
Cheng Xi Lei ◽  
Zhong Wen Xing ◽  
Hong Ya Fu
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Hot Stamping ◽  
High Strength ◽  
Hot Forming ◽  
Forming Process ◽  
Stamping Process ◽  
Ultra High Strength Steel ◽  
Mechanical Properties Testing ◽  
Simulation Results

The numerical simulation of hot-stamping process was carried out for UHSS square-cup parts, and the influence of dies temperature on the hot-stamping process was anlysised. Besides, through the microstructure analysis and mechanical properties testing of the formed parts, effects of dies temperature on microstructures and mechanical properties of hot-stamping square-cup parts were obtained. The experiment and simulation results showed that the mechanical properties of the UHSS are strongly dependent on the temperature, so the dies temperature is one of the most important parameters that have to be taken into account in designing the hot-forming dies and the hot-forming process.

Identification of Process-Based Limit Stress States Applying a Stretch-Bending-Test

2012 ◽  
Vol 504-506 ◽  
pp. 47-52
Author(s):  
Christian Hezler ◽  
Marion Merklein ◽  
Joachim Hecht ◽  
Bernd Griesbach
Keyword(s):  
High Strength ◽  
Bending Test ◽  
Forming Limit ◽  
Limit Curve ◽  
Forming Process ◽  
Forming Limit Curve ◽  
Distribution Diagram ◽  
Stress Limit ◽  
Stretch Bending ◽  
Strain Paths

The evaluation of forming simulation by using the forming limit curve has only limited validity if it is applied on car body components with non-linear strain paths. If modern high strength materials are used, the forming limit criteria can also provide invalid predictions. Especially high strength multiphase steels show a specific behaviour in forming, necking and crack initiation. If bending loads are applied to these materials, the onset of cracking occurs partially not within the range of the forming limit curve (FLC). The stress limit indicates the failure beginning more accurate. It is independent of the forming history and should be less sensitive to the behaviour of high strength steels. In the post processing of a simulation it could be used similar to the forming limit. A limit curve applied on the in-plane-stress-diagram of an analysed component defines areas that are more vulnerable for cracking. The required stress limit curve will be obtained in this research by applying a stretch-bending-test. It is selected in order to reach loads, which are comparable to the forming process in the components’ production. The forming state that is affecting the specimen is a combination of bending and stretching load. Different load conditions can be applied at the test by altering the stamp-radius and the specimen geometry. Since stresses cannot be measured directly in the experiment, the test is modelled in the simulation where the stresses can be calculated for a given material model. Finally the stress limit criterion was applied on the test parts’ stress distribution diagram. Occurring stresses above the stress limit curve are displayed on the simulation. Thereby it is possible to show a good correlation in critical areas between the failure prediction in the simulation and occurring rupture on the test component.

Investigation on Shearing and Local Formability of Hot-Rolled High-Strength Plates

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Liang Dong ◽  
Shuhui Li ◽  
Ji He ◽  
Ronggao Cui
Keyword(s):  
High Strength ◽  
Bending Test ◽  
Peak Hardness ◽  
Shear Surface ◽  
Forming Process ◽  
Junctional Zone ◽  
Microhardness Distribution ◽  
Sheared Edge ◽  
Edge Cracking ◽  
Hot Rolled

In order to evaluate the shearing quality, the material inhomogeneity through thickness after shearing is introduced by the authors. This study investigates the shearing and local formability of hot-rolled high-strength steel (HSS) plate, which is generally exploited for the manufacturing of the beam of heavy trucks. Various kinds of plates with different thicknesses and strengths are used to figure out the effect of material properties on the shearing quality. Both the shear surface morphology and microhardness distribution of the sheared edge are considered for evaluating the influence of the sheared-edge quality on local formability during the following forming process. Vickers hardness tests are conducted to analyze the microhardness distribution on the shear surface, which is proved to have significant effect on the local formability of the sheared edge. Furthermore, two kinds of bending tests and simulation are employed to study the edge cracking phenomenon, and the results indicate that the junctional zone of burnished zone and fracture zone, which is defined as peak hardness zone (PHZ), has a significant impact on major strain distribution on shear surface in the side bending test and this region is the main cause of edge cracking in normal bending test.

Deformation Characteristics of Advanced High Strength Steel under Cyclic Bending and Reversed Bending

2015 ◽  
Vol 651-653 ◽  
pp. 175-180
Author(s):  
Fuh Kuo Chen ◽  
Sin Liang Lin ◽  
Heng Kuang Tsai ◽  
Yi Wei Lin ◽  
I Kai Lin
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Metal Forming ◽  
Bauschinger Effect ◽  
High Strength ◽  
Bending Test ◽  
Forming Process ◽  
Element Analysis ◽  
Bending Tests ◽  
The Finite Element Analysis

