Hole-flange forming of high-strength steel sheet using one-step hot stamping-forging method

Cheng, Fang

doi:10.1177/0954405415604121

Cited by 3 publications

(5 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then HERs of holes under different damage values in the range of 1%-10% for both materials could be obtained with the help of EFSR values in Figure 7. The method to obtain the HERs under given damage value in this study is shown in equation (15) …”

Section: Results Of Experiments and Comparison With Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

A method for evaluating the degradation of edge stretchability incorporating punching damage based on Marciniak and Kuczynski model

Chen

2016

Proceedings of the Institution of Mechanical Engineers, Part B:

View full text Add to dashboard Cite

Edge stretchability refers to a sheet metal's capability to resist edge cracking during edge forming and flanging. In this article, a quantitative method has been proposed to evaluate the effect of punching or trimming of sheet metals on the degradation of their edge stretchability. This method adopts the Marciniak and Kuczynski concept to quantify edge damages due to punching or trimming. A novel index, the effective failure strain ratio, is introduced. Effective failure strain ratio is strain-based, and it is defined as the ratio of the actual edge failure strain to the theoretical edge failure strain. The algorithm to calculate effective failure strain ratio based on hole-expansion simulations is detailed. The magnitude of effective failure strain ratio depends on the damage value, which corresponds to the edge damage caused by preprocessing such as punching. Numerical studies are conducted to demonstrate the applicability of this method. The results show that the degradation of edge stretchability of materials with higher hardening exponent (n-value in power hardening law) is more sensitive to edge damage. Hole-expansion experiments using two grades of dual-phase steels are conducted to validate the conclusions deduced from the simulations. The comparison between the experimental and numerical results shows that the proposed method is able to predict phenomena appearing in the experiments. The quantitative relationship between damage value and the punching clearance has not been established in this work yet, which requires extensive experimental investigation. However, a qualitative link has been clearly demonstrated, and this method provides a new perspective to express the pre-damage and its effect straightforwardly.

show abstract

Section: Results Of Experiments and Comparison With Simulationsmentioning

confidence: 99%

“…Butcher et al 14 found that surface roughness and void initiation due to the shearing process were not significant factors on the edge cracking of baron steel used in hot stamping applications. Cheng 15 developed a one-step hot stamping–forging method to increase the tensile strength of high-strength steel.…”

Section: Introductionmentioning

confidence: 99%

A method for evaluating the degradation of edge stretchability incorporating punching damage based on Marciniak and Kuczynski model

Chen

2016

Proceedings of the Institution of Mechanical Engineers, Part B:

View full text Add to dashboard Cite

show abstract

“…For a more precise control of the final product hardness, the applied method for heating of the blank with the pre-hole needs to be adapted. A targeted use of several electrodes similar to Mori et al [25], or hot cutting in same stroke with hot hole-flanging comparable to Cheng [13], is conceivable. The latter allows a blank with a constant cross-section to be heated.…”

Section: Control Of Product Propertiesmentioning

confidence: 99%

“…Motaman et al [12] improved the expansion ratio during laser-assisted warm (~250 °C to 400 °C) hole-flanging of DP1000 sheet material in a progressive-die by taking advantage of dynamic strain aging. Cheng [13] developed a onestep hot stamping-forging method that enables the hole-flanging of high strength quenchable steel sheet 15B22. Despite the ongoing research, a control-oriented analysis of the relationships between the product properties and the process parameters during hot holeflanging with simultaneous heat treatment is not known.…”

Section: Introductionmentioning

confidence: 99%

Control-Oriented Characterization of Product Properties during Hot Hole-Flanging of X46Cr13 Sheet Material in a Progressive-Die

Martschin

Meya

Klöser

et al. 2021

Metals

View full text Add to dashboard Cite

Robust and versatile production is enabled by a closed-loop control of product properties. This essentially relies on the characterization of the interaction between properties and available degrees of freedom to control the process. In particular, this work examines the setting of collar height, thinning, curvature, and hardness during hot hole-flanging of X46Cr13 sheet material with simultaneous heat treatment to identify approaches for a closed-loop property control in hot hole-flanging during multi-stage hot sheet metal forming. To scrutinize the adjustability of the hardness of X46Cr13 sheet material by heat treatment with rapid heating and short dwell times, quenching tests with austenitizing temperatures from 900 to 1100 °C and dwell times from 1 to 300 s were carried out. A hardness between 317 and 680 HV10 was measured. By analyzing the force-displacement curve and the contact situation between tools and blank during hot hole-flanging, an understanding for the process was established. To determine the adjustability of geometrical collar properties and the hardness of the collar, collars were formed at punch speeds between 5 and 100 mm/s and at different temperatures. Here, a dependency of the geometry of the collar on temperature and punch speed as well as setting of the hardness was demonstrated.

show abstract

“…Hot hole flanging operations have been conducted on AHSS because of their low stretch flange ability at room temperature. Cheng [8] performed one-step hot stamping to form flanges from high strength steel 15B22. The tensile strength and breaking toughness of the formed flanges increased by 7.4% and 33% compared to flanges formed by the cold working process.…”

Section: Introductionmentioning

confidence: 99%

Increasing the Forming Limits in Hole Flanging of Dual-Phase (DP) 1000 Steel Using Punch Rotation

Besong

Buhl

Härtel

et al. 2022

KEM

View full text Add to dashboard Cite

Dual-phase (DP) steels are widely used in sheet metal stamping. However, they are typically characterized by low hole expansion ratios. Since hole flanging is very often applied to sheet metal parts, solutions for improving hole flangeability are needed. In this study, high-speed punch rotation is applied in hole flanging of DP 1000 to generate frictional heat and increase formability. The flanges were formed using a punch rotating at 8000 rev/min and varying axial feeds. A maximum hole expansion ratio (HER) of 3.6 is obtained in the tests compared to ~1.58 in conventional hole flanging. The high formability is explained by the high temperature recorded in the process. The effects of temperature and strain rate on the formability of DP 1000 are examined by tensile tests conducted at different conditions. The tensile tests show an increase in formability at high temperatures. Optical microscopy at the flange edge reveals a change in the microstructure of the steel from the characteristic dual phase to a martensitic structure with elongated grains.

show abstract

Hole-flange forming of high-strength steel sheet using one-step hot stamping-forging method

Cited by 3 publications

References 15 publications

A method for evaluating the degradation of edge stretchability incorporating punching damage based on Marciniak and Kuczynski model

A method for evaluating the degradation of edge stretchability incorporating punching damage based on Marciniak and Kuczynski model

Control-Oriented Characterization of Product Properties during Hot Hole-Flanging of X46Cr13 Sheet Material in a Progressive-Die

Increasing the Forming Limits in Hole Flanging of Dual-Phase (DP) 1000 Steel Using Punch Rotation

Contact Info

Product

Resources

About