Hot-rolled steel sheet excellent in fatigue properties and stretch-flange formability and method for manufacturing the same
    4.
    发明授权
    Hot-rolled steel sheet excellent in fatigue properties and stretch-flange formability and method for manufacturing the same 有权
    疲劳特性和拉伸凸缘成型性优异的热轧钢板及其制造方法

    公开(公告)号:US08657970B2

    公开(公告)日:2014-02-25

    申请号:US12934039

    申请日:2008-11-12

    摘要: This hot-rolled steel sheet contains, in terms of mass %, C: 0.015% or more to less than 0.040%; Si: less than 0.05%; Mn: 0.9% or more to 1.8% or less; P: less than 0.02%; S: less than 0.01%; Al: less than 0.1%; N: less than 0.006%; and Ti: 0.05% or more to less than 0.11%, with the remainder being Fe and inevitable impurities, wherein Ti/C is in a range of 2.5 or more to less than 3.5, Nb, Zr, V, Cr, Mo, B and W are not included, a microstructure includes a mixed microstructure of polygonal ferrite and quasi-polygonal ferrite in a proportion of greater than 96%, a maximum tensile strength is 520 MPa or more and less than 720 MPa, an aging index AI is more than 15 MPa, a product of a hole expansion ratio (λ) % and a total elongation (El) % is 2350 or more, and a fatigue limit is 200 MPa or more.

    摘要翻译: 该热轧钢板以质量%计含有C:0.015%以上且小于0.040% Si:小于0.05%; Mn:0.9%以上至1.8%以下; P:小于0.02%; S:小于0.01%; Al:小于0.1%; N:小于0.006%; 和Ti:0.05%以上至小于0.11%,其余为Fe和不可避免的杂质,其中Ti / C在2.5以上且小于3.5的范围内,Nb,Zr,V,Cr,Mo,B 并不包括W,微结构包括多数铁素体和准多边形铁素体的混合微结构,其比例大于96%,最大拉伸强度为520MPa以上且低于720MPa,老化指数AI更多 超过15MPa时,孔膨胀率(λ)%和总伸长率(E1)%的乘积为2350以上,疲劳极限为200MPa以上。