Q345E钢Φ140mm材晶粒度对-40℃冲击功的影响及轧制工艺改进

Effect of Grain Size on Impact Energy of Φ140 mm Products of Steel Q345E at-40℃ and Rolling Process Improvement

试验的Q345E钢(/%:0.13C,0.23Si,1.45Mn,0.012P,0.005S,0.045V,0.030Nb,0.030Al)的冶炼工艺为100 t EAF-LF-VD-Φ500 mm坯连铸-Φ140 mm材轧制。通过Q345E钢热处理试验得出晶粒度级别对试验钢-40℃冲击功有显著影响;当钢材晶粒度级别为7.0时,-40℃冲击功仅为12～16 J,当晶粒度级别为9.0～10.0时,-40℃冲击功为80～198 J。通过将终轧温度从960℃降至865～910℃,钢材晶粒度级别由7.0提高至8.5～9.6,-40℃冲击功由12～16 J提高到61～82 J,满足-40℃冲击功34 J的标准要求。

The steelmaking process of tested steel Q345 E(/%:0.13 C,0.23 Si,1.45 Mn,0.012 P,0.005 S,0.045 V,0.030 Nb,0.030 A1) is 100 t EAF-LF-VD-Φ500 mm bloom casting-Φ140 mm bar rolling.By heat treatment test of steel Q345 E,it is obtained that the effect of grain size rating on impact energy of tested steel at-40℃ is obvious,as the rating of grain size of products is 7.0,the impact energy of steel at-40 ℃ is only 12 ~16 J,and as the rating of grain size is9.0~10.0,the impact energy of steel at -40℃ is increasing to 80~198 J.With decreasing finished rolling temperature from 960 ℃ to 865 ~910 ℃,the rating of grain size of steel products increases from 7.0 to 8.5 ~9.0 and the impact energy of steel at-40℃ increases from 12~16 J to 61 ~82 J to meet the standard requirement of impact energy 34 J of steel at -40℃.