Improvement of Hole Expansion Properties in Micro-Alloyed Dual Phase Steels
The stretch-flangeability of dual phase (DP) steel containing several micro-alloying additions such as Nb,Ti,and Mo was investigated as a means to improve the stretch-flangeability of Advanced High Strength Steels (AHSS).The stretch-flangeability of materials can be studied by analysis of their hole expansion ratio (HER) properties.The HER,i.e.the ratio of the diameter at edge fracture to the initial diameter in the HE test,was evaluated for various factors known to have an effect on the test results such as the blanking method,the addition of micro-alloying elements,and differences in the microstructure.Several DP steels having different volume fractions of ferrite and martensite were produced by simulating heat treatment cycles used in industrial continuous annealing lines (CAL).The presence of epitaxial ferrite formed during slow cooling after the holding at intercritical annealing temperature (IAT) was identified using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS),and its effect on the properties was also evaluated.
Micro-alloying element Stretch-flangeability Hole expansion ratio Dual phase steel epitaxial ferrite
LEE Jewoong LEE Seok-Jae DE COOMAN Bruno C
Graduate Institute of Ferrous Technology,Pohang University of Science and Technology,Pohang 790-784,Korea
国际会议
Asia Steel International conference 2012(第五届亚洲钢铁大会)
北京
英文
1-4
2012-09-23（万方平台首次上网日期，不代表论文的发表时间）