Robust Shearing Process for Improving AHSS Sheared Edge Stretchability

2012 ◽  
Author(s):  
Hua-Chu Shih ◽  
Ming F. Shi
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Straight Edge ◽  
Edge Condition ◽  
Advanced High Strength Steel ◽  
Forming Process ◽  
Sheared Edge ◽  
Steel Grades ◽  
Edge Tension

Results from a previous study have shown that a newly developed beveled shearing process is able to improve the quality of advanced high strength steel (AHSS) sheared edges and their edge stretchability. The objective of the current study is to further investigate and validate this phenomenon and to develop robust shearing conditions for improving the AHSS sheared edge stretchability. A straight edge shearing device with the capability of adjusting the shearing variables is used in this study. Two different advanced high strength steel grades, DP600 and DP980, with similar thicknesses are selected to assess the edge condition using various shearing variables. The edge stretchability of the straight edge sheared specimen is evaluated using the sheared edge tension test and a half specimen dome test. It was discovered that an optimal selection of the die clearance and other shearing variables would result in a less damaged sheared edge which would greatly delay edge fracture in the forming process and increase the edge stretchability of AHSS.

An Innovative Shearing Process for AHSS Edge Stretchability Improvements

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Hua-Chu Shih ◽  
Ming F. Shi
Keyword(s):  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Straight Edge ◽  
Forming Process ◽  
Expansion Test ◽  
Advanced High Strength Steels ◽  
Sheared Edge ◽  
Shear Edge

A beveled shear hole piercing process has recently been developed for advanced high strength steel (AHSS). The preliminary results have shown the new process is able to improve the quality of the sheared edge and the edge stretchability of AHSS. The goal of the current study is to optimize the beveled shearing process and identify the optimal shearing conditions for AHSS. Four different advanced high strength steels, including DP600, DP780, TRIP780, and DP980 with various thicknesses together with a conventional high strength steel, HSLA50, are selected in this study. The hole expansion test is used to evaluate the effect of shear edge conditions on the edge stretchability. The results show that an optimal selection of the die clearance and the shearing angle results in a less damaged edge, which significantly delays edge fracture in the forming process and increases the edge stretchability for AHSS. To further validate the advantages of the beveled shearing process in improving the shear edge quality of AHSS, a straight edge shearing device with the capability of adjusting the shearing variables (rake angles and die clearance) with respect to different sheet thicknesses was also developed and built. The edge stretchability of the straight edge sheared specimen was then evaluated using the sheared edge tension test. A similar trend to the beveled shear hole piercing process of AHSS is observed, and a significant improvement in the edge stretchability is also obtained with optimal shearing conditions.

Direct Punching in Inclined Ultra-High Strength Steel Sheets

2014 ◽  
Vol 622-623 ◽  
pp. 1051-1057 ◽  
Author(s):  
Yohei Abe ◽  
Ken Ichiro Mori ◽  
Shigehiro Nakanoshita ◽  
Purwo Kadarno
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Bottom Edge ◽  
Steel Sheets ◽  
Sheared Edge ◽  
Ultra High Strength Steel ◽  
Grade Steel ◽  
Inclined Sheet

A direct punching of inclined ultra-high strength steel sheets having low ductility was carried out to improve the quality of the sheared edge. In the direct punching of an inclined sheet, the contact between the sheet and punch became gradual because of touch from the bottom edge of the punch, and thus the sheared portion tended to bend in the latter half of punching. As the strength of the sheet increased, defects such as burr and secondary burnished surface were occurred around the sheared edge due to the low ductility. The range of direct punching for sheared edge without defects was shown for the high strength steel sheets. To prevent the occurrence of defects, a punch having inclined bottom was used. In this punch, the contact with the sheet was changed, the uniform contact with the inclined bottom was given. In the punch having the inclined bottom, the secondary burnished surface in the edge of 980 MPa grade steel sheet was prevented.

Ductility of Advanced High-Strength Steel in the Presence of a Sheared Edge

JOM ◽  
2016 ◽  
Vol 68 (7) ◽  
pp. 1839-1849 ◽  
Author(s):  
Tim Ruggles ◽  
Stephen Cluff ◽  
Michael Miles ◽  
David Fullwood ◽  
Craig Daniels ◽  
...  
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Advanced High Strength Steel ◽  
Sheared Edge

Copper brazing response of some advanced high strength steel grades

2009 ◽  
Vol 209 (1) ◽  
pp. 70-76 ◽  
Author(s):  
R. Song ◽  
J.G. Schroth ◽  
J.G. Speer ◽  
D.K. Matlock
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Advanced High Strength Steel ◽  
Steel Grades

Die Compensation Design for Stamping a High Strength Automotive Bumper Inner

2013 ◽  
Vol 712-715 ◽  
pp. 796-799
Author(s):  
Fuh Kuo Chen ◽  
Shi Wei Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Strength Steel ◽  
High Strength ◽  
Structure Design ◽  
Advanced High Strength Steel ◽  
Forming Process ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Compensation Approach

Due to the requirement of lightweight in the automotive body structure design, the application of advanced high strength steel (AHSS) has been widely adopted in the automotive industry. However, the technical difficulties are also experienced in the forming process of stamping the advanced high strength steel. One of the major defects is springback. In this study, both the experimental approach and the finite element analysis were adopted to examine the springback phenomenon occurred in the stamping of a front bumper inner made of 590Y advanced high strength steel. The die compensation approach was employed to adjust the amount of springback to make the dimension of the automotive part conforming to the design specification. The accurate dimension of the production part validates the finite element analysis and the die compensation approach adopted in the present study provides a useful guideline for improving the springback defect in the stamping of advanced high strength steel sheets.

Finite Element Analysis of Reinforcement Rocker Part Made from JAC780Y Steel Sheets

2021 ◽  
Vol 877 ◽  
pp. 83-89
Author(s):  
Aeksuwat Nakwattanaset ◽  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
High Strength Steel ◽  
High Strength ◽  
Material Model ◽  
Advanced High Strength Steel ◽  
Forming Process ◽  
Element Analysis ◽  
Steel Sheets ◽  
Springback Prediction

The manufacturing industries for automotive parts aim to develop technologies for reducing vehicle weight in order to decrease fuel consumption. However, passive safety function for drivers and passengers must not be impaired or should be even improved. Therefore, advanced high strength steel sheet plays more and more important role in designing automotive components. Nowadays, prediction of formability for sheet metal stamping has high capability more than the past. The major challenge is springback prediction. Moreover, it assists in the tooling design to correctly compensate for springback. Especially in automotive production, springback effects have been generally exhibited distinct after forming process of the high strength steel sheets. The springback effect occurred in the deformed state of metal parts must be taken into account by designing any sheet metal panels. Then, the purpose of the present research is to investigate the springback phenomenon of an automotive part named Reinforcement Rocker RL made from an advanced high strength steel grade JAC780Y, after stamping. In addition, the tools design has been carried out. Finite Element (FE) program known as DYNAFORM (based on LS-DYNA solver), has been applied to analyze and improve the springback effect on such forming part. An anisotropic material model according to type 36 (MAT_036 3-PARAMETER_BARAT) was applied. The results obtained from simulations were compared with required parts in each section. Then, the die surface from compensation in 2nd step forming was modified to use. Finally, the simulation part was verified with the real stamping part. It was found that the finite element simulation showed high capability for prediction and compensation of springback in high strength steel sheets forming.

Sign in / Sign up

Export Citation Format

Share Document