Minimisation of Heating Time for Full Hardening in Hot Stamping Using Direct Resistance Heating

Maeno, Tomoyoshi; Mori, Ken-ichiro; Sakagami, Masato; Nakao, Yoshitaka; Talebi-Anaraki, Ali

doi:10.3390/jmmp4030080

Cited by 9 publications

(8 citation statements)

References 28 publications

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“…The microstructure of the as-received tube consists of the striped area of pearlite, dark area of ferrite, and small precipitates of cementite. The results revealed that the steel tube was heated above the austenitizing temperature, and then was rapidly cooled by contacting with dies during bulging to ensure a martensitic transformation, even for the comparatively short heating time of resistance heating [27]. The microstructures at the center of the formed tubes were analyzed by scanning electron microscopy (SEM; JSM-5510, JEOL Ltd., Tokyo, Japan) as shown in Figure 22.…”

Section: Influence Of Sealed-air Hot Tube Gas Forming On Hardness Dis...mentioning

confidence: 99%

Integration of Hot Tube Gas Forming and Die Quenching of Ultra-High Strength Steel Hollow Parts Using Low Pressure Sealed-Air

et al. 2022

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A low pressure sealed-air hot tube gas forming process of ultra-high strength steel tubes was developed not only to change the cross-section of the hollow products by bulging but also to increase the strength of components. Gas-formed components are typically formed by a controlled-gas pressure with extremely high internal pressure, which leads to affected production costs and safety. Moreover, compressing the gas with high pressure requires high energy during its preparation. Therefore, to simplify the internal pressure controlling system and improve the safety factor in gas forming processes, the sealed-air tubes are formed with a quite low initial pressure. The pressure of the sealed air increased with increasing temperature of the air inside the resistance-heated tube, and the bulging deformation was controlled only by axial feeding. The effects of the initial pressure and heating temperature on the bulging deformation and quenchability of the tubes, and the effect of the starting time of axial feeding on the bulging behavior were examined. Consequently, ultra-high strength steel bulged parts were produced even in low initial internal pressure and with the rapid heating of the tubes.

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Section: Influence Of Sealed-air Hot Tube Gas Forming On Hardness Dis...mentioning

confidence: 99%

Integration of Hot Tube Gas Forming and Die Quenching of Ultra-High Strength Steel Hollow Parts Using Low Pressure Sealed-Air

et al. 2022

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“…The causes of the occurrence of forging defects can also be other aspects, e.g., improper temperature of the charge material, the use of too strong drafts, badly made tools, imprecise removal of scale or underdeveloped technology. Most of the reasons for defect formation are related to the activities of the production plant, but sometimes there are also discrepancies independent of the forge, whereby die forges have the possibility to control and supervise such defects/problems in order to prevent a reduction in product quality [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Industrial Process of Producing a Hub Forging Used in Motorcar Power Transmission Systems—A Case Study

Hawryluk

Rychlik²,

Więcław

et al. 2021

JMMP

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The article refers to an analysis of the multi-operation process of manufacturing a hub type forging used to transmit power in motorcar gear boxes, by way of die forging on a crank press. The investigations were performed in order to improve the currently realized production technology, mainly with the use of numerical simulations. Through the determination of the key parameters/quantities during forging, which are difficult to determine directly during the industrial process, an in-depth and complex analysis was performed by way of FE (Finite Element) modelling. A thermomechanical model of producing a hub forging with deformable tools was developed with the use of the Qform 9.0.9 software. For the elaboration and construction of the forging tool CAD (Computer Aided Design) models, the Catia V5R20 program was applied. The results of the performed numerical modelling made it possible to determine the material flow and the properness of the filling of impressions, as well as the temperature field distributions and plastic deformations in the forging; it was also possible to detect the forging defects often observed in the industrial process. On this basis, the changes in the process were determined, which enabled an improvement of the presently realized technology and the obtaining of proper forgings, both in respect of quality and dimensions and shape.

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“…Although the use of high strength steel sheets is generally employed to balance the high strength and weight reduction of the body-in-white, the application of hot stamping increases [1]. In hot stamping, quenchable steel sheets or tubes are transformed into austenite by heating to about 900 • C and then into martensite by die quenching [2,3]. The high strength of the hot-stamped parts is attained by the heat treatment.…”

Section: Introductionmentioning

confidence: 99%

Corner Strengthening by Local Thickening and Ausforming Using Planar Compression in Hot Stamping of Ultra-High Strength Steel Parts

Maeno

Mori

Homma

et al. 2021

Metals

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Hot-stamped products are widely used for the body-in-white of an automobile as they are lightweight and improve crashworthiness. A hot-stamping process using planar compression was developed to strengthen corners of ultra-high strength parts by local thickening and hardening. In this process, the corners are thickened by compressing the blank in the planar direction with the upper and lower dies while blocking the movement of both edges with stoppers in the latter stage of forming. Thickening of the corners largely heightens the strength of the formed parts. Not only the thickness but also the hardness of the corner was increased by large plastic deformation and die quenching. For a hot hat-shaped part, a 30% increase in thickness and a 530 HV20 hardness around the corners were attained. The bending rigidity and strength of the formed parts thickened by 30% in the corners increased by 25% and 20%, respectively. In addition, the improvements of the part shape accuracy and the sidewall quenchability were obtained.

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Minimisation of Heating Time for Full Hardening in Hot Stamping Using Direct Resistance Heating

Cited by 9 publications

References 28 publications

Integration of Hot Tube Gas Forming and Die Quenching of Ultra-High Strength Steel Hollow Parts Using Low Pressure Sealed-Air

Integration of Hot Tube Gas Forming and Die Quenching of Ultra-High Strength Steel Hollow Parts Using Low Pressure Sealed-Air

Analysis of the Industrial Process of Producing a Hub Forging Used in Motorcar Power Transmission Systems—A Case Study

Corner Strengthening by Local Thickening and Ausforming Using Planar Compression in Hot Stamping of Ultra-High Strength Steel Parts

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