High tensile strength cold rolled steel sheet having excellent strain age hardening characteristics and the production thereof
    5.
    发明申请
    High tensile strength cold rolled steel sheet having excellent strain age hardening characteristics and the production thereof 有权
    具有优异的应变时效硬化特性的高抗拉强度冷轧钢板及其制造

    公开(公告)号:US20030188811A1

    公开(公告)日:2003-10-09

    申请号:US10341165

    申请日:2003-01-13

    IPC分类号: C21D008/02

    摘要: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800null C. or above, and is subsequently coiled at the coiling temperature of 750null C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900null C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500null C. or below at a cooling rate of 10 to 300null C./s, and furthermore if necessary, by secondary cooling in which a residence time is 300 seconds or less in a temperature range of the primary cooling stopping temperature or higher and 350null C. or higher. Provided is a steel sheet containing a ferritic phase having an average crystal grain size of 10 nullm or less at an area ratio of 50% or more, and if necessary, a martensitic phase at an area ratio of 3% or more as a second phase.

    摘要翻译: 本发明提供一种成型性,耐冲击性和应变时效硬化特性优异的高拉伸强度的冷轧钢板及其制造方法。 作为具体的方法,具有以质量%计含有0.15%以下C,0.02%以下Al,N / Al为0.0050〜0.0250%N,0.3以上N组成的板坯, 在0.0010%以上的固溶状态下,首先在800℃以上的精轧条件下进行热轧,然后在卷取温度为750℃以下的条件下卷取,制成热 轧板。 然后,冷轧后,在10〜120秒的保持时间内,从再结晶温度至900℃的温度下连续冷却热轧板,通过一次冷却冷却,将热轧板冷却至 500℃以下,冷却速度为10〜300℃/秒,另外,如果需要,通过在一次冷却停止温度以上的温度范围内停留时间为300秒以下的二次冷却 和350℃以上。 本发明提供一种钢板,其含有平均结晶粒径为10μm以下的面积比为50%以上的铁素体相,根据需要,作为第二相的面积比为3%以上的马氏体相 。