Abstract: The hot ductility of 150 mm x 150 mm casting billet of 10B15 cold heading steel (% ： 0. 17C, 0. 16Si, 0. 46Mn, 0. 017P, 0. 025S, 0.000 2Ti, 0.000 8A1, 0.001 4B) with strain rate 0.000 5 -0. 001 s^-1 at 700 1 000 ℃ has been studied by using Gleeble-1500 thermal simulator. Results show that the casting billet of 10B15 cold heading steel has hot brittleness at 850 ~ 900 °C ； the dynamic recrystallization is promoted by decreasing strain rate led to increase of hot ductility ； the nitrides of B, Ti and Al precipitate at grain boundary to take pin pinning effect on grain boundary to hinder slide of boundary and occurrence of dynamic recrystallization led to decrease of the hot ductility of steel.

摘要： 通过Gleeble-1500热模拟机研究了10B15冷镦钢(%:0.17C、0.16Si、0.46Mn、0.017P、0.025S、0.0002Ti、0.000 8Als、0.001 4B)150 mm×150 mm连铸坯应变速率0.0005～0.001s-1在700～1 000℃的热塑性。结果表明,10B15冷镦钢连铸坯在850～900℃有高温脆性;应变速率的降低促进动态再结晶的发生,可以提高高温塑性;细小的B、Ti和Al的氮化物在晶界的析出起晶界钉扎作用,阻碍了晶界的滑移和动态再结晶的发生,从而使钢的高温塑性降低。

关键词: 10B15冷镦钢, 150mm×150mm连铸坯, 高温塑性, 动态再结晶