Abstract: The metallurgical process flowsheet of 280 mm x 380 mm casting bloom of steel 10B21 (/% : 0. 19C, 0.05Si, 0.79Mn, 0.017P, 0. 002S, 0. 17Cr, 0.032Ti, 0.002 0B, 0.025Als) is 100 t BOF-LF-VD-GC. By using Gleeble-3800 thermo-mechanical simulator, the dilatometric curves steel 10B21 with cooling rate 0. 2 〜50 ℃/s has been measured and to combined with thermal dilation method and metallography-hardness method the continuous cooling transformation (CCT) curves are obtained. Results show that with cooling rate 0. 2 〜1 ℃/s the structure of steel is ferrite ( F) and pearlite ( P) ； the cooling rate 5 ~20 ℃/s may be the cooling rate range to form Widmannstatten (W) structure; with >5 ℃，the bainite structure (B) initially occurs in tested steel; with >10 ℃/s, the martensite structure (M) occurs in steel; with > 25 ℃/s the main structure in steel consists of B + M ； and with >50 ℃/s it is obtained M structure in steel.

摘要： 10B21钢280 mm×380 mm连铸坯(/%:0.19C,0.05Si,0.79Mn,0.017P,0.002S,0.17Cr,0.032Ti,0.002 0B,0.025Als)的冶金工艺流程为100 t BOF-LF-VD-CC。利用Gleeble-3800热模拟试验机,测定了10B21钢冷却速度0.2～50℃/s的膨胀曲线,结合热膨胀法和金相-硬度法,获得了该钢的动态连续冷却转变(CCT)曲线。结果表明,在冷却速度0.2～1℃/s时,该钢组织为铁素体(F)和珠光体(P);5～20℃/s可能是魏氏组织(W)形成的冷却速度范围; >5℃/s时,实验钢开始出现贝氏体(B)组织; >10℃/s时,实验钢的组织出现马氏体(M)组织; >25℃/s实验钢的组织主要由B+M组成; >50℃/s时,得到单一的M组织。

关键词: 10B21合金冷镦钢, 热模拟, 动态连续冷却转变, 组织