In the present study, the Bauschinger effect exhibited in the advanced high strength steel under cyclic bending and reversed bending deformation was examined by both the experimental approach and the finite element analysis. The cyclic tension-compression tests were first conducted for the DP590 steel sheet to determine the material constants required in the Yoshida-Uemori model used in the finite element simulations. Since the deformation mode occurred in the reversed bending tests is similar to that presented in the sheet metal passing across the draw bead or die corner, a three-point reversed bending test apparatus was also developed and the experiments were conducted in the present study. The reversed bending test results clearly demonstrate that the Bauschinger effect presents in the reversed bending process. It confirms that the cyclic reversed bending tests can be applied to examine the Bauschinger effect exhibited in the sheet metal forming process. The finite element analysis was also performed to simulate both the U-hat bending and cyclic reversed bending processes. The comparison of the simulation results with the experimental data reveals that the finite element predictions in both springback and reversed bending load are more accurate if the Yoshida-Uemori model is adopted. It implies that consideration of the Bauschinger effect is necessary in the sheet metal forming if a reversed loading path is present during the forming process.

Hot-Stamping Process Simulation and Optimize Research for Collision Beam of Automobile Door

2011 ◽  
Vol 201-203 ◽  
pp. 3-8 ◽  
Author(s):  
Chao Wang ◽  
Bin Zhu ◽  
Yi Sheng Zhang ◽  
Jie Shi ◽  
Han Dong
Keyword(s):  
Material Selection ◽  
Hot Stamping ◽  
High Strength ◽  
Die Design ◽  
Effect Of Temperature ◽  
Forming Process ◽  
Molding Process ◽  
Stamping Process ◽  
Key Factor ◽  
Forming Defects

Hot-stamping molding for ultra-high-strength steel have some similarities with traditional cold-stamping molding in the aspects of molding process and die design. But due to the effect of temperature variation of blank, hot-stamping have some differences in ultra-high-strength products design, material selection and forming process design. Some special forming defects, such as local thinning, cracking and wrinkling, could appear in hot-stamping process due to these differences. In order to obtain uniform phase structure and get high-quality products, it is very important to be able to predict and control the blank temperature and the consistence of blank cooling rate. The thermo-mechanical characteristics of hot-stamping are studied with the material of ADVANCE1500 (22SiMnTiB). Based on the results of simulations and experiments, conclusion are drawn that the complexity of the product and the blank which contacts with die asynchronously causes the uneven distribution of the blank temperature. This is the key factor that leads to the poor mobility of the blank material and local thinning, cracking, wrinkling and other defects in forming process. Proper clearance between punch and die can reduce the probability of defects which could contribute to the improvement of hot-stamping process.

Advances in Constitutive Modeling of Plasticity for Forming Applications

2016 ◽  
Vol 725 ◽  
pp. 3-14 ◽  
Author(s):  
Frédéric Barlat ◽  
Youngung Jeong ◽  
Jin Jin Ha ◽  
Carlos Tomé ◽  
Myoung Gyu Lee ◽  
...  
Keyword(s):  
Constitutive Models ◽  
High Strength Steels ◽  
Computation Time ◽  
High Strength ◽  
Industrial Applications ◽  
Dislocation Dynamics ◽  
Forming Process ◽  
Advanced High Strength Steels ◽  
Process Simulations ◽  
Multi Phase

A succinct description of advanced constitutive models for applications to forming process simulations is provided. These models are continuum-based because they are more efficient in terms of computation time than microstructure–based models. However, they are so–called advanced because they are considered in many scientific studies but rather scarcely used in industrial applications. In addition, the relationship between these continuum constitutive models and multi-scale approaches based on crystal plasticity, dislocation dynamics and mechanics of multi-phase materials, such as advanced high strength steels, is substantiated.

scholarly journals Effect of initial blank temperature in hot press forming towards 22MnB5 springback failure

2019 ◽  
Vol 13 (2) ◽  
pp. 5137-5149
Author(s):  
C. H. Ng ◽  
C. F. Lai ◽  
S. N. M. Yahaya ◽  
S. Shamsudin ◽  
S. N. A. S. Ahmad ◽  
...  
Keyword(s):  
High Strength ◽  
Boron Steel ◽  
Hot Press ◽  
Forming Process ◽  
Quenching Rate ◽  
Press Forming ◽  
Initial Blank ◽  
Hot Press Forming ◽  
Formed Part ◽  
The Impact

The springback failure of ultra-high strength boron steel (22MnB5) in hot press forming (HPF) process was characterized under bending and membrane conditions. Hot press forming for U–shaped parts with ultra-high strength boron steel were experimented and simulated to study the effect of initial blank temperatures on springback failure in the automotive industry. The results specify the various preheated temperature of 22MnB5 blank effect toward springback occurrences with reference to hot press forming dies design. ANSYS Workbench was used to verify finite element (FE) simulations of the processes in order to consolidate the knowledge of springback. The validated numerical simulation model were used in analyzing the stress and strain distributions along the formed part in the FE models, it was found that the springback angle was related in averaging value throughout quenching, regardless of the forming conditions. Springback failure mainly caused dimension deviation in hot press form parts due to the impact of thermal restoring moments and quenching rate of hot press forming process.

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