Fracture Mechanical Study on Stretch Flange-Ability of Hot-Rolled High Tensile Strength Steel Sheets
In order to clarify the governing factors of stretch flange-ability,a study to elucidate the mechanism of crack growth on pierced edges during hole expanding tests was carried out and the following conclusions were obtained.1) In the beginning and the middle stage of crack growth,cracks on the pierced edge grow through its thin surface where a large strain has been introduced by piercing.In the following final stage one of them grows rapidly into deeper area where the material is not or only slightly strained by piercing.Hole expansion ratio is characterized by the final rapid crack growth.2) In the beginning and the middle stage of hole expansion,crack initiation and growth occur faster in the steel sheets with higher stretch flange-ability.But crack growth into deeper area is retarded in these steel sheets,and it gives superior stretch flange-ability to these steel sheets.3) Materials with good stretch flange-ability have strong crack growth resistance which can be measured by the test method based on fracture mechanics.This is due to the fact that stretch flange-ability is characterized by the final rapid growth of edge cracks and its occurrence is basically dependent on the crack growth resistance based on fracture mechanics.
hot-rolled high tensile strength steel sheets formability stretch flange-ability hole expansion ratio fracture mechanics J integral crack growth piercing
Yuzo Takahashi Osamu Kawano Kohsaku Ushioda Shuji Aihara
Nippon Steel Corporation Oita R&D,Nishinosu 1 Oita City,Oita,870-0992,Japan;Kanazawa University Grad Nippon Steel Corporation Oita R&D,Nishinosu 1 Oita City,Oita,870-0992,Japan Nippon Steel Corporation,Technical Development Bureau,20-1 Shintomi,Futtsu City,Chiba,293-8511,Japan The University of Tokyo,Graduate School of Engineering,Department of Systems Innovation,7-3-1,Hongo,
国际会议
Asia Steel International conference 2012(第五届亚洲钢铁大会)
北京
英文
1-6
2012-09-23（万方平台首次上网日期，不代表论文的发表时间）