Effect of two-stage press blanking on edge stretchability with third-generation advanced high-strength steels

Won, Chan-Hee; Lee, Wonju; Lee, Hyoun-Young; Kang, Yeonsik; Yoon, Jonghun

doi:10.1007/s00170-020-05854-1

Cited by 12 publications

(7 citation statements)

References 21 publications

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“…For this study, the shape of the specimen edge was fixed to a hole geometry for HET. Although a linear-shaped edge [ 32 , 33 ] is more advantageous for visual inspection, the anisotropic geometry of the specimen can induce stress concentration effects that affect crack initiation. In this case, the geometry of the edge is less relevant to the edge quality.…”

Section: Materials and Experimentsmentioning

confidence: 99%

Prediction of Hole Expansion Ratio for Advanced High-Strength Steel with Image Feature Analysis of Sheared Edge

Jeong

Lee

et al. 2023

Materials

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The punching process of AHSS induces edge cracks in successive process, limiting the application of AHSS for vehicle bodies. Controlling and predicting edge quality is substantially difficult due to the large variation in edge quality, die wear induced by high strength, and the complex effect of phase distribution. To overcome this challenge, a quality prediction model that considers the variation of the entire edge should be developed. In this study, the image of the entire edge was analyzed to provide a comprehensive evaluation of its quality. Statistical features were extracted from the edge images to represent the edge quality of DP780, DP980, and MART1500 steels. Combined with punching monitoring signals, a prediction model for hole expansion ratio was developed under punch conditions of varying clearance, punch angle, and punch edge radius. It was found that the features of grayscale variation are affected by the punching conditions and are related to the double burnish and uneven burr, which degrades the edge quality. Prediction of HER was possible based on only edge image and monitoring signals, with the same performance as the prediction based solely on punching parameters and material properties. The prediction performance improved when using all the features.

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Section: Materials and Experimentsmentioning

confidence: 99%

Prediction of Hole Expansion Ratio for Advanced High-Strength Steel with Image Feature Analysis of Sheared Edge

Jeong

Lee

et al. 2023

Materials

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“…Advanced high-strength steels (AHSSs) have been widely applied to body-in-white (BIW) structures for both weight reduction and crass worthiness because they exhibit higher tensile strength compared with conventional mild steels [1][2][3]. However, unexpected edge fractures occur during the metal forming process due to low sheared edge cracking resistance, which prevents their use in automotive body applications [4,5].…”

Section: Introductionmentioning

confidence: 99%

Integrated Machine Vision System for Evaluating Hole Expansion Ratio of Advanced High-Strength Steels

et al. 2022

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In this paper, we propose a new method to estimate the hole expansion ratio (HER) using an integrated analysis system. To precisely measure the HER, three kinds of analysis methods (computer vision, punch load, and acoustic emission) were utilized to detect edge cracks during a hole expansion test. Cracks can be recognized by employing both computer vision and a punch load analysis system to determine the moment of crack initiation. However, the acoustic emission analysis system has difficulty detecting the instant of crack appearance since the magnitude of the audio signal is drowned out by noise from the press, which interrupts the differentiation of crack configuration. To enhance the accuracy for determining the HER, an integrated analysis system that combines computer vision with punch load analysis, and improves on the shortcomings of each analysis system, is newly suggested.

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“…The main directions of process improvements to obtain the geometric accuracy of the workpieces are considered in the works [1,[5][6]. The main directions of scientific research [12][13][14][15][16] were: the creation favorable of metal stress state in the cutting zone and; the development of new designs of stamp and cutting tools.…”

Section: Introductionmentioning

confidence: 99%

Development and research of the stamp for cutting of a rolled stock with a differentiated clamp

Karnaukh¹,

Марков²,

Shapoval³

et al. 2022

FME Transactions

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The work aims to develop and research a stamp with a differentiated clamp of a rolled stock for cutting by shear. A new stamp design with a differentiated clamp of the rolled stock has been developed. In terms of their technical and economic indicators, these stamps meet or exceed the modern samples of similar punch tools. At the same time, in the process of vertical cutting, a constant position of the rolled stock axis is ensured. The transmission of force to the clamp through the rolled stock is excluded. The stamp design ensures its sufficiently high rigidity and relatively small overall dimensions. Based on the analysis of the mathematical model of a stamp with a differentiated clamp, the effective angles of force transmission to the clamp and the cutting of the rolled stock between the stamp parts have been established. The resulting model was used to optimize the angles of force transfer to the clamp, and the cutting rolled stock, respecting the force from the side of a buffer and the minimum required press force. At the same time, the vertical stroke of the moving parts is reduced, the overall dimensions of the stamp are decreased, and the buffer also has a minimum size. To reduce the required force of the press, it is necessary to reduce the value of a frictional slipping coefficient by using antifriction materials on contact surfaces and ensuring good lubrication conditions. The results of the conducted experiments confirm the adequacy of the mathematical model. The value of the required force on the press slide available from experiments is slightly higher than the values obtained by the developed analytical model. The results of the stamp implementation show that: the stamps are efficient and reliable in exploitation; the quality of the cutoff workpieces corresponds to the quality indicators of the workpieces cut on similar modern equipment.

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Effect of two-stage press blanking on edge stretchability with third-generation advanced high-strength steels

Cited by 12 publications

References 21 publications

Prediction of Hole Expansion Ratio for Advanced High-Strength Steel with Image Feature Analysis of Sheared Edge

Prediction of Hole Expansion Ratio for Advanced High-Strength Steel with Image Feature Analysis of Sheared Edge

Integrated Machine Vision System for Evaluating Hole Expansion Ratio of Advanced High-Strength Steels

Development and research of the stamp for cutting of a rolled stock with a differentiated clamp

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