公开(公告)号：US4502897A

公开(公告)日：1985-03-05

申请号：US438844

申请日：1982-10-15

申请人： Masahiko Morita ,  Junichi Mano ,  Minoru Nishida ,  Tomoo Tanaka ,  Nobuo Aoyagi ,  Syoichi Takizawa

发明人： Masahiko Morita ,  Junichi Mano ,  Minoru Nishida ,  Tomoo Tanaka ,  Nobuo Aoyagi ,  Syoichi Takizawa

IPC分类号： C22C38/00 ,  C21D1/19 ,  C21D8/02 ,  C21D9/46 ,  C22C38/18 ,  C22C38/38

CPC分类号： C21D1/19 ,  C21D8/0226 ,  C22C38/18 ,  C22C38/38 ,  C21D2211/005 ,  C21D2211/008 ,  C21D8/0263

摘要： The present invention aims to obtain C-Si-Mn-Cr system of hot-rolled dual phase structured steel sheets having a low yield ratio YR of not greater than 65%, an excellent strength-elongation balance M, a low variation in quality and an excellent cold formability through stepwise cooling regulation in the course of cooling from the final rolling to coiling.The present invention is a method for producing hot-rolled steel sheets having a low yield ratio and a high tensile strength due to dual phase structure by effecting the final rolling of a hot-rolled steel sheet containing 0.02-0.2% of C, 0.05-2.0% of Si, 0.5-2.0% of Mn and 0.3-1.5% of Cr as the essential components at a temperature of finishing the final rolling of 780.degree. C., rapidly cooling the thus treated steel sheet at a cooling rate of more than 40.degree. C./S to the temperature range wherein the transformation of .gamma. into .alpha. is efficiently caused corresponding to the components in the steel and the rolling hysteresis, holding the steel sheet at this temperature range for more than 5 seconds and rapidly cooling the thus treated steel sheet at a cooling rate of more than 50.degree. C./S from said held temperature to a temperature of 550.degree.-200.degree. C. to obtain a hot-rolled steel sheet having YR of not greater than 65%, M of not less than 60 and a low variation of quality and an excellent cold formability.

摘要翻译： PCT No.PCT / JP82 / 00030 Sec。 371日期1982年10月15日 102（e）日期1982年10月15日PCT提交1982年2月2日PCT公布。 公开号WO82 / 02902 日本1982年9月2日。本发明旨在获得低收率比YR为65％以下的热轧双相结构钢板的C-Si-Mn-Cr系，优异的强度伸长率平衡M ，通过从最终轧制到卷取的冷却过程中的逐步冷却调节，质量的差异和优异的冷成形性。 本发明是通过对含有0.02-0.2％C，0.05〜0.2％的热轧钢板进行最终轧制，由于双相结构而制造具有低屈服比和高拉伸强度的热轧钢板的方法， 在2.0％的Si，0.5-2.0％的Mn和0.3-1.5％的Cr作为必要组分，在最终轧制的最终轧制温度为780℃，快速冷却如此处理的钢板以大于 40℃/秒到对应于钢中的成分和轧制滞后有效地将γ转变成α的温度范围，将钢板保持在该温度范围超过5秒并迅速冷却 将处理后的钢板以大于50℃/秒的冷却速度从所述保持温度升温至550〜-200℃，得到YR为65％以下的热轧钢板，M 不低于60，质量变化不大， 优良的冷成型性。