公开(公告)号：US20040187982A1

公开(公告)日：2004-09-30

申请号：US10807693

申请日：2004-03-24

申请人： JFE Steel Corporation, a corporation of Japan

发明人： Hiroshi Nakata ,  Nobuyuki Kageyama ,  Koji Iwata ,  Tetsuo Shimizu ,  Chikara Kami

IPC分类号： C21D009/52

CPC分类号： C22C38/02 ,  B23K35/3053 ,  C21D8/0205 ,  C21D8/105 ,  C21D9/50 ,  C21D9/52 ,  C21D2211/002 ,  C22C38/04 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16

摘要： A hot-rolled steel strip having superior low temperature toughness and weldability, which is suitably used as a starting material for high strength electric resistance welding pipe, is provided at a low cost without constructing new production facilities and increasing cost. The hot-rolled steel strip is low carbon steel containing at least one of about 0.5.% or less of Cu, about 0.5% or less of Ni, and about 0.5% or less of Mo, wherein Pcm represented by the following equation (1) is 0.17 or less: Pcmnull(% C)null(% Si)/30null((% Mn)null(% Cu))/20null(% Ni)/60null(% Mo)null7null(% V)/10 nullnullEquation (1), (where (% M) indicates the content of element M on a mass percent basis), and the balance includes Fe and incidental impurities. In addition, in the entire microstructure, the ratio of bainitic ferrite, which is a primary phase, is controlled to be about 95 percent by volume or more.

摘要翻译： 以低成本提供适合用作高强度电阻焊接管的起始材料的具有优异的低温韧性和焊接性的热轧钢带，而不需要构建新的生产设备并增加成本。 热轧钢带是含有Cu的0.5％以下，Ni约0.5％以下，Mo约0.5％以下中的至少一种的低碳钢，其中，Pcm为下述式（1 ）为0.17以下：Pcm =（％C）+（％Si）/ 30 +（（Mn％）+（％Cu））/ 20 +（％Ni）/ 60 + V）/ 10等式（1），（其中（％M）表示元素M的质量百分比的含量），余量包括Fe和杂质。 此外，在整个微观结构中，将作为主相的贝氏体铁素体的比例控制在约95体积％以上。