Hot-Rolled High Strength Steel Sheet Having Excellent Ductility, Stretch-Flangeability, and Tensile Fatigue Properties and Method for Producing the Same
    9.
    发明申请
    Hot-Rolled High Strength Steel Sheet Having Excellent Ductility, Stretch-Flangeability, and Tensile Fatigue Properties and Method for Producing the Same 有权
    热轧高强度钢板具有优异的延展性,拉伸 - 可弯曲性和拉伸疲劳性能及其制造方法

    公开(公告)号:US20090050244A1

    公开(公告)日:2009-02-26

    申请号:US12226039

    申请日:2006-12-27

    IPC分类号: C21D6/02 C22C38/02

    摘要: The present invention provides a hot-rolled high strength steel sheet in which, without using expensive Mo, by effectively using Ti which is an inexpensive element and the amount of precipitation hardening of which is large, both ductility and stretch-flangeability are improved at a tensile strength of 780 MPa or higher, and excellent tensile fatigue properties are exhibited; and a method for producing the hot-rolled high strength steel sheet. A hot-rolled high strength steel sheet having a composition including, in percent by mass, C: 0.06% to 0.15%, Si: 1.2% or less, Mn: 0.5% to 1.6%, P: 0.04% or less, S: 0.005% or less, Al: 0.05% or less, and Ti: 0.03% to 0.20%, the balance being Fe and incidental impurities, wherein the steel sheet has a structure in which the volume fraction of ferrite is 50% to 90%, the balance is substantially bainite, the total volume fraction of ferrite and bainite is 95% or more, precipitates containing Ti are precipitated in the ferrite, and the precipitates have an average diameter of 20 nm or less; and 80% or more of the Ti content in the steel is precipitated.

    摘要翻译: 本发明提供一种热成型高强度钢板,其中,通过有效地使用廉价元素的Ti,析出硬化量大,不使用昂贵的Mo,可以提高延展性和拉伸凸缘性, 拉伸强度为780MPa以上,拉伸疲劳特性优异; 以及制造该热轧高强度钢板的方法。 1.一种热塑性高强度钢板,其组成为:C:0.06〜0.15%,Si:1.2%以下,Mn:0.5〜1.6%,P:0.04%以下,S: 0.005%以下,Al:0.05%以下,Ti:0.03%〜0.20%,余量为Fe和附带杂质,其中,铁素体的体积分率为50〜90%的结构, 余量基本上是贝氏体,铁素体和贝氏体的总体积分率为95%以上,含有Ti的析出物析出在铁素体中,析出物的平均直径为20nm以下, 钢中的Ti含量为80%以上。