scholarly journals Effect of Quality of Sheared Edge on Formability of Hole Expansion ofUltra High Strength Steel Sheets

2009 ◽  
Vol 50 (580) ◽  
pp. 414-418 ◽  
Author(s):  
Yohei ABE ◽  
Ken-ichiro MORI ◽  
Yoshio SUZUI
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Hole Expansion ◽  
Steel Sheets ◽  
Sheared Edge

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.

scholarly journals Influence of Ti and Nb on the Strength–Ductility–Hole Expansion Ratio Balance of Hot-rolled Low-carbon High-strength Steel Sheets

2012 ◽  
Vol 52 (1) ◽  
pp. 151-157 ◽  
Author(s):  
Kyohei Kamibayashi ◽  
Yutaka Tanabe ◽  
Yoshito Takemoto ◽  
Ichirou Shimizu ◽  
Takehide Senuma
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Expansion Ratio ◽  
Low Carbon ◽  
Hole Expansion ◽  
Steel Sheets ◽  
Hole Expansion Ratio ◽  
Hot Rolled

scholarly journals Review of Shearing Processes of High Strength Steel Sheets

2020 ◽  
Vol 4 (2) ◽  
pp. 54 ◽  
Author(s):  
Ken-ichiro Mori
Keyword(s):  
Fatigue Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Steel Sheets ◽  
Sheared Edge ◽  
Ultra High Strength Steel ◽  
Edge Quality ◽  
Automobile Parts

Shearing processes of high strength steel sheets increasingly applied to lightweight automobile parts were reviewed. With the increase in strength of the high strength steel sheets, shearing operations become hard. First, the sheared edge quality in shearing of high strength steel sheets and the effects on the formability and fatigue strength were shown. Next, ironing processes with a taper punch and a punched slug, a slight clearance punching with a punch having a small round corner and a thickening process of the sheared edge were explained as processes for improving the sheared edge quality. Finally, hydrogen-induced delayed fractures of cold-sheared ultra-high strength steel sheets and of hot-trimmed parts were evaluated.

scholarly journals Hole Expansion Ratio and Fatigue Properties in Piercing of High-Strength Steel Sheets by PW Punch

2011 ◽  
Vol 52 (606) ◽  
pp. 795-800 ◽  
Author(s):  
Takashi MATSUNO ◽  
Yukihisa KURIYAMA ◽  
Hiroya MURAKAMI ◽  
Shota YONEZAWA ◽  
Naonobu KANAMARU
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Expansion Ratio ◽  
Fatigue Properties ◽  
Hole Expansion ◽  
Steel Sheets ◽  
Hole Expansion Ratio

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.

Effect of anisotropy evolution on circular and oval hole expansion behavior of high-strength steel sheets

2018 ◽  
Vol 146-147 ◽  
pp. 556-570 ◽  
Author(s):  
Toshiya Suzuki ◽  
Kazuo Okamura ◽  
Gustavo Capilla ◽  
Hiroshi Hamasaki ◽  
Fusahito Yoshida
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Hole Expansion ◽  
Steel Sheets ◽  
Expansion Behavior

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.

Study for Sheared Edge Quality of High Strength Steel Sheet

2014 ◽  
Vol 626 ◽  
pp. 252-257
Author(s):  
Soo Sik Han
Keyword(s):  
Process Parameters ◽  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Material Strength ◽  
Burr Height ◽  
Sheared Edge ◽  
Edge Quality ◽  
Line Direction

The empirical approach was adopted to investigate the process parameters that effect on the quality of high strength steel sheet sheared edge. As a result of study, the quality of sheared edge that can be represented as the ratio of the shiny burnished surface to the sheared surface was not under influence of die clearance, lubrication and cutting line direction but under influence of the material strength and the usage of lower pad. The roll-over and burr height is highly affected by the die clearance and the usage of lower pad. The lower pad underneath of blank is of help to reduce the amount of roll-over and burr even at large die clearance.

